Switched to a Shared Outstation Set - Nuisance Comm Alarm from Spotty Backup Channel

[Tanquen]

They have around 30 sites that use radio and Modbus to talk to SCADAPacks at each site.

They have a newly added Cell Modem at one site so we setup a New Shared Outstation Set added the Serial and TCP channels to it and converted all the sites Outstations to shared Outstations to use the new Shared Outstation Set and it in turn uses the Serial channel for Line A and the TCP channel for Line B. All the sites with only a radio, have their switch type set to Fixed on Line A. Only the one site with a Cell Modem and Radio is set to Independent with Line B (the Cell Modem) as the Preferred Line.

This all seems to work on the two servers but some of the view nodes show random communication errors at some of the sites. The two servers do not, they show all sites communicating. Maybe the view only nodes did not sync everything but they are not polling so it's odd.

The main issue now is the one site with Cell and Radio keeps showing a comm loss error on the Radio Channel. That is why this site has the Cell Modem as the Radio is spotty but can get data. Is there a way to lessen the nuisance Comm Fails for this site?

It's Preferred Line B to the Cell is ok but it would be nice not to get the Line A channels comm fail alarm every five minutes or so.

We enabled the Heartbeat on the sites Shared Outstation so that if it fails over the the Radio it will move back to the Cell Modem when it is back up. If we don't it looks like it will stay on the Radio as it gets data often enough not to cause a failover. This also seems to stop the Line A channels comm fail alarm but then it will not fail back over from then Radio when the Cell Modem comes back.

[BevanWeiss]

So you have a central 'office' which has two Geo SCADA Expert servers, and a number of ViewX clients ('view only nodes')?

ViewX can only get it's data from a server.  So if the server is showing healthy communications, then all the clients shall be showing healthy communications for those sites also.

If you're seeing otherwise on the ViewX clients, then it might pay to confirm that the ViewX clients are pointing at the servers that you believe they are.

The outstation that has the two channels available should be showing 'Healthy, Multidrop' if both channels are available (according to heartbeats) and will change to 'Healthy, A Failed' or 'Healthy, B Failed' depending on which channel fails of the two.

If we expect noisy failures, we will often disable alarms from the outstation entirely.

And then implement alarming via some logic, and an internal digital alarm point, this lets us have more control over what is a failure, and how long before the failure is alarmed etc etc.

It can also be possible to do the time masking stuff by using Alarm Severities which are not displayed, and then alarm redirections to escalate the Severity into a displayable range.  But that does have quite a bit of reconfiguration and maintenance overhead to it.  Especially if you've started with the default 1 (Low) through 1000 (Critical) alarm severities... really doesn't leave you any obvious gap at the bottom to put hidden alarms. 

[Tanquen]

There are only the two servers. The view node with the issue is on a laptop so maybe it's not fully synced or did not update correctly. All the other view nodes also look at the same servers and are ok as was the laptop top before the Outstation reconfig. Everything should be coming from the servers so it seems odd that one view node thinks there are different communication errors. Maybe the operator is misstaken or it's a 2020 bug like the online help just opening a black screen?

For the Nuisance Comm Alarms we just disabled the Heartbeat. So it should fail over to the radio if the cell modem goes out but won't fail back to the preferred line unless the radio fails completely but it gets rid of the random communication alarms. It's always spotty but not enough to fail back over to the cell modem.

We just added a button to use the switch line function so the operators can put it back.