jesusvasquez posted a topic in SiemensHello everybody, I'm designing a safety system for a HV power supply. The idea is to use a series of 2 contactors to supply power to the system controlled by a safety PLC. So, it is a typical application. The problem is that the power supply and the contactors are are installed on HV platform, isolated from ground, where the PLC is installed. I think the only possibility is to use an optic fiber link. Does any body know is there is any way to connect a contactor to a PLC output using an optic fiber link, without compromise the cyclical checking performed by the safety module (as I understand, the outputs are continuously check in order to detect wire breaking). The alternative that I have is to use a distributed IO system installed on the platform, connected with a Ethernet Optic Fiber to the PLC: for example using a simens S7-400 PCL with a IM467FO modules (on ground) and a ET200M system with a IM153-2FO module on the platform. But I wonder if there is something more simple and cheaper. Thanks!