Prevent PLC program from writing to output

Say I have a PLC program that depending on some condition writes an output to a configured I/O point (Modbus in this case). When the condition I was controlling the writing is false I don’t want anything written. I tried doing this with a multiplexer where the write trigger condition controls which input to the mux is going to the output and where there is no mux input for the false condition, but this just writes 0 all of the time when the write condition is false. What is the correct way to do this?


Which of our devices is this question in regards to?

This is the SG gateway with I/O (ASG1XXX).

Thanks, I’m going to escalate this to find out what can be done in this situation.

Awesome, thanks!

I just followed up to see why I haven’t got a response yet. We have been having an issue with our ticketing system so maybe that is why. I will let you know when I get a rewsponse.


Thanks Kyle. It’s pretty key that I get this sorted out soon, let me know if you need me to get on a call with the folks in Sweden as I am in the EU this week and am in their time zone through Friday.


I understand and I apologize for the delay on this. The original ticket was titled IXXAT SG Gateway, but you referred to an Anybus article number. Can you confirm which one this is (there are both IXXAT and Anybus SG Gateways…) and which firmware it is running. Also, the serial number if you have it.

While you are in the EU if you want to contact the local offices in Sweden or Germany due to the time difference with us, I opened a ticket with both of them:

 || Sweden  || Ticket 201909-8445 || +46 35 17 29 20    ||
 || Germany || Ticket 201909-8383 || +49 721 989777-000 ||


Sorry for the confusion, I misspoke with the Anybus comment as that’s what these devices were called some years ago and how I still think of them. Here is the info for the devices I am working with:


Don’t worry about it, I still get confused by the branding here all the time.