GE Freezer CTR 80 User Manual

GE Kaye  
CTR –80  
Cold Temperature Reference  
Users Guide  
 
Table of Contents  
i
 
ii  
 
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iii  
 
1 Before You Start  
1
Before You Start  
1.1  
Symbols Used  
Table 1 lists the International Electrical Symbols. Some or all of these symbols  
may be used on the instrument or in this manual.  
Table 1 International Electrical Symbols  
Symbol  
Description  
AC (Alternating Current)  
AC-DC  
Battery  
Complies with European Union directives  
DC  
Double Insulated  
Electric Shock  
Fuse  
PE Ground  
Hot Surface (Burn Hazard)  
Read the User’s Manual (Important Information)  
Off  
On  
1
 
 
1 Before You Start  
Symbol  
Description  
Canadian Standards Association  
OVERVOLTAGE (Installation) CATEGORY II, Pollution Degree 2 per IEC1010-1 refers to  
the level of Impulse Withstand Voltage protection provided. Equipment of OVERVOLTAGE  
CATEGORY II is energy-consuming equipment to be supplied from the fixed installation.  
Examples include household, office, and laboratory appliances.  
CAT  
C-TIC Australian EMC mark  
1.2  
Safety Information  
Use this instrument only as specified in this manual. Otherwise, the protection  
provided by the instrument may be impaired. Refer to the safety information  
below.  
The following definitions apply to the terms “Warning” and “Caution”.  
“Warning” identifies conditions and actions that may pose hazards to the  
user.  
“Caution” identifies conditions and actions that may damage the instru-  
ment being used.  
1.2.1  
Warnings  
To avoid personal injury, follow these guidelines.  
GENERAL  
DO NOT use the instrument for any application other than calibration  
work. The instrument was designed for temperature calibration. Any other  
use of the unit may cause unknown hazards to the user.  
DO NOT use the unit in environments other than those listed in the user’s  
guide.  
DO NOT overfill the bath. Overflowing extremely cold or hot fluid may  
be harmful to the operator. See Section 5.3, Bath Preparation and Filling,  
for specific instructions.  
Follow all safety guidelines listed in the user’s manual.  
Calibration Equipment should only be used by Trained Personnel.  
2
 
 
1 Before You Start  
If this equipment is used in a manner not specified by the manufacturer,  
the protection provided by the equipment may be impaired.  
Before initial use, or after transport, or after storage in humid or semi-hu-  
mid environments, or anytime the instrument has not been energized for  
more than 10 days, the instrument needs to be energized for a "dry-out"  
period of 2 hours before it can be assumed to meet all of the safety re-  
quirements of the IEC 1010-1. If the product is wet or has been in a wet  
environment, take necessary measures to remove moisture prior to apply-  
ing power such as storage in a low humidity temperature chamber operat-  
ing at 50 degree centigrade for 4 hours or more.  
DO NOT operate high temperature baths (500°C) near flammable materi-  
als. Extreme temperatures could ignite the flammable material.  
Overhead clearance is required. Do not place the instrument under a cabi-  
net or other structure. Always leave enough clearance to allow for safe  
and easy insertion and removal of probes.  
The instrument is intended for indoor use only.  
BURN HAZARD  
Extremely cold temperatures may be present in this equipment. Freezer  
burns and frostbite may result if personnel fail to observe safety precau-  
tions.  
High temperatures may be present in this equipment. Fires and severe  
burns may result if personnel fail to observe safety precautions.  
ELECTRICAL HAZARD  
These guidelines must be followed to ensure that the safety mechanisms  
in this instrument will operate properly. This instrument must be plugged  
into a 115 VAC, 60Hz (230 VAC, 50Hz optional), AC only electric outlet.  
The power cord of the instrument is equipped with a three-pronged  
grounding plug for your protection against electrical shock hazards. It  
must be plugged directly into a properly grounded three-prong receptacle.  
The receptacle must be installed in accordance with local codes and ordi-  
nances. Consult a qualified electrician. DO NOT use an extension cord or  
adapter plug.  
DO use a ground fault interrupt device. This unit contains a liquid. A  
ground fault device is advised in case liquid is present in the electrical  
system and could cause an electrical shock.  
Always replace the power cord with an approved cord of the correct rat-  
ing and type. If you have questions, contact Kaye Customer Service.  
3
 
1 Before You Start  
High voltage is used in the operation of this equipment. Severe injury or  
death may result if personnel fail to observe the safety precautions. Before  
working inside the equipment, turn off the power and disconnect the  
power cord.  
BATH FLUIDS  
Fluids used in this unit may produce noxious or toxic fumes under certain  
circumstances. Consult the fluid manufacturer’s MSDS (Material Safety  
Data Sheet). Proper ventilation and safety precautions must be observed.  
The instrument is equipped with a soft cutout (user settable firmware) and  
a hard cutout (set at the factory). Check the flash point, boiling point, or  
other fluid characteristic applicable to the circumstances of the unit opera-  
tion. Ensure that the soft cutout is adjusted to the fluid characteristics of  
the application. As a guideline, the soft cutout should be set 10°C to 15°C  
below the flash point of the bath fluid. See Section , Heat Transfer Fluid,  
for specific information on bath fluids and Section , Cutout.  
1.2.2  
Cautions  
THE DRAIN VALVE MUST BE INSTALLED ON THE BACK OF THE  
BATH BEFORE ATTEMPTING TO FILL THE TANK WITH FLUID.  
See Section 5.3, page 17 for drain installation instructions.  
Always operate this instrument at room temperature between 41°F and  
122°F (5°C to 50°C). Allow sufficient air circulation by leaving at least 6  
inches (15 cm) of clearance around the instrument.  
DO NOT overfill the bath. Overflowing liquid may damage the electrical  
system. Be sure to allow for thermal expansion of the fluid as the bath  
temperature increases. See Section 5.3, Bath Preparation and Filling, for  
specific instructions.  
DO NOT change the values of the bath calibration constants from the fac-  
tory set values. The correct setting of these parameters is important to the  
safety and proper operation of the unit.  
The refrigeration may be damaged or the lifetime shortened if the  
set-point temperature is set above 60°C for more than one hour with the  
refrigeration manually on. Ensure that the refrigeration is off when the  
unit is used above 60°C.  
The Factory Reset Sequence should be performed only by authorized  
personnel if no other action is successful in correcting a malfunction. You  
must have a copy of the most recent Report of Test to restore the test pa-  
rameters.  
4
 
 
1 Before You Start  
DO NOT operate this instrument in an excessively wet, oily, dusty, or  
dirty environment.  
The unit is a precision instrument. Although it has been designed for opti-  
mum durability and trouble free operation, it must be handled with care.  
Position the unit before the tank is filled with fluid. Use the handles pro-  
vided to move the unit. Due to the weight of the compressor, it may re-  
quire two people to safely move the bath. If two people are used, place  
one person in the front and one person in the back of the unit, carefully  
slide hands under the unit and lift in unison. The area containing the com-  
pressor will be heavier than the rest of the unit. Do not move a unit filled  
with fluid.  
Most probes have handle temperature limits. Be sure that the probe handle  
temperature limit is not exceeded in the air above the instrument.  
The instrument and any thermometer probes used with it are sensitive in-  
struments that can be easily damaged. Always handle these devices with  
care. Do not allow them to be dropped, struck, stressed, or overheated.  
COLD BATHS  
Refrigerated baths require that the condensing coil be cleaned periodi-  
cally. Accumulation of dust and dirt on the condenser will result in pre-  
mature failure of the compressor.  
This bath has been equipped with a brownout and over voltage protection  
device as a safety feature to protect the system components.  
Mode of Operation: This bath needs to be plugged into the line voltage  
for at least 2 minutes before operation. This is only necessary for the first  
time that the bath is energized or when it is moved from one location to  
another. Turning the bath ON or OFF does not trigger the delay.  
If a High/Low voltage condition exists for longer than 5 seconds, the bath  
de-energizes. An amber indicator on the back panel lights when this con-  
dition exists.  
Re-energization is automatic upon correction of the fault condition and af-  
ter a delay cycle of about 2 minutes. If a fault condition exists upon appli-  
cation of power, the bath will not energize.  
Under and Over Voltage Protection at 115 VAC  
Voltage Cutout: 12.5% (101 - 129 VAC)  
Voltage Cut In: 7.5% (106 - 124 VAC)  
Under and Over Voltage Protection at 230 VAC  
Voltage Cutout: 12.5% (203 - 257 VAC)  
5
 
1 Before You Start  
Voltage Cut In: 7.5% (213 - 247 VAC)  
1.3  
Customer Service Information  
Kaye Instruments can be contacted by writing to:  
World Headquarters  
GE Kaye Instruments, Inc.  
101 Billerica Avenue, Building 7  
North Billerica, MA 01862  
tel. +1 (978) 262 0005  
fax +1 (978) 439 8181  
European Headquarters  
GE Kaye Europe GmbH  
Sinsheimer Strasse 6  
D-75179 Pforzheim, Germany  
tel. +49-(0)-7231-14335-0  
fax +49-(0)-7231-14335-29  
When contacting Kaye Instruments Customer Service, please have the follow-  
ing information available:  
Model Number  
Serial Number  
Voltage  
Complete description of the problem  
6
 
 
2 Introduction  
2
Introduction  
The Kaye CTR –80 is an ultra low temp bath useful in temperature calibration  
and other applications requiring stable temperatures. An innovative state of the  
art solid-state temperature controller has been incorporated which maintains the  
bath temperature with extreme stability. The temperature controller uses a mi-  
cro-controller to execute the many operating functions.  
The user interface is provided by the 8-digit LED display and four  
key-switches. Digital remote communications is available with an RS-232  
interface.  
The CTR –80 was designed to be compact and low cost without compromising  
performance. The CTR –80 operates over a wide temperature range from  
–80°C to 30°C and 50°C 100°C.  
7
 
 
3 Specifications and Environmental Conditions  
3
Specifications and Environmental Conditions  
3.1  
Specifications  
Range  
–80°C to 100°C  
(–112°F to 212°F)  
Ambient Operating Range  
Stability  
15°C to 25°C  
(59°F to 77°F)  
0.006°C at –80°C (ethanol)  
0.010°C at 0°C (ethanol)  
0.010°C at 100°C (oil)  
Uniformity  
0.008°C at –80°C (ethanol)  
0.012°C at 0°C (ethanol)  
0.012°C at 100°C (oil)  
Set-Point Accuracy  
Set-Point Repeatability  
Resolution  
0.5°C  
0.01°C  
0.01°  
Access Opening  
Immersion Depth  
Tank Capacity  
3.25" x 4.5" (86 x 114 mm)  
7" (180 mm) max  
1 gallon (4 liters)  
Cooling Time  
From 25°C to –80°C,  
130 minutes  
Refrigeration Cascade  
Heater Power  
Two ¼ HP compressors  
500 W  
Automation Package  
Power  
Interface-it software and RS-232 included  
115 VAC ( 10%), 60 Hz, 16 A or 230 VAC ( 10%), 50 Hz, 8 A, specify,  
1700 W  
Size  
12" W x 30" H x 24" D  
(305 x 762 x 610 mm)  
Weight  
115 lb. (52 kg)  
3.2  
Environmental Conditions  
Although the instrument has been designed for optimum durability and trou-  
ble-free operation, it must be handled with care. The instrument should not be  
operated in an excessively dusty or dirty environment. Maintenance and clean-  
ing recommendations can be found in the Maintenance Section of this manual.  
The instrument operates safely under the following conditions:  
temperature range: 15–30°C (59–86°F)  
9
 
