Rick Christopherson
Senior Member
I apologize if this is not the correct forum to be posting this question, but I know there are a lot of extremely knowledgeable engineers that hang out here.
As a hobby, I design and build PLC-based testers that evaluate portable electrical power distribution cables and panels. The newest generation of my tester also includes a "load test", where I drive high-current through the cable and look for unexpected voltage drops due to poor connections. For my actual testers, I use an expensive panel voltmeter that can read the high voltage (ranging from line voltage down to voltage drop) and convert it into an analog signal that my PLC can interpret.
The problem I have now is that I need to build a low-cost demonstration unit where I simulate this function without the high cost of a load bank and panel meter. I know I could do this with a simple voltage-divider potentiometer, but I was wondering if anyone had any knowledge of a low-cost voltage sampler that would isolate my PLC from accidentally ever seeing full line voltage. Having a digital display like the actual panel meter would be icing on the cake.
The image below is the actual unit I built that uses this feature. I want to build a demonstration unit that looks like this, but without the high cost.
As a hobby, I design and build PLC-based testers that evaluate portable electrical power distribution cables and panels. The newest generation of my tester also includes a "load test", where I drive high-current through the cable and look for unexpected voltage drops due to poor connections. For my actual testers, I use an expensive panel voltmeter that can read the high voltage (ranging from line voltage down to voltage drop) and convert it into an analog signal that my PLC can interpret.
The problem I have now is that I need to build a low-cost demonstration unit where I simulate this function without the high cost of a load bank and panel meter. I know I could do this with a simple voltage-divider potentiometer, but I was wondering if anyone had any knowledge of a low-cost voltage sampler that would isolate my PLC from accidentally ever seeing full line voltage. Having a digital display like the actual panel meter would be icing on the cake.
The image below is the actual unit I built that uses this feature. I want to build a demonstration unit that looks like this, but without the high cost.
