Black Box Network Card 945 User Manual

How To Use  
Data Communications  
with the Watlow  
Series 945  
User's Manual  
Watlow Controls, 1241 Bundy Blvd., P.O.Box 5580, Winona, MN 55987-5580, Phone: 507/454-5300, Fax: 507/452-4507  
$5.00  
W945-SA50-9210  
March, 1992  
Supersedes:  
W945-SA40-9119  
Made in the U.S.A.  
Printed on Recycled Paper  
 
Data Comm  
How to Use Data Communications  
with the Watlow Series 945  
This manual is a supplement to the Series 945 User's Manual. It is for users with  
the data communications option. Use in conjunction with the Series 945 User's  
Manual.  
This is expert user-level material and requires previous experience with data  
communications.  
Two Serial Hardware Interfaces and  
Two Software Protocols  
Depending on your units model number, you may have one of two hardware  
interfaces:  
1)RS-422A for a "multidrop" or (multiple device) network, up to ten devices total;  
with 4000 ft. network length limit, or RS-423A (RS-232C compatible) for one on  
one communication with a 50 ft. network length limit with a 945 and a host  
computer (945A-XXXX--B000). Selecting RS-422A or RS-423A is user select-  
able via internal switches. See Page 7.  
2)EIA-485 (945A-XXXX-D000) also for a multidrop network, up to 32  
addresses total, and with a 4000 ft. network length limit.  
There are two protocols available to you. Depending on the type of network you  
need, you must use the correct combination of interface and protocol.  
We use ANSI X3.28 Protocol, based on ANSI X3.28 - 1976 Subcategories 2.2,  
and A3, with the RS-422A and EIA-485 interface to run a multiple device network.  
We also use XON/XOFF Protocol, a simpler protocol, to run a two device network  
with an RS-423A interface. XON/XOFF will also work with the RS-422A and EIA-  
485 interface, but the network is limited to two devices (one computer or printer  
and a Series 945). XON/XOFF Protocol requires no responses to messages like  
the ANSI X3.28 Protocol does. Likewise, ANSI X3.28 Protocol, which provides a  
response to every message, will work with the RS-423 interface. But again you are  
limited to one Series 945 and a host computer or printer.  
To select which protocol you are going to use, go into the SETUP menu and use  
the MODE key to advance to the Prot parameter. Select either FULL, for ANSI  
X3.28 2.2 - A.3, or On for XON - XOFF.  
If you are using ANSI X3.28 Protocol, choose an address number for the control  
under the Addr parameter following the Prot parameter. This parameter will only  
appear if Prot = FULL.  
Communications Wiring  
To connect your Series 945 to a computer or printer, use the next three pages as a  
reference. Your computer or printer hardware manual will provide more detailed  
serial port pin information. Also refer to the noise prevention section in Appendix 1  
of the Series 945 User's Manual. In the often noisy environments of industrial  
locations, it is important not to take noise isolation lightly.  
3
WATLOW Series 945  
How to Use Data Communications  
 
RS-422A  
RS-422A Interface Pinouts  
945A-XXXX-B000  
The RS-422A communications uses a four wire (full duplex) system. There are  
two separate lines for transmitting, and two lines for receiving data between the  
computer and the Series 945. With RS-422A you can have from one to ten Series  
945 controls connected to a single computer.  
This diagram is a typical wiring example. The connections on the host computer  
may vary depending on models. Refer to your computer user's manual for more  
information.  
Figure 1 -  
RS-422A Interface,  
Pin Designations.  
Twisted Pair Wire  
T +  
19  
20  
T -  
R +  
21  
22  
R -  
Signal Common  
(Optional)  
Series 945  
#1  
23  
Host Computer  
(rear view)  
Twisted Pair Wire  
T +  
T -  
19  
20  
21  
R +  
R -  
22  
Signal Common  
(Optional)  
Series 945  
#10 23  
DB-9 female  
connector  
(viewed from wire side)  
Com  
R +  
R -  
T -  
T +  
NOTE:  
The Electronic  
Industry Association  
(EIA) RS-422A  
standard recom-  
mends a maximum  
4000 ft. total network  
distance.  
4
How to Use Data Communications  
 
WATLOW Series 945  
RS-423A  
RS-423A Interface Pinouts (RS-232C Compatible)  
945A-XXXX-B000  
The RS-423A communications uses a three wire (full duplex) system. There is a  
separate line for transmitting, a line for receiving data, and a line for signal common  
between the computer and the Series 945. With RS-423A you can have only one  
Series 945 control connected to a single computer or printer.  
This diagram is a typical wiring example. The connections on the host computer  
may vary depending on models. Refer to your computer user's manual for more  
information.  
Host Computer  
(rear view)  
Figure 2 -  
RS-423A Interface,  
Pin Designations.  
DB-25 female  
connector  
T
(viewed from wire side)  
R
RTS (Request To Send)  
CTS (Clear To Send)  
DSR (Data Set Ready)  
Com  
R, and RLSD together.  
DTR (Data Terminal Ready)  
RLSD (Received Line Signal Detector)  
S and CTS together.  
mputer's user manual.  
T
20  
Jumper to Signal Common  
21  
R
22  
Signal Common  
945  
#1 23  
NOTE:  
The Electronic  
Industry Association  
(EIA) RS-423A  
standard recom-  
mends a maximum  
50 foot total point-  
to-point distance.  
5
WATLOW Series 945  
How to Use Data Communications  
 
EIA-485  
EIA-485 Interface Pinouts  
945A-XXXX-D000  
The EIA-485 communications uses a two wire (half duplex) system. There are only  
two lines, both lines used for transmitting and receiving. Only one device, the  
computer or the control, can be speaking at a time. There is a 1 millisecond delay  
requried for the Series 945 to go between transmission and receipt of data. With  
EIA-485 you can have from one to thirty-two Series 945 controls connected to a  
computer.  
Figure 3 -  
EIA-485 Interface, Pin  
Designations.  
This diagram is a typical wiring example. The connections on the host computer  
may vary depending on models. Refer to your computer user's manual for more  
information.  
Twisted Pair Wire  
T+/R+  
19  
20  
T-/R-  
Signal Common  
(Optional)  
Series 945  
#1  
23  
Host Computer  
(rear view)  
Twisted Pair Wire  
T+/R+  
19  
T-/R-  
20  
Signal Common  
(Optional)  
Series 945  
23  
#32  
DB-9 female  
connector  
Com  
(viewed from wire side)  
T-/R-  
+/R+  
T+/R+  
/R-  
NOTE:  
The Electronic  
Industry Association  
EIA-485 standard  
recommends a  
maximum 4000 ft.  
total network dis-  
tance.  
Connecting the Control and the Computer  
Remove power from both the Series 945 and your computer or printer before  
connecting them together. This prevents noise or static interference from entering  
the data communication lines. Assemble a cable and the appropriate wiring at your  
computer or printer. Refer to the wiring on Page 4 through 6. As soon as you  
connect the data communications line(s), you're ready to apply power to your  
system.  
6
How to Use Data Communications  
WATLOW Series 945  
 
