Modbus datapoint definitions
- dominik.kurfner (Unlicensed)
- Reinhard Mayr (Unlicensed)
- Nahel Falhout (Unlicensed)
File location
<WorkspaceDirectory>\DataFiles\xio.Modbus.DatapointDefinitions.dat
The Modbus interface provides the opportunity to read and write Modbus datapoints. The current version of the NETx BMS Core Server 4.0 supports the handling of Modbus discrete inputs, coils, holding registers, and input registers.
The encoding of Modbus datapoint types is vendor-specific. To be able to deal with the different vendor-specific encoding, configuration parameters to set the swapping of Words, Double Words, and Bits are available. These parameters can be defined for each device and for each datapoint. Furthermore, it is possible to specify the endianess that is used within the device.
Note that using the correct encoding settings is at utmost importance. If these parameters are incorrect, the corresponding values of the Modbus datapoints are interpreted, stored, and displayed in a wrong way. Furthermore, it has to be considered that these parameters are affecting each other. To choose the correct parameters please refer to the manual and datasheet of the used Modbus devices.
The structure of the Modbus datapoint definition file is as follows:
| Â Col# | Â Parameter | Â Description | Scope | Unit | Default |
|---|---|---|---|---|---|
| 1 | Device name | Name of the device which holds the datapoint. This name must match the device name used in the Modbus device definition. | |||
| 2 | Modbus DP type | Data type of the data point. | Modbus datapoint type | ||
| 3 | Address | Specifies the memory address of the Modbus register. | |||
| 4 | Data type | Specifies the data type of Server Item that shall represent the Modbus data point. | |||
| 5 | Size | Specifies the size of the Modbus data (only considered if DataType is set to "string" or "wstring"). | byte | ||
| 6 | Description | Can be used to specify a human-readable text that further describes the data point. Optional. | |||
| 7 | Polling interval | Specifies the interval that is used to poll the value of the data point. | |||
| 8 | Persistent | Specifies whether the value of the datapoint is persistent (restored from the database after server start up ) or not. | boolean | F | |
| 10 | Synchronize | Specifies the synchronization behavior in a Main/Backup setup.
| boolean | T | |
| 11 | Wordswap | Can be used to overwrite the Word Swap parameter of the Modbus device. If this parameter is set to "T" ("TRUE") or "F" ("FALSE"), the word swapping for this datapoint is overwritten. If this parameter is empty (or set to a value unequal to "T" or "F"), the word swapping specified in the device definition is used. | device setting | ||
| 12 | DWordswap | Can be used to overwrite the Double Word Swap parameter of the Modbus device. If this parameter is set to "T" ("TRUE") or "F" ("FALSE"), the double word swapping for this datapoint is overwritten. If this parameter is empty (or set to a value unequal to "T" or "F"), the double word swapping specified in the device definition is used. | device setting | ||
| 13 | Bitswap | Can be used to overwrite the Bit Swap parameter of the Modbus device. If this parameter is set to "T" ("TRUE") or "F" ("FALSE"), the bit swapping for this datapoint is overwritten. If this parameter is empty (or set to a value unequal to "T" or "F"), the bit swap specified in the device definition is used. | device setting | ||
| 14 | Read on Reconnect | If set to "T", a read request is sent if the connection status of the gateway changes to ONLINE. | boolean | F | |
| 15 | Write Mode | If not specified, the write mode that is defined within the Modbus Device Definition is used. | device setting |