 
3 Specifications and Environmental Conditions  
ambient relative humidity: 15–50%  
pressure: 75kPa–106kPa  
mains voltage within 10% of nominal  
vibrations in the calibration environment should be minimized  
altitude less than 2,000 meters  
3.3  
Hardware Warranty and Assistance  
3.3.1  
Instrument Warranty  
GE Kaye Instruments, Inc. warrants its products against defects in materials  
and workmanship for a period of 12 months from the date of shipment. GE  
Kaye Instruments, Inc. will, at its option, repair or replace products which  
prove defective during this warranty period provided they are returned to our  
facility in Billerica, Massachusetts, European warranty returns are sent to  
Pforzheim, Germany. Repairs necessitated by misuse of this product are not  
covered by this warranty. No other warranties are expressed or implied, includ-  
ing but not limited to the implied warranties of merchantability and fitness for a  
particular purpose. GE Kaye Instruments, Inc. is not liable for consequential  
damages.  
3.3.2  
In-Warranty Repairs  
Customers are requested to discuss their problem with a Kaye Service Repre-  
sentative to insure a prompt and accurate assessment of their needs. Frequently,  
a problem can be resolved via phone or FAX with minimal inconvenience or  
delay.  
If necessary, the Customer Service Representative will send replacement parts  
or authorize the return of the instrument to the factory for repair. Instruments  
serviced in this manner will be repaired, completely tested, and calibrated prior  
to shipment.  
When an instrument is returned to the factory, the customer must prepay the  
freight charges. Kaye will prepay freight charges for the instrument's return via  
a comparable shipment method.  
If Field Service is required under the warranty, the customer is responsible for  
travel and living expenses incurred by the Field Service Representative.  
3.3.3  
After-Warranty Repairs  
Customers are requested to discuss their problem with a Kaye Service Repre-  
sentative to insure a prompt assessment of their needs. Frequently, a customer  
10  
 
 
3 Specifications and Environmental Conditions  
installed exchange part will solve the problem with minimal inconvenience and  
expense.  
Factory repairs can frequently be completed on a fixed price basis. A base ser-  
vice fee plus labor and materials will be charged in lieu of the fixed repair price  
upon customer request or if extensive repairs are required.  
Customers are requested to obtain a return authorization number prior to re-  
turning any instrument for service.  
All instruments serviced at the factory will be repaired, updated, calibrated, and  
completely tested prior to shipment.  
3.3.4  
3.3.5  
Equipment Maintenance Agreements  
An optional Equipment Maintenance Agreement provides an annual preventive  
maintenance visit with certified recalibration, plus replacement parts through-  
out the year. Contact the Customer Service Department at (800) 964-5293 for  
details and prices. European customers contact the Customer Service Depart-  
ment at +49 (0) 7231 14335 0.  
Customer Support  
Within 90 days of shipment from the factory, installation and initial configura-  
tion assistance will be provided by a Customer Service Representative via  
phone or FAX at no charge.  
After 90 days from shipment, technical assistance or consultation will be lim-  
ited to identification and resolution of instrument failures, unless a Customer  
Support Agreement has been purchased.  
3.3.6  
3.3.7  
Customer Support Agreement  
An optional Customer Support Agreement provides additional phone or FAX  
technical assistance for installation or program development. Contact the Cus-  
tomer Service Department for details.  
Customer Site Assistance  
Kaye can provide optional onsite assistance with installation, initial operation,  
and training of plant personnel. Contact the Customer Service Department for  
details.  
11  
 
 
4 Quick Start  
4
Quick Start  
Caution: READ SECTION 6 TITLED BATH USE before placing the bath  
in service. Incorrect handling can damage the bath and void the warranty.  
This chapter gives a brief summary of the steps required to set up and operate  
the bath. This should be used as a general overview and reference and not as a  
substitute for the remainder of the manual. Please read Section 5 through 8  
carefully before operating the bath.  
4.1  
Unpacking  
Unpack the bath carefully and inspect it for any damage that may have oc-  
curred during shipment. If there is shipping damage, notify the carrier immedi-  
ately. Verify that all components are present:  
CTR –80 Bath  
Access Hole Cover  
Manual  
RS-232 Cable  
Report of Test  
Drain Valve  
4.2  
Set-up  
Caution: The drain valve must be installed on the back of the bath before  
attempting to fill the tank with fluid. See Section 5.3, on page 17 for drain  
installation instructions.  
Warning: The instrument is equipped with a soft cutout (user settable firm-  
ware) and a hard cutout (set at the factory). Check the flash point, boiling  
point, or other fluid characteristic applicable to the circumstances of the  
unit operation. Ensure that the soft cutout is adjusted to the fluid charac-  
teristics of the application. As a guideline, the soft cutout should be set  
10°C to 15°C below the flash point of the bath fluid. See Section , Heat  
Transfer Fluid, for specific information on bath fluids and Section , Cut-  
out.  
13  
 
 
4 Quick Start  
Set up of the bath requires careful unpacking and placement of the bath, install-  
ing the drain valve, filling the bath with fluid, and connecting power. Consult  
Section 5 for detailed instructions for proper installation of the bath. Be sure to  
place the bath in a safe, clean and level location. Install the drain valve onto  
the pipe fitting at the back of the bath and make sure the valve is closed. See  
Section 5.3, Bath Preparation and Filling. Be sure to place the bath in a safe,  
clean and level location.  
Fill the bath tank with an appropriate liquid. For operation at moderate bath  
temperatures, clean distilled water works well. For lower temperatures, ethanol  
(denatured) works well but is NOT USABLE AT HIGHER TEMPERA-  
TURES due to flammability.  
Carefully pour the fluid into the bath tank through the large rectangular access  
hole above the tank avoiding spilling any fluid. The fluid must not exceed a  
height of 1/2 inch below the top of the tank or be less than 2 inches below the  
top.  
4.3  
Power  
Plug the bath power cord into a mains outlet of the proper voltage, frequency,  
and current capability. See Section 3.1, Specifications, for power details. Refer  
to and read the CAUTION at the front of this manual concerning brownout and  
over voltage protection.  
Turn the bath on using the front panel “POWER” switch. The bath will turn on  
and begin to heat or cool to reach the previously programmed temperature  
set-point. The front panel LED display will indicate the actual bath tempera-  
ture. Set the cooling switch to “OFF” for temperatures above approximately  
50°C. Set the switch to “ON” for lower temperatures. When the cooling switch  
has been turned on, the first stage compressor will power up. The second stage  
will come on automatically when proper conditions are met. This will take 2 to  
4 minutes. Cooling in the bath will not begin until the second stage starts.  
4.4  
Setting the Temperature  
In the following discussion and throughout this manual a solid box around the  
word SET, UP, DOWN or EXIT indicates the panel button to press while the  
dotted box indicates the display reading on the front panel. Explanation of the  
button function or display reading is written at the right.  
To view or set the bath temperature set-point proceed as follows. The front  
panel LED display normally shows the actual bath temperature.  
24.68 C  
Bath temperature display  
14  
 
 
4 Quick Start  
When “SET” is pressed the display shows the set-point memory that is cur-  
rently being used and its value. Eight set-point memories are available.  
Access set-point selection  
S
1. 25.0  
Set-point 1, 25.0°C currently used  
Press “SET” to select this memory and access the set-point value.  
Access set-point value  
S
C 25.00  
Current value of set-point 1, 25.00°C  
Press “UP” or “DOWN” to change the set-point value.  
Increment display  
U
C 30.00  
New set-point value  
Press SET to accept the new value. The bath begins heating or cooling to the  
new set-point.  
Store new set-point  
S
Press “EXIT” and the bath temperature will be displayed again.  
Return to the temperature display  
E
24.73 C  
Bath temperature display  
The bath heats or cools until it reaches the new set-point temperature. Turn off  
the cooling to reach and control at higher temperatures.  
When setting the set-point temperature be careful not to exceed the temperature  
limit of the bath fluid.  
To obtain optimum control stability adjust the proportional band as discussed in  
Section 9.6.  
15  
 
5 Installation  
5
Installation  
Caution: READ SECTION 6 TITLED BATH USE before placing the bath  
in service. Incorrect handling can damage the bath and void the warranty.  
5.1  
Bath Environment  
The CTR –80 Bath is a precision instrument which should be located in an ap-  
propriate environment. The location should be free of drafts, extreme tempera-  
tures and temperature changes, dirt, etc. The surface where the bath is placed  
must be level. Allow at least six inches around the bath for air circulation. The  
top surface of the bath may become hot at high temperatures. Beware of the  
danger of accidental fluid spills.  
A fume hood should be used to remove any vapors given off by hot bath fluid.  
5.2  
“Dry-out” Period  
Before initial use, after transport, and any time the instrument has not been en-  
ergized for more than 10 days, the bath will need to be energized for a  
“dry-out” period of 1-2 hours before it can be assumed to meet all of the safety  
requirements of the IEC 1010-1.  
5.3  
Bath Preparation and Filling  
Caution: Before filling the tank with fluid the drain valve must be installed  
onto the pipe fitting at the back of the bath.  
5.3.1  
Drain Valve Installation Instructions  
The drain valve attaches to the swage fitting located on the lower backside of  
the bath. (See Figure 1.)  
1.  
2.  
Place the valve onto the drain fitting and hand tighten in place by turn-  
ing the hex nut (attached to the bath) counter clockwise while holding  
the valve stationary.  
Using open-end wrenches, hold the valve in place and tighten the hex  
nub one quarter turn from the hand tightened position above.  
The valve should be secured in place at this point. If not, repeat step number 2  
being careful not to over tighten the assembly.  
17  
 
 
5 Installation  
Ensure the valve handle is in the closed position before attempting to add fluid  
to the tank.  
Hex Nut  
Valve body  
Back of bath  
Figure 1 Drain Valve Installation—IMPORTANT: Do Not Over Tighten. Follow the  
installation instructions above.  
5.3.2  
Filling With Fluid  
The CTR –80 Bath is not provided with a fluid. Depending on the desired tem-  
perature range, any of the following fluids, as well as others, may be used in  
the bath:  
Water  
Ethanol (Ethyl Alcohol)  
Ethylene glycol/water  
Mineral oil  
Silicone oil  
Halocarbon 0.8  
Fluids are discussed in detail in Section 8.1.  
Remove any access hole cover from the bath and check the tank for foreign  
matter (dirt, remnant packing material, etc.).  
Fill the bath with clean unpolluted fluid. Fill the bath carefully through the  
large square access hole to a level that will allow for stirring and thermal ex-  
pansion. DO NOT turn on the bath without fluid in the tank. The fluid should  
never exceed a height of 1/2" below the top of the tank or be less than 2 inches  
18  
 
