Modbus Interface Specification; Modbus Physical Layer; Modbus Registers; Control And Status Registers - HMS Networks Intesis INMBSDAI001I000 User Manual

INMBSDAI001I000 Modbus RTU Gateway

5. Modbus Interface Specification

5.1. Modbus Physical Layer

The INMBSDAI001I000 gateway implements a Modbus RTU (server) interface to be connected to an EIA-485 bus.
It features 8-N-2 communication (eight data bits, no parity, and two stop bits) with several baud rates available
(2400 bps, 4800 bps, 9600 bps -default-, 19200 bps, 38400 bps, 57600 bps, 76800 bps, and 115200 bps). It also
supports 8-N-1 communication (eight data bits, no parity, and one stop bit). The default Modbus server address
is 1.
NOTE
AUTO-DETECT FUNCTION. The gateway will automatically detect the communication type (8-N-1 or
8-N-2) and set itself accordingly. No user action or manual settings are required.

5.2. Modbus Registers

All registers are 16-bit unsigned holding register type and use the standard Modbus big-endian notation.
IMPORTANT
The INMBSDAI001I000 gateway has a polling limit of 50 registers. Therefore, it is not possible to poll
more than 50 registers simultaneously, for example, if the same TX frame asks for the status of more
than 50 registers.

5.2.1. Control and Status Registers

Table 6. Control and Status registers
Register Address Register Address
(protocol address)
0
1
2
3
Page 14 of 23
(PLC address)
AC unit On/Off
1 0: Off
1: On
AC unit Mode
0: Auto (default value)
1: Heat
2
2: Dry
3: Fan
4: Cool
AC unit Fan Speed
0: Auto
1: Low
3
2: Mid 1
3: Mid 2
4: Mid 3
5: High
AC unit Up/Down Vane Position
4 0: Off
10: Swing
Description
1
1
1
Modbus Interface Specification
R/W
R, W
R, W
R, W
R, W
USER MANUAL Version 1.0.0