Overview of Modbus TCP protocol

MindSphere supports the Modbus protocol for the MindConnect IoT2040 and MindConnect Nano plugin. You can select the protocol type Modbus TCP while adding a new data source in Asset Manager.

NOTE

Modbus configuration

The Modbus configuration view is only visible after a successful onboarding of the MindConnect IoT2040/Nano. The MindConnect Nano Version must be higher than V3.3.0.2.

For the connection Modbus supports cables with 3 wires.

The following picture shows the protocol selection in Asset Manager:

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Modbus

For more information about how to create a new data source see chapter Adding a data source and data points.

Modbus TCP data source parameter

In order to connect a Modbus TCP device, you need to select the Modbus TCP protocol and enter the following data source parameters:

Parameter

Description

IP Address

IP address of the Modbus device

Port

Port number of the Modbus device (default: 502)

Modbus TCP data point parameter

In order to collect the data of your Modbus TCP device, you must add new data points.

The following picture shows the data point parameter window:

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The following table shows the parameter of the Modbus RTU data point window:

Parameter

Description

Data Type

Data type supported by backend (e.g. INT).

Function Type

Function type - depends on the type of the data (see manual of the Modbus device).

1: Read Coils

2: Read Inputs

3: Read Holding Registers

4: Read Input Registers

Currently function codes 1..4 are supported.

Slave Number

Address/Slave number of the Modbus device.

Start Address

Start address (offset) of the data.

Quantity

Quantity of data to be read.

VariableType

You can choose the following variable types of the Modbus data to be read:

1: char

2: unsigned char

3: short

4: unsigned short

5: long

6: unsigned long

7: float

8: double

9: ASCII-Text

Real Type

Real type - determines, if the registers of real values have to be processed in reversed order

0: Normal order

1: Reversed order

Response Address Offset

Offset of the data to return in register units.

Response Quantity

Quantity of the returned data. Only for string data  a value greater than 1 is supported.

NOTE

TCP Gateway slave number

If you are using a TCP Gateway, you must select the appropriate slave number for the configuration of the data points.