 
5 Installation  
below the top. Carefully monitor the bath fluid level as the bath temperature  
rises to prevent overflow or splashing. Cautiously, remove excess hot fluid if  
necessary.  
5.4  
Power  
With the bath power switch off, plug the bath into an AC mains outlet of the  
appropriate voltage, frequency, and current capacity. See Section 3.1, Specifica-  
tions, for power details. Refer to and read the CAUTION at the front of this  
manual concerning brownout and over voltage protection.  
19  
 
 
6 Bath Use  
6
Bath Use  
Caution: READ this section BEFORE PLACING THE BATH IN SERVICE  
The information in this section is for general information only. It is not de-  
signed to be the basis for calibration laboratory procedures. Each laboratory  
will need to write their own specific procedures.  
6.1  
General  
Be sure to select the correct fluid for the temperature range of the calibration.  
Bath fluids should be selected to operate safely with adequate thermal proper-  
ties to meet the application requirements. Also, be aware that some fluids ex-  
pand and could overflow the bath if not watched. Refer to General Operation,  
Section8, for information specific to fluid selection and to the MSDS sheet spe-  
cific to the fluid selected. The temperature range of any single fluid is likely  
less than that of the bath itself. This means that the type of bath fluid may have  
to change to cover the full range of the bath (see Section8.1.1). Baths are most  
often set up to operate with a single fluid only over the useful range of that  
fluid. Other baths can be set up with other fluids to cover other temperature  
ranges required. This is generally the most productive and efficient approach.  
The bath generates extreme temperatures. Precautions must be taken to prevent  
personal injury or damage to objects. Probes may be extremely hot or cold  
when removed from the bath. Cautiously handle probes to prevent personal in-  
jury. Carefully place probes on a heat/cold resistant surface or rack until they  
are at room temperature. It is advisable to wipe the probe with a clean soft cloth  
or paper towel before inserting it into another bath. This prevents the mixing of  
fluids from one bath to another. Always be sure that the probe is completely  
dry before inserting it into a hot fluid. Some of the high temperature fluids  
react violently to water or other liquid mediums. Be aware that cleaning the  
probe can be dangerous if the probe has not cooled to room temperature.  
For optimum accuracy and stability, allow the bath adequate stabilization time  
after reaching the set-point temperature.  
6.2  
Comparison Calibration  
Comparison calibration involves testing a probe (unit under test, UUT) against  
a reference probe. After inserting the probes to be calibrated into the bath, al-  
low sufficient time for the probes to settle and the temperature of the bath to  
stabilize.  
One of the significant dividends of using a bath rather than a dry-well to cali-  
brate multiple probes is that the probes do not need to be identical in construc-  
21  
 
 
6 Bath Use  
tion. The fluid in the bath allows different types of probes to be calibrated at  
the same time. However, stem effect from different types of probes is not to-  
tally eliminated. Even though all baths have horizontal and vertical gradients,  
these gradients are minimized inside the bath work area. Nevertheless, probes  
should be inserted to the same depth in the bath liquid. Be sure that all probes  
are inserted deep enough to prevent stem effect. We suggest a general  
rule-of-thumb for immersion depth to reduce the stem effect to a minimum: 20  
x the diameter of the UUT + the sensor length. Do not submerge the probe  
handles. If the probe handles get too warm during calibration at high tempera-  
tures, a heat shield could be used just below the probe handle. This heat shield  
could be as simple as aluminum foil slid over the probe before inserting it in  
the bath or as complicated as a specially designed reflective metal apparatus.  
When calibrating over a wide temperature range, better results can generally be  
achieved by starting at the highest temperature and progressing down to the  
lowest temperature.  
Probes can be held in place in the bath by using probe clamps or drilling holes  
in the access cover. Other fixtures to hold the probes can be designed. The ob-  
ject is to keep the reference probe and the probe(s) to be calibrated as closely  
grouped as possible in the working area of the bath. Bath stability is maximized  
when the bath working area is kept covered.  
In preparing to use the bath for calibration start by:  
Placing the reference probe in the bath working area.  
Placing the probe to be calibrated, the UUT, in the bath working area as  
close as feasibly possible to the reference probe.  
6.3  
Calibration of Multiple Probes  
Fully loading the bath with probes increases the time required for the tempera-  
ture to stabilize after inserting the probes. Using the reference probe as the  
guide, be sure that the temperature has stabilized before starting the calibration.  
22  
 
 
7 Parts and Controls  
7
Parts and Controls  
7.1  
Control Panel  
The following controls and indicators are present on the controller front panel  
(see Figure 2 below): (1) the digital LED display, (2) the control buttons, (3)  
the on/off power switch, (4) the heater mode light, and (5) the cooling on/off  
switch.  
1)  
The digital display is an important part of the temperature controller. It  
displays the set-point temperature and bath temperature as well as the  
various other bath functions, settings, and constants. The display shows  
temperatures according to the selected scale units °C or °F.  
2)  
The control buttons (SET, DOWN, UP, and EXIT) are used to set the  
bath temperature set-point, access and set other operating parameters,  
and access and set bath calibration parameters. A brief description of  
the functions of the buttons follows:  
SET - Used to display the next parameter in a menu and to set parame-  
ters to the displayed value.  
DOWN - Used to decrement the displayed value of parameters.  
UP - Used to increment the displayed value.  
EXIT - Used to exit from a menu. When EXIT is pressed any changes  
made to the displayed value will be ignored.  
3)  
The on/off switch controls power to the entire bath including the stir-  
ring motor.  
CTR –80  
1
Cooling  
I
Power  
I
4
-80.00 C  
3
5
Heater  
Mode  
Set  
Down  
Up  
Exit  
O
O
2
Figure 2 CTR-80 Control Panel  
23  
 
 
7 Parts and Controls  
4)  
5)  
The heater mode is a red light emitting diode (LED). This indicator lets  
the user visually see the ratio of heating to cooling. When the indicator  
is lit the heater is on, and when it is off the heater is off and the bath is  
cooling.  
The cooling switch turns on the refrigeration for control below 50°C  
and rapid cool down.  
7.2  
Bath Tank and Lid  
The bath tank and lid assembly includes: the tank, the control probe, the stir-  
ring motor, the access hole, and the access hole cover.  
The bath tank is constructed of stainless steel. It is very resistant to oxida-  
tion in the presence of most chemicals and over a wide range of tempera-  
tures.  
The control probe provides the temperature feedback signal to the con-  
troller allowing the controller to maintain a constant temperature. The  
control probe is a precision platinum resistance thermometer (PRT). It is  
delicate and must be handled carefully. The probe is placed in the small  
hole in the top of the bath so that the probe tip is fully immersed in the  
bath fluid. It is located underneath the motor cover.  
The stirring motor is mounted on the bath tank lid under the motor cover.  
It drives the stirring propeller to provide mixing of the bath fluid. Proper  
mixing of the fluid is important for good constant temperature stability.  
On the bath lid is a work area access hole. This is used for filling the bath  
with fluids and placement of thermometers and devices into the bath.  
When possible the access hole should be covered (must be covered to  
reach minimum temperatures).  
An insulated access hole cover is provided and should be used to cover  
the access opening in the top of the bath. This improves bath temperature  
stability, prevents excess fluid evaporation or fumes and increases safety  
with hot fluid. The user may drill or cut holes in the cover to accommo-  
date the instruments to be calibrated or immersed in the bath. Spare cov-  
ers are available from GE Kaye Instruments. An optional access cover  
which provides locations for two reference thermometers and three wells  
for units under test is available.  
7.3  
Back Panel  
On the back of the bath are 1) the system fuses, 2) the non-removable power  
cord, 3) the drain valve, 4) the RS-232 interface connector, and 5) removable  
vent panel.  
24  
 
 
7 Parts and Controls  
1
POWER  
FUSE  
FUSE  
RS-232  
2
4
3
DRAIN  
5
Figure 3 Back Panel  
1)  
2)  
3)  
The system fuses are 20 amp SB, 250V for 115 VAC operation and 10  
amp ST, 250 V for 230 VAC operation.  
The power cord is rated at 115 VAC, 20 amps. (230 VAC, 10 amps op-  
tional.)  
A drain plug is provided for ease of removing the fluid media from the  
bath. Always use a container of adequate size to hold the FULL LOAD  
of fluid. Some oils are more easily drained at higher temperatures.  
Caution: Do not exceed a 100°C fluid temperature for draining. The valve  
could be damaged if 100°C is exceeded. Insulate the container from the  
floor and other objects.  
4)  
5)  
The serial RS-232 interface attaches to the back of the bath at the con-  
nector labeled "RS-232".  
The removable vent panel can be removed to access the condensor for  
cleaning. See Section 12, Maintenance.  
25  
 
 
8 General Operation  
8
General Operation  
8.1  
Bath Fluid  
Many fluids work with the CTR –80 bath. Choosing a fluid requires consider-  
ation of many important characteristics of the fluid. Among these are tempera-  
ture range, viscosity, specific heat, thermal conductivity, thermal expansion,  
electrical resistivity, fluid lifetime, safety, and cost. If the viscosity becomes too  
great, the stirrer may not function.  
8.1.1  
Temperature Range  
One of the most important characteristics to consider is the temperature range  
of the fluid. Few fluids work well throughout the complete temperature range  
of the bath. The temperature at which the bath is operated must always be  
within the safe and useful temperature range of the fluid. Set the cutout to meet  
the temperature limits of the selected fluid. The lower temperature range of the  
fluid is determined by the freeze point of the fluid or the temperature at which  
the viscosity becomes too great. The upper temperature is usually limited by  
vaporization, flammability, or chemical breakdown of the fluid. Vaporization of  
the fluid at higher temperatures may affect temperature stability because of  
cool condensed fluid dripping into the bath from the lid.  
8.1.2  
Viscosity  
Viscosity is a measure of the thickness of a fluid, how easily it can be poured  
and mixed. Viscosity affects the temperature stability of the bath. With low vis-  
cosity, fluid mixing is better which creates a more uniform temperature  
throughout the bath. This improves the bath response time which allows it to  
maintain a more constant temperature. For good control the viscosity should be  
less than ten centistokes. Twenty centistokes is about the upper limit of allow-  
able viscosity. Viscosities greater than this cause very poor control stability and  
may also overheat or damage the stirring motor. With oils viscosity may vary  
greatly with temperature.  
When using fluids with higher viscosities the controller proportional band may  
need to be increased to compensate for the reduced response time (see Sec-  
tion9.6). Otherwise the temperature may begin to oscillate.  
8.1.3  
Specific Heat  
Specific heat is the measure of the heat storage ability of the fluid. Specific  
heat, to a small degree, affects the control stability. It also affects the heating  
and cooling rates. Generally, a lower specific heat means quicker heating and  
cooling. The proportional band may require some adjustment depending on the  
specific heat of the fluid.  
27  
 
