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Modbus Registers

Below is a list of available MODBUS registers. The same register numbers are also used by the MIOS-2 protocol.

Modbus Read / Write (0x17) Function

METEL IO modules have implemented the MODBUS function (0x17) Read/Write of Multiple registers. Typically it is required to have two separate requests (and responses) for:

1. Writing of outputs via MODBUS function (0x16) Writing Multiple Registers

2. Reading of inputs via MODBUS function (0x03) Read Holding Registers

This requires a total of 4 frames to be sent over MODBUS. If using 0x17 function only one request is needed for the reading and writing of outputs. This requires a total of 2 frames to be sent over MODBUS.

Default Settings of Communication

Device ID: 1
Baudrate: 115 200
Parity: None
Data bits: 8
Stop bits: 1

Note: The MODBUS address is the same as the address of the main device of which the IF module is part.

Subject Channel Type R/W Value Offset
States of
Open Collector 1 DO#33 bit RW 0 = inactive
1 = active
Open Collector 2 DO#34 bit RW 4034
Open Collector 3 DO#35 bit RW 4035
Open Collector 4 DO#36 bit RW 4036
Outputs DI#33 - DI#48 u16 R 0x0000 - 0x000F