COMPATIBLE · Modbus RTU/TCP
Modbus RTU/TCP Integration into the production control center
VFDs, smart meters, temperature controllers, sensor gateways... as long as it supports Modbus and has a register table, it is a standard integration. This note covers the RTU and TCP paths and the three most common pitfalls.
01 · INTEGRATION PATHS
Three paths, chosen by site conditions
Required: register point table
For each point to collect: register address, function code (03/04 read, 06/16 write), data type (int/float/long), scaling factor, read/write attribute. Connect as soon as the table is ready.
Recommended: confirm communication specs
RTU: baud rate/parity/unique station number; TCP: device IP and port, per-device connection limit; match the polling cycle to device response capability.
02 · COLLECTIBLE & CONTROLLABLE
Readable, writable and typical cycle
All points in the register point table: address, function code, data type, scaling factor, read/write attribute
Per point-table read/write attributes: 03/04 read, 06/16 write; confirm slave support before writing
Match the polling cycle to device response capability; for RTU watch baud rate and bus load
KEY POINTS
Remember these before integrating
- The most universal protocol, covering VFDs/meters/temperature controllers/sensor gateways
- Two paths: RTU and TCP
- Required: register point table (address/function code/data type/scaling)
- Connect as soon as the table is ready; first real data curve the same day
03 · COMMON PITFALLS
The three most common pitfalls
Address offset (0-based vs 1-based)
The manual says 40001, but different tools read 0 or 1 — one digit off reads a different register. Verify point by point with a debug tool before integrating; do not rely on "should".
Serial bus interference
High baud rate, long distance, or poor grounding on RTU cause CRC errors. The control center does checksum retry and bad-point marking (quality code BAD) instead of trusting bad data.
Multi-master conflict
A slave connected to two masters (an existing system also polling) will collide. When planning the acquisition path, first map out "who is reading this bus", adding a gateway mirror if needed.
Unsure about your site?
Have a device model but no point table? Send us the brand and model — register mappings for common brands are mostly already accumulated; a few are sorted out by on-site survey.