14. RS-485 INTERFACE WITH MODBUS
PROTOCOL
14.1. Introduction
The RE72 controller is equipped with a serial interface
in RS-485 standard, with implemented asynchronous communication
protocol MODBUS.
Combination of serial interface parameters for the RE72 controller:
- device address: 1..247,
- baud rate: 4800, 9600, 19200, 38400, 57600 bit/s,
- operating mode: RTU,
- information unit: 8N2, 8E1, 8O1, 8N1,
- data format: integer (16 bit), fl oat (32 bit), fl oat (2x16 bit),
- maximum response time: 500 ms,
- maximum number of
registers read out/ written
by a single Modbus frame: 116.
The RE72 controller realizes following protocol functions:
Table 8
Code Meaning
03 read out of n-registers
06 write of 1 register
16 write of n-registers
17 identifi cation of the slave device