 
8 General Operation  
8.1.4  
Thermal Conductivity  
Thermal conductivity measures how easily heat flows through the fluid. Ther-  
mal conductivity of the fluid affects the control stability, temperature unifor-  
mity, and probe temperature settling time. Fluids with higher conductivity  
distribute heat more quickly and evenly improving bath performance.  
8.1.5  
8.1.6  
Thermal Expansion  
Thermal expansion describes how the volume of the fluid changes with temper-  
ature. Thermal expansion of the fluid used must be considered since the in-  
crease in fluid volume as the bath temperature changes may cause overflow.  
Excessive thermal expansion may also be undesirable in applications where  
constant liquid level is important. Many fluids including oils have significant  
thermal expansion.  
Electrical Resistivity  
Electrical resistivity describes how well the fluid insulates against the flow of  
electric current. In some applications, such as measuring the resistance of bare  
temperature sensors, it may be important that little or no electrical leakage oc-  
cur through the fluid. In such conditions choose a fluid with very high  
resistivity.  
8.1.7  
8.1.8  
Fluid Lifetime  
Many fluids degrade over time because of evaporation, water absorption, gel-  
ling, or chemical breakdown. Often the degradation becomes significant near  
the upper temperature limit of the fluid, substantially reducing the fluid’s  
lifetime.  
Safety  
When choosing a fluid always consider the safety issues associated. Obviously  
where there are conditions of extreme hot or cold there can be danger to people  
and equipment. Fluids may also be hazardous for other reasons. Some fluids  
may be considered toxic. Contact with eyes, skin, or inhalation of vapors may  
cause injury. A proper fume hood must be used if hazardous or bothersome va-  
pors are produced.  
Warning: Fluids at high temperatures may pose danger from BURNS,  
FIRE, and TOXIC FUMES. Use appropriate caution and safety equip-  
ment.  
Fluids may be flammable and require special fire safety equipment and proce-  
dures. An important characteristic of the fluid to consider is the flash point. The  
28  
 
 
8 General Operation  
flash point is the temperature at which there is sufficient vapor given off so that  
when there is sufficient oxygen present and a ignition source is applied the va-  
por will ignite. This does not necessarily mean that fire will be sustained at the  
flash point. The flash point may be either of the open cup or closed cup type.  
Either condition may occur in a bath situation. The closed cup temperature is  
always the lower of the two. The closed cup represents the contained vapors in-  
side the tank and the open cup represents the vapors escaping the tank. Oxygen  
and an ignition source will be less available inside the tank.  
The cutout should be set to meet the temperature limits of the selected fluid.  
Environmentally hazardous fluids require special disposal according to applica-  
ble federal or local laws after use.  
8.1.9  
Cost  
Cost of bath fluids may vary greatly, from cents per gallon for water to hun-  
dreds of dollars per gallon for synthetic oils. Cost may be an important consid-  
eration when choosing a fluid.  
8.1.10  
Commonly Used Fluids  
Below is a description of some of the more commonly used fluids and their  
characteristics.  
8.1.10.1  
Water (Distilled)  
Water is often used because of its very low cost, availability, and excellent tem-  
perature control characteristics. Water has very low viscosity and good thermal  
conductivity and heat capacity which makes it among the best fluids for control  
stability at low temperatures. Temperature stability is much poorer at higher  
temperatures because water condenses on the lid, cools and drips into the bath.  
Water is safe and relatively inert. The electrical conductivity of water may pre-  
vent its use in some applications. Water has a limited temperature range, from a  
few degrees above 0°C to a few degrees below 100°C. At higher temperatures  
evaporation becomes significant. Water used in the bath should be distilled or  
softened to prevent mineral deposits. Consider using an algaecide chemical in  
the water to prevent contamination.  
8.1.10.2  
Ethanol  
Denatured ethanol (ethyl alcohol) is often used at lower temperatures between  
–80°C and 10°C. It has good viscosity over its range and is inexpensive. Toxic-  
ity, vapors, and flammability at temperatures higher than 10°C are significant  
issues that must be considered.  
29  
 
 
8 General Operation  
8.1.10.3  
Mineral Oil  
Mineral oil or paraffin oil is often used at moderate temperatures above the  
range of water. Mineral oil is relatively inexpensive. At lower temperatures  
mineral oil is quite viscous and control may be poor. At higher temperatures  
vapor emission becomes significant. The vapors may be dangerous and use of a  
fume hood is highly recommended. As with most oils mineral oil will expand  
as temperature increases so be careful not to fill the bath too full that it over-  
flows when heated. The viscosity and thermal characteristics of mineral oil is  
poorer than water so temperature stability will not be as good. Mineral oil has  
very low electrical conductivity. Use caution with mineral oil since it is flam-  
mable and may also cause serious injury if inhaled or ingested.  
8.1.10.4  
8.1.10.5  
Silicone Oil (Dow Corning 200.05, 200.10, 200.20)  
Silicone oils are available which offer a much wider operating temperature  
range than mineral oil. Like most oils, silicone oils have temperature control  
characteristics which are somewhat poorer than water. The viscosity changes  
significantly with temperature and thermal expansion also occurs. These oils  
have very high electrical resistivity. Silicone oils are fairly safe and non-toxic.  
Silicone oils are fairly expensive.  
Halocarbon 0.8  
Halocarbon 0.8 is a low temperature fluid with a wide temperature  
range. It may be used as low as –90 to –100°C before viscosity be-  
comes too great. It may be used as high as 70°C before evaporation be-  
comes excessive. Halocarbon does not absorb water and will therefore  
form ice at temperatures below 0°C. Ice crystals turn the fluid into a  
slush which effectively increases the viscosity and reduces temperature  
stability. Pumping systems may be rendered ineffective due to ice block-  
age. The ice (water) can be removed occasionally by heating the fluid up  
to 100°C for brief periods of time. Use halocarbon under a fume hood at  
higher temperatures to remove vapors. Toxicity is low but caution is al-  
ways recommended. Halocarbon has excellent electrical resistivity. This  
fluid is fairly expensive.  
8.1.11  
Fluid Characteristics Table  
Table 2 on page 31 provides help in selecting a heat exchange fluid media for  
your constant temperature bath. This table provides a numerical representation  
of most of the physical qualities important in making a selection. The list is not  
all inclusive. There may be other useful fluids not shown in this listing.  
The table includes information on a variety of fluids which are often used as  
heat transfer fluid in baths. Because of the temperature range some fluids may  
not be useful with your bath.  
30  
 
 
8 General Operation  
Table 2 Table of Various Bath Fluids  
Fluid  
Lower  
Upper Temperature  
Limit*  
Thermal  
Conductivity  
(cal/s/cm/°C)  
Thermal  
Expansion  
(cm/cm/°C)  
(# = Hart Part No.) Temperature  
Limit*  
Flash  
Point  
Viscosity  
(centistokes)  
Specific  
Gravity  
Specific Heat  
(cal/g/°C)  
Resistivity  
(10 -cm )  
Halocarbon 0.8  
#5019  
–100°C (v)** 70°C (e)  
NONE 5.7 @ –50°C  
0.8 @ 40°C  
1.71 @ 40°C  
0.2  
0.0004  
0.0011  
0.5 @ 70°C  
Methanol  
Water  
–96°C (fr)  
10°C (fl,cc)  
12°C  
1.3 @ –35°C  
0.66 @ 0°C  
0.45 @ 20°C  
0.810 @ 0°C  
0.792 @ 20°C  
0.6  
0.0005 @ 20°C 0.0014 @ 25°C  
0°C (fr)  
95°C (b)  
90°C (b)  
NONE 1 @ 25°C  
0.4 @ 75°C  
1.00  
1.05  
1.00  
0.0014  
0.001  
0.0002 @ 25°C  
Ethylene  
Glycol—50%  
#5020  
–30°C (fr)  
NONE 7 @ 0°C  
2 @ 50°C  
0.8 @ 0°C  
0.7 @ 100°C  
Mineral Oil No.7  
#5011  
10°C (v)  
166°C (fl)  
168°C 15 @ 75°C  
5 @ 125°C  
0.87 @ 25°C  
0.84 @ 75°C  
0.48 @ 25°C  
0.53 @ 75°C  
0.00025 @ 25°C 0.0007 @ 50°C 5 @ 25°C  
0.81 @ 125°C 0.57 @ 125°C  
Silicone Oil Type  
200.05 #5010  
–40°C (v)**  
–30°C (v)**  
130°C (fl, cc)  
209°C (fl, cc)  
133°C 5 @ 25°C  
0.92 @ 25°C 0.4  
0.00028 @ 25°C 0.00105  
0.00032 @ 25°C 0.00108  
1000 @ 25°C  
10 @ 150°C  
Silicone Oil Type  
200.10 #5012  
211°C 10 @ 25°C  
3 @ 135°C  
0.934 @ 25°C 0.43 @ 40°C  
0.45 @ 100°C  
1000 @ 25°C  
50 @ 150°C  
0.482 @ 200°C  
Silicone Oil Type  
200.20 #5013  
10°C (v)  
30°C (v)  
230°C (fl, cc)  
278°C (fl, cc)  
232°C 20 @ 25°C  
280°C 50 @ 25°C  
0.949 @ 25°C 0.370 @ 40°C 0.00034 @ 25°C 0.00107  
1000 @ 25°C  
50 @ 150°C  
0.393 @ 100°C  
0.420 @ 200°C  
Silicone Oil Type  
200.50 #5014  
0.96 @ 25°C  
1.07 @ 25°C  
0.4  
0.00037 @ 25°C 0.00104  
1000 @ 25°C  
50 @ 150°C  
Silicone Oil Type 550 70°C (v)  
#5016  
230°C (fl, cc)  
300°C (fl, oc)  
232°C 50 @ 70°C  
10 @ 104°C  
0.358 @ 40°C 0.00035 @ 25°C 0.00075  
0.386 @ 100°C  
100 @ 25°C  
1 @ 150°C  
0.433 @ 200°C  
Silicone Oil Type 710 80°C (v)  
#5017  
300°C (fl, oc)  
302°C 50 @ 80°C  
7 @ 204°C  
1.11 @ 25°C  
0.96 @ 25°C  
0.363 @ 40°C 0.00035 @ 25°C 0.00077  
0.454 @ 100°C  
0.505 @ 200°C  
100 @ 25°C  
1 @ 150°C  
Silicone Oil Type  
210-H  
66°C (v)  
313°C (fl, oc)  
550°C  
315°C 50 @ 66°C  
14 @ 204°C  
0.34 @ 100°C 0.0003  
0.00095  
0.00041  
100 @ 25°C  
1 @ 150°C  
1.7 /cm3  
Heat Transfer Salt  
#5001  
180°C (fr)  
NONE 34 @ 150°C  
6.5 @ 300°C  
2.0 @ 150°C  
1.9 @ 300°C  
1.7 @ 500°C  
0.33 0.0014  
2.4 @ 500°C  
*Limiting Factors — b - boiling point e - high evaporation fl - flash point fr - freeze point v - viscosity — Flash point test oc = open cup cc = closed cup  
**Very low water solubility, ice will form as a slush from condensation below freezing.  
8.1.11.1  
Limitations and Disclaimer  
The information given in this manual regarding fluids is intended only to be  
used as a general guide in choosing a fluid. Though every effort has been made  
to provide correct information we cannot guarantee accuracy of data or assure  
suitability of a fluid for a particular application. Specifications may change and  
sources sometimes offer differing information. GE Kaye Instruments cannot be  
liable for any personal injury or damage to equipment, product or facilities re-  
sulting from the use of these fluids. The user of the bath is responsible for col-  
lecting correct information, exercising proper judgment, and insuring safe  
operation. Operating near the limits of certain properties such as the flash point  
or viscosity can compromise safety or performance. Your company’s safety  
31  
 
