Reg event callback while loop

[CarlosSp]

Hi, I try to put a Reg Event Callback inside a while loop where it has to be refreshing constantly,and I have the next error:

"LabVIEW:  (Hex 0x4A5) You cannot register the same event on an object multiple times."

If I remove the while loop it works fine, but I need that loop. How do I solve the problem?

Thanks

[Jarrod_S. · Accepted solution]

Are you registering the event with the same callback VI everytime? You don't need to do this. Once registered, the callback VI will trigger on every event fired.

You would only need to re-register the event if you wanted to change to a different callback VI. To do that, you'd first have to call Unregister for Events on the first event registered.

[jcarmody]

You only need to register once, so you can put the Reg Event Callback function outside the loop.  No?

[CarlosSp]

Oh!! Thank you, I didn't know. Now works fine.

Thank you

[CarlosSp]

Well, now I think I have another problem. In my VI Ref of the callback event, I have an operation of +1 that goes to a property of an activeX so I put the callback in a sequence structure before the while and now doesn't increase in 1 that activeX property.

[CarlosSp]

Ok, solved. Thank you once again 🙂