How you can inform the PLC that an alarm has been acknowledge in the XBTG

Goals and Symptoms

How you can inform the PLC that an alarm has been acknowledge in the XBTG

Causes and Fixes

Currently Vijeo-Designer V4.3 does have a way of allowing the user to tell the PLC which alarms have been ACK'd. You can do this by creating a trigger action for the alarm variable that sets a PLC bit-variable to True each time the alarm is ACK'd. If the customer would like to know exactly which alarms were ACK'd, then a separate bit-variable must be defined for each Alarm Variable.

In section "17.3.3.1 Trigger Actions" of the Online Help, there is an outline of the actions that can be setup whenever the alarm changes states. There can be up 32 trigger actions for each alarm variable. I believe that the customer will only need to set up one trigger action to set the flag to true when the alarm is ACK'd and one trigger action to set the flag to false when the alarm is active. If necessary, many other actions can be setup for the other state changes of the alarm.


In V4.4, we have a new feature called a Diagnostic Alarm Group that interacts with TSX Premium PLCs and Quantum PLCs. This Diagnostic Alarm Group has the ability to interact with alarm records directly on the PLC's Diagnostic Buffer. With this feature, the PLC instead of the HMI, will always contain the most up-to-date alarm information. The user will have the ability to ACK the Diagnostic Alarms just like how they have the ability to ACK HMI Alarms. With this feature, there would be some programming needed on the PLC; but this programming would be very trivial to the experienced user.

So far I have attached a sample project of the first proposed solution. Please have a look.