Configuration  
(Up) RS-423A  
A  
(Down) RS-422A  
Figure 4 -  
RS-422A/RS-423A  
Switch Selection.  
A007-1830  
NOTE:  
The Series 945  
leaves the factory in  
RS-423A operation (C1).  
How to Set the Hardware Protocol Switches  
for 945A-XXXX-B000 Units Only  
The RS-422/RS-423 switches are on the Communication Module Board (A007-  
1830). Figure 4 shows the location of this board. You can select C1 for RS-423 or  
C2 for RS-422 operation. Both switches must be set the same for the desired  
protocol.  
To change the position of a switch, remove the power from the Series 945 and turn  
the front panel locking screw 90° counterclockwise. To remove the control chas-  
Control Chassis - Top View  
sis, grip the front panel bezel and pull it straight out from the control case. Set the  
switches, C1 (towards you for RS-423) or C2 (away from you for RS-422) then  
return the control chassis to the case. Be sure it is oriented correctly. Press firmly,  
but gently, to seat the chassis. Secure the front panel locking screw and reapply  
power.  
Network Connections  
You can connect a data communication equipped Series 945 to any computer with  
an RS-422A or RS-423A (RS-232C compatible) or EIA-485 serial interface. The  
serial interface is the key. The IBM™PC® with an RS-232C serial output card,  
for instance, will talk to a single RS-423A equipped Series 945. For a multiple 945  
network with the same PC, you'll need an RS-232 to RS-422 converter to act as a  
"bus," or multiple connection point.  
Watlow recommends the Burr-Brown LDM 422 for that purpose. The address is:  
Burr-Brown, Inc., 1141 West Grant Rd,. Suite 131, Tucson, AZ 85705, Phone:  
(602) 624-2434, Fax: (602) 623-8965.  
For EIA-485, we recommend the Black Box LD485A. Their address is: Black Box  
Corporation, Mayview Road at Park Drive, Box 12800, Pittsburgh, PA 152421,  
Phone: (412) 746-5530.  
Series 945 Comunication Parameters  
To communicate with the Series 945, match the serial port settings of your com-  
puter with the available settings in the 945:  
bAUd Rate  
dAtA  
=
300, 600, 1200, 2400, 4800, 9600 (choose one)  
= 7o = 7 data bits and odd parity  
7E = 7 data bits and even parity (choose one)  
8n = 8 data bits and no parity  
Start Bit  
Stop Bits  
= 1  
= 1  
7
WATLOW Series 945  
How to Use Data Communications  
 
Parameters  
Setup Menu - Communications Parameters  
Enter the Setup menu by pressing the UP/DOWN keys simultaneously for 3  
seconds. The lower display shows the LOC parameter, and the upper display  
shows its current level. All keys are inactive until you release both keys. You can  
reach the LOC parameter from anywhere. This is only a listing and brief explana-  
tion of the parameters, refer to Pages 22 through 26 for a thorough explanation of  
Statistical Process Control (SPC).  
Baud: Represents the current baud rate for serial communications.  
bAUd  
dAtA  
Range: 300, 600, 1200, 2400, 4800, 9600  
Default: 1200  
Data: Allows the user to select the data bits and parity for communication.  
Range: 7 o = 7 data bits and odd parity  
7E = 7 data bits and even parity  
8 n = 8 data bits and no parity  
Default: 7 o  
Protocol: Selects the communication protocol. Must be On for data logging to  
occur. FULL = ANSI X3.28 2.2 - A.3 On = XON - XOFF  
Prot  
Range: FULL or On  
Default: FULL  
Addr  
Log  
Address: Selects the address device if Prot = FULL. Range: 0 to 31 Default: 0  
Log: Selects the data logging function for a printout of the data. Appears if Prot =  
On. For further expon on SPC, the parameters and printouts, see Page 22 - 26.  
Range: OFF, tAbL, CHrt, SPCA, SPCd, SPCn Default: OFF  
Lower Specification Limit: This value is the specified deviation below set point,  
which statistically the process should not exceed. Appears if Prot = On and Log =  
LSL  
USL  
SPCA or SPCd. SPCA Range: rL to Lower USL -2°F/-1°C  
SPCd Range: 1 to 99 Default: 10  
Default: rL  
Upper Specification Limit: This value is the specified deviation above set point,  
which statistically the process should not exceed. Appears if Prot = On and Log =  
SPCA or SPCd.SPCA Range: rH to upper LSL +2°F/1°C Default: rL  
SPCd Range: 1 to 99  
Default: 10  
Time Base: Selects the time in minutes over which 30 random samples are taken  
for computing SPC values. Appears if Prot = On and Log = SPCA or SPCd.  
tbS  
Range: 1 to 60  
Default: 5  
Line: Selects the number of lines per page of data logged output. Match this  
parameter to the number of lines per page your printer prints. After you select the  
number of lines to print, a form feed character is sent to the printer, resetting the  
top of the page. Range: 10 to 127 Default: 65  
LinE  
Year: Select the current year for the data logging header. Appears if Prot = On  
and Log = tAbL, CHrt or SPCA, SPCd, SPCn. Parameter resets to default after a  
power interruption. Default: 92  
YEAr  
Month: Select the current month for the data logging header. Appears if Prot =  
On and Log = tAbL, CHrt or SPCA, SPCd, SPCn. Parameter resets to default after  
a power interruption. Default: 01  
Mon  
dAY  
Day: Select the current day for the data logging header. Appears if Prot = On and  
Log = tAbL, CHrt or SPCA, SPCd, SPCn. Parameter resets to default after a  
power interruption. Default: 01  
Hour: Represents the 24 hour time-of-day clock setting for minutes. Appears if  
HOUr  
Prot = On and Log = tAbL, CHrt or SPCA, SPCd, SPCn. Parameter resets to  
default after a power interruption. Range: 0 to 23  
Default: 0  
8
How to Use Data Communications  
WATLOW Series 945  
 
