I am new to plc and have a question. I'm currently using a level transmitter to control water level in a tank. when the level gets low it sends an output to the controller and tells the solenoid to open and allows water to start filling the tank. while trouble shooting this solenoid I was reading the voltage on it and noticed that I was on the com to ground and the power wire when I checked them to ground but when connected to the solenoid it would not open, This does not make sense how I can have voltage on each wire to ground.