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Hi All
Has anyone out there seen any problems with ControlLogix PLC's apparently caused by problems with the power supply or any other mysterious failures? One PLC we have used has had some strange behaviour. The symptoms are that the PLC stops communicating (by serial or Ethernet)and the program stops executing, but the run light on the processor shows that it is still running.. If the power is cycled the PLC returns to normal. On one occasion after restoring communication the processor showed it was running but the program was not executing (outputs not coming on). A loose wire was found on the power supply to the PLC and IO cabinet, and also on the power to the Ethernet switch that the PLC was communicating through. After fixing these the problem has not returned. The PLC was sent to AB but they did not find a problem and said that they have not seen this happen before. The PLC in question is a 5555 with V8.02 firmware.
It seems clear that a loose wire could cause some strange problems, but I need to be able to assure the customer that we have solved this issue. Without some feedback from AB or others that have seen similar problems the customer may not be convinced and still fear that there is some danger of future failures.
Regards,
Dave Campain
Has anyone out there seen any problems with ControlLogix PLC's apparently caused by problems with the power supply or any other mysterious failures? One PLC we have used has had some strange behaviour. The symptoms are that the PLC stops communicating (by serial or Ethernet)and the program stops executing, but the run light on the processor shows that it is still running.. If the power is cycled the PLC returns to normal. On one occasion after restoring communication the processor showed it was running but the program was not executing (outputs not coming on). A loose wire was found on the power supply to the PLC and IO cabinet, and also on the power to the Ethernet switch that the PLC was communicating through. After fixing these the problem has not returned. The PLC was sent to AB but they did not find a problem and said that they have not seen this happen before. The PLC in question is a 5555 with V8.02 firmware.
It seems clear that a loose wire could cause some strange problems, but I need to be able to assure the customer that we have solved this issue. Without some feedback from AB or others that have seen similar problems the customer may not be convinced and still fear that there is some danger of future failures.
Regards,
Dave Campain