Is it a relay output or not ???

Status
Not open for further replies.
V

VinceS

Senior Member
While using an AB 1794-OW8 module FLEX Digital Contact Output Module, provides 8 isolated Form A (normally open) contacts capable of switching up to 2.0 A at up to 230V ac and 125V dc. I found, under no load, 15V ac voltage leaking through the contact in the open (off state), this should be a dry contact reed relay. When energized the voltage potential was 100V ac. Yes the module was bad and when replaced the true potential of 115V ac was again applied to the output in the closed (energized state) and 0V ac in the open (off state). I have always thought this was a true relay output. I am speculating that carbon on contacts may have allowed for leakage when closed, and maybe acted as a resistance when closed. Any thoughts or speculation...
 
A-B description in the 1794-OW8 manual is:

Specifications - 1794-OW8, -OW8K Relay Output Module

Outputs per Module: 1 group of 8 Form A isolated (normally open)
electromechanical relays

I also see these as isolated relay contacts (similar to the 1771-OQ16 that I use in a PLC5 system) as opposed to a sourcing, sinking, or open collector output.

Not sure what you had happen to your circuit. The voltage readings you gave do not make sense, but you can't argue with the module replacement correcting it. There might also still be a system wiring, logic, or other cause that could rear it's ugly head as time goes on.
 
Status
Not open for further replies.
Top