Not sure if this applies to other HMIs, but for iFix specifically I would like to be able to enter a tag into the watchdog that is constantly changing (AI, for example) rather than being forced to use an alarm tag (DA) that needs to be triggered on and off.
This would work like how the heartbeat in Win911 sends an incrementing value every minute to an iFix tag so that iFix can know if Win911 is still active and available. In iFix I have it setup to do a check every minute or two to see if the value has changed from the last known value, and if it has, update the last known value with the current value. If the value has not changed in that time, it triggers an alarm in iFix.
The watchdog could be programmed in a similar manner and wouldn't require any specialized scripting on the iFix side. This would also remove a nuisance alarm that is generated every minute.
I have the same request for the same reason except my HMI of choice is FactoryTalk View. Using an alarm tag creates unnecessary entries in alarm logs and creates false notifications for the operators.