Functionality of Modbus Commands READ_VAR / WRITE_VAR

Join Date
Feb 2008
Location
Walnuc Creek, CA
Posts
31
I'm programming a Modicon M340 with Unity Pro S.

Do the READ_VAR and WRITE_VAR instructions cause the processors execution to pause and wait for a response/timeout, or does the program continue executing while waiting for the response/timeout?
 
I'm programming a Modicon M340 with Unity Pro S.

Do the READ_VAR and WRITE_VAR instructions cause the processors execution to pause and wait for a response/timeout, or does the program continue executing while waiting for the response/timeout?

The program continues to execute, it couldnt work any other way !!

The READ_VAR looks after itself once initiated, if you need to check it has completed or there is an error\timeout read the management word section on the online help.
 

Similar Topics

I'm quite sure this usb modbus converter is toast. While trying to get a hold of another one, I wonder if there's any better option out there...
Replies
2
Views
1,243
Hey All, I am sorry to ask this, but i still gotta do it. What happens if I close RS linx? Will it cause network interruption and PLCs will lose...
Replies
5
Views
111
I am wondering if anyone has seen an input IO block that has a built in AND function for the inputs and the output of the block is a normal M12 5...
Replies
13
Views
821
Hello all, I've been working on a siemens PLC system using an S7-1200 and a KTP400 Basic HMI. Essentially this system takes in some setup...
Replies
3
Views
1,349
Insufficient resources exist on SOME_CLX_PLC to support Alarm & Event functionality. Hi All AB question. Please help me sort out this error in FT...
Replies
4
Views
2,199
Back
Top Bottom