Changing the Micro820 Modbus-RTU Slave address

[RMore]

I am using a Micro820 controller setup with the Modbus RTU in slave mode. Is there a way to change the slave address from within the application?

 

[KirkC]

Changing the Modbus slave address at runtime (I think that's what you mean) would be very tricked out. That sort of feature would be in Control Microsystems' wheelhouse, not Allen Bradley's
.
I'm guessing you want to write one and the same program to many sites and have each program self-identify on startup. OK, but how? With an external thumbwheel or equal? It'scertainly a valid problem, but I don't a solution off hand.

 

[RMore]

We would like the user to be able to select from one of 4 available unit addresses using jumpers on the PLC inputs.

 

[damica1]

We would like the user to be able to select from one of 4 available unit addresses using jumpers on the PLC inputs.

I realize this would cost more money, but it would be so much easier for the operator to use an HMI.

Then on the HMI have 4 buttons - then all the operator would need to do is press the button for the location the unit needs to talk with.

Forgive me, if I have not understood your question!

 

[RMore]

I appreciate the feedback. We have considered the HMI and it remains an option. This is not the issue. My question how is this done in the code. I have looked at the users guide and do not see information for changing the unit address during run-time.

 

[RMore]

I have a solution.


It appears that I can use the MSG_CIPGENERIC function to over-ride the Modbus RTU address during run-time.


Example can be found in the Micro820 Programmable Controllers User Manual. Search for RMCC.


You can also use this method to over-ride the Ethernet IP settings