Creating Modbus Variables
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As part of defining a
Modbus Custom Slave, you need to set up the Modbus variables read
by a Modbus frame.- Click Edit frame.
A dialog box appears and allows you to set up each variable.
- Click New item to create a new variable,
and fill in these different fields:
Field Description Comment Name and Unit Enables you to select a variable name from the Name list. This variable name determines the Unit options. You can select Customized in the drop-down list and type a new text string for the name field and the unit field. Format Specifies the format of this number. Several formats are available as described in the table below. First register address Specifies the first register number. The register number must belong to the range of the frame. If the format contains more than 1 register, the setting checks that the last register used by this measurement is inside the frame content. Factor The displayed measure = (transmitted value x factor) + offset. The displayed measure is the value displayed in the measurement tables. Transmitted value is the measure done by the meter. Offset Invalid value Indicates the transmitted value is invalid. – - When you finish adding and configuring frame settings,
click OK to close the dialog, then click Save changes.
The table describes the available formats:
Format Description Minimum Value Maximum Value Use "Endian" Setting INT16
1 register with signed integer value –32768 32767 No UINT16
1 register with positive integer value 0 65535 No INT32
2 registers with signed integer value –2147483648 2147483647 Yes UINT32
2 registers with positive integer value
0 4294967295 Yes FLOAT32
2 registers with signed floating point value coded according to IEEE754 standard –1E–10 +1E–10 Yes UINT32_MOD10K
2 registers with positive integer value from 0 to 9999 0 99999999 Yes INT64
4 registers with signed integer value –2 (^63) –2 (^63)–1 Yes UINT64
4 registers with positive integer value 0 –2 (^63)–1 Yes UINT64_MOD10K
4 registers with positive integer value from 0 to 9999
0 9 999 999 999 999 999 Yes