 
8 General Operation  
policies regarding flash points, toxicity, and such issues must be considered.  
You are responsible for reading the (material safety data sheets) and acting  
accordingly.  
8.2  
8.3  
Stirring  
Stirring of the bath fluid is very important for stable temperature control. The  
fluid must be mixed well for good temperature uniformity and fast controller  
response. The stirrer is precisely adjusted for optimum performance.  
Power  
Power to the bath is provided by an AC mains supply. See Section 3.1, Specifi-  
cations, for power details. Refer to and read the CAUTION at the front of this  
manual concerning brownout and over voltage protection. Power to the bath  
passes through a filter to prevent switching spikes from being transmitted to  
other equipment.  
To turn on the bath switch the control panel power switch to the ON position.  
The stirring motor will turn on, the LED display will begin to show the bath  
temperature, and the heater will turn on or off until the bath temperature  
reaches the programmed set-point. When powered on the control panel display  
will briefly show a four digit number. This number indicates the number of  
times power has been applied to the bath. Also briefly displayed is data which  
indicates the controller hardware configuration. This data is used in some cir-  
cumstances for diagnostic purposes.  
8.4  
8.5  
Heater  
The power to the bath heater is precisely controlled by the temperature control-  
ler to maintain a constant bath temperature. Power is controlled by periodically  
switching the heater on for a certain amount of time using a solid-state relay.  
The front panel LED heater mode shows the state of the heater. The indicator  
glows red when the heater is on and is off when the heater is off. The indicator  
will pulse constantly when the bath is maintaining a stable temperature.  
Refrigeration  
This bath uses a two-stage refrigeration system which requires special refriger-  
ants to enable it to reach low temperatures. This section describes some aspects  
of the cooling system and provides important information regarding  
refrigerants.  
32  
 
 
8 General Operation  
8.5.1  
8.5.2  
Operation  
The bath controller automatically switches off cooling when the bath is oper-  
ated above 50°C to protect the system from extreme pressures. The refrigera-  
tion system is also protected by a brownout and over voltage protection device  
that switches off power to the system when the line voltage is outside the safe  
operating range. The display indicates “LoLinE” when this condition exists. A  
time delay prevents the refrigeration from restarting for a short time after ade-  
quate line voltage has been restored.  
Important Refrigerant Information  
The refrigeration system in this bath has been designed to perform at ultra-low  
temperatures. As a result, aspects of the design are uncommon and the refrig-  
erants are non-standard.  
The system is cascaded, meaning there are two separate systems with the first  
one chilling the second. This is required to reach temperatures below –40°C.  
Normal refrigeration does not use a cascading technique, and many refrigera-  
tion technicians are not familiar with such systems.  
The first stage refrigerant is an HFC known as R-507. The second stage per-  
forms the ultra-low cooling. Its refrigerant is an HFC R-508B, also known as  
SUVA-95.  
What this means to you:  
The cascade system is complex and its uncommon nature means that  
many local refrigeration service technicians may not be able to service it.  
If your bath needs survice, call GE Kaye Instruments Customer Service at  
1-800-964-KAYE  
The compressor manufacturer does not warranty their compressors when  
used with non-standard refrigerants. Warranty of these compressors must  
be handled through GE Kaye Instruments only. There is no other way for  
you to receive parts or service on your compressor. You must receive your  
parts or service from GE Kaye Instruments.  
8.6  
Temperature Controller  
The bath temperature is controlled by a special digital temperature controller.  
The controller features a 24-bit analog-to-digital converter (DAC) that gives it  
remarkable accuracy and stability.  
The bath temperature is monitored with a platinum resistance sensor in the con-  
trol probe. The controller uses a proportional-integral-derivative (PID) algo-  
rithm to determine how much heat the bath needs. The bath is heated by a  
solid-state relay (SSR) controlled 500W heater.  
33  
 
 
8 General Operation  
The bath is operable within the temperature range given in the specifications.  
For protection against solid-state relay failure or other circuit failure, a thermo-  
couple cutout automatically turns off the heater anytime the bath temperature  
exceeds the maximum temperature.  
The controller allows the operator to set the bath temperature with high resolu-  
tion, adjust the proportional band, monitor the heater output power, and pro-  
gram the controller configuration and calibration parameters. The controller  
may be operated in temperature units of degrees Celsius or Fahrenheit. The  
controller is operated and programmed from the front control panel using the  
four key switches and digital LED display. The controller is equipped with a  
serial RS-232 digital interface for remote operation. Operation of the controller  
using the front control panel is discussed following in Section 9. Operation us-  
ing the digital interfaces is discussed in Section 10.  
When the controller is set to a new set-point the bath heats or cools to the new  
temperature. Once the new temperature is reached the bath usually takes 15-20  
minutes for the temperature to settle and stabilize. There may be a small  
amount of overshoot or undershoot.  
34  
 
9 Controller Operation  
9
Controller Operation  
This section discusses in detail how to operate the bath temperature controller  
using the front control panel. Using the front panel key-switches and LED dis-  
play the user may monitor the bath temperature, set the temperature set-point in  
degrees C or F, monitor the heater output power, adjust the controller propor-  
tional band, and program the calibration parameters, operating parameters, and  
serial interface configuration. Operation of the functions and parameters are  
shown in the flowchart in Figure 4 on page 36. This chart may be copied for  
reference.  
In the following discussion a button with the word SET, UP, EXIT or DOWN  
inside indicates the panel button while the dotted box indicates the display  
reading. Explanation of the button or display reading are to the right of each  
button or display value.  
9.1  
Bath Temperature  
The digital LED display on the front panel allows direct viewing of the actual  
bath temperature. This temperature value is what is normally shown on the dis-  
play. The units, C or F, of the temperature value are displayed at the right. For  
example,  
Bath temperature in degrees Celsius  
10.00C  
The temperature display function may be accessed from any other function by  
pressing the “EXIT” button.  
9.2  
Temperature Set-point  
The temperature set-point can be set to any value within the range and resolu-  
tion as given in the specifications. Be careful not to exceed the safe temperature  
limits of any devices inserted into the bath.  
Setting the temperature involves two steps: (1) select the set-point memory and  
(2) adjust the set-point value.  
To protect the refrigeration system from excessive pressures, it will not operate  
above 50°C.  
9.2.1  
Programmable Set-points  
The controller stores 8 set-point temperatures in memory. The set-points can be  
quickly recalled to conveniently set the calibrator to a previously programmed  
temperature set-point.  
35  
 
 
9 Controller Operation  
Display  
Temperature  
SET  
+
SET  
DOWN  
Select Setpoint  
Display of Rs  
Adjust Setpoint  
Units °C/°F  
SET  
+
UP  
Toggles °C / °F  
EXIT  
EXIT  
Secondary Functions  
+
Cal  
SET  
EXIT  
Scan On/Off  
Scan Rate  
Menu  
EXIT  
SET  
X5  
Display Power  
Hard  
Cut-out  
Set Proportional Band  
Cut-out  
Adj. Hard  
Cut-out  
Set Cut-out Temp  
R0  
Configuration Menu  
SET  
Adj. R0  
ALPHA  
EXIT  
EXIT  
Adj. ALPHA  
UP  
UP  
Operating  
Parameters  
Menu  
Serial  
Interface  
Menu  
DOWN  
DOWN  
DELTA  
Adj. DELTA  
BETA  
Menu Legend:  
SET  
SET  
Press “SET” to step through the menu  
and to store the parameter value.  
BAUD  
Rate  
HL  
Press “EXIT” briefly to skip a parameter  
without storing the parameter value.  
Adjust  
BAUD Rate  
Adj. HL  
Adjust  
BETA  
Hold “EXIT” to exit the menu and  
display the temperature  
Sample  
Period  
LL  
Adj. Sample  
Period  
Adj. LL  
Duplex  
Mode  
COOL  
Adj. Duplex  
Mode  
Adj. COOL  
Linefeed  
Adjust  
Linefeed  
Figure 4 Controller Operation Flowchart  
36  
 
 
9 Controller Operation  
To set the temperature one must first select the set-point memory. This function  
is accessed from the temperature display function by pressing “SET”. The  
number of the set-point memory currently being used is shown at the left on the  
display followed by the current set-point value.  
Bath temperature in degrees Celsius  
10.00C  
Access set-point memory  
Set-point memory 1, 25°C currently used  
To change the set-point memory press “UP” or “DOWN”.  
New set-point memory 4, –25°C  
S
1. 25.0  
4. -25.0  
Press “SET” to accept the new selection and access the set-point value.  
Accept selected set-point memory  
S
9.2.2  
Set-point Value  
The set-point value may be adjusted after selecting the set-point memory and  
pressing “SET”.  
4 -25.0  
Set-point 4 value in°C  
If the set-point value is correct, hold “EXIT” to resume displaying the well  
temperature. Press “UP” or “DOWN” to adjust the set-point value.  
-28.00  
New set-point value  
When the desired set-point value is reached press “SET” to accept the new  
value and access the temperature scale units selection. If “EXIT” is pressed in-  
stead of “SET”, any changes made to the set-point are ignored.  
Accept new set-point value  
S
9.2.3  
Temperature Scale Units  
The temperature scale units of the controller can be set by the user to degrees  
Celsius (°C) or Fahrenheit (°F). The selected units are used in displaying the  
well temperature, set-point, and proportional band.  
Press “SET” after adjusting the set-point value to change display units.  
37  
 
