COM troubleshooting

[CReese]

Hello again.

I am reading a DoMore with a couple ProFace screens with some scripts, and having some problems with TCP/IP Socket Errors and Connection Open Errors. I know these are not necessarily DoMore problems, but I thought you all might have some ideas about how to detect stale and/or unused sockets/connections and maybe clean things up from this end. I don't see anything obviously bad when sniffing traffic, and the programs will often work just fine. They error more often when I have the DMD running with status updates, so I think this may just be an issue of my screen not waiting gracefully. In any case, ideas are welcome ...

I'd throw the program into a read on a DL260, but I'd really rather not.

C

[ATU]

Can you add a slight com's delay in the Proface protocol settings?

[rlp122]

It sounds like an overloaded Ethernet connection as hard as that is to do with DoMore.  The devices need to give up some time slices so the Ethernet port has some breathing room to answer all of the packet requests.

[CReese]

The delay didn't really help, but what did was changing the maximum bit/byte sizes. I haven't tested enough to know the exact limit, but 75 words and 500 bits seems to work ok.

[BobO]

Just put together a test with 4 different Modbus TCP clients reading 100 input registers, 100 holding register, 300 inputs, and 300 coils, while the controller is running the new Ethernet I/O master function to 2 EBCs, and connected to DmD with status screens running. Haven't shown a single retry on any of the functions.

In fairness, that is on 1.1 RC3...not 1.0.9...and there have definitely been some fixes to networking. But I don't know that anything has been fixed that would affect Modbus/TCP. That is not to conclude that it isn't our problem, but I haven't been able to demonstrate any issues.