Dynamically Create Tags

Ignition
1

Is it possable in the runtime to dynamically creat new tags.

I do not know at development and deployment all the Alarms (Events) that there may be but when can identify new alarms from the PLC requiring the creation of a new alarm.

If so how would you do it?

Thanks in advance.

2

You can do it with SQLTags described here

Although I have to ask, If this is going to be a new alarm comming from a PLC, How would you know about it without knowing about it to poll for it? :scratch:

3

We have a block in the plc. These blocks are put in a fast scan. (usually 20ms or less). We sync the PLC with and IRIG-B signal. We tie bits to function blocks that look for a change in the value. If there is a change we put the bit (assigned and event number in the PLC) into a buffer with the time of the scan and a -priority number. We have an array of strings in the PLC. That way an new alarm and event can be added to the system from the PLC program without ever having to touch an HMI or SCADA. The ALRM/EVENT will be auto created in the SCADA :stuck_out_tongue:

4

Hmmm… that sounds something I would try :smiling_imp:

Alerting is totally internal (for now). You would have to create your own SQLTag on the fly with the correct alert states. It should then pop into existence in alarm :wink: .

The nicer way would be to talk nicely to Carl to get the API for the alerting bus and then write your own module that will place alerts on the bus and clear them again as required. Then no tags need to be created. How is your Java?

5

The buffer we populate with the scanned pointsalso contain entries from SOE cards. This allows us 1ms timing on enevts. We use this in power plants to stam breaker operations to ms timing.

If there was an API to the alarm and event system I would have no problem with the java.

6

The Module SDK is being released tomorrow. Posting events to the alert bus is really easy to do via the SDK. Creating tags is easy too. You could even go straight from OPC to the Alert system without creating tags inbetween, but of course then you’d be evaluating the data for when it is in/out of alert state.