I am using RSLogix 5. I have several conditions in a program that will generate a alarm. Any of the alarms will close a common single digital ouput that goes to a local annunciator panel. If the alarm condition still exists when the local annunciator is acknowledged, the alarm window will remain lit. If another alarm is generated, I need the output to the local the local annunciator to open then close again to get the operators attention. Are there any suggestions for a simple logic fix using only one digital output?

A lot depends on how your present logic to drive the Alarm Ouput of the PLC is written. This can be done, but it will involve adding what I call memory logic. And probably involve giving each alarm a unique identifier either bit or number if it does not already.