PV550 alarm banner trouble HELP

I'm working on a PV550 connected to a SLC 5/03. Here's what happening... The machine went into alarm last night and the machine stopped. The alarm banner said that there was stepper drive fault. We checked the drive and it turned out to be fine. Seems like the proper alarm screen is not always coming up. Here's my question. How do I figure out what address has activated what alarm text in the alarm banner. In the "alarm triggers" the trigger tag is defined as N7:0 (tag name "Alarm"). The trigger type is LSBit.In "Alarm messages" there are 151 messages defined. The value/bit goes from 0 to 150. The first entry 0 doesn't have a message text entered. The trigger is the same tag name "Alarm". The alarm on the PV550 alarm banner is the last alarm message text that refers to value/bit 150 or entry 151. In the text editor window the text ID that refers to it is 982 entry number 656. The program was written in Italy and the original program with comments (probably in Italian) is lost. If I could just know what address is making that message pop-up I think I could figure out where the problem comes from. I read some posts about alarms banners, but I still can't get it.

Hmmm... I'm not quite sure I follow everything... What is the alarm number of the message text for the stepper drive fault again? Is it message number 151, with an alarm bit value of 150?

Tom,

In alarms set-up window, click on the alarm messages tab. On the left side you have numbers 1 to 151. The alarm I'm getting is 151. It's value/bit is 151. I just noticed something pretty important. The alarm values they are sending to the alarm banner are from N7:0 to N7:7. I think I know what is going on. If the trigger tag is N7:0 and the number of the value/bit is from 0 to 151, n7/1 should correspond to 1 and N7:9/6 should be 151.?.?

Yes, that's absolutely correct

Although, I think that 151 should correspond to n7:9/7, not 6.....

Tom,
You're right N7:9/7.... I'm getting tired! What a crazy way to address the alarms. I always use bits to activate the alarms. Much easier to follow.
Thanks

Also, something to think about...

How exactly is the "alarm" tag defined? Is it limited to 152 places, or does it have some "extra" room? I'm almost certain that if you try to trigger an undefined alarm it will give you a specific error message, but I'd hate for you to be looking at N7:9/7 when the only reason it was showing up was because it's the last alarm in the list..... And the actual alarm bit was N7:9/12 or something similar.

Tom,
I've double checked and it is the right alarm. When I looked at the ladder program it refers to fault I have on the PV550. I think I've found the problem after understanding how the alarm address system works. There is a problem in the ladder rung that turns on this alarm. They didn't allow for type of noise on the input. I'll add a slight delay before accepting the alarm to latch to filter out any junk. I hope I've got it. The only thing that worries me is if the real alarm happens just before the 151 alarm. With this type of set-up, I think the first alarm will be overwritten.
Thanks for all your help.

That's one reason that I don't actually use alarm banners, but instead switch the panelview to an separate screen with an alarm list. It takes a little more code in the plc to control the alarm resets/latching and the screen switching, but you see EVERY active alarm all at once....

When I started here, all of our machines still used the DL40 displays, so you could only display one message at a time, and nothing was set up to scroll thru the alarms if you had more than one active at a time.... I've been converting them to PV-550's as time permits, so that the other maintenance techs could actually see ALL of the alarms, instead of just one...

With the LSBit type alarm setup, the more important alarms are supposed to be assigned to the lower bits. All of the alarms can be active at the same time, but the lowest one will be displayed in the banner. When it is ack'd, the next active one will be displayed. So, the higher alarms aren't overwritten, they may be hidden in the banner, though, until the lower bit numbered (higher priority) alarms are ack'd.

In the alarm list (if used) all the active alarms will appear. It's not a bad way to set up alarming, once you understand how it works.

OkiePC,
That makes sense. I'm really not familiar with this method of alarms. I'm not sure how the priority for alarms was set-up. I'll take a look at that in more detail. I'll have to read up on that LSBit set-up a bit also... If I understand right, if alarm #1 goes on and at the same time #150 goes on, #1 N7:0/1 (in my case)will be displayed until it's ack'd. Then the hidden alarm #150 N7:9/6 (in my case) will then be shown. I may have dismissed this system a little too quickly...... But I do like the fact that if you make an alarm screen, like Tom suggests, that you can see all the other active alarms before ack'd any. Just depends on the situation.