 
9 Controller Operation  
Un= C  
Scale units currently selected  
Press “UP” or “DOWN” to change the units.  
New units selected  
Un= F  
9.3  
Scan  
The scan rate can be set and enabled so that when the set-point is changed the  
bath heats or cools at a specified rate (degrees per minute) until it reaches the  
new set-point. With the scan disabled the bath heats or cools at the maximum  
possible rate.  
9.3.1  
Scan Control  
The scan is controlled with the scan on/off function that appears in the main  
menu after the set-point function.  
Scan function off  
Press “UP” or “DOWN” to toggle the scan on or off.  
Scan function on  
Sc=OFF  
Sc=On  
Press “SET” to accept the present setting and continue.  
Accept scan setting  
S
Scan Rate  
9.3.2  
The next function in the main menu is the scan rate. The scan rate can be set  
from .1 to 99.9°C/min. The maximum scan rate however is actually limited by  
the natural heating or cooling rate of the instrument. This will be less than  
10°C/min.  
The scan rate function appears in the main menu after the scan control function.  
The scan rate units are in degrees per minute, degrees C or F depending on the  
selected units.  
Scan rate in°C/min  
Press “UP” or “DOWN” to change the scan rate.  
New scan rate  
Sr= 5.0  
Sr= 2.0  
38  
 
 
9 Controller Operation  
Press “SET” to accept the new scan rate and continue.  
Accept scan rate  
S
9.4  
9.5  
Secondary Menu  
Functions which are used less often are accessed within the secondary menu.  
The secondary menu is accessed by pressing “SET” and “EXIT” simulta-  
neously and then releasing. The first function in the secondary menu is the  
heater power display. (See Figure 4 on page 36.)  
Heater Power  
The temperature controller controls the temperature of the bath by pulsing the  
heater on and off. The total power being applied to the heater is determined by  
the duty cycle or the ratio of heater on time to the pulse cycle time. By knowing  
the amount of heating the user can tell if the calibrator is heating up to the  
set-point, cooling down, or controlling at a constant temperature. Monitoring  
the percent heater power will let the user know how stable the bath temperature  
is.  
The heater power display is accessed in the secondary menu. Press “SET” and  
“EXIT” simultaneously and release. The heater power will be displayed as a  
percentage of full power.  
Bath temperature  
10.00C  
Access heater power in secondary menu  
Flashes  
S+E  
SEC  
Heater power in percent  
12.0 P  
To exit out of the secondary menu hold “EXIT”. To continue on to the propor-  
tional band setting function press “EXIT” momentarily or “SET”.  
9.6  
Proportional Band  
In a proportional controller such as this the heater output power is proportional  
to the well temperature over a limited range of temperatures around the  
set-point. This range of temperature is called the proportional band. At the bot-  
tom of the proportional band the heater output is 100%. At the top of the pro-  
portional band the heater output is 0. Thus as the temperature rises the heater  
power is reduced, which consequently tends to lower the temperature back  
39  
 
 
9 Controller Operation  
down. In this way the temperature is maintained at a fairly constant  
temperature.  
The temperature stability of the bath and response time depend on the width of  
the proportional band. If the band is too wide the temperature will deviate ex-  
cessively from the set-point due to varying external conditions. This is because  
the power output changes very little with temperature and the controller cannot  
respond very well to changing conditions or noise in the system. If the propor-  
tional band is too narrow the temperature may swing back and forth because  
the controller overreacts to temperature variations. For best control stability the  
proportional band must be set for the optimum width. This value is usually two  
to three times the largest value at which the bath temperature oscillates.  
The proportional band width is set at the factory to a value between 0.5 and  
1.0°C. The proportional band width may be altered by the user if he desires to  
optimize the control characteristics for a particular application.  
The proportional band width is easily adjusted from the front panel. The width  
may be set to discrete values in degrees C or F depending on the selected units.  
The proportional band adjustment is be accessed within the secondary menu.  
Press “SET” and “EXIT” to enter the secondary menu and show the heater  
power. Then press “SET” to access the proportional band.  
Access heater power in secondary menu  
S+E  
Heater power in percent  
12.0 P  
Access proportional band  
S
ProP  
15.0  
Flashes “ProP” and the setting  
Proportional band setting  
To change the proportional band press “UP” or “DOWN”.  
New proportional band setting  
1.5  
To store the new setting press “SET”. Press “EXIT” to continue without storing  
the new value.  
Accept the new proportional band setting  
S
40  
 
9 Controller Operation  
9.7  
Cutout  
As a protection against software or hardware fault or user error, the bath is  
equipped with an adjustable cutout device that shuts off power to the heater if  
the temperature exceeds a set value. This protects the instrument, probes, and  
fluid from excessive temperatures. The cutout temperature is programmable by  
the operator from the front panel of the controller. The cutout should be set to  
the temperature limits of the selected fluid.  
If the cutout is activated because of excessive temperature, power to the heater  
shuts off and the instrument cools. The bath cools until it reaches a few degrees  
below the cutout set-point temperature. At this point the cutout resets and al-  
lows normal operation.  
The cutout set-point may be accessed within the secondary menu. Press “SET”  
and “EXIT” to enter the secondary menu and show the heater power. Then  
press “SET” twice to access the cutout set-point.  
Access heater power in secondary menu  
S+E  
12.0 P  
Heater power in percent  
Proportional band setting  
Access proportional band  
S
Pb= 0.05C  
Access cutout set-point  
Cutout set-point  
To change the cutout set-point press “UP” or “DOWN”.  
New cutout set-point  
S
CO= 80C  
CO= 70C  
To accept the new cutout set-point press “SET”.  
Accept cutout set-point  
S
The next function is the configuration menu. Press “EXIT” to resume display-  
ing the temperature.  
41  
 
 
9 Controller Operation  
9.8  
Controller Configuration  
The controller has a number of configuration and operating options and calibra-  
tion parameters which are programmable via the front panel. These are ac-  
cessed from the secondary menu after the proportional band function by  
pressing “SET”. Pressing “SET” again enters the first of three sets of configu-  
ration parameters: operating parameters, serial interface parameters, and cali-  
bration parameters. The menus are selected using the “UP” and “DOWN” keys  
and then pressing “SET”. (See Figure 4 on page 36.)  
9.9  
Operating Parameters  
The operating parameters menu is indicated by,  
Operating parameters menu  
PAr  
The operating parameters menu contains the High Limit, Stir Speed, and Cool-  
ing parameters.  
9.9.1  
High Limit  
The High Limit Parameter adjusts the upper set-point temperature. The factory  
default and maximum temperature are set to 100°C. For safety, a user can ad-  
just the High Limit down so the maximum temperature set-point is restricted.  
HL  
High Limit parameter  
Press “SET” to enable adjustment of HL.  
HL  
Flashes “HL” and then displays the setting  
Current HL setting  
H=100  
Adjust the HL parameter using “UP” or “DOWN”.  
New HL setting  
H=90  
Press “SET” to accept the new temperature limit.  
9.9.2  
Low Limit  
The Low Limit (LL) Parameter adjusts the lower set-point temperature limit.  
The factory default and minimum temperature are set to –90°C. For safety, a  
user can adjust the Low Limit up so the minimum temperature set-point is  
restricted.  
42  
 
 
9 Controller Operation  
LL  
Low Limit parameter  
Press “SET” to enable adjustment of LL.  
LL  
Flashes “ ” and then displays the setting  
Current LL setting  
L=-90  
Adjust the LL parameter using “UP” or “DOWN”.  
New LL setting  
L=-20  
Press “SET” to accept the new temperature limit.  
9.9.3  
Cooling  
This menu function allows the operator to disable cooling and corresponds to  
the remote cooling control function (see Table 3). Switching the cooling off  
temporarily allows the bath to heat up more quickly from a low temperature.  
Cooling can be manually switched off using the cooling switch on the front  
panel or automatically switched off any time the bath temperature or set-point  
is higher than about 35°C. As a result, cooling is ON only if the cooling func-  
tion is ON, the cooling switch is ON, and both the bath temperature and the  
set-point are less than about 35°C. The cooling function is indicated by,  
CooL  
Flashes “CooL” and then displays the setting  
Current cooling setting  
CooL=OFF  
The setting may be changed using “UP” or “DOWN” and pressing “SET”.  
New cooling setting  
CooL=On  
9.10  
Serial Interface Parameters  
The serial RS-232 interface parameters menu is indicated by,  
Serial RS-232 interface parameters menu  
SErIAL  
The serial interface parameters menu contains parameters which determine the  
operation of the serial interface. These controls only apply to instruments fitted  
with the serial interface. The parameters in the menu are — BAUD rate, sample  
period, duplex mode, and linefeed. Press “UP” to enter the menu.  
43  
 
 
9 Controller Operation  
9.10.1  
Baud Rate  
The baud rate is the first parameter in the menu. The baud rate setting deter-  
mines the serial communications transmission rate.  
The baud rate parameter is indicated by,  
Flashes “  
” and then displays the stetting  
bAUd  
Current BAUD rate  
2400 b  
The baud rate of the serial communications may be programmed to 300, 600,  
1200, 2400, 4800, or 9600 baud. Use “UP” or “DOWN” to change the baud  
rate value.  
New BAUD rate  
4800 b  
Press “SET” to set the baud rate to the new value or “EXIT” to abort the opera-  
tion and skip to the next parameter in the menu.  
9.10.2  
Sample Period  
The sample period is the next parameter in the serial interface parameter menu.  
The sample period is the time period in seconds between temperature measure-  
ments transmitted from the serial interface. If the sample rate is set to 5, the in-  
strument transmits the current measurement over the serial interface  
approximately every five seconds. The automatic sampling is disabled with a  
sample period of 0. The sample period is indicated by,  
Flashes “SPEr” and then displays the setting  
Current sample period (seconds)  
SPer  
SP= 1  
Adjust the value with “UP” or “DOWN” and then use “SET” to store the sam-  
ple rate to the displayed value. “EXIT” does not store the new value.  
New sample period  
SP= 60  
9.10.3  
Duplex Mode  
The next parameter is the duplex mode. The duplex mode may be set to full du-  
plex or half duplex. With full duplex any commands received by the calibrator  
via the serial interface are immediately echoed or transmitted back to the device  
of origin. With half duplex the commands are executed but not echoed. The du-  
plex mode parameter is indicated by,  
44  
 
 
9 Controller Operation  
Flashes “dUPL” and then displays the setting  
Current duplex mode setting  
dUPL  
d=FULL  
The mode may be changed using “UP” or “DOWN” and pressing “SET”.  
New duplex mode setting  
d=HALF  
9.10.4  
Linefeed  
The final parameter in the serial interface menu is the linefeed mode. This pa-  
rameter enables (on) or disables (off) transmission of a linefeed character (LF,  
ASCII 10) after transmission of any carriage-return. The linefeed parameter is  
indicated by,  
Flashes “LF” and then displays the setting  
Current linefeed setting  
LF  
LF= On  
The mode may be changed using “UP” or “DOWN” and pressing “SET”.  
New linefeed setting  
LF= OFF  
9.11  
Calibration Parameters  
The operator of the CTR –80 controller has access to the Hard Cutout and a  
number of the bath calibration constants namely R0, ALPHA, DELTA, and  
BETA. These values are set at the factory and should not be altered. The cor-  
rect values are important to the accuracy and proper and safe operation of the  
bath. Access to these parameters is available to the user only so that in the  
event that the controller memory fails the user may restore these values to the  
factory settings. The user should have a list of these constants and their settings  
with the manual.  
Caution: DO NOT change the values of the bath calibration constants  
from the factory set values. The correct setting of these parameters is im-  
portant to the safety and proper operation of the bath.  
The calibration parameters menu is indicated by:  
CAL  
Calibration parameters menu  
Press “SET” five times to enter the menu.  
45  
 
