Fault not showing up in Alarm Window

Hi Guys,

I have a peculiar problem. I have a Compact Logix PLC, which is hooked to another device. I have a PERIODIC routine, which cycles at every 213ms and reads a bit from this device. If this bit is HIGH, its a fault and it should show up on the ALARM panel.

I have other Digital I/O which do show up as faults when they are HIGH, in the ALARM window, but they are part of the MAIN Program [Continuous task].

How do I set the ALARM list in the PanelView touchpanel to display this fault, which happens in the periodic routine.

Thanks,

Sunnyvaleplc

The only way is to latch the alarm auxiliary bit, no matter how fast the alarm takes place it will stay on. That´s the way I do it, maybe some else has a better idea. You can unlatch this bit when you acknowledge it.

I would agree with having the alarm latch or hold state. You can check the alarm settings as well. There are settings for how long the alarm has to hold for it to show up. I think the min is 50msec, you could try that. There is also an update or refresh time that you could change. But, latching in the PLC is to me the best way to do it.

Thanks a lot for suggestions both of you. I will try the latching and unlatching inside the PLC. if there is a FAULT, then I will latch it, start a timer for 100ms and when the timer expires, I will unlatch it. This should allow enough time for the alarm window to update.

Thanks,

sunnyvaleplc