OK... from your comment, "the 'first coil' would be addressed by 00001"
So, "from Modbus perspective", is this the first coil used in the ladder? If I have a coil addressed in the program as %Q0.1, and a following coil addressed as %M0.1, would the Modbus addresses be 00001, and 00002, respectively? My conundrum is how to separate real world output coils from internal coils.
I was able to read and write to the internal %M.x coils using modbus 00001 etc, but couldn't figure out how to address the real world PLC outputs.
Pending your reply, I'll look up the documentation on my PLC next week ,and get you a screen capture of it