We have a multi-turn actuator that operates a 3" butterfly valve where we are experiencing intermittent issues where the valve will pause operation. This results in a fault in our system program due to excessive time for valve to open (> 120 sec) which shuts down the system. The valve actuator does not fault, but does occasionally shows a warning of WRN NO REACTION, which makes sense with the operation issue.
We have had a control company check out the data logging in the controller, and it shows repeated simultaneous open/close commands which result in the valve stopping. Command signals are coming from an Allen-Bradley PLC (Compact Logix L36ERM) through Allen-Bradley AC Output (1769-OA16) for the open/close command and Allen-Bradley AC Input (1769-IA16) for limit switch open/close. The program has been reviewed for discrepancies and there are no identified faults in the PLC components. We have replaced the Close command relay from the PLC and swapped out both of the Input/Output components of the PLC.
At this point, we cannot seem to identify where the simultaneous commands are originating, and as this is an intermittent issue, it is difficult to pinpoint a source.
We have had a control company check out the data logging in the controller, and it shows repeated simultaneous open/close commands which result in the valve stopping. Command signals are coming from an Allen-Bradley PLC (Compact Logix L36ERM) through Allen-Bradley AC Output (1769-OA16) for the open/close command and Allen-Bradley AC Input (1769-IA16) for limit switch open/close. The program has been reviewed for discrepancies and there are no identified faults in the PLC components. We have replaced the Close command relay from the PLC and swapped out both of the Input/Output components of the PLC.
At this point, we cannot seem to identify where the simultaneous commands are originating, and as this is an intermittent issue, it is difficult to pinpoint a source.