Minutes: Represents the 24 hour time-of-day clock setting for minutes. Appears  
if Prot = On and Log = tAbL, CHrt or SPCA, SPCd, SPCn. Parameter resets to  
Setup  
default after a power interruption. Range: 0 to 59  
Default: 0  
Min  
Interval: Selects the time interval for the logging function. The logging interval is in  
tenth of a minute increments. Appears if Prot = On and Log = tAbL, CHrt or  
Int  
SPCA, SPCd, SPCn. Range: 0.0 to 60.0 minutes  
Default: 0.0  
Tag: Selects what variables are to be transmitted out during the data logging  
function. Any combination of process, set point and alarms may be "tagged" for  
logging. Appears if Prot = On and Log = tAbL.  
tag  
P = Process  
S = Set Point A = Alarm Set Points  
Range: PSA, PS -, P-A, P- -, -SA, -S-, --A, --- Default: ---  
Setup Menu  
Table 1 -  
Setup Menu  
Prompts and  
Descriptions.  
Use this page as a master copy for your Series 945 data communications Setup  
parameters. Do not enter any values here; make photocopies instead.  
Parameter  
Value  
Range  
Factory Default Appears If:  
bAUd  
dAtA  
300, 600, 2100, 2400, 4800, 9600  
1200  
7 o = 7 data bits and odd parity  
7E = 7 data bits and even parity  
8 n = 8 data bits and no parity  
7 o  
Prot  
FULL = ANSI X3.28 2.2 - A.3  
On = XON - XOFF  
FULL  
Addr  
Log  
0 to 31  
0
Prot = FULL  
Prot = On  
OFF, tAbL, CHrt, SPC  
OFF  
LSL  
SPCA = rL to Lower USL -2°F/-1°C  
rL  
Prot = On &  
SPCd = 1 to 99  
10  
Log = SPCA, SPCd  
USL  
tbS  
SPCA = rH to Upper LSL +2°F/1°C  
SPCd = 1 to 99  
rL  
10  
Prot = On &  
Log = SPCA, SPCd  
1 to 60  
5
Prot = On &  
Log = SPCA, d, n  
LinE  
YEAr  
Mon  
dAY  
HOUr  
Min  
10 to 127  
65  
92  
01  
01  
0
Prot = On & Log = tAbL  
CHrt or SPCA, d, n  
--  
Prot = On & Log = tAbL  
CHrt or SPCA, d, n  
--  
Prot = On & Log = tAbL  
CHrt or SPCA, d, n  
--  
Prot = On & Log = tAbL  
CHrt or SPCA, d, n  
0 to 23  
Prot = On & Log = tAbL  
CHrt or SPCA, d, n  
0 to 59  
0
Prot = On & Log = tAbL  
CHrt or SPCA, d, n  
Int  
0.0 to 60.0 minutes  
0.0  
---  
Prot = On & Log = tAbL  
CHrt or SPCA, d, n  
tag  
PSA, PS-, P-A, P--, -SA, -S-, --A, ---  
Prot = On & Log = tAbL  
P = Process  
S = Set Point  
A = Alarm Set Points  
Operation Menu  
This parameter follows the Aut parameter in the Operation menu. See Page 25 for  
more information.  
Control Limit Update: When YES is selected, it calculates and prints out control  
limits according to the time base. If no is selected, the current control limit is  
printed and no subsequent limits are printed. Range: YES or no Default: YES  
CLUP  
9
WATLOW Series 945  
How to Use Data Communications  
 
ASCII Char.  
ASCII Character Set  
Dec Hex Char Dec Hex Char Dec Hex Char Dec Hex Char  
00 00 NUL  
01 01 SOH 17 11 DC1  
02 02 STX  
03 03 ETX  
04 04 EOT  
16 10 DLE  
32 20 SP  
48 30  
49 31  
50 32  
51 33  
52 34  
53 35  
54 36  
55 37  
56 38  
57 39  
58 3A  
59 3B  
60 3C  
61 3D  
62 3E  
63 3F  
0
1
2
3
4
5
6
7
8
9
:
33 21  
34 22  
35 23  
36 24  
37 25  
38 26  
39 27  
!
"
18 12 DC2  
19 13 DC3  
20 14 DC4  
#
$
%
&
'
Table 2 -  
ASCII Character  
Set  
05 05 ENQ 21 15 NAK  
06 06 ACK  
07 07 BEL  
08 08 BS  
09 09 HT  
10 0A LF  
11 0B VT  
12 0C FF  
13 0D CR  
14 0E SO  
15 0F SI  
22 16 SYN  
23 17 ETB  
24 18 CAN 40 28  
25 19 EM  
26 1A SUB  
27 1B ESC  
28 1C FS  
29 1D GS  
30 1E RS  
31 1F US  
(
41 29  
42 2A  
43 2B  
44 2C  
45 2D  
46 2E  
47 2F  
)
*
+
,
-
.
;
<
=
>
?
/
Dec Hex Char Dec Hex Char Dec Hex Char Dec Hex Char  
64 40  
65 41  
66 42  
67 43  
68 44  
69 45  
70 46  
71 47  
72 48  
73 49  
74 4A  
75 4B  
@
A
B
C
D
E
F
G
H
I
80 50  
81 51  
82 52  
83 53  
84 54  
85 55  
86 56  
87 57  
88 58  
89 59  
90 5A  
91 5B  
P
Q
R
S
T
U
V
W
X
Y
Z
[
96 60  
97 61  
98 62  
99 63  
100 64  
101 65  
102 66  
103 67  
104 68  
105 69  
106 6A  
107 6B  
108 6C  
109 6D  
110 6E  
111 6F  
`
112 70  
113 71  
114 72  
115 73  
116 74  
117 75  
118 76  
119 77  
120 78  
121 79  
122 7A  
123 7B  
124 7C  
125 7D  
126 7E  
127 7F  
p
q
r
s
t
u
v
w
x
y
z
{
|
}
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
J
K
76 4C L  
77 4D M  
78 4E  
79 4F  
92 5C \  
93 5D ]  
94 5E  
95 5F  
N
O
^
_
~
DEL  
ASCII Control Characters (Partial Set)  
ASCII  
Char.  
ENQ  
ACK  
NAK  
STX  
ETX  
EOT  
DLE  
CR  
Ctrl Key  
Equiv.  
Ctrl E  
Ctrl F  
Ctrl U  
Ctrl B  
Ctrl C  
Ctrl D  
Ctrl P  
Ctrl M  
Ctrl Q  
Ctrl S  
Definition  
Dec.  
Equiv.  
5
Hex.  
Equiv.  
05  
Enquiry  
Acknowledge  
Neg. Acknowledge  
Start of Text  
End of Text  
6
06  
Table 3 -  
21  
2
15  
ASCII Control  
Characters  
(Partial Set)  
02  
3
03  
End of Transmission  
Data Link Escape  
Carriage Return  
XON  
4
04  
16  
13  
17  
19  
10  
0D  
11  
DC1  
DC3  
XOFF  
13  
10  
How to Use Data Communications  
 
