Siemens LOGO

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

ward

Well-known member
Joined
Jun 4, 2004
Messages
348
Location
Belgium
At the risk of being way off topic for this forum, here goes...
I'm installing some relay boards and trying to control them with a Siemens LOGO which is a small plc.

The relay boards have 12 relays that are tied to each other over a common V+ (24V).
Now, I bought a LOGO with transistor outputs (24V) ...
transistor output LOGO

With my previous cabling I had relayoutputs on my logo and I basically used them to open a path to ground.
Now, I don't see the way I can use these transistoroutputs to switch my relays ?
They don't switch to ground, even if they're on digital zero, they're not connected to ground.

thanks, ward
 
Last edited:
..need more info on what it actually outputs. The link does not shoe or mention anything on this.

Perhaps add simple external open-collector transistor stage?

/Jakob E.
 
..need more info on what it actually outputs. The link does not shoe or mention anything on this.
I'm not sure how to answer that:
My test told me that a digital zero is about 0.4Vdc.
A digital 1 is 24Vdc.
 
4EE482F9-07B9-4690-9761-EF92165ED6E4.jpeg
this is what the outputs look like,
Maybe that helps in identifying what it actually does?
The T4140 is an N-channel mosfet.
T4140
 
Last edited:
Thanks for your answer Jakob, but I’m afraid I don’t understand the question.
Maybe this drawing explains better what I’m actually doing.
The problem is that i can’t switch the relayboard with a positive pulse since there’s a positive common.
 

Attachments

  • image.jpg
    image.jpg
    60.6 KB · Views: 4
Back
Top