If the alarm status is "IO" it is just not visible in alarm view

Same problem here.

I still can't reproduce it willingly.

The HMI just think the alarm has been acknowledged already, if the alarm status is "IO" it is just not visible in alarm view. only way to acknowledge it is to force the alarm signal back and then acknowledge it, or restart the HMI.

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Split from Not possible to acknowledge alarm.

I’m not sure if this will help you Darius, but I think I have experienced a similar problem, but it doesn’t cause me the problem it seems to be causing you, because I have my own ‘Acknowledge All’ button – not part of the Alarm pop-up window – that raises the acknowledge bit to every single alarm.

But on the phenomenon I think you are describing, I have this. We have some doors on our equipment that can be opened, but because of controlling pressures between chambers, they should not be left open. So we have an alarm that activates after a time period, just to nudge the operators that the door is still open. Whereas a high-pressure alarm, for example, must be acknowledged by the operator even if the high pressure has been resolved, the door open alarms self-acknowledge. So as soon as you close the door, the annunciator shuts up and the alarm disappears off the window. That is done by setting the configured acknowledge bit, and it works every time with complete reliability.

We have another alarm that warns if there has been an interruption to the power supply, because the equipment can be left unattended for some time periods. So on a first scan of the PLC, I generate a power interrupted alarm. Because there is no ’alarm conditioned cleared’ circumstance for this alarm, the operator must explicitly reset it. I tried to make it that when the alarm acknowledge button in the alarm pop-up window is operated, that would also reset the alarm, again using the alarm acknowledge bit. And that works, sometimes, but it is iffy. Sometimes, for no reason I can discern, it does not. The alarm acknowledges, but it does not reset. The reason that is not so much of a problem is that the operator can still go to the ‘Acknowledge All’ button and reset it that way. So perhaps it is that iffyness of the acknowledge bit working that is causing your problem and if it is, you might consider an acknowledge all, or even a specific reset for your alarm that is accessible separately from the alarm pop-up window and raises the acknowledge bit for that alarm.

Sorry, just spotted the date issue with this thread. This reply should be on the other new thread.