WATLOW Series 945  
Syntax  
Series 945 General Message Syntax  
As soon as you link the devices, you'll be able to talk to the Series 945 using ASCII  
characters.  
The Series 945 will respond to any Operating or Setup parameter, plus some  
others. The control will respond to either upper or lower case ASCII characters  
from your computer.  
Both protocol/interface combinations will respond to the general syntax, providing  
the commands or queries are correctly transmitted. However, the ANSI X3.28  
Protocol requires beginning and ending characters, and the XON/XOFF Protocol  
requires ending characters. We'll look at those shortly.  
Message Syntax  
Messages from your computer to the Series 945 must take this general form. All  
commands do not require the full number of data fields.  
Command <Space> Data.1 <Space> Data.2 <Space> Data.3... Data.N  
"Command" is a character set to which the Series 945 will respond. The brackets  
"< >" enclose a non-literal description. "Space" is simply a delimiter, an ASCII  
space character (Hex 20). "Data Fields" are parameters and values specific to a  
command; the number of possible data fields depends on the particular command  
you use. Data 1 is here abbreviated, "Data.1", Data 2 is "Data.2" and so on.  
In the syntax explanations ahead, we'll show you the specific arguments for each  
command. It will speed the process, if you remember this general syntax.  
Data Rules  
Data fields are parameters and values specific to particular commands. These rules  
govern their use. Specific data for each command is listed later in this chapter.  
• Data will be ASCII 0 through 9, unless otherwise noted.  
• Data can go up to seven total characters, including a minus sign. A + or - sign, if  
used, must be first, and it must have a decimal point if applicable.  
• Data can use leading zeros. (Up to 7 digits.)  
• Data does use decimal points.  
• Data.1 portion of message can be up to four total characters.  
Command List  
These commands, represented by their respective ASCII characters, will enable  
you to program the Series 945 from your computer. More detailed descriptions of  
the commands are on the pages noted.  
?
=
Finds the value of a specific parameter.  
Sets a specific parameter to a specific value.  
p. 19  
p. 20  
11  
WATLOW Series 945  
How to Use Data Communications  
 
ASCII  
Example Format  
For your benefit, we're presenting message/response examples with syntax re-  
quired for Series 945 communication. Information bracketed by < > indicates a  
description, rather than literal characters. We show each ASCII character that you  
must transmit to the Series 945, including space between the characters. (A  
"space" is itself an ASCII character, hex 20). For clarity, we also represent each  
ASCII character as a hexadecimal pair. The pairs are spread apart on the page for  
easy reading. However, electronic devices "see" the hex pairs all together in  
"strings," with no spaces in between.  
For instance, from the example just below, you want to set the Alarm 1 Low  
(A1LO) parameter to 500°. Notice the syntax just below which uses the "=" com-  
mand.  
= <Space> A1LO <Space> 500  
=
<Space>  
A
1
ASCII  
Characters  
L
O
Space  
Figure 5 -  
5
Series 945  
General Message  
Syntax Example.  
0
0
<CR>  
HEX  
Value  
3D 20 41 31 4C 4F 20 35 30 30 0D  
To send this message, key the ASCII characters into your computer, or write them  
into your program. The computer, in turn, will send a string similar to the one at the  
bottom of the example, 3D2041314C4F20353030.  
Notice that we haven't mentioned protocol here, or any characters added to this  
syntax by a protocol. With XON/XOFF, the message above can be transmitted  
with only an additional Carriage Return <CR> (hex 0D) character at the end.  
However, the ANSI X3.28 Protocol requires an envelope of Start of Text <STX>  
(hex 02) and End of Text <ETX> (hex 03) characters around the information you  
see above. You'll learn how to do that in the pages ahead.  
XON/XOFF Protocol for RS-423A  
XON/XOFF (flow control) Protocol allows a communicating device (either a 945 or  
the host) to suspend transmission of all messages from the other device, and then  
to continue transmission when it's again ready.  
The device that needs to suspend transmission sends the XOFF character  
(hex 13) to stop the other device's transmitter, and XON (hex 11) to restart it. Note  
that technically any character will restart the transmitter, but only the XON character  
is not a part of any regular message that may be transferring.  
Messages transmit according to the syntax described in the XON/XOFF formats  
which follow for each command.  
The XON/XOFF Protocol requires a Carriage Return character  
(hex 0D) at the end of every message.  
12  
How to Use Data Communications  
WATLOW Series 945  
 
XON/XOFF "="  
How To Start and Stop Communicating  
with the Series 945 and XON/XOFF  
Starting communications with XON/XOFF Protocol is simple. You just configure  
your computer to agree with the Series 945 communication parameters and open its  
serial communication port in software. Then begin to "talk" by transmitting a mes-  
sage to the Series 945. You stop communicating with XON/XOFF Protocol simply by  
ceasing to send messages.  
XON/XOFF "=" Command Example  
The general command syntax is the one you've already seen. Each command uses a  
slightly different variation of it, depending on the number of arguments required for a  
message.  
• You want to change the Alarm 1 Low (A1LO) value to 500°. The "=" command will  
do the job.  
The syntax with XON/XOFF Protocol requires an ending Carriage Return <CR>.  
"=" Command Syntax with XON/XOFF Protocol:  
= <space> Data.1 <space> Data.2 <CR>  
With the "=" Command, Data.1 is the Series 945 parameter, in this case Alarm 1 Low,  
A1LO. Data.2 is the value you want to set for that parameter, in this example, 500.  
Enter in ASCII:  
= <space> A1LO <space> 500 <CR>  
The hex string will be:  
3D2041314C4F203530300D  
=
<Space>  
A
1
ASCII  
L
O
Characters  
Space  
Figure 6 -  
XON/XOFF "="  
Command Example.  
5
0
0
<CR>  
HEX  
Value  
3D 20 41 31 4C 4F 20 35 30 30 0D  
Response from the Series 945:  
It sends an "XOFF" when a carriage return is received and then an "XON" when the unit  
is done processing the command.  
<XON>  
<XOFF>  
13  
11  
• The complete list of "=" Command data (parameters and value limits) is in  
Table 6, Pages 20 - 21.  
13  
WATLOW Series 945  
How to Use Data Communications  
 
XON/XOFF "?"  
XON/XOFF "?" Command Example  
You want to know the Alarm 1 Low (A1LO) value. The "?" uses a variation of the  
message syntax shown just below. This protocol requires an ending carriage  
return character.  
"?" Command syntax with XON/XOFF Protocol:  
? <space> Data.1 <CR>  
Enter in ASCII:  
? <space> A1LO <CR>  
The hex string will be:  
3F2041314C4F0D  
?
Space  
A
1
ASCII  
Characters  
L
Figure 7 -  
XON/XOFF "?"  
Command Example.  
O
CR  
HEX  
Value  
3F 20 41 31 4C 4F 0D  
The value of A1LO will be between rL (Range Low) and rH (Range High), say, 500.  
Response from the Series 945:  
<XOFF> <XON> <current value of A1LO> <CR>  
The hex response string is:  
13113530300D  
<XOFF>  
<XON>  
5
ASCII  
Characters  
0
0
CR  
HEX  
Value  
13  
11 35 30 30 0D  
14  
How to Use Data Communications  
 
