1794-OA16 Relay output module off-state voltage

[bigLee]

Hello,

Is anyone familiar with the off state voltage of the channel for this module? I have it wired up according the page 14/15 of this manual:

https://literature.rockwellautomation.com/idc/groups/literature/documents/in/1794-in103_-en-p.pdf

When energized I get 120VAC L1 to L2. When de-energized it drops to 117/118 VAC.

Is this normal? Seems like that would still keep equipment connected to that channel powered.

I haven't tested with relays yet but figured I'd throw it out there to see what anyone thinks.

Thanks for any information.

 

[Mickey]

It's called leakage

Off state leakage is 2.25ma see pdf. And link

Depending on the load that should not be enough to power the device. Maybe solid state load but not inductive of resistive(low).

http://www.plctalk.net/qanda/showthread.php?t=87521

 

[GaryS]

An OA16 output is not a relay output it's a triac (Solid State)
for relay it should be OW
relays don't have an off state leakage

 

[Bit_Bucket_07]

An OA16 output is not a relay output it's a triac (Solid State)
for relay it should be OW
relays don't have an off state leakage

That's not really true. Off state leakage with a relay output is less than with a triac output though, since it is caused by leakage through a surge suppressor installed in parallel with the relay contact -- typically an MOV.

 

[Bob O]

This is for a 1756-OW16I but been nailed by it.


KB Doc ID QA423

 

[bigLee]

It's called leakage

Off state leakage is 2.25ma see pdf. And link

Depending on the load that should not be enough to power the device. Maybe solid state load but not inductive of resistive(low).

http://www.plctalk.net/qanda/showthread.php?t=87521

16
Is the 1794-OA16 a suitable replacement for a 1771 ODD B?

 

[Mickey]

See manual..

http://literature.rockwellautomation.com/idc/groups/literature/documents/in/1771-in020_-en-p.pdf

Looks like the 1771-OOD has isolated outputs the 1994-OA16 does not if that is important to you. Other then that they are both solid state and should work for you.

 

[bigLee]

See manual..

http://literature.rockwellautomation.com/idc/groups/literature/documents/in/1771-in020_-en-p.pdf

Looks like the 1771-OOD has isolated outputs the 1994-OA16 does not if that is important to you. Other then that they are both solid state and should work for you.

Mickey, thanks for the info. Thanks everyone. Just tested some pilot lights and a conveyor and everything works as with the 1771 module.

Thanks again!

 

[Mickey]

Mickey, thanks for the info. Thanks everyone. Just tested some pilot lights and a conveyor and everything works as with the 1771 module.

Thanks again!

As long as the lights are incandescent, LED's might be a problem with solid state outputs (leakage).

 

[77nomad]

As long as the lights are incandescent, LED's might be a problem with solid state outputs (leakage).

This is true. I had LED pilots running on a triac card. It was just what I had laying around at the time. I want to say I added a 1K resistor to keep the LED from glowing dim when off.