MicroLogix 1400 MSG Instruction

I will be using a MSG instruction in my program to write to a Modbus slave device. I want to write different values to consecutive registers in the slave. I have designated N7:0-N7:8 for this. The target addresses are 40011-40019.

My question is can I use the write multiple registers function for this? Will the MSG instruction map N7:0>40011, N7:1>40012, etc. Or will it write the value of N7:0 to all of the target addresses?

I haven't done this before with a Micrologix, and I don't have the PLC or slave device on hand to test this. Any insight is greatly appreciated.

Welcome to the forum!

I haven't set up a Modbus MSG instruction before specifically, but on every other message instruction I've set up it works as you desire. N7:0 -> 40011, N7:1 -> 40012, etc. etc. I can't see any reason this one would be any differently, otherwise you'd need 10 MSG instructions for 10 values, and that just seems silly

We use the Modbus MSG instructions frequently. They do work as expected with N7:0 being the address of the start of the source information. Most of the time though we have to add 1 to the Modbus address within the unit. Check for that possibility (if it shows 40011 as the address within the unit you may have to use '12' as the 'MB Data Address' in the MSG to give 40012 as the 'Modbus Address'.)