WATLOW Series 945  
ANSI X3.28  
ANSI X3.28 Protocol for RS-422A and EIA-485  
The ANSI X3.28 Protocol provides high quality communications by requiring a  
response to every message. With a multiple device or "multidrop" network, this  
protocol prevents confusion among the separate devices. Furthermore, if noise  
occurs somewhere in the system, no parameter will change because noise can't  
comply with the protocol.  
By placing messages inside a protocol envelope, the messages are protected. In  
the examples to come you'll see how this works.  
The ANSI X3.28 Protocol requires STX characters at the beginning of a  
message and ETX characters at the end.  
Device Address  
If you are using the ANSI X3.28 Protocol, you must have a device address (identifi-  
cation) number. A Watlow RS-422A multidrop network can handle up to 10 de-  
vices with this protocol. EIA-485 can handle up to 32 devices. Set the address  
number with the Series 945 in the Addr parameter under the Setup menu.  
Table 4 -  
Address to ASCII  
Conversion.  
Address  
0 - 9  
10 - 31  
ASCII Equivalent  
0 - 9  
A - V  
Starting Communications in ANSI X3.28 Protocol  
Here's the syntax for starting communications with ANSI X3.28 Protocol. The  
master device, your computer, must initiate the data link. The example below  
uses the ASCII number 4 as a Series 945 device address.  
Enter in ASCII, using this syntax: <Address # 4><ENQ>  
ASCII  
Characters  
4
<ENQ>  
HEX Value  
34 05  
Response from the 945:  
<Address # 4><Acknowledge (ACK)>  
ASCII  
4
Characters  
<ACK>  
HEX Value  
34 06  
15  
WATLOW Series 945  
How to Use Data Communications  
 
ANSI X3.28 "="  
Stopping Communications in ANSI X3.28 Protocol  
The master device, your computer, must end communications with Device #4 by  
using Data Link Escape (DLE) and End of Transmission (EOT) characters.  
Enter in ASCII: <DLE><EOT>  
ASCII  
Characters  
<DLE>  
<EOT>  
HEX Value  
10 04  
Response from the 945:  
None  
ANSI X3.28 "=" Command Example  
The "=" Command sets a specific 945 parameter to a specific value. The general  
command syntax applies to all commands. The definition and number of argu-  
ments depends on the command itself. See Table 6, Pages 20 - 21.  
In this example, you want to change the Alarm 1 Low value to 500°. Here, the "="  
command will do the job.  
'"=" command Syntax with ANSI X3.28 Protocol:  
<STX> = <space> Data.1 <space> Data.2 <ETX>  
With the "=" command, Data.1 is the Series 945 parameter, in this case Alarm 1  
Low , A1LO. Data.2 is the value you want to set for that parameter, in this ex-  
ample, 500.  
Enter in ASCII:  
<STX> = <space> A1LO <space> 500 <optional carriage return> <ETX>  
The hex string is:  
023D2041314C4F2035303003  
<STX>  
=
<Space>  
A
1
Figure 8 -  
ANSI X3.28 "="  
Command Example.  
ASCII  
Character  
L
O
Space  
5
0
0
<ETX>  
HEX  
Value  
02 3D 20 41 31 4C 4F 20 35 30 30 03  
Optional  
Carriage  
Return  
16  
How to Use Data Communications  
 
WATLOW Series 945  
ANSI X3.28 "?"  
Response from the Series 945:  
<ACK>  
The hex response string is:  
06  
• You'll find the the complete list of "=" command arguments (parameters and  
value limits) in Table 6, Pages 20 - 21.  
ANSI X3.28 "?" Command Example  
You need to know the Alarm 1 Low value (A1LO). The "?" uses a variation of the  
message syntax shown just below. This syntax requires the protocol start of  
text and end of text characters.  
"?" command syntax with ANSI X3.28 Protocol:  
<STX> ?<space> <Data.1> <ETX>  
Enter in ASCII:  
<STX> ? <space> <A1LO> <optional carriage return> <ETX>  
The hex string will be:  
023F2041314C4F03  
Optional  
Carriage  
Return  
<STX>  
?
Space  
A
1
Figure 9 -  
ANSI X3.28 "?"  
Command Example.  
ASCII  
Characters  
L
O
<ETX>  
HEX  
Value  
02 3F 20 41 31 4C 4F 03  
First response from the Series 945:  
<ACK>  
The <ACK> hex response string is:  
06  
Your computer's confirming response:  
<EOT>  
The <EOT> response hex string is:  
04  
Second response from the Series 945:  
<STX> <current A1LO value> <carriage return> <ETX>  
The hex string is:  
023530302003  
<STX>  
5
ASCII  
0
0
Characters  
<CR>  
0
<
HEX  
Value  
20  
Your computer's next response:  
<ACK> or < NAK> (if the message needs to be repeated).  
The hex string is:  
06 or 15  
Final response from the Series 945:  
<EOT>  
The hex string is:  
04  
17  
WATLOW Series 945  
How to Use Data Communications  
 
Commands  
Data.1 Respns Information  
Comments  
C1  
ACTUAL  
Actual process value  
Between R1L and R1H  
IN  
0
1
J T/C  
K T/C  
2
T T/C  
3
N T/C  
4
5
PT2 T/C  
C T/C  
6
7
Not Used  
R T/C  
Table 5 -  
8
9
10  
11  
12  
13  
S T/C  
B T/C  
RTD whole  
RTD tenths  
0-5V  
"?" Commands  
and Responses.  
These commands  
are READ ONLY.  
4-20mA  
MODE  
ERR  
1
2
4
8
16  
Auto mode  
Manual mode  
Configuration mode  
Calibration mode  
Alarm silence active  
Multiple modes are possible.  
Multiple errors are possible.  
0
1
2
4
8
16  
32  
64  
128  
No error  
Open sensor  
Reversed sensor  
Ambient sensor  
Configuration  
EE Checksum  
A/D underflow  
A/D overflow  
Not used  
ER2  
0
1
2
No error  
Cleared when ER2 is read.  
Only 1 ER2 response is valid.  
Transmit buffer overflow  
Receive buffer overflow  
Framing error  
3
4
Overrun error  
5
Parity error  
6
7
8
Talking out of turn  
Invalid reply error  
Noise error  
16  
17  
18  
19  
20  
21  
22  
23  
24  
25  
26  
27  
Process input active  
Local/remote is local  
Local/remote is remote  
Remote not enabled  
Command not found  
Parameter not found  
Incomplete command line  
Invalid character  
Number of chars. overflow  
Input out of limit  
Read only command  
Write allowed only  
BTYP  
0
1
2
3
T/C Only  
T/C, RTD whole, process  
T/C, RTD tenths, process  
R, S, B T/C  
MDL  
Displays 945 X  
X = software revision  
Remote set point setting  
RSP1  
Remote SP  
"?" Command  
The "?" Command reads a specific value of the Series 945 parameter (Data.1).  
Tables 5 and 6 provide the complete list of parameters you may use, plus re-  
sponses.  
18  
How to Use Data Communications  
WATLOW Series 945  
 
