FactoryTalk View SE Tag Group Change Event

I want to use the change event to run some VBA code. It seems that sometimes the change event is missed causing the changed tag to be ignored.
Has anyone experienced this problem?

More details, please. Which object are you referring with the change event?

I have set up a tag group and I am using the change event for the group. The tag I am expecting to trigger the event is a Boolean tag.

Is the display always loaded? Did you use the Withevents key word?

Yes the display is always loaded. The Withevents keyword I have not come across! I do know that the change event triggers OK most of the time, its just intermittently it seems to miss!

Actually, I do use WithEvents as follows:
"Public WithEvents oGroupFlags As TagGroup" and oGroupFlags is the group which has the change event coded.

Can you post the code?

Sure:
Private Sub oGroupFlags_Change(ByVal TagNames As IGOMStringList)
'this function monitors flags from PLC to call required functions 16/01/13 krm
Dim lTagErrorList As StringList, blnReturn As Boolean

If gblnRecordingMix Then Exit Sub 'in case routine is already active recording a mix
gblnRecordingMix = True
If fncGetTagValue_Flags("{::[CPLX]Program:Mixers.HMI_Record_Mix_Med}") Then
subRecordMix 'record batch
Call subSetTagValue_Flags("{::[CPLX]Program:Mixers.HMI_Record_Mix_Med}", False) 'reset flag
End If
gblnRecordingMix = False
End Sub

the flag gblnRecordingMix is used to ensure any secondary calls to subroutine are ignored. The group has 2 tags at present, one is the tag being monitored here and alos a cyclic 3 second bit to call routine in case it is missed by change of state of Record_Mix flag.

The monitored tag, in the PLC... Does it latch in the PLC? or is it just an OTE?

For my event based triggers in FTView, I latch the trigger bit in the PLC (with a 30 second timer to unlatch it and set a fault in the PLC for when View decides it is time for a reboot), and then unlatch it as you are after the routine has processed.

Doing that, you also don't need to add your gbInRecordingMix flag and logic, as the event is only triggered once from the PLC, so you can just exit if your PLC tag is zero. If it is 1, then process your logic.

Tks rdrast, I'll put that code into action.