2 posts in this topic

I have a scenario that's been bugging me for some time now.
The scenario consists of a Micrologix 1400 that I need to control it's output from modbus/tcp.
In detail what I really need is to be able to manipulate the O0:0 through modbus/tcp. The PLC would be the master and I would be the slave that triggers the connection to the master.
I'm using a Modbus-Client on my PC and that should be the slave.
Any idea as to how I can manage that?
Currently I can send data to the master but everything is "stored" on B10 and I have no idea how I could write directly on O0.
Thanks a bunch guys.

PS: I'm borderline noob. 

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To control a bit at a time, investigate the XIC and OTE instructions. To control a word or 2 at a time (all outputs at once), look at the MOV and COP instructions.

Consider also how to handle problems. You WILL at some point have a communications error between the PC and PLC, invalidating the data stored in B10. You need to have a way to detect that failure and respond to it in a fail-safe manner.



Edited by Joe E.

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