Parameter

Description

Request

Area for request description.

Description

Free definable text.

Default: empty

Slave/Unit

Unit ID of the slave/device.

Default: 0

MODBUS Request

Function code for Modbus Request.

Settings:

• <1> Read Coil Bits
• <2> Read Input Bits
• <3> Read Holding Registers
• <4> Read Input Registers
• <5> Write single coil bit
• <6> Write single holding register
• <15> Write Coil Bits
• <16> Write Holding Registers

Default: <2> Read Input Bits

Data block

Settings for Data block address.

Base address

Start offset in the requested table depending on the function code.

Default: 1

Nb items

Number of requested items depending on the function code (word, bit).

Default: 1

Activation

Operation mode for requests.

Periodic

Frequency, at which the data is read.

Settings:

• Enter the cycle time in milliseconds.
• Enter a time span for activation in case of an error.

On call

Data is written to the Slave on a call of a Control variable:

• Command (one shot): sent only once
• Command (enable): sent while the control variable is TRUE

The corresponding internal command variable has to be defined inside this block manually.

On change

Data is written to the Slave on every value change. Enter a time span for activation in case of an error.

Misc

Area for timeout and connection trial settings.

Timeout

Timeout for response messages.

Default: 3000

Nb trials

Number of trials after timeout occured.

Default: 1

Declare variables

Allows to declare variables for the data block following the address sceme of the function code.

Default: inactive

Prefix

% is the placeholder for digits.

Example: V%%% = V000

Default: V%

Datatype Dropdown menu

Allows to select predefined Datatypes according to the setting in the MODBUS Request area.

Default: BOOL

From

Startnumber for automatic naming (digits)

Default: 1

Option

Description

OK

Applies settings and closes the dialog.

Cancel

Discards all changes and closes the dialog.

Slave/Data Block configuration

IEC 61131-3 Automation platform > Drivers - Fieldbus configuration > MODBUS Master > Fieldbus configuration > Settings in the fieldbus dialogs > Slave/Data Block configuration