FB_MBUdpReadWriteRegs (Modbus function 23)

VAR_INPUT

VAR_INPUT
    sIPAddr        : STRING(15);
    nTCPPort       : UINT:= MODBUS_TCP_PORT;
    nUnitID        : BYTE:=16#FF;
    nReadQuantity  : WORD;
    nMBReadAddr    : WORD;
    nWriteQuantity : WORD;
    nMBWriteAddr   : WORD;
    cbDestLength   : UDINT;
    pDestAddr      : POINTER OF BYTE;
    cbSrcLength    : UDINT;
    pSrcAddr       : POINTER OF BYTE;
    bExecute       : BOOL;
    tTimeout       : TIME;
END_VAR

sIPAddr : Is a string containing the IP address of the target device.

nTCPPort : Port number of the target device.

nUnitID: Identification number of a serial sub-network device. If a device is addressed directly via TCP/IP, this value must be 16#FF.

nReadQuantity : Number of output registers (data words) to be read. The value of nReadQuantity must be > 0.

nMBReadAddr : Start address of the output registers to be read (word offset).

nWriteQuantity : Number of output registers (data words) to be written. The value of nWriteQuantity must be > 0.

nMBWriteAddr : Start address of the output registers to be written (word offset).

cbDestLength : Contains the max. byte size of the destination buffer. The minimum destination buffer byte size must be nReadQuantity * 2.

pDestAddr : Contains the address of the destination buffer into which the data are to be read. The buffer can be a single variable, an array or a structure, whose address can be found with the ADR operator.

cbSrcLength : Contains the max. byte size of the source buffer. The minimum source buffer byte size must be nWriteQuantity * 2.

pSrcAddr : Contains the address of the source buffer containing the data to be written. The buffer can be a single variable, an array or a structure, whose address can be found with the ADR operator.

bExecute: The function block is activated by a rising edge at this input.

tTimeout: States the length of the timeout that may not be exceeded by execution of the ADS command.

VAR_OUTPUT

VAR_OUTPUT
    bBUSY     : BOOL;
    bError    : BOOL;
    nErrId    : UDINT;
    cbRead    : UDINT;
END_VAR 

bBusy : When the function block is activated this output is set. It remains set until an acknowledgement is received.

bError : If an ADS error should occur during the transfer of the command, then this output is set once the bBusy output is reset.

nErrId : Supplies the ADS error number when the bError output is set.

cbRead: Contains the number of bytes currently read.

Requirements