SLC500 "FLT" indicator

Can anybody help me? We have a newly installed slc500 run by rslogix 500 Professional. During trial runs on our conveyor, the plc unit is in a "RUN" mode with the pilot lamp lit beside the "RUN" which is OK. When we try it again it shifted to "FLT" with the red light blinking beside it. What is the cause and how can we solve the problem? We tried to turnoff the power supply to the plc and turn it again but still the "FLT" is blinking. The conveyor doesn't work anymore. Can anybody help me? Thanks a lot.

If you have a blinking fault light, it could be a couple of things:
1) a recoverable major fault
2) a minor fault
3) a memory error (program corruption or total loss of program)

Connect your PC to the SLC and open RSLinx. Look for whatever communications driver you are using to communicate with it and expand the driver. Make sure you can still see the SLC in the tree under the appropriate comms driver. If the SLC shows up with the name of the program that was loaded in it, you have some sort of recoverable fault. If it is listed with the name "Default", you have either suffered program corruption or program loss and you will have to reload the program using RSLogix500. In the case of a recoverable fault, go online with the SLC using RSLogix500 and open the processor status tab in the project tree. Click on the error tab and read both the Major Fault Code (S:6) and the text description of the fault below it. Refer to the fault codes in RSLogix500 online help to determine the possible root cause/solution to the fault.

The reason you get the FLT light is that there is an error in the PLC logic which is causing your PLC to fault. You must go online with the processor using RSLogix 500 (or other suitable software programming software for the SLC) and look at the processor status. The type of error and the rung in which the error occurs will be displayed in the processor status.

Good Luck.

Ed McClure
Delta Automation