Symbol

Function

Symbol

Name of the variable.

Operation

Defines, if the variable is used as:

• variable for process data exchange via MODBUS (Data exchange)
• a status (diagnostic information provided to the application)
  Available status variables see chapter Configuration.
• a command (using a variable for dynamically operations by the application)

Hint: See also chapter Status and command variables.

Default: Data exchange

Offset

Address within the Data block.

Default: 0

Mask

For exchanging boolean variables through MODBUS words, a hexadecimal mask is available in order to define to which bit of a word a variable is attached. For example, enter the mask "0001" to map a boolean variable to the less significant bit of a word.

Default: FFFF

Storage

For exchanging 32 bit variables (DINT, REAL...), you can select to map the variable on two consecutive words. For exchanging 64 bit variables (LINT, LREAL...), you can select to map the variable on four consecutive words.

STRING variables are supported only if a "string" data format is specified.

Available settings:

• Default
• 2 words (DWORD) High - Low
• 2 words (DWORD) low - High
• 4 words (LWORD) High - Low
• 4 words (LWORD) Low - High
• STRING(10)
• STRING (12)
• ...
• STRING(240)

Default: Default

Hint: The STRING length has even numbers only.

Range (Low)

Low value of the adjusted value.

This is the minimum value for scaling the signal.

Default: empty

Range (High)

High value of the adjusted value.

This is the maximum value for scaling the signal.

Default: empty

Signal (Low)

Low signal value received via MODBUS.

Default: empty

Signal (High)

High signal value received via MODBUS.

Default: empty

Other topics in this chapter

Status and command variables

Variable Parameters

IEC 61131-3 Automation platform > Drivers - Fieldbus configuration > MODBUS Master > Variables > Variable Parameters