 
9 Controller Operation  
The calibration parameters R0, ALPHA, DELTA, and BETA characterize the  
resistance-temperature relationship of the platinum control sensor. These pa-  
rameters may be adjusted by an experienced user to improve the accuracy of  
the bath.  
9.11.1  
Hard Cutout  
This parameter is the temperature above which the unit shuts down automati-  
cally. The parameter is set at the factory to approximately 120°C and can be  
changed only through the variable resistor. This parameter cannot be changed  
through the instrument menu or the communications port and is user settable.  
9.11.2  
9.11.3  
R0  
This probe parameter refers to the resistance of the control probe at 0°C. The  
value of this parameter is set at the factory for best instrument accuracy.  
ALPHA  
This probe parameter refers to the average sensitivity of the probe between 0  
and 100°C. The value of this parameter is set at the factory for best instrument  
accuracy.  
9.11.4  
9.11.5  
DELTA  
This probe parameter characterizes the curvature of the resistance-temperature  
relationship of the sensor. The value of this parameter is set at the factory for  
best instrument accuracy.  
BETA  
This probe parameter characterizes the low temperatures. The value of this pa-  
rameter is set at the factory for best instrument accuracy.  
46  
 
 
10 Digital Communication Interface  
10  
Digital Communication Interface  
The CTR –80 Bath calibrator is capable of communicating with and being con-  
trolled by other equipment through the digital serial interface.  
With a digital interface the instrument may be connected to a computer or other  
equipment. This allows the user to set the set-point temperature, monitor the  
temperature, and access any of the other controller functions, all using remote  
communications equipment. Communications commands are summarized in  
Table 3 on page 50.  
10.1  
Serial Communications  
The bath is installed with an RS-232 serial interface that allows serial digital  
communications over fairly long distances. With the serial interface the user  
may access any of the functions, parameters and settings discussed in Section 9  
with the exception of the baud rate setting.  
47  
 
 
10 Digital Communication Interface  
10.1.1  
Wiring  
The serial communications ca-  
ble attaches to the calibrator  
through the DB-9 connector at  
the back of the instrument. Fig-  
ure 5 shows the pin-out of this  
connector and suggested cable  
wiring. To eliminate noise the  
serial cable should be shielded  
with low resistance between the  
connector (DB-9) and the  
shield. If the unit is used in a  
heavy industrial setting, the se-  
rial cable must be limited to  
ONE METER in length.  
RS-232 Cable Wiring for  
IBM PC and Compatibles  
Instrument  
Connector  
(DB 9-Pin)  
Computer (DTE)  
Connector  
(DB 9-Pin)  
1 NC  
1 DCD  
2 RxD  
3 TxD  
4 DTR  
5 GND  
6 DSR  
7 RTS  
8 CTS  
9 NC  
2 RxD  
3 TxD  
4 NC  
5 GND  
6 NC  
7 RTS  
8 CTS  
9 NC  
Instrument  
Connector  
(DB 9-Pin)  
Computer (DTE)  
Connector  
10.1.2  
Setup  
(DB 25-Pin)  
Before operation the serial in-  
terface must first be set up by  
programming the baud rate and  
other configuration parameters.  
These parameters are pro-  
grammed within the serial inter-  
face menu. The serial interface  
parameters menu is outlined in  
Figure 4 on page 36.  
1 NC  
2 RxD  
3 TxD  
4 NC  
2 TxD  
3 RxD  
4 RTS  
5 CTS  
5 GND  
6 NC  
6 DSR  
7 GND  
8 DCD  
20 DTR  
7 RTS  
8 CTS  
9 NC  
Figure 5 Serial Cable Wiring  
To enter the serial parameter  
programming mode first press “EXIT” while pressing “SET” and release to en-  
ter the secondary menu. Press “SET” repeatedly until the display reads “PAr”.  
Press “UP” until the serial interface menu is indicated with“SErIAL”. Finally  
press “SET” to enter the serial parameter menu. In the serial interface parame-  
ters menu are the baud rate, the sample rate, the duplex mode, and the linefeed  
parameter.  
10.1.2.1  
Baud Rate  
The baud rate is the first parameter in the menu. The display prompts with the  
baud rate parameter by showing “bAUd”. Press “SET” to choose to set the  
baud rate. The current baud rate value is displayed. The baud rate of the instru-  
ment serial communications may be programmed to 300, 600, 1200, 2400,  
4800, or 9600 baud. The baud rate is pre-programmed to 2400 baud. Use “UP”  
or “DOWN” to change the baud rate value. Press “SET” to set the baud rate to  
the new value or “EXIT” to abort the operation and skip to the next parameter  
in the menu.  
48  
 
 
10 Digital Communication Interface  
10.1.2.2  
Sample Period  
The sample period is the next parameter in the menu and prompted with  
SPEr”. The sample period is the time period in seconds between temperature  
measurements transmitted from the serial interface. If the sample rate is set to  
5, the instrument transmits the current measurement over the serial interface ap-  
proximately every five seconds. The automatic sampling is disabled with a  
sample period of 0. Press “SET” to choose to set the sample period. Adjust the  
period with “UP” or “DOWN” and then use “SET” to set the sample rate to the  
displayed value.  
10.1.2.3  
Duplex Mode  
The next parameter is the duplex mode indicated with “dUPL”. The duplex  
mode may be set to half duplex (“HALF”) or full duplex (“FULL”). With full  
duplex any commands received by the thermometer via the serial interface are  
immediately echoed or transmitted back to the device of origin. With half du-  
plex the commands are executed but not echoed. The default setting is half du-  
plex. The mode may be changed using “UP” or “DOWN” and pressing “SET”.  
10.1.2.4  
10.1.3  
Linefeed  
The final parameter in the serial interface menu is the linefeed mode. This pa-  
rameter enables (“On”) or disables (“OFF”) transmission of a linefeed charac-  
ter (LF, ASCII 10) after transmission of any carriage-return. The default setting  
is linefeed off. The mode may be changed using “UP” or “DOWN” and press-  
ing “SET”.  
Serial Operation  
Once the cable has been attached and the interface set up properly the control-  
ler will immediately begin transmitting temperature readings at the pro-  
grammed rate. The serial communications uses 8 data bits, one stop bit, and no  
parity. The set-point and other commands may be sent via the serial interface to  
set the temperature set-point and view or program the various parameters. The  
interface commands are discussed in Section10.2. All commands are ASCII  
character strings terminated with a carriage-return character (CR, ASCII 13).  
10.2  
Interface Commands  
The various commands for accessing the calibrator functions via the digital in-  
terfaces are listed in this section (see Table 3). These commands are used with  
the RS-232 serial interface. The commands are terminated with a carriage-re-  
turn character. The interface makes no distinction between upper and lower  
case letters, hence either may be used. Commands may be abbreviated to the  
minimum number of letters which determines a unique command. A command  
may be used to either set a parameter or display a parameter depending on  
49  
 
 
10 Digital Communication Interface  
Table 3 Controller Communications Commands  
Command  
Format  
Command  
Example  
Returned  
Example  
Acceptable  
Values  
Command Description  
Display Temperature  
Read current set-point  
Set current set-point to n  
Returned  
s[etpoint]  
s
set: 999.99 {C or F}  
set: 90.00 C  
s[etpoint]=n  
s=80.00  
Instrument  
Range  
Read temperature  
t[emperature]  
u[nits]  
t
t: 999.99 {C or F}  
u: x  
t: 55.6 C  
u: C  
Read temperature units  
u
C or F  
Set temperature units to Celsius  
u[nits]=c  
u[nits]=f  
u=c  
u=f  
Set temperature units to  
Fahrenheit  
Read scan mode  
sc[an]  
sc  
scan: {ON or OFF}  
scan:ON  
Set scan mode  
sc[an]=on/off  
sr[ate]  
sc=on  
sr  
ON or OFF  
.1 to 99.9  
Read scan rate  
srat: 99.9 {C or F}/min srat:12.4C/min  
Set scan rate  
sr[ate]=n  
sr=1.1  
Secondary Menu  
Read proportional band setting  
Set proportional band to n  
pr[opband]  
pr  
pb: 999.9  
pb: 15.9  
pr[opband]=n  
pr=8.83  
Depends on  
Configuration  
Read cut-out setting  
cu[tout]  
cu  
cu:9999 {C or F}  
po: 999.9  
cu:105 C, in  
po: 1.0  
cu-95  
po  
25 to 115°C  
Set cut-out setting to n degrees  
cu[tout]=n  
po[wer]  
Read heater power  
(duty cycle)  
Configuration Menu  
Read high limit  
Set high limit  
hl  
hl  
hl:999  
hl:126  
ll:-90  
hl=n  
hl=90  
ll  
25 to 100  
–90 to 25  
ON or OFF  
Read low limit  
Set low limit  
ll  
ll:999  
ll=n  
ll=-90  
co  
Read cooling setting  
Set cooling setting  
co[ol]  
cool: {ON or OFF}  
cool: ON  
co[ol]=on/of[f]  
co=on  
Read serial sample setting  
sa[mple]  
sa  
sa: 9  
sa: 1  
sa[mple]=n  
sa=0  
0 to 999  
Set serial sampling setting to n  
seconds  
FULL or HALF  
Set serial duplex mode to full  
Set serial duplex mode to half  
du[plex]=f[ull]  
du[plex]=h[alf]  
du=f  
du=h  
50  
 
 
10 Digital Communication Interface  
Controller Communications Commands continued  
Command  
Format  
Command  
Example  
Returned  
Example  
Acceptable  
Values  
Command Description  
Returned  
ON or OFF  
Set serial linefeed mode to on  
Set serial linefeed mode to off  
lf[eed]=on  
lf=on  
lf=of  
lf[eed]=of[f]  
Read R0 calibration parameter  
r[0]  
r
r0: 999.999  
r0: 100.578  
r[0]=n  
r=100.324  
al  
90 to 110  
Set R0 calibration parameter to n  
Read ALPHA calibration parameter al[pha]  
al: 9.9999999  
al: 0.0038573  
Set ALPHA calibration parameter al[pha]=n  
al=0.0038433  
.002 to .005  
to n  
Read DELTA calibration parameter de[lta]  
Set DELTA calibration parameter de[lta]=n  
Read BETA calibration parameter be[ta]  
de  
de:9.99999  
be:99.999  
de: 1.507  
be:03427  
de=1.3742  
be  
0–3.0  
Set BETA calibration parameter  
be[ta]=n  
be=0.342  
–20 to 20  
Read firmware version number  
Read structure of all commands  
Read all operating parameters  
Legend:  
*ver[sion]  
*ver  
h
ver.9999,9.99  
ver.7103,2.00  
h[elp]  
list of commands  
list of parameters  
all  
all  
[] Optional Command data  
{} Returns either information  
n Numeric data supplied by user  
9 Numeric data returned to user  
x Character data returned to user  
Note:  
When DUPLEX is set to FULL and a command is sent to READ, the command is returned followed by a car-  
riage return and linefeed. Then the value is returned as indicated in the RETURNED column.  
whether or not a value is sent with the command following a “=” character. For  
example “s”<CR> will return the current set-point and “s=150.0”<CR> will set  
the set-point to 150.0 degrees.  
In the following list of commands, characters or data within brackets, “[” and  
“]”, are optional for the command. A slash, “/”, denotes alternate characters or  
data. Numeric data, denoted by “n”, may be entered in decimal or exponential  
notation. Characters are shown in lower case although upper case may be used.  
Spaces may be added within command strings and will simply be ignored.  
Backspace (BS, ASCII 8) may be used to erase the previous character. A termi-  
nating CR is implied with all commands.  
51  
 
