I have a 5/04 which is in Fault and I am unable to clear the fault. I am also unable to go online with the unit. I have tried the following to clear the fault –
1. Placed the keyswitch in Program then Run.
2. Cycled power.
3. Removed CPU from the rack.
The PLC consists of a 5/04, AC Input Card, and a Analog Input Card. The RS-232 is used to communicate with a Redlion HMI. The system has been in service for at least 5 years.
I have been trying to chase down this problem for a few months. I get a call from the customer and they tell me that the CPU is in Fault. I instruct them to cycle the keyswitch and they tell me it’s still in Fault. When I get there (generally the next morning) the CPU is no longer in Fault. Either my version of RSLogix (V6.0) or the CPU does not have a Last Fault, so I have been unable to determine the problem.
This morning I went to the sight and the CPU wasn’t in Fault. I went online with the processor. I noticed that the units that send the 4-20mA signal to the PLC were not functioning correctly. We turned off the power to the cabinet and the customer swapped out the 4-20mA units. When we turned the power back on the CPU was in Fault. I tried going online with the CPU but couldn’t. RSLinx will show the CPU when it first goes searching for processors, but on the second round of the search it shows the processor unavailable.
My first thought is that it has something to do with the 4-20mA units (load cell displays) but since I can’t even go online with the CPU I’m not sure what’s up with it.
1. Placed the keyswitch in Program then Run.
2. Cycled power.
3. Removed CPU from the rack.
The PLC consists of a 5/04, AC Input Card, and a Analog Input Card. The RS-232 is used to communicate with a Redlion HMI. The system has been in service for at least 5 years.
I have been trying to chase down this problem for a few months. I get a call from the customer and they tell me that the CPU is in Fault. I instruct them to cycle the keyswitch and they tell me it’s still in Fault. When I get there (generally the next morning) the CPU is no longer in Fault. Either my version of RSLogix (V6.0) or the CPU does not have a Last Fault, so I have been unable to determine the problem.
This morning I went to the sight and the CPU wasn’t in Fault. I went online with the processor. I noticed that the units that send the 4-20mA signal to the PLC were not functioning correctly. We turned off the power to the cabinet and the customer swapped out the 4-20mA units. When we turned the power back on the CPU was in Fault. I tried going online with the CPU but couldn’t. RSLinx will show the CPU when it first goes searching for processors, but on the second round of the search it shows the processor unavailable.
My first thought is that it has something to do with the 4-20mA units (load cell displays) but since I can’t even go online with the CPU I’m not sure what’s up with it.