# Modbus TCP two way data exchange

**URL:** <https://forum.universal-robots.com/t/modbus-tcp-two-way-data-exchange/40800>\
**Category:** Robot Communication\
**Created:** [August 11, 2025, 7:31am UTC](https://forum.universal-robots.com/t/modbus-tcp-two-way-data-exchange/40800 "2025-08-11T07:31:45Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![robert.becker](https://avatars.discourse-cdn.com/v4/letter/r/90ced4/32.png) [@robert.becker](https://forum.universal-robots.com/u/robert.becker)\
**Post date:** [August 11, 2025, 7:31am UTC](https://forum.universal-robots.com/t/modbus-tcp-two-way-data-exchange/40800/1 "2025-08-11T07:31:45Z")

</div>

**I want to use the UR as Modbus client exchange data in both directions.**  
A Modbus server is set up in the network.

I defined a _Register Input_ with Address 0 Name MODBUS\_1  
And a _Register Output_ with Address 1 Name MODBUS\_2

All connections are fine!

If I change the value of MODBUS\_2, I can see the value on the server (using a second client , reading some registers) !

If I change the 1st register (by the second client) , I expect to see the value in MODBUS\_1.  
But this dose not work.

What did I wrong ?