Group related questions

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#1

In FSQL I have a block group. In this block groups I am writing plenty of information to various PLC on the production floor. I have been getting some error messages from the block group and want some clarification so I know where I can go to fix the issues.

  1. In the block group When I expand one of the ITEMS. There are three things that as far as I can tell are the items that can be displayed. One of course is the actual value, in the event I am talking about is it boolean so it is either TRUE or FALSE. The next is E_FAIL which I can only assume means that the channel is active but that the opc server can not link up to the devise. The third is NOT CONNECT which I can only assume means that the OPC channel is not enabled so it ignores it. Would this all be a correct way of understanding these values?

  2. What controls these values? Mainly the difference between E_FAIL and NOT CONNECTED?

  3. If I have a device that reports back NOT CONNECTED, in most case so far it seems that that device will not try to send and receive data. And if I have a device a reports back E_FAIL it still attempts to send and receive data. Would this be a correct understanding?

  4. If the above is correct why is it that I have a block data item reporting back NOT CONNECTED, yet when the block group runs the error message in the status window stills says: GROUP EXECUTION ERROR. The following OPC write errors occured. And although in the block data items the device is reporting back NOT CONNECTED in this error message it says the device is E_FAIL. I only have one OPC item that is acting this way. The other 60 that are reporting back NOT CONNECTED, are working quite well and do not throw the error message.

The version we are running of FSQL is 4.1.5

#2

Generally your observations are correct.

One thing to mention off the bat is that the item state “NOT_CONNECTED” is also the default value for an item- so it basically means that it has never received a value update from the OPC server. E_FAIL is a message back from the OPC server when FactorySQL tries to subscribe to an item it doesn’t like (this varies from server to server, some will report OK at the subscription level and then send a bad opc quality code). So, in those particular cases it may not be sending an error code, but then it may not be sending anything else, and thus the quality stays “NOT_CONNECTED”.

Now, I’m pretty sure that in either case FactorySQL will try to write to OPC if it thinks it should. And if it tries to write to an item that’s not available, the majority of the time it will result in an “E_FAIL” message (I say majority, because different opc servers can vary a tad). This e_fail is referring to something different than the other- this is the write operation. The other was the subscribe operation.

Hope this helps a bit,