Commands  
"=" Command  
"The "=" Command sets a specific Series 945 parameter (Data.1) to a specific  
value (Data.2) when the unit is in the HOLD mode. Use Tables 5 and 6 to select  
parameters (Data.1) in the lefthand column. In Table 6 the low and high limit or  
code values (Data.2) are in the three center columns.  
Data.1  
Data.2  
Low Limit  
High Limit  
Code Function  
Alarm High X value  
AXHI  
AXLO  
ALM  
Process RL value  
±555/Deviation ±999  
Process RL value  
±555/Deviation ±999  
RH value  
NOTE:  
An X means it  
applies to either  
Output 1 or  
RH value  
Alarm Low X value  
0
1
2
4
8
0
No alarms occurring  
A1H occurring  
A1L occurring  
A2H occurring  
A2L occurring  
2
Writing a 0 will clear all  
alarms if the alarm  
condition no longer  
exists.  
Output 2.  
AL1  
AL2  
0
1
2
0
1
2
1
Alarm 1 = deviation  
Alarm 1 = process  
No Alarm 1  
Alarm 2 = deviation  
Alarm 2 = process  
No Alarm 2  
Auto/Manual toggle must  
be sent twice within 5 sec.  
No auto-tuning  
Slow response tuning  
Medium response tuning  
Fast response tuning  
Calibration offset  
Table 6 -  
"=" and "?" Com-  
mands. These are  
READ or WRITE  
commands. See  
Table 4 for more "?"  
Commands.  
0
2
ATMN  
AUT  
1
0
1
3
0
1
2
3
CAL*  
-180°F  
-100°C  
-180 Units  
0
180°F  
100°C  
180 Units  
1
CF  
0
1
Display °C  
Display °F  
SPC control limits update  
Output X cycle time  
Day of the month/data log  
Dead band  
* When the 945 RTD  
input is 0.1°, these  
parameters will have  
a decimal point to  
the left of the least  
significant digit.  
CLUP  
CTX  
DAY  
DB  
Yes  
No  
60  
31  
1
1
0
99°F  
55°C  
99 Units  
2
0
0 Units  
0
DEC  
0
1
2
No decimal point  
0.0  
0.00  
DEX  
DFL  
0.00  
0
9.99  
1
Output X derivative  
US prompts  
SI prompts  
0
1
HOUR  
HYSX  
0
1°F  
23  
99°F  
Hour for data logging  
Output X switching hys.  
1°C  
1 Unit  
1
55°C  
99 Units  
1
INDC  
INT  
1
UP/DOWN key action  
Time interval in minutes  
for logging  
0.0  
60.0  
0.0 = logging OFF  
Output X integral  
ITX  
0.00  
9.99  
How to Use Data Communications  
 
19  
WATLOW Series 945  
Commands  
Data.1  
Data.2  
Low Limit  
High Limit  
Code  
Function  
Latched alarms  
Non-latched alarms  
Lines per page for data logging  
Lock front panel  
Logging OFF See Page 22.  
Table  
Chart  
SPCA  
SPCd  
SPCn  
Local set point  
Remote set point  
SPC lower spec limit  
Manual % output  
Minute for data logging  
Month for data logging  
Heat  
LATX  
0
1
0
1
LINE  
LOC  
LOG  
10  
0
0
127  
3
3
NOTE:  
0
1
2
3
4
5
0
1
An X means it  
applies to either  
Output 1 or  
Output 2.  
L-R  
0
1
LSL  
MAN  
MIN  
MON  
OTX  
rL USL Lower -2°F/-1°C  
-100  
100  
59  
12  
0
1
0
1 or 2*  
0
1
Cool  
2*  
No action  
*only applies to Ot2  
Output 4 = Process Retransmit  
Output 4 = Set Point Retransmit  
No action  
Proportional Band  
dFL = US  
OT4  
0
0
2
0
1
2
Table 6 -  
Continued  
PBX  
999°F  
555°C  
999 Units  
999.9  
PBX%  
0.0  
Output X proportional  
band DFL = SI  
Rate  
Reset  
Range High  
Range Low  
OFF  
0-5  
420  
DIN  
JIS  
Alarm silence OFF  
Alarm silence ON  
Set point  
- - - = no logging  
- - A  
RAX  
REX  
RH  
RL  
RSP  
0.00  
0.00  
Min. IN range  
Min. IN range  
0
9.99  
9.99  
Max. IN range  
Max. IN range  
2
0
1
2
0
1
0
1
RTD  
SIL  
0
0
1
1
SPX  
TAG  
rL  
0
rH  
7
0
1
2
3
4
5
6
7
NOTE:  
- S -  
P = Process  
S = Set Point  
A = Alarm Set Point  
- - - = no logging  
- SA  
P - -  
P - A  
l
PS -  
PSA  
tbS  
USL  
YEAR  
1
LSL Upper 2°F/1°C  
0
60  
rH  
99  
SPC time interval in minutes  
SPC upper spec limit  
Year for data logging  
20  
How to Use Data Communications  
WATLOW Series 945  
 
Data Logging  
Data Logging  
The data logging feature is a convenient replacement for chart recorders. Informa-  
tion is sent directly from the Series 945 to a serial printer, or to a computer disk file.  
No computer is needed, although the 945 can be connected to a computer with a  
serial port and terminal emulation software.  
Data logging provides a handy reference to review process performance. The time  
intervals between each entry and data printed are user selectable, with the time  
display resetting every 24 hours. If there is a power interruption, the time is reset to  
0.0. There are several options for the printer output. Choose from table, chart or  
SPC (Statistical Process Control). See the following pages for more information on  
printer outputs.  
Printer  
Figure 10 -  
Data Logging  
Interface Wiring  
Example.  
R
DB-25 female connector  
(located on back of printerRTS (Request To Send)  
CTS (Clear To Send)  
DSR (Data Set Ready)  
Com  
viewed from wire side)  
DTR (Data Terminal Ready)  
Jumper DTR, DSR, and RLSD together.  
Also, jumper RTS and CTS together.  
Refer to your printer's user manual.  
RLSD (Received Line Signal Detector)  
T
20  
Jumper to Signal Common  
21  
22  
R
Signal Common  
Series 945  
#1 23  
Connect the 945 to the printer as in Figure 10; this is a typical wiring example. The  
connections on the printer may vary depending on the model, refer to the printer's  
user manual. Enter the Setup menu by pressing the UP/DOWN keys simulta-  
neously for three seconds. Mode through the parameters until you reach bAUd  
and follow the parameter listing on Page 8. Select the appropriate data for each  
prompt and enter your values in the table on Page 9. Data logging begins once  
you return to the control set point.  
After each line the 945 emits a carriage return. Your printer can be set up to  
handle line feeds. The printer must supply a line feed (LF) following a carriage  
return (CR). Refer to your printer user's manual for more information.  
A data header is printed once the logging function begins. When you change the  
time interval (Int) or any selected data (tag), or power is cycled, the header is  
printed again. The header always remains the same, regardless of the control  
configuration. The time display wraps around to 0.0 every 24 hours. If there is a  
power interruption, the control will restart at 0.0 when power is restored.  
How to Use Data Communications  
21  
WATLOW Series 945  
 
