FB_ReadCouplerRegs

This function block FB_ReadCouplerRegs provides read access to the table register in the coupler and the registers of the intelligent terminals. The coupler itself is referred to as terminal 0 (null). All the other terminals in the terminal block, with the exception of passive terminals (such as power supply terminals), are counted in ascending sequence (beginning with 1). All registers or only a subrange (between nStartReg and nEndReg) can be read. Several seconds are required to read all registers (0.255) of a coupler table. Register values that have been successfully read are found in the structure stCouplerTable. The structure is an array of high and low bytes. Each array element corresponds to a register value (e.g.: stCouplerTable[ 5 ] == Register 5).

Inputs

VAR_INPUT
    stState       : PLCINTFSTRUCT;
    nTerminal     : BYTE:= TERM_COUPLER;
    nTable        : BYTE;
    nStartReg     : BYTE;
    nEndReg       : BYTE;
    bExecute      : BOOL;
    tTimeout      : TIME;
END_VAR

Name	Type	Description
stState	PLCINTFSTRUCT	Status word of the 2-byte PLC interface.
nTerminal	BYTE	Terminal number whose table register is to be accessed. The coupler has terminal number null. Passive terminals are not to be counted.
nTable	BYTE	Table number whose register values are to be read. Intelligent terminals only have one table for each terminal channel. A 4-channel terminal has the following table numbers: 0-3. However, an intelligent terminal only has a maximum of 64 register values per terminal channel.
nStartReg	BYTE	The number of the first register to be read.
nEndReg	BYTE	The number of the last register to be read.
bExecute	BOOL	The function block is enabled by a positive edge at this input.
tTimeout	TIME	Specifies the time-out period that must not be exceeded when the function is executed.

Outputs

VAR_OUTPUT
    stCtrl          : PLCINTFSTRUCT;
    bBusy           : BOOL;
    bError          : BOOL;
    nErrId          : UDINT;
    stCouplerTable  : ST_CouplerTable;
END_VAR

Name	Type	Description
stCtrl	PLCINTFSTRUCT	Control word of the 2-byte PLC interface.
bBusy	BOOL	When the function block is activated, this output is set and remains set until the function is completed.
bError	BOOL	If an error occurs during the execution of the function, this output is set after the bBusy output has been reset.
nErrId	UDINT	Supplies the error number when the bError output is set.

Error number	Error description
0	No error
0x100	Error at initialisation of the communication via the 2 byte PLC interface
0x200	Error during communication
0x300	Timeout-Error. The permitted execution time was exceeded
0x400	Wrong parameter value at register number
0x500	Wrong parameter value at table number

Name	Type	Description
stCouplerTable	ST_CouplerTable	Structure with the read register values of the terminal or coupler.

Requirements

Development environment	Target system type	PLC libraries to include (category group)
TwinCAT v3.1.0	PC or CX (x86, x64, ARM)	Tc2_Coupler (IO)