Watlow Series 942 Data Communications - Manual (Page 25)

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How to Use Data Communications WATLOW Series 942
Error Codes
Data fields emitted are determined by the tag parameters and the control
configuration. As in the example above, the tag parameter was set for PSA
(Process, Set Points, Auxiliary Status).
The 942 can also be connected to a computer with a serial port and terminal
emulation software. Logged data can be sent via the terminal program to a
disk file.
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 4, Page 18.
With XON/XOFF protocol and the RS-423A interface, the 942 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 942 unit itself. There is always a
communications error code generated when a 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 942 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.)
Problem Cause Action
Printing all on The line feed Set the printer for a carriage
the same line. is missing. return and line feed.
The printing is Data formats are 1. Match the Series 942 data
garbled. not compatible. format to the printers data
format using the "Data" prompt.
2. The Baud rate is not set correctly.
The printer will The printer is off line. Bring the printer on line.
not print.
The transmit and Make sure Terminal #20 and
receive lines are #22 go to the printers appropriate
reversed. receive and transmit terminals.
Table 9 -
Printer
Troubleshooting.