Inside V1210 we can see advanced power suply with TRANSIENT VOLTAGE SUPPESSOR DIODE on input side BFM marked on foto. In my opinion, protection against reverse polarity is not provided in V1210 - because a symmetrical suppessor diode is used. It only limits the maximum supply voltage to 33V (in normal and wrong reversed polarity) . Therefore, incorrect power polarity can cause problems in the PLC power supply. If the PLC does not start in the normal polarity, I do not reco