H0-CTRIO PROBLEM

[trevorstripling]

I HAVE TWICE FOUND MY CARD WITH THE LIGHT BLINKING INDICATING PROGRAM MODE WHEN IT WAS SUPPOSED TO BE IN RUN MODE. THE INPUTS WERE WORKING FINE READING RPM, THEN THE RPM READING HANGS AND I FIND THE CARD IN PROGRAM MODE. I CYCLED THE POWER TO THE PLC AND IT STARTS WORKING AGAIN.
ANY IDEAS WHAT COULD BE CAUSING IT TO GO INTO PROGRAM MODE?

TREVOR

[MikeS]

can we assume the plc stays in run mode when the ctrio led is blinking?

it would also be interesting to know if you were to do a run-to-pgm-to-run transition to see if that will also put the ctrio back into run mode. if it doesn't, that could indicate the ctrio's ram has been compromised.

[trevorstripling]

YES THE PLC STAYS IN RUN MODE WHEN THE CTRIO LED STARTS BLINKING.

I WAS CHECKING AND TRACING WIRES LAST NIGHT AND IT DID IT AGAIN.  AND A RUN-PRGM-RUN OF THE PLC DID NOT CHANGE THE CTRIO STATUS.  I EVEN CYCLED POWER ONCE AND IT STILL BLINKED.  THEN I POWERED IT DOWN FOR A FEW MINUTES AND BROUGHT IT BACK UP AND IT STOPPED BLINKING.

I ALSO NOTICED THAT WHEN I TOGGLE SOME INPUTS THAT CONTROL OUTPUTS ON THE PLC, THE "A" LIGHT ON THE CTRIO WITH BLINK LIKE IT IS RECEIVING A PULSE, MAINLY WHEN I AM TURNING THE OUPUT OFF.  IF I SWITCH IT RAPIDLY, THE CARD WILL ACTUALLY READ AN RPM??

TREVOR

[plcnut]

I ALSO NOTICED THAT WHEN I TOGGLE SOME INPUTS THAT CONTROL OUTPUTS ON THE PLC, THE "A" LIGHT ON THE CTRIO WITH BLINK LIKE IT IS RECEIVING A PULSE, MAINLY WHEN I AM TURNING THE OUPUT OFF.  IF I SWITCH IT RAPIDLY, THE CARD WILL ACTUALLY READ AN RPM??

Do you have any inductive loads on your outputs (solenoids, motor starters,  relays, etc.)? If you do then they can easily induce currents into your input wiring and burn up I/O cards and also they can falsly trigger your inputs. Make sure that you separate any inductive load wiring from all other control wiring and use an isolation relay wherever you can with a shunt to protect your system.

[MikeS]

the only legitimate reasons for the ok led to blink are either the ctrio is unconfigured or the plc is in pgm mode. since the ctrio will go back into run mode after a power-cycle, that tells me the ctrio's configuration (in rom) is still intact. which only leaves the option that the ctrio thinks the plc is in pgm mode.

the ctrio knows the plc's mode because the plc places a code in the ctrio's shared ram. for the ctrio to change to pgm mode, that value must be something other than the 'run mode' code.

so now the question is what's changing that shared ram value in the ctrio, or, (assuming the correct value is getting written to the module) what's preventing the ctrio from successfully reading and/or acting on that value.

but before we go any further, is the problem still present, and if so, is there any more information you can give me about it, or any more symptoms?