I have a cpu SIE6ED1052-2HB08-0BA1 with a 6ED1055-1MD00-0BA2 RTD expansion module. Sometimes, when I give power supply to systems the cpu doesn't recognize the expansion module (I suppose) and all analog input are at minimun value. I try to replace cpu and expansion module but I still have the problem. I give 24V power supply to all modules at the same time. How can I solve my problem?

Thank you