Hello Dear all,

I need to know that what is the pending and unacknowledged alarms? and what is their applications in WinCC?

Best regards

Tekabi

• Pending alarm: The alarm bit is still high
• Unacknowledged alarm: The alarm bit has gone low but you have not acknowledged yet

Keep in mind that not all classes of alarms need acknowledgement.

Hi Jeremy,

Thanks a lot for your reply.

Now, may you please tell me that, what do you mean "Alarm bit"?

Best regards

Tekabi

What I mean is the trigger for the alarm.

• Discrete alarms: this is usually one bit out of a word, the plc writes to this bit and triggers the alarm.
• Analogue alarms: a value exceeding certain limits

Kind regards,

Pending and unacknowledged alarm are categorized on basis of operator's notification. sometimes alarm triggering process condition is reached and resumes back to healthy state and the operator might have not noticed it. It may be critical to note this alarm that's why there is introduction to such two categories.

1) Pending Alarm is the active alarm. This means alarm is active and the process is still in abnormal condition.

2) Unacknowledged Alarm is the alarm which was triggered on reaching abnormal condition of the system and now system process is in healthy state. However it requires operator's attention to note its occurrence.

Once operator acknowledges the alarm, the alarm in second category will disappear but alarm in the first category will not disappear until unless alarm condition is removed. Once, alarm condition is removed the alarm will be moved to unacknowledged alarm list.