#modbus
7 posts filed under this tag, newest first.
Building a Modbus energy monitoring gateway that stays up
Polling design, store-and-forward, timestamping at the edge, SD card wear and the naming convention you cannot change later — a field-grade gateway.
7 min read
MQTT, Modbus TCP or HTTP: moving meter data to a server
Poll versus publish, what each protocol costs in bandwidth and firewall holes, how to design topics and payloads, and where each one genuinely belongs.
7 min read
Choosing an RS485 to Modbus TCP gateway
Transparent tunnel or protocol gateway, multi-master handling, unit ID mapping and isolation — the specification that decides whether it works in year two.
7 min read
Modbus RTU not responding: a diagnostic sequence
Timeouts, CRC errors and silent devices, worked from what you can observe. Two minutes with a multimeter settles the two commonest causes.
7 min read
Modbus RTU on energy meters: six things that break
Wiring, termination, byte order, register offsets, phantom registers and polling intervals — the real RS485 failure modes, and how to tell them apart.
7 min read
RS485 wiring for Modbus: topology, termination, shields
Daisy chain not star, 120 Ω at both ends only, one earth on the shield, and the third wire everybody omits — the physical layer that decides if polling works.
7 min read
Choosing an energy meter for IoT: what actually matters
Accuracy class, register map, protocol and documentation — the four things that decide whether a meter becomes a data source or an expensive display.
6 min read