ModbusPoll is a commercially available software from Witte GmbH.


1. Intro to Modbus rtu on smet

All SME devices implement a MODBUS RTU compliant RTU slave. The default configuration of the MODBUS RTU slave is 38400 and ODD parity. Connection is by RS485-2W where the interface is not electrical isolated. The SME device allows the configuration of the Modbus address using the RCP software. Please refer to the RCP manual for instructions.


Factory default settings of Modbus parameters:

Address=1

Baudrate=38400

Parity=odd

Databits:8

Slave Id: 1



2. Intro to Modbuspoll tool RTU

        2.1. Open the modbuspoll tool. Below it is showcased how to set every parameter for the correct performance of the tool and to monitor the input registers of the SMET. 

Figure 1. Modbuspoll tool

        2.2. Go to the communication Tab and select the connect option 

Figure 2. Selection on the communication tab

2.3. Set all the parameters as shown below                                                                               Figure 3. Connection configuration for Modbus RTU

       2.4. Go to the “Setup” tab and select “Read/Write Definition” 

Figure 4. Set the parameters to read the input registers in Modbus RTU.

        2.5. The data from address 40 up to 49 is going to appear on the screen, this data corresponds to parameter 0. Check the following      link for the mapped parameters

Figure 5. Input Registers data display

3. Correcting data types of registers and endianness

    3.1.  Right-click in the parameter to fix a value that is readable, a special menu is going to appear. Select “Format”

Figure 6. Menu editor for data format

    3.2. Pay attention to the correct format of each parameter.                                                                Figure 7. All options for data display

    3.3. In the sample above, the address 40 corresponds to the following format (Float 32, Depending on the endianness of the host it might be necessary to swap high/low byte and/or the respective registers.)

Figure 8. Seleccting the appropriate data type.

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