After a comm failure, Lookout will not accept poll poll responses after comm is good again without a restart. Why?

[BobM]

After a comm failure, Lookout will not accept poll poll responses after comm is good again without a restart. Why?

[Khalid]

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What's very likely happening is that Lookout is skipping the set number of Poll requests. Most driver Objects have this setting where you specify Skip every 'x' poll requests after comm failure with a default value of 5. If you change this to 0, you should be able to Poll again.

Hope this helps.

Rgds,

Khalid 🙂


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[BobM]

Khalid,

I appreciate you taking time to help me. Iam afraid I did not articulate the problem very well. Here is another try.

Lookout is polling a remote RTU 11 miles away thru a radio link. At some time ( usually about 2 am), the radio link goes down (I have no idea why but I think it is a radio propagation problem). Lookout continues to poll (skip poll requests after comm failure is set to 0). When the link comes back up (usually about 7 am), the remote RTU starts responding. Lookout will not accept the response until you close Lookout and then rerun it.

Thanks again for you help.

[Khalid]

Hmm.. what driver Object are you using? What radio modems are you using? I have seen similar issues with ScanData RTUs and Bell 202 modems.

Did you check the diagnostic log file in Lookout for any anomalies? For more prompt resolution, I guess you should contact NI's Support team and bring this to their attention.

Let us know what the outcome is.. and if there's anything that we can discuss here.

Thanks and regards,

Khalid

[BobM]

Khalid,

I am using the ScanData LMX RTU with the Bell 202 modem option. Were there any resolutions of the issues that you mentioned?

I have looked for anomalies in the diagnostic file. There were none that I could see, but I am relatively new at Lookout programming.

Thanks again

[Khalid]

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We found this problem only on some machines. So, a quick resolution would be to try some other make of computer (at least one with a different motherboard).

After a lot of trouble-shooting we reached the conclusion that the incompatibility will come up most frequently with this particular combination:

Scan-Data Bell 202 modem + Lookout's serial routines + certain UARTs on certain motherboards.

Scan-Data can say that it is not their problem, since it doesn't happen with other software. However, an interesting note - we were also able to replicate the lack of communication from the UART with PortMon, which is a third-party freeware tool. So, we think that there is something
unusual about the way the RTUs' modems communicate with that type of UART and Lookout is more sensitive to this situation.

After changing values for RTS, CTS, timeouts and other comm. parameters, we decided to try one of NI's serial cards. It worked. I am not suggesting you buy NI's serial card.. but that's what we did.

Disclaimer: Though your problems sounds similar.. it could something else.. so please don't hold me for anything!

Hope this helps.

Regards,

Khalid

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[BobM]

Thank you. You have been extremely helpful. I won't hold you responsible for anything. This gives me new avenues to exolore.

Thanks again and best regards.