Hi folks,
I am trying to setup an ml1500 as a modbus slave for a 3rd party device, and I have little (none) experience with the modbus comm protocol.

Here are my questions:

1. Does anyone know of a good "how it works"/ basic walkthrough of setting up a modbus rtu communication between 2 devices?

2. In my application, I have configured channel 0 as the modbus slave channel. However, I am not sure how to fill out the data. From what I've read about, I believe that the modbus terms "coils" = discrete outputs, "contacts" = discrete inputs, "input registers" = AI, and "holding registers" =AO (more or less). I see on the help screen (not much detail) that the addressing allowed for these values can be 3, 7, and 9-255. Is it a coincidence, or do these address restrictions correspond to 3=B3, 7=N7, and 9-255= N9-255?? I attempted to follow this thought process, as one of the values I want to monitor is B3:0. So, I put in the value "3" in the field contacts(1xxxx). Am I on the right path here?

3. How do I then configure the modbus master addressing?? I do not believe that generic devices understand the AB addressing terminology, ie if contact (1xxxx)=B3:0, how does this translate to a generic modbus address??

I'm sorry if I'm babbling/not making sense....any help/advice/pointers would be greatly appreciated.

-Mike