16
Technical support / Corrupted response from PLC
« on: June 19, 2008, 11:19:22 AM »
Lately we've been having a lot of problems with the communications between our HMI software and the T100MD888+ PLCs in our machine. We started logging the comms using Hyperterminal and a split cable and noticed a strange pattern. It seemed the response from the PLC was corrupted but it was always the same character of the response. For example, here are some of the corrupted responses:
@01Wb?4*
@01RD00003?001F001F001F001F001F001F001F001F0000000002B82B*
The "?" is what Hyperterminal prints in place of an unprintable ASCII code I think. These errors have been captured multiple times and the "?" always appears in the same location for those errors (there are others). This tells me it's not random glitches or RS232 noise.
Has anyone seen this pattern before? I'm at a loss as to what could be causing it.
@01Wb?4*
@01RD00003?001F001F001F001F001F001F001F001F0000000002B82B*
The "?" is what Hyperterminal prints in place of an unprintable ASCII code I think. These errors have been captured multiple times and the "?" always appears in the same location for those errors (there are others). This tells me it's not random glitches or RS232 noise.
Has anyone seen this pattern before? I'm at a loss as to what could be causing it.