dmmons
Member
Not really a PLC question, but I know you folks have run across a lot of stuff in your collective experience:
I have a pressure switch with two normally closed contacts. When the pressure builds the needle moves a pin and it actuates the switches (breaks the contacts) as it reaches their respective setpoints. When I put an ohmmeter on the wiring terminals for each switch, I see some resistance (~1000 ohms) when i actuate the switches i lose all connectivity as expected.
However, when I run 24VDC through the switch and then actuate it, the circuit remains closed. It acts almost like it is latching itself.
I tested the switches with just a power supply and a light to remove any possibility of something being wrong with my control circuit. With the same results.
I have contacted the manufacturer and explained what I found. They said it sounds broken and I should return it. But it seems odd that two separate switches would be broken. I don't want to waste any time by swapping in a new set of pressure switches and having the same result.
Any ideas?
I have a pressure switch with two normally closed contacts. When the pressure builds the needle moves a pin and it actuates the switches (breaks the contacts) as it reaches their respective setpoints. When I put an ohmmeter on the wiring terminals for each switch, I see some resistance (~1000 ohms) when i actuate the switches i lose all connectivity as expected.
However, when I run 24VDC through the switch and then actuate it, the circuit remains closed. It acts almost like it is latching itself.
I tested the switches with just a power supply and a light to remove any possibility of something being wrong with my control circuit. With the same results.
I have contacted the manufacturer and explained what I found. They said it sounds broken and I should return it. But it seems odd that two separate switches would be broken. I don't want to waste any time by swapping in a new set of pressure switches and having the same result.
Any ideas?