E |
Error Messages During Operation
While you are executing a screen, the following errors may occur:
ERROR WRITING TO DEVICE COM1
You can test for the presence of COM 1 by typing >DIR >COM1. If you get a message ªERROR WRITING TO DEVICE COM1.... º, you probably
need something else jumpered in your COM1 serial port, or you don't have a COM1 port defined, or physically available.
TIME OUT This message means that a response was not received from the Micro PLC. The problem could be lack of proper COM1 configuration, bad cabling, or an improperly set target ID in the Micro PLC.
CHECKSUM This message indicates that the received data had a checksum error. The integrity of the data is suspect. Usually, a checksum error is caused by a noise burst. It can also be caused by running at the wrong baud rate, or a baud rate higher than your computer can properly support when running DISPLAY (4800 baud for an AT, 2400 baud for an XT).
If this message appears only occasionally, you may need to lower the baud rate to the next lower value.
A checksum can also occur if too much data is requested from the Micro PLC in when using the software in manual mode. The ability of DISPLAY to handle large blocks of data depends on the baud rate, computer speed, and other factors.
WRONG ID This message means that the wrong remote device answered your polling request. This is not likely to occur, but the check is in there anyway.
WRONG HEADER / BAD REQUEST
Since the DISPLAY software uses only RTU functions 1±3 in auto mode, this is unlikely in automatic mode. In manual mode, you may get this error while experimenting. It will also occur if you ask for data beyond the end of a table, e.g. register 17K in a 16K system.
NO MESSAGE
This message appears in the message window if the message pointer register contains a value for which no message has been programmed. it also occurs if an error is detected in the data from the message pointer register.
Appendix E Data Acquisition, Logging, and Display Program |