Data Logging  
Data fields emitted are determined by the tag parameters and control configuration.  
As in the following example, tag is set for PSA (Process, Set Points, and Alarm Set  
Points). SET-2 is only transmitted when there is a secondary control output, and is  
configured the same as the primary output. In the example below, notice A1LO was  
changed to 125 resulting in an alarm condition shown as an * (asterisk) in the  
PROCESS and LOW-1 columns. After a latching or non-latching alarm is cleared,  
the * is removed. The ATUNE column reports the auto-tune status. START de-  
notes the beginning of the sequence, RSTRT signifies auto-tune has been re-  
started, and END is displayed when complete.  
Table Printout  
Example: Log = On, Int = 0.5, tag = PSA  
P = Process  
S = Set Points  
A = Alarm Set Points  
Parameters represented:  
(C1) (SP1) (SP2) (A1LO)  
DATE: 01-01-92  
TIME PROCESS SET-1 SET-2 LOW-1 HIGH-1 LOW-2 HIGH-2 ATUNE  
(A1HI) (A2LO) (A2HI)  
(AUt)  
10:03:47  
10:03:58  
10:04:34  
10:05:10  
10:05:46  
10:06:02  
10:06:38  
10:07:14  
10:07:50  
10:08:26  
10:09:02  
144 *  
157 *  
185 *  
177 *  
182 *  
179 *  
196  
198  
199  
199  
200  
200  
200  
200  
200  
200  
200  
200  
200  
200  
200  
200  
150 *  
150  
150  
150  
150  
150  
150  
150  
150  
150  
150  
240  
240  
240  
240  
240  
240  
240  
240  
240  
240  
240  
190 *  
190 *  
190 *  
190 *  
190 *  
190 *  
190  
190  
190  
190  
190  
210  
210 START  
210  
210  
210  
210  
210  
210  
210  
210  
210  
Figure 11 -  
Table Printout  
Example.  
END  
SPC - Statistical Process Control  
SPC tracks variability to help you distinguish between natural variability (common  
causes) from unnatural variability (special causes). Based upon measurements,  
SPC gives you a picture of how the process is performing. By showing when  
special causes are occurring, the SPC printout gives you written changes in the  
process. An SPC printout is a picture of the operation. Typically, past data gives  
information about what the average measurements and limits should be. These  
are traditionally shown by upper and lower control limits. It also gives us a picture  
of what is happening now. By comparing the process we can determine when  
special, or assignable causes occur. This is advanced user-level material and  
requires previous experience with Statistical Process Control (SPC).  
For more information we recommend:  
Juran's Quality Control Handbook  
by J.M. Juran, Editor in Chief & Frank M. Gryna, Associate Editor  
Hardcover, 1988  
ISBN: 0-7-033176-6  
Available from:  
McGraw Hill  
1221 Avenue of the Americas  
New York, NY 10020  
1-800-2-MCGRAW  
22  
How to Use Data Communications  
 
WATLOW Series 945  
SPC  
The Difference Between Control & Specification Limits  
Control limits are established on the control chart at ± 3 standard deviations (3 sigma).  
They are based upon the distribution of sample averages and are calculated from the  
actual performance of the process. They are typically narrower than specification limits.  
Specifications are limits for individual measurements, not averages. They are based upon  
engineering or customer requirements, rather than process capability. Process capability  
predicts the process performance to predetermined specification limits.  
When the LCL (Lower Control Limit) and UCL (Upper Control Limit) values have been  
determined, the values for CPKL, CPKU, and CP are calculated and printed once on the  
chart. The smaller of these two numbers will be your actual process capability or CPK.  
Mean - LSL  
USL - Mean  
CPKL =  
CPKU =  
3σ  
3σ  
If the system is too stable "variation insignificant" is printed. Your process is so stable that  
even a severe shift or variation greater than ±6 sigma will still maintain a larger CPK  
value. If both LSL and USL are left at their default value, they are set to the 4σ values  
below and above the process mean value. Once the mean value has been calculated,  
these values are used to calculate CPKL and CPKU values.  
Average: The mean, or the arithmetic average, ( x ).  
Control Limits: Limits on a control chart, based on actual process data, which are used  
as criteria for signalling the need for action, or for judging whether a set of data does or  
does not indicate a "state of statistical control."  
Lower Control Limit (LCL): Control limit derived by the average minus 3 standard  
deviation ( x - 3σ ).  
Mean: The arithmetic average, obtained by adding all the values together and dividing by  
the number of values ( x ).  
Process Capability (CPKL and CPKU): A comparison of process performance with  
product specifications over a period of time and while the process is in statistical control.  
CPK < 0  
CPK between 0 and 1  
CPK = 1  
Average value is outside the specification limits  
Variation is greater than the limits.  
Variation and the specification limits are the same  
CPK between 1 and 1.33 Acceptable process control  
CPK between 1.33 and 2 Good process control  
CPK > 2  
Excellent process control  
Sigma: The unit of standard deviation. Sigma is the greek letter "s" written σ.  
SPCA (Specification limits Absolute): Represents SPC with fixed values that do not  
track the set point. When SPCA is chosen, the USL range is the LSL parameter + 2 (LSL  
+ 2) to the sensor's range high. Default is the sensor's default range high. The LSL range  
is from the sensor's default range low to the sensor's default range high. Default is the  
sensor's default range low.  
SPCd (Specification limits Deviation): Represents SPC with deviation values that  
follow changes to the set point. When SPCd is chosen the range for USL it will be nu-  
meric values from 1 to 99. Default is 10. The LSL range is from -1 to -99. Default is -10.  
SPCn : There are no user defined values. The USL and LSL parameters are masked.  
How to Use Data Communications  
23  
WATLOW Series 945  
 
