Program PLC 5 To Fault

The Plc Kid · Feb 20, 2015

Is there a way to program a plc 5 to fault after a few minutes? Customer wants to setup something like this for testing interview candidates.

I have made a rig like this using the math overflow in slc systems but AFAIK plc 5 units will not fault on that. Any other ideas?

jstolaruk · Feb 20, 2015

Indirect address into never never land. Change a good one to a bad one after a timer gets done.

Bob O · Feb 20, 2015

Would a negative value in a Timer Preset do it?

harryting · Feb 20, 2015

The infamous divide by zero?

oops, you ready mentioned it?

How about array out of bound, ie Address[11] but Address only goes to 10.

Bob O · Feb 20, 2015

Negative value in Emulator didn't fault.

Bob O · Feb 20, 2015

Indirect address as suggested worked like a champ in my emulator. I must be bored. lol

jkerekes · Feb 20, 2015

Do a repetitive jump to a label backwards in ladder. Eventually the watchdog will timer will trip.

Ron Beaufort · Feb 20, 2015

poke around on the Errors tab of the Processor's Status file ...

notice that you can make an assortment of faults occur in a running processor just by typing various bit patterns into S:11 (Major Errors Flags) ...

find something "juicy" that you like – and then set up something to MOV (Move) the "bogus" value into the flags location ... you can even move different values into S:14 (Rung Number Where Fault Occurred) and into S:13 (File Number Where Fault Occurred) to see if the applicant realizes that that all-information is also available ...

if you want to get crazy with it, try sending MSG (Message) commands over a network into the "test" PLC ... you can make it respond to all sorts of "ghost" problems like this ...

remember – you must use these powers only for good ...

daba · Feb 20, 2015

Ron Beaufort said:
remember – you must use these powers only for good ...

I've dropped a few Easter Eggs in various systems through the years, nothing that will damage the system or stop it working as it should... does that qualify as "for good" ??

Bit_Bucket_07 · Feb 20, 2015

daba said:
I've dropped a few Easter Eggs in various systems through the years, nothing that will damage the system or stop it working as it should... does that qualify as "for good" ??

Did you ever have Santa's sleigh drive across the HMI's plant overview display on Christmas Eve?

jdbrandt · Feb 21, 2015

The Plc Kid said:
Is there a way to program a plc 5 to fault after a few minutes? Customer wants to setup something like this for testing interview candidates.

I have made a rig like this using the math overflow in slc systems but AFAIK plc 5 units will not fault on that. Any other ideas?

Not "fault" specifically, but an interesting thing to troubleshoot....Set S:77 to 499.

Cody · Feb 21, 2015

When I do a training class I have a lab like this. I have a series of faults that occur in progression....

1. In one subroutine, move a negative number into a Timer Preset, where the TON is in a different subroutine

2. Jump to a subroutine that doesn't exist (after a delay)

3. Have an indirect address point to a contact with a non-existent data table bit

4. Overflow the nested subroutine limit

The Plc Kid · Feb 21, 2015

Thanks for all the great ideas Gentlemen. I think this will help me setup something that will give the customer what he wants.

They have hired a few tech recently that had lots of classroom training like local tech school, AB classes,etc. and could do the basics but when they had to troubleshoot something difficult they were forced to wait on a contractor when they were down.

They want a test rig to separate the men from the boys. They have a lot of PLC 5 stuff still.

I told them they should consider sending all their guys to Ron's PLC 5 class and that would help them with troubleshooting.

Ron Beaufort · Feb 21, 2015

They have a lot of PLC 5 stuff still.

yep - there's still TONS of those systems out there – and I still have a lot of requests to cover them ...

They want a test rig to separate the men from the boys.

quite a few years ago I wrote a test for a local company that you might want to consider using – especially if analog input and output signals are involved ...

once a guy had made it far enough through the interview process, they'd put him into a room with a PLC-5 system – basically just a stack of parts – not even mounted in the chassis – and a working laptop ... the test was to set up a simple 4 to 20 mA analog input signal – and "call us when you've got it working" ... there was no time limit – and all of the manuals were available too ...

the "men" who knew how to handle the Block Transfer Reads and Writes could have it set up and working in about ten minutes ... the "boys" who didn't – well – they'd always just give up and go home ...

The Plc Kid · Feb 22, 2015

Ron

I think they are looking to hire 10-12 people total. I am thinking of using some of the fault ideas in a running chassis to seperate the men from the boys but they also want 4 wise men (lead men) out of that group of 10-12 so one for each shift.

I am thinking I may use your suggestion of assemble, wire, program some analogs and maybe some RIO remote chassis as they have a lot of that.

Your test will be good to seperate those 4 wise men from the men. Thanks for the suggestion.

Program PLC 5 To Fault

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