Isotherm (Customer) asked a question.
comm session failed
Greetings
what might be some potential reasons for this?
it doesn't appear to be anything in my code and it happens unpredictably but consistently. It only lasts for a few seconds but disrupts operation.
thanks and regards,
Isotherm
Hard to say. It appears that there were a series of timeouts first, and then the session failures were due to the session handle being bad following those timeouts. The comm server attempts to re-stablish the session, and then the errors clear. Sporadic timeouts like that are frequently due to something in the PC disrupting the comm server. Windows things... 😏
It happens when I'm disconnected from the plc (and it's in run mode) as well as when I'm connected. Could a loose connection on an i/o someplace cause it? I've checked it over and don't see anything but I have quite a few.
Something else may be happening when you are disconnected, but it isn't that. That particular error is the comm server reporting errors in the connection to the PLC. It has nothing to do with the PLC itself.
I'm using:
BX-DM1-18ED2-D
BX-P-USB-B
BX-08TR
BX-4AD4DA-3
could the usb module be causing this? even when not hooked to a pc?
sorry to be such a dolt, but where does the comm server reside?
The comm server is the part of Do-more Designer (DmD) that handles all PLC communications. The USB POM isn't causing any issues, I'm guessing that's what your connected through.
When you day "disconnected", are you meaning DmD is offline, or do you mean you pulled the cable? If you pulled the cable, but left DmD online, it's just reporting bad comma due to the cable.
disconnected means that I've put the plc into run mode (using the switch), used the "disconnect from plc" command, closed the project in the pc, pulled the usb cable and shut off the pc.
Ok, while disconnected, there can't be any comm errors, since DmD isn't talking to the PLC.
Greetings (again),
the timeouts and comm session failure shown above are being caused by a hardware watchdog that is rebooting the plc
how do I figure out what is tripping the watchdog?
thanks
How do I figure out what is tripping the watchdog?
Probably best to get you talking to technical support, either at ADC or here at Host. You can start the process at Host by emailing support@hosteng.com.