Dear all, i am using Omron PLC havin CPU CJ1M and three I/O modules i.e. first one is the digital input module ID211 the second one is relay output module OC201 the the last on is Analog output module MAD42. whenever the system is turned ON the error LED on the CPU unit lights up and stays ON indicating FATAL error i have checked in the manual the remedy of this error message and tried it as well but still the system sustain the fault status and doesn't moves to the next state i have tried the remedies illustrated in the user manual of this CPU but it didn't turned out to be successful. moreover it was stated in the manual that the error Flag having the following address 80CF is turned ON due to this Flag the error LOG keeps on showing the error message of "I/O bus error"............. what else i can do to over come this error.. please help me out.... waiting for your generous replies.........