FB_VN_ReadRegister

Syntax

Definition:

FUNCTION_BLOCK FB_VN_ReadRegister_ULINT
VAR_INPUT
    nAddress                 : GVCP_REGISTER_ADDRESS;
    nEndian                  : UINT;
    bRead                    : BOOL;
    nTimeout                 : TIME;
END_VAR
VAR_OUTPUT
    nValue                   : ULINT;
    bBusy                    : BOOL;
    bError                   : BOOL;
    nErrorId                 : UDINT;
END_VAR
VAR
    oidITcVnGevImageProvider : OTCID;
END_VAR

Inputs

Name	Type	Default	Description
nAddress	GVCP_REGISTER_ADDRESS		The address of the register that should be read
nEndian	UINT		OPTIONAL: The endianness of the register. 0 = Big, 1 = Little. Default: 0
bRead	BOOL		Reading the register is triggered by a rising edge at this input.
nTimeout	TIME	VISION_ADS_TIMEOUT	Indicates the time before the function is cancelled.

Outputs

Name	Type	Description
nValue	ULINT	The read value
bBusy	BOOL	This output remains TRUE until the function block has executed a command, but at the longest for the duration supplied to the 'nTimeout' input. While bBusy = TRