Fixed_Image

Parameter

Description

Symbol

Process variable that is mapped to the fieldbus variable.

Default: ???

Offset:

Position of the data inside the MODBUS map.

Default: 0

Mask:

A hexadeciamal Mask (e.g. 0001) for exchanging boolean variables through MODBUS words.

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)

Hint: The STRINGs contain even numbers only.

Default: Default (MODBUS Default = Store in 1 WORD)

Rage

Min/Max value of the process variable in the application.

The Range and Signal settings allow to decode the Master values for the Slave without any code.

Min:

Defines the minimal value of the process variable.

Default: empty

Max:

Defines the maximum value of the process variable.

Default: empty

Signal

Min/Max value sent or received in the MODBUS frame.

The Range and Signal settings allow to decode the Master values for the Slave without any code.

Min:

Defines the minimum range value.

Default: empty

Max:

Defines the maximum range value.

Default: empty

Each variable is identified by a valid symbol of a variable in the open project and an offset in the data block according to MODBUS addressing.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. For exchanging 32 bit variables (DINT, REAL...), you can select to map the variable on two consecutive words.

At any time you can sort the variables of each data block according to their offset using the Edit / Sort symbols menu command.

info Information

The creation of Modbus slave blocks requires especially register blocks like "Read Holding Registers". This block has a maximum length of 65535 bytes, what corresponds to 32767 registers.

To have a larger address range than up to 32768 create a second block for the same function (e.g. Holding Register) .

Example: To realize a Holding Register for the whole range of Modbus (max address: 65534), the following settings are required:

  • First Block: Offset 1 Length 32767
  • Second Block: Offset 32768 Length 32767

Close dialog

Option

Description

OK

Applies settings and closes the dialog.

Cancel

Discards all changes and closes the dialog.

Configuration

IEC 61131-3 Automation platform > Drivers - Fieldbus configuration > MODBUS Slave > Variables > Configuration

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