Modbus Device Function Block

 

Figure 1: Modbus Device Function Block

Figure 2: Modbus Device Property Sheet

Output

Output Name

Description

n:child

Shows the relation to the corresponding Modbus Read and Write points.

Table 2: Outputs of Modbus Device Function

Parameter

Parameter Name

Description

Device Address

It is slave device address (Mobus Slave devices connected to the Modbus network)

Device Address is unique across modbus network.

Numeric: 32-Bit (integer); Range: 1-247; Default:0

Byte order

It determines the byte order to be considered when communicating with the modbus registers.
Enumerated; Range: 0-3; Default: 1

0: Big Endian (e.g.Byte1, Byte2, Byte3, Byte4 for a 32-bit integer value) - For Register and for Word (2 register read), you get MSB first from slave device.

1: Little Endian (e.g. Byte2, Byte1 or Byte4, Byte3, Byte2, Byte1) - For Register and for Word, you get LSB (2 register read) first from slave device.

2: Little Endian with word swap (e.g. Byte2, Byte1, Byte4, Byte3) - For Register, you get LSB first and for Word (2 register read), you get MSB first from slave device.

3: Big Endian with word swap (e.g. Byte3, Byte4, Byte1, Byte2) - For Register, you get MSB first and for Word (2 register read), you get LSB first from slave device.

MaxReadPointsCount

It provides the max number of registers to be read in a single time from slave device

Numeric: 32-Bit (integer); Valid Address Range: 1-20; Default:5

Table 3: Parameters of Modbus Device Function

Modbus Configuration Screen

The Modbus device is configured via a double click on the Modbus Device function block. A special configuration screen is opened, where Modbus points can be engineered.

Figure 3: Modbus Device Configuration Screen

Refer to General Description for general information about IRMN4 Function Blocks.