 
11 Calibration Procedure  
11  
Calibration Procedure  
11.1  
Calibration Procedure  
Calibration of this instrument should be performed at regularly scheduled inter-  
vals by qualified authorized personnel in accordance with your company’s pol-  
icy. Following is the recommended procedure for calibrating this instrument.  
11.1.1  
11.1.2  
Calibration Equipment  
Calibration requires a standard thermometer that is adequately accurate and fits  
properly into one of the reference holes in the block. Recommended equipment  
includes a laboratory grade PRT with a length of 30 to 300 mm (9 to 12 inches)  
and a diameter of 4.76 or 6.35 mm (3/16 or 1/4 inches). The combined accu-  
racy of the PRT and the readout which used to display the temperature should  
be 0.025°C or better.  
Calibration  
The accuracy of the instrument over the full range is determined by the values  
of the calibration parameters R0, ALPHA, DELTA, and BETA. The calibration  
procedure involves measuring the error between the instrument and the refer-  
ence thermometer at several temperature throughout the range and adjusting the  
calibration parameters as necessary to reduce the errors to within acceptable  
limits. The stated accuracy of the instrument can be found in the specification  
table in Section 3.1. Because of the way the calibration parameters affect the  
temperature the simplest way to proceed is to measure the errors at 0°C, 100°C,  
50°C, and –70°C and adjust R0, ALPHA, DELTA, and BETA at each point re-  
spectively. Be aware that you must use the appropriate fluid at each tempera-  
ture. Follow these steps:  
Set the set-point to 0°C and allow adequate time for the bath to reach this  
temperature and stabilize. Adjust the R0 calibration parameter (see Sec-  
tion 9.11.2) to make the bath temperature as measured with the standard  
thermometer match the set-point. The approximate ratio between a  
change in R0 and a change in temperature at 0°C is about 0.4 to 1. For ex-  
ample, if the bath temperature is high by 0.1°C at 0°C then decrease R0  
by 0.04.  
Set the set-point to 100°C and allow adequate time for the bath to reach  
this temperature and stabilize. Adjust the ALPHA calibration parameter  
(see Section 9.11.3) to make the bath temperature as measured with the  
standard thermometer match the set-point. The approximate ratio between  
a change in ALPHA and a change in temperature at 100°C is about  
0.00004 to 1. For example, if the bath temperature is high by 0.1°C at  
100°C then decrease ALPHA by 0.000004.  
53  
 
 
11 Calibration Procedure  
Set the set-point to 50°C and allow adequate time for the bath to reach  
this temperature and stabilize. Adjust the DELTA calibration parameter  
(see Section 9.11.4) to make the bath temperature as measured with the  
standard thermometer match the set-point. The approximate ratio between  
a change in DELTA and a change in temperature at 50°C is about 4.0 to 1.  
For example, if the bath temperature is high by 0.1°C at 50°C then de-  
crease DELTA by 0.4.  
Set the set-point to –70°C and allow adequate time for the bath to reach  
this temperature and stabilize. Adjust the BETA calibration parameter  
(see Section 9.11.5) to make the bath temperature as measured with the  
standard thermometer match the set-point. The approximate ratio between  
a change in BETA and a change in temperature at –70°C is about –1.0 to  
1. For example, if the bath temperature is high by 0.1°C at –70°C then in-  
crease BETA by 0.1.  
54  
 
12 Maintenance  
12  
Maintenance  
The calibration instrument has been designed with the utmost care. Ease  
of operation and simplicity of maintenance have been a central theme in  
the product development. Therefore, with proper care the instrument  
should require very little maintenance. Avoid operating the instrument in  
dirty or dusty environments.  
If the outside of the bath becomes soiled, it may be wiped clean with a  
damp cloth and mild detergent. Do not use harsh chemicals on the surface  
which may damage the paint.  
Periodically check the fluid level in the bath to ensure that the level has  
not dropped. A drop in the fluid level affects the stability of the bath.  
Changes in fluid level are dependent upon several factors specific to the  
environment in which the equipment is used. A schedule cannot be out-  
lined to meet each environmental setting. Therefore, the first year the bath  
should be checked weekly with notes kept as to changes in bath fluid. Af-  
ter the first year, the user can set up a maintenance schedule based on the  
data specific to the application.  
Heat transfer medium lifetime is dependent upon the type of medium and  
the environment. The fluid should be checked at least every month for the  
first year and regularly thereafter. This fluid check provides a baseline for  
knowledge of bath operation with clean, usable fluid. Once some fluids  
have become compromised, the break down can occur rapidly. Particular  
attention should be paid to the viscosity of the fluid. A significant change  
in the viscosity can indicate that the fluid is contaminated, being used out-  
side of its temperature limits, contains ice particles, or is close to a chemi-  
cal break-down. Once data has been gathered, a specific maintenance  
schedule can be outline for the instrument. Refer to the General Operation  
section (Section 8) for more information about the different types of flu-  
ids used in calibration baths.  
If a hazardous material is spilt on or inside the equipment, the user is re-  
sponsible for taking the appropriate decontamination steps as out-lined by  
the national safety council with respect to the material. MSDS sheets ap-  
plicable to all fluids used in the baths should be kept in close proximity to  
the instrument.  
If the mains supply cord becomes damaged, replace it with a cord with  
the appropriate gauge wire for the current of the bath. If there are any  
questions, call GE Kaye Instruments Customer Service for more informa-  
tion.  
Before using any cleaning or decontamination method except those rec-  
ommended by Kaye, users should check with GE Kaye Instruments Cus-  
55  
 
 
12 Maintenance  
tomer Service to be sure that the proposed method will not damage the  
equipment.  
The condensing coil should be cleaned regularly. Inspect the coil through  
the vented rear panel. If any dust or dirt accumulation is visible, remove  
the rear panel to clean out the dust or dirt. Use a vacuum with a brush to  
remove the dirt. Do not use compressed air as it might drive the dirt be-  
tween the fins where it may become lodged preventing airflow.  
If the instrument is used in a manner not in accordance with the equip-  
ment design, the operation of the bath may be impaired or safety hazards  
may arise.  
56  
 
13 Trouble Shooting  
13  
Trouble Shooting  
If problems arise while operating the CTR –80, this section provides some sug-  
gestions that may help you solve the problem. A wiring diagram is also  
included.  
13.1  
Troubleshooting  
Below are several situations that may arise followed by suggested actions to  
take for fixing the problem.  
Incorrect Temperature Reading  
Power the unit on and watch the display. If the first number displayed is  
less than “-0005-”, the unit has been re-initialized. The unit needs to be  
reprogrammed for R0, ALPHA, DELTA, and BETA. These numbers can  
be found on the Report of Calibration that was shipped with the unit.  
The unit heats slowly  
Check the Scan and Scan Rate settings. The Scan may be on with the  
Scan Rate set low.  
If the display flashes any of the following:  
“err 1" - This error means there is a RAM error  
“err 2" - This error means there is a NVRAM error  
“err 3" - This error means there is a RAM error  
“err 4" - This error means there is an ADC set up error  
“err 5" - This error means there is an ADC ready error  
“err 6" - This error means there is a SENSOR error  
“err 7" - This error means there is a HtrCTL error  
Cycle the power off and on again. If the unit repeats the error code, con-  
tact GE Kaye Instruments Customer Support for a return authorization  
and for assistance.  
The bath does not turn on  
If a fault condition exists upon application of power, the bath will not en-  
ergize.  
This bath needs to be plugged into the line voltage for at least 2 minutes  
before turning power on. This is only necessary for the first time that the  
bath is energized or when it is moved from one location to another.  
57  
 
 
13 Trouble Shooting  
If a High/Low voltage condition exists for longer than 5 seconds, the  
compressor will be de-energized. The controller display will flash “Lo  
LinE“ o and off while the condition exists.  
Re-energization is automatic upon correction of the fault condition and af-  
ter a delay cycle of about 2 minutes.  
High and Low Voltage Protection at 115 VAC  
Voltage Cutout: +/- 12.5 % (101 - 129 VAC)  
Voltage Cut-In: +/- 7.5 % (106 - 124 VAC)  
High and Low Voltage Protection at 230 VAC  
Voltage Cutout: +/- 12.5 % (203 - 257 VAC)  
Voltage Cut-In: +/- 7.5 % (213 - 247 VAC)  
See the Caution in the front of this manual for additional information.  
13.2  
CE Comments  
13.2.1  
EMC Directive  
This instrument has been tested to meet the European Electromagnetic Compat-  
ibility Directive ( EMC Directive, 89/336/EEC). The Declaration of Confor-  
mity for your instrument lists the specific standards to which the unit was  
tested.  
13.2.2  
Low Voltage Directive (Safety)  
In order to comply with the European Low Voltage Directive (73/23/EEC), this  
instrument has been designed to meet the IEC 1010-1 (EN 61010-1) and IEC  
1010-2-010 (EN 61010-2-010) standards.  
58  
 
 
13 Trouble Shooting  
13.3  
Wiring Diagram  
2 2 G r n  
W 5 5  
S H L D  
W H T  
W H T  
R E D  
R E D  
2 2  
l
Y e  
W 5 4  
M T 1  
G
M T 2  
1 6  
W h t / O r g / B l k  
1 6  
W h t / O r g  
6 1 G r y  
W25  
Vio 18  
W 4 0  
1 6  
1 6  
i o / B l k W h t / V  
i o / B l k W h t / V  
W 3 9  
W 3 8  
1 4 i o  
W h t / V  
N C  
N O  
C O M  
L 1  
1 8 l / B e l k W h t / Y  
8 1  
B l u e  
1 1 5 V L 2  
2 3 0 V 2  
L
1 8  
B r o w n  
4 1 l  
e
G r e e n / Y  
1 4  
4 1  
B r o w n  
B l u e  
Figure 6 Wiring Diagram  
59  
 
 

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