event history

Hi,
I've just started working with logix5000 and have an awful lot to learn! My question is I want our engineers before clearing a fault that's stopping our production to save a the program so we can see the event history before the fault occurred, what's the best way of doing this?? Very grateful for any help received!

Welcome to the forums! If you mean that the PLC is faulting, the easiest way I know is just to go online, and befor eyou clear the fault go File>Save As. Save the file somewhere, then close the program and reopen the original file. Reset the fault and restart the PLC. Then the file you saved gives you a snapshot of exactly what was going on in the PLC at that moment.

If you're talking about machine alarms stopping production, it gets a bit more complicated...if you can give us a bit more info on what you want to achieve we can probably make some more helpful suggestions

Thanks for that!
What we want to see is what inputs were activated (ie What the operators were doing !!) before a fault occurs on our system. System is controlled by SCADA factory talk. We've been taking screenshots on the SCADA when we have issues, but we need to delve a bit deeper than that and see what caused whatever issue we've had. Would a snapshot of the program when saved online do this?
If it does great!

Ah, so you mean machine alarms, not a PLC fault. Just to clarify, a PLC fault is when the actual processor faults and stops executing code because of bad logic or something. Which is NOT what you want here, right?

The critical piece of information in that question is "what inputs were activated BEFORE a fault occurs"...very difficult to pre-empt a fault! To me, this is a case for diagnostic coding. Once the fault occurs, save the file as described above before anything is reset or cleared. That will show you the state of all inputs/outputs/tag values at the moment you save it. From there you may have to dig into the logic a bit. If you find that "Fault ABC came up because timer XYZ timed out", then you have to trace back and ask "what can cause timer XYZ to time out?" If there's only one thing - great, you're one step closer to the root cause. Repeat previous step! If there are multiple things, and you're now not sure which one caused it, that's when you would write some diagnostic logic. There are simple and complicated ways of doing it, the more information you want the more complicated your diagnostic code will be. The simplest way is something like this: say you have three tags that can activate the timer. Call them Tag 1, Tag 2, Tag 3. Create 3 more tags, Tag 1 Trap, Tag 2 Trap, Tag 3 Trap. Then put in a line of code so that when the alarm occurs, you use a oneshot to latch the "Trap" tags for each of the tags that are on at the time. So you can come along to the PLC and say "at the instant this fault occurred, Tag 2 was on". And so on. Of course, this doesn't necessarily give you the whole picture. Tag 1 might be coming on for 1 second, then Tag 2 comes on just before Tag 1 turns off, and then Tag 3 does the same thing - so all three tags are contributing to the fault but you only see the one that was on when the fault actually occurs. Like I say, the more detail you want, the more complicated your diagnostic logic gets!

Good luck, if you get stuck post some more details and we'll try and help out!

I agree with ASF. You will have to write some code in the PLC to monitor your input conditions and trigger alarms (latched) on the HMI based on incorrect input sequence or anything such which you assume would fault the machine. Having the alarms on the HMI would mean that you can also have a time stamp on each alarm which would be helpful when troubleshooting. Only engineers should be able to clear alarm history. Hope this helps.