adccommunitymod (AutomationDirect) asked a question.
BRX Relay output module
Created Date: February 16,2019
Created By: BobbyS
**** This post has been imported from our legacy forum. Information in this post may be outdated and links contained in the post may no longer work.****
I have a Bx-12TR relay module. I am wanting to switch 120 vac but am getting about 10 vac bleed through and it keeps my 120 vac LED indicator on my switch slightly lit. Is there a work around for this?
Created Date: February 16,2019
Created by: BobbyS
I have a Bx-12TR relay module. I am wanting to switch 120 vac but am getting about 10 vac bleed through and it keeps my 120 vac LED indicator on my switch slightly lit. Is there a work around for this?
Created Date: February 17,2019
Created by: ControlsGuy
Leakage is surprising with a mechanical output. Must have an RC around the contact. Add more load.
Created Date: February 17,2019
Created by: BobbyS
Leakage is surprising with a mechanical output. Must have an RC around the contact. Add more load.
That is what I was thinking too. Thanks for the input, I'll load it up lol.
Created Date: February 17,2019
Created by: BobO
There is an RC to quiet noise. It does produce a small amount of AC leakage.
Created Date: February 17,2019
Created by: BobbyS
There is an RC to quiet noise. It does produce a small amount of AC leakage.
OK, thanks, BobO
Created Date: February 18,2019
Created by: Mike Nash
I 've personally decided LED indicators on AC with the BRX relay outputs is just a bad idea. "Small " leakage is relative and LEDs sure become ambiguous when one that is "off " leaves you wondering. I went back and replaced them with incandescent.
I tried RC snubbers across the lamp and found I could get them almost "off " but it took quite a high value capacitor and low value resistor and snubbers aren't cheap. The D2-12TR doesn't use RCs and doesn't have the glowing when off problem on 120VAC.
Just my experience.
Created Date: February 19,2019
Created by: ControlsGuy
Typically, I'll drive pilot lights with DCDOs. Not sure the RDOs need snubbing, though. Never had an issue with any of the older modules that didn't have it (and I never snub the loads).
Created Date: February 19,2019
Created by: ControlsGuy
Oh, when you say "noise " are you referring to the effect on logic in the PLC rather than output circuit electrical design? If so, then that would be another matter
Created Date: February 19,2019
Created by: BobO
Oh, when you say "noise " are you referring to the effect on logic in the PLC rather than output circuit electrical design? If so, then that would be another matter
The modern world of low voltage and high speeds doesn’t blend as well with inductive loads and dry contacts as slow 5v stuff of yesteryear. So yes, much of this is about us protecting us. It’s a different world now. Out on the backplane it’s easier to control, but onboard the margin for failure is small. We err on the side of caution. I would rather apologize for the leaky led indicators (which ironically is also a fast/low voltage issue) than for stuff falling down.
Created Date: February 19,2019
Created by: BobbyS
The modern world of low voltage and high speeds doesn’t blend as well with inductive loads and dry contacts as slow 5v stuff of yesteryear. So yes, much of this is about us protecting us. It’s a different world now. Out on the backplane it’s easier to control, but onboard the margin for failure is small. We err on the side of caution. I would rather apologize for the leaky led indicators (which ironically is also a fast/low voltage issue) than for stuff falling down.
Yes, I agree with you. Thanks!