Engineering notes
Duplicate Modbus addresses: two meters as slave 1, half the bus goes dark
One address per slave. Two meters left at 1 — the software sees one, loses the other, or the number jumps. Write the ID on the schedule.
Ten meters on one DDC. They leave the factory as slave 1, 9600 baud. Someone lands them all on the bus. The software sees one meter, then none; CRC errors. The gateway is fine. Two nodes, one address, two people talking at once.
We put a planned slave ID, baud and parity on the schedule — and the label must be set before the door closes. You can still change an ID after the cable is pulled, but someone with a laptop has to be there. Send the register map, not only the model.