We have 14 ac450 plc's connected through mb300 protocol. Beside 5 as500 series operator stations are installed to monitor and control the plant.

A problem has arisen in which events are being printed in duplicate on the printer as well as shown twice on operator stations.
They appear like this<pre>
KKS1 Pump1 command start
KKS1 Pump1 command start
KKS2 Pump1 Event running
KKS2 Pump1 Event running
KKS3 valve1 Event opened
KKS3 valve1 Event opened</pre>

 

Well, theres a bunch of things that maybe could possibly cause a problem like this. But most likely a "new" problem like this isnt just going to happen on its own. And you really dont provide anything like enough detail to do a proper diagnosis.

So, First up ... Is the problem real? Are you sure you arent confusing the "Active" and "Cleared" events that can generate very similar or apparently duplicated messages. Are the timestamps identical?

When did the problem start?

How many workstations are affected? All, Some? Just the one connected to the printer?

How many controllers are affected? All, Some?

What other work have you been doing on the operators stations, controllers or MB300 Network?

Did you mess with Process Sectioning or Alarm List configurations?

Did you mess with the RTA Event configuration files? If yes, have you got backups of the originals?

Is this the only problem you have or are there problems on network status displays? Missing events? Subscription problems?

Have you contacted supportline? What did they say?

Rob
www[.]lymac.co.nz