Showing results for 
Search instead for 
Did you mean: 

Micrologix 1400 - MODBUS



I'm currently developing a project that uses the following hardware/software:

  • PC;
  • LV16;
  • DSC Module;
  • Micrologix 1400 PLC.

My goal is to read only two addresses in the Micrologix 1400: N10:5 and N10:8. As far as I have searched, there are 3 ways to develop the communication:

  • OPC Server;
  • TCP/IP.

The first option, OPC Server, is out of question, because of limited budget. However, everytime I search for a guide, I end up in a solution that uses OPC Server. The only solutions that do not use OPC Server are not well explained.


So, my questions are the following:

  • Can I use MODBUS to communicate my PC with my PLC?
  • If yes, how do I map the tags and the addresses, i.e, in this example, NI explains how to set up a communication. However, it does not specify how I can map the address with the register. Like, I want to read the N10:5 value, how do I set up this configuration?
  • Can I use TCP/IP?
  • If yes, how do I map the tags and the addresses?

It is important for me to only use the softwares/hardwares I described above, any other purchases are out of question.


Kind regards,


André Kruger

0 Kudos
Message 1 of 3

You can use the MODBUS capabilities of the Micrologix 1400. You will have to configure MODBUS TCP in RSlogix and use a couple of rungs of ladder logic to map your N registers to the MODBUS registers. I'm not at a computer with RSLogix but I think the MODBUS configuration is under controller properties or communication properties.

0 Kudos
Message 2 of 3

Hello andkrugeralves,


Did you try something similar these links below?

Modbus configuration example for an Allen Bradley Micrologix 1400

Setting up the Allen Bradley Micrologix 1100 & 1400 for Communications via Modbus RTU Slave

I don't know if I am correct, but I understood that you have first to configure the adresses inside RSlogix, as jbesselm said, and as showed on links above. 

0 Kudos
Message 3 of 3