Defining a Modbus Custom Slave
After you have created the new Modbus custom slave model,
you can complete its definition in the Custom Library.
This procedure requires that you have created a custom model.
- Select the new model in the model tree view, then click the Slave collapsible menu.
- Select the reading order in the Endianness drop-down list.
This setting describes the register order to be used when a variable is formatted with more than one register.
NOTE: The endianness depends on the device and must be selected in the Com’X settings. For example, PM700 is big endian and PM800 is little endian. The endianness setting is not used if variables are formatted with 16-bit registers. - Click New frame.
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Modbus Custom Slave Register Examples
| Register | Register Number | Read/write | Scale | Unit | Format | Interval | Description |
|---|---|---|---|---|---|---|---|
| 1037 | 1 | R | x1 | kW | INT | +/–0...32767 | Total active power |
| 1041 | 1 | R | x1 | kVAR | INT | +/–0...32767 | Total reactive power |
| 1049 | 1 | R | x1000 | None | INT | –1000...1000 | Total power factor |
| 1054 | 1 | R | x10 | Hz | INT | 0...4000 | System frequency |
When reading the device documentation, it appears that all variables can be read with 1 frame of registers (Function code 03) starting from register 1037 and ending with register 1054 (count = 18).
Continue to Creating a Modbus Frame to define a new frame.
**Creating a Modbus Frame related link