MBSlaveRTUexD

Function Block - MODBUS RTU Slave protocol on serial port.

Inputs

Input	Data type	Description
IN	BOOL	Enabling command: the port is open when this input is TRUE.
PORT	STRING	Settings string for the serial port (e.g. 'COM1:9600,N,8,1').
SLV	DINT	MODBUS slave number.
SrvID	STRING	MBSlaveRTUex only: ID of the server in the configuration.

Outputs

Output	Data type	Description
Nrec	DINT	Number of received valid requests addressed to this slave.
Nx	DINT	Number of received valid requests addressed to this slave or any other slave.
Nerr	DINT	Number of processed requests leading to an error response.
Nok	DINT	Number of requests processed without error.
Nbr	DINT	Number of received broadcast requests.
Nb Bad	DINT	Number of received invalid requests addressed to this slave.

Remarks

When active, this function block manages the MODBUS RTU Slave protocol on the specified serial communication port. The configuration of the MODBUS Slave map (designing MODBUS addresses) is done using the MODBUS configuration tool, from the Fieldbus Configurator.

There can be several instances of the MBSlaveRTU working simultaneously on different serial ports. Other MODBUS Slave connections (TCP server, UDP) can also be active at the same time.

The slave number entered in the MODBUS Slave configuration tool is ignored when MODBUS Slave protocol is handled by this function block. Instead, the SLV input specifies the MODBUS slave number.

With MBSlaveRTUex, you can specify the ID of a server from the MODBUS slave configuration. If you specify an empty string, the first server is used. MBSlaveRTU always works with the first server in the configuration.

MBSlaveRTUexD offers additional information about the MODBUS communication.

ST Language

MySlave is a declared instance of MBSlaveRTU function block.

MySlave (IN, PORT, SLV, SrvID);
Q := MySlave.Q;

MBSlaveRTUexD

IEC 61131-3 Automation platform > Programming - Reference guide > Driver specific function blocks > Modbus Slave > MBSlaveRTUexD

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