Spurious Tripping of Guard PLC.

R

Thread Starter

Ravichandran

Dear all,

We are using Allen Bradley Guard PLC 2000 for our boiler’s burner management system.

We are getting spurious trips of the boiler without any events generated.

Some times we are getting ‘signal out of limit’ alarms in some of the connected inputs (analogue) and the next moment, the PLC trips the boiler.

We have trends for some of the tags which are coming through ASCII from PLC to DCS. These tags sometimes show momentary fall to zero and resumes back (around 10 sec.)

Field devices are ok in all respect.

Somebody please explain about the guard plc concept and how to come out of this problem.

All the diagnostic LEDs are healthy.

Can the PLC go to failure stop mode if any one of the input malfunctions?

Is there anything about the controller setting?

With Best Regards,
Ravichandran
 
I can suggest you to use Autem products http://www.autem.de with the ADD USB box you will can to analyze your signals independently that your controller or I/O cards, so you can determine where is your real problem.

contact me at autcon20ATyahooDOTcomDOTar if you are interested for further assistance.

Best
 
I can suggest you to use Autem products http://www.autem.de with the ADD USB box you will can to analyze your signals independent that your controller or I/O cards, so you wil can determine where is your real problem
contact me at autcon20ATyahooDOTcomDOTar if you are interest for further assistance
Best
 
Dear user of AB Guard PLC 2000, Mr. Ravichandran

We have exactly the same problem like you had with a BMS application with GuardPLC 2000 for a refinery in Chile, South America.

Please, could you indicate the solution you used to solve that problem ? Or could you give us a contact in Rockwell Automation/ Allen Bradley who helped you to solve this problem? We need an urgent solution because of all the problems this is causing in the refinery.

Thank you very much in advance for your help.
Best regards,

Hugo Fernández
[email protected]
 
G

Gaston Vallejos

i solve the problem. (my english is not good)

if the guard plc (any family) is switching the outputs off or spuriously, you must reconfigure the peer to peer comunications, chosy a prfile medium and nousy. then check the watch dog time in all modules and pull up the rto time.

other causes of this is the source. if your power suply is a 24vdc, secure that the negative pole is grounded earth. if not, please put a bridge in to guard plc negative pole to earth, this elimintate de voltage diferents and noises.
 
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