Introduction

Use of the OUT_IN_MBUS block requires prior correct configuration of the serial link.

The following parameters are used:

  • linked to transmission and configured from Control Expert

  • linked to the application and passed as function arguments

Reminder of Transmission Parameters

The serial link of the cards is configured from Control Expert. These parameters are the following:

  • Transmission speed

  • Delay between characters

  • Data

  • Stop

  • Parity

To allow exchange of data between all equipment connected on the bus, configuration of the serial link should be identical for all.

The configuration screen used to enter the parameters depends on the configuration selected in nominal mode.

Transmission Parameters of the Modbus Mode

The figure below shows a configuration screen when the nominal mode is in Modbus mode.

NOTE: The value of the Databit input parameter of the OUT_IN_MBUS block should match the value checked in the Data window of the configuration screen.

Use of OUT_IN_MBUS requires dynamic switching to character mode. In this mode, the conditions for stopping (on characters or silence) are disabled and not modifiable by the application. The OUT_IN_CHAR function is thus no longer usable in receive mode (stop on timeout), and only the INPUT_CHAR and INPUT_BYTES functions may be used for receiving by specifying the number of characters to receive.

Transmission Parameters of the Character Mode

The figure below shows a configuration screen when the nominal mode is in character mode.

NOTE: The value of the Databit input parameter of the OUT_IN_MBUS block should match the value checked in the Data window of the configuration screen.

When the card configuration is the character mode:

  • The conditions for stopping (on characters or silence) configurable in this mode must be disabled for proper operation of OUT_IN_MBUS. The function OUT_IN_CHAR is thus no longer usable in receive mode (stop on timeout), and only the functions INPUT_CHAR and INPUT_BYTES may be used for receiving by specifying a number of characters to receive.

  • The delay between characters cannot be configured. It is thus necessary to make sure that the value of this parameter in the remote Modbus devices is compatible with the character mode configuration.

Parameters for the Application

Two parameters for the application are sent as arguments of the OUT_IN_MBUS function.

These parameters are the following: