FB_MBWriteSingleCoil (Modbus function 5)

VAR_INPUT

VAR_INPUT
    sIPAddr     : STRING(15);
    nTCPPort    : UINT:= MODBUS_TCP_PORT;
    nUnitID     : BYTE:=16#FF;
    nMBAddr     : WORD;
    nValue      : WORD;
    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.

nMBAddr: Address of the digital output (bit offset).

nValue: Value to be written into the digital output. The value 16#FF00 switches the output on, 16#0000 switches it off.

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;
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.

Example of calling the block in FBD:

PROGRAM Test
VAR
    fbWriteSingleCoil      : FB_MBWriteSingleCoil;
    bWriteCoil             : BOOL;
    bWriteCoilBusy         : BOOL;
    bWriteCoilError        : BOOL;
    nWriteCoilErrorId      : UDINT;
    nMBAddr                : WORD := 3;
    nValue                 : WORD := 16#FF00;
END_VAR

After a rising edge of "bExecute" and successful execution of the WriteSingleCoil command, digital output 4 is switched on.

Requirements