RSLinx Classic Professional Question on Station Diagnostics

[Cranbarry 0]

In RSLinx (Rev. 2.51.00.21(CPR7)) If you go to the Station Diagnostics (Right clicking on a SLC-5/04) it brings up a box full of ALL KINDS of neat information... Problem being - I can't find ANY information on what this stuff is.... and/or what it means... We are having communications issues with (1)PLC out of 15 - Messages are getting dropped or lost. Although we can take another processor and put it right underneath it and put the "messaging" portion of the program into this processor and it works fine.... We have changed the processor, the backplane, the power supply.... Where can I find out what this information means and/or what it takes to fix it??? ABSS.bmp

[Eddie Willers 2]

I think your problems are not coming from the messaging application running inside the SLC-5/04, but rather from another node on the network, maybe one of those computers. Two diagnostic counters in Node 52 stand out: Queue Errors: 40552 Buffer Not Armed: 40552 This indicates that incoming messages to this SLC-5/04 were not able to be serviced because the incoming message buffer was full. You can increase the ability of an SLC-5/04 to service incoming messages by clearing the Comms Service Bit or adding SVC instructions inside the ladder program. The best thing to do is to figure out which one of those PC's is hammering the SLC-5/04. There may also be some media or noise issues on this system that are indicated by the token passing error counters.

[BobLfoot 302]

Nice analysis Eddie, but the original posters question and mine as well was where do you find the definitions of all the Diagnostics Information.

[Eddie Willers 2]

A fine point. I found another list of the same statistical counters in the DF1 protocol command reference (1770-6.5.16, I think) and in the RSLinx online help file. But a lot of the DH+ diagnostic counters have to do with the token-passing mechanism of DH+, and that's the part that is proprietary to A-B, and they don't describe or publish.

[BobLfoot 302]

Thanks for the manual reference Eddie, I'll check it out.

[Cranbarry 0]

Will turn off the PC's and see if that makes any difference... Sure would be nice, if AB would provide information on the tools they provide. We have done the SVC in a couple of places in the ladder logic in the PLC that seems to be having the issues...

[paulengr 44]

Sounds to me like you need to take a close look at your communication traffic and set everything to reasonable values. This is not uncommon stuff at all. In the plant I work at we had constant problems with the network being slow in one particular area. It didn't help that it had both HMI and PC stuff sharing the same network. When we carefully analyzed what was going on, it was kind of obvious. The MSG instructions were all reasonable. It was the fact that the SCADA was set to poll every 10 milliseconds on almost everything. This was a major performance issue for the PLC's, the SCADA, and the network in general.