Alan Case
Lifetime Supporting Member
Hi, Wondering if anyone has ever installed 24VDC limit switches and PE sensors in close proximity to a railway track. The track is the return of a 25kV AC electric train system. In theory the voltage at the track is zero or ground potential and the current would not be excessively high as the trains are 25kV. What I am worried about is inductive voltage or noise on the signal wires feeding to the PLC.
Well not quite a PLC but a safety relay that uses 24V DC test pulses. ie 24 V is output from the relay with a millisec gap in the voltage level at a specific timing. There are 4 distinct test pulses and each one uses a different timing. The inputs of the relay monitor this 24V and also looks at the pulse timing to ensure it is the correct signal.
Any comments.
Regards Alan Case
Well not quite a PLC but a safety relay that uses 24V DC test pulses. ie 24 V is output from the relay with a millisec gap in the voltage level at a specific timing. There are 4 distinct test pulses and each one uses a different timing. The inputs of the relay monitor this 24V and also looks at the pulse timing to ensure it is the correct signal.
Any comments.
Regards Alan Case