Chart & SPC  
Chart and SPC Printout  
Example: Log = SPCA, Int = 0.1  
P = Process  
S = Set Points  
Set Point  
DATE: 01-01-90  
75  
PROCESS  
125  
100°F  
Temperature  
*
s
01:00:01  
*
Set Point Variable  
s
s
s
*
*
*
*
s
*
*
Temperature Variable  
*
NOTE:  
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
s
01:00:31  
*
The time is printed  
every 5th interval  
(Int). The tempera-  
ture variable (*) is  
printed every 10th  
interval.  
*
Temperature Variable  
*
*
101  
*
*
01:01:01  
01:01:31  
01:02:01  
01:02:31  
01:03:01  
01:03:31  
*
One Int = 6 seconds.  
*
*
*
100  
*
*
Lower Control Limit  
(SPCA & SPCd only)  
Upper Control Limit  
(SPCA & SPCd only)  
*
*
s
s
*
Figure 12 -  
Chart and SPC  
Printout Example  
CPKL = 1.36  
CPKU = 1.32  
CP = 1.34  
(SPCA & SPCd only)  
L
L
*
U
U
(SPCA & SPCd only)  
*
99  
s
s
s
s
s
*
L
U
L
L
L
U
U
U
*
*
90  
92  
s
s
s
s
s
s
110  
110  
L
L
U
U
L
L
L
U
U
U
Maximum Excursion  
Maximum Excursion  
101  
s
*
s
s
s
s
s
L
L
L
U
U
U
*
*
*
*
L
L
U
U
s
s
*
(A
n
y
m
e
s
s
a
g
es  
c
o
n
c
e
rn  
i
n
g
c
nges  
ha  
in the system are printed here)  
Time  
The Chart and SPC (Statistical Process Control) format are very similar. The only  
difference is the SPC output displays the lower (L) and upper (U) control limit.  
They are calculated based upon the mean value of the process variable, and are  
derived from 30 random samples taken over the selected time base (tbS), the  
mean value used is from the previous timebase samples (ex. the mean from the  
first 30 samples is used to compute the control limits for the second 30 samples  
and so on for every sample period. If SPCA (Specification limits Absolute or SPCd  
(spec. limits Deviation) is selected then the CPKL, CP, or CPKu values will also be  
printed. If the variation in the process value is too small to calculate the control  
limits, L and U and the message "Variation Insignificant" are printed. If at any time  
the process value exceeds the control limits during a print interval, the maximum  
process excursion value will be printed (if both L and U are exceeded, both maxi-  
mum values will be printed) on the next line printed. At any time the control limits  
can be locked in by setting CLUP to "no" . If CLUP = no, new control limits can be  
set by CLUP = YEs.  
24  
How to Use Data Communications  
WATLOW Series 945  
 
Error Codes  
Problem  
Cause  
Action  
Printing all on  
the same line.  
The line feed  
is missing.  
Set the printer for a carriage  
return and line feed.  
Table 7 -  
Printer  
Troubleshooting.  
The printing is  
garbled.  
Data formats are  
not compatible.  
Match the Series 945 data  
format to the printers data  
format using the "Data" prompt.  
The printer will  
not print.  
The printer is off line.  
Bring the printer on line.  
The transmit and  
receive lines are  
reversed.  
Make sure Terminal #20 and  
#22 go to the printers appropriate  
receive and transmit terminals.  
NAKs and Error Codes  
When your message is "not acknowledged" (NAK) in RS-422A or EIA-485 with  
ANSI X3.28 Protocol, you may clear ER2 code by reading it. That is, use "?"  
Then try the message again; you may have made a syntax error. See the error  
code listing in Table 5, Page 19.  
With XON/XOFF protocol and the RS-423A interface, the 945 sends no  
feedback on commands. Therefore, you may want to query the status of ER 2  
after each command you send.  
All communications-related error codes are ER2 error codes, that is they are  
not considered cause for a shutdown of the 945 unit itself. There is always a  
communications error code generated when a <NAK> character is sent under  
the ANSI X3.28. With XON/XOFF flow control error codes may be generated,  
but there will be no standard indication of this fact.  
User Responsibility  
All of the previous commands are available on all models of the Series 945 that  
have communications capability. It is the responsibility of the user to refrain  
from altering parameters which may not appear on the unit. (Example: AXLO  
should not be set to 1 or 2 if the unit is not equipped with alarm outputs.)  
How to Use Data Communications  
25  
WATLOW Series 945  
 
I
Index  
Identification Number, 16  
IN, 19  
INDC, 20  
A
INT, 20  
ALM, 20  
Interface Wiring,  
RS-422A, Fig. 1, 4  
RS-423A, Fig. 2, 5  
EIA-485, Fig. 3, 6  
L
ANSI X3.28 "=" Command, Fig. 8, 17  
ANSI X3.28 "?" Command, Fig. 9, 18  
ANSI X3.28 Protocol for RS-422A & EIA-485, 3, 16  
ASCII Character Set, Table 1, 10  
ASCII Control Characters (Partial Set), Table 2, 10  
AXHI, 20  
LATX, 21  
LOC, 21  
AXLO, 20  
LOG, 8, 21, 22  
L-R, 21  
ATMN, 20  
AUT, 20  
LSL, 21  
B
M
Baud Rate, 8  
BTYP, 19  
MAN, 21  
MDL, 19  
C
Message Syntax, 11  
MODE, 19  
Multidrop, 3  
C1, 19  
CAL, 20  
Carriage Return, 13  
CF, 20  
N
NAKs and Error Codes, 26  
Network connections, 7  
Chart Printout, 25  
CLUP, 9, 20  
Command, "?", 19  
Command, "=", 20  
Command Data & Responses, Partial Set for "?", 19  
Command Data "=" and "?", Table 6, 20  
Command List, 12  
O
OTX, 21  
P
PBX, 21  
Protocol,  
Communications  
Parameters, 8  
Switch Selection, 7  
Wiring, 3  
XON-XOFF, 13  
ANSI X3.28, 16  
R
Connecting the Control and the Computer, 7  
CTX, 20  
RAX, 21  
REX, 21  
RS-422A, 3, 4  
RS-423A, 3, 5  
RSP, 19, 21  
RH, 21  
D
Data Parameters, 8  
Data Link Escape (DLE), 17  
Data Logging, 22  
Data Rules, 11  
DB, 20  
RL, 21  
S
DEC, 20  
Device Address, 16  
Setup Menu, 8  
SPC, 23  
SPX, 21  
Space, 12  
E
EIA-485, 3, 6  
End of Text (ETX), 13  
End of Transmission (EOT), 17  
ERR, 19  
ER2, 19  
Example Format, 12  
Starting Communications in ANSI X3.28 Protocol, 16  
Start of Text (STX), 13  
Stopping Communications in ANSI X3.28 Protocol, 17  
T
Table Printout, 23  
TAG, 21  
tbS, 20  
F
Flow Control, 13  
Two Hardware Interfaces & Protocols, 3  
G
General Message Syntax, 11  
U
USL, 21  
H
W
How to Use Data Comms. with the Series 945, 3  
Wiring Data Communications, 4 - 6  
HYSX, 20  
X
XON/XOFF  
"=" Command Example, Fig. 6, 14  
"?" Command Example, Fig. 7, 15  
How to Use Data Communications  
26  
WATLOW Series 945  
 
Notes  
How to Use Data Communications  
 
27  
WATLOW Series 945  
Series 945 Data Communications User's Manual  
Watlow Controls, 1241 Bundy Blvd., Winona, MN 55987, Phone: 507/454-5300, Fax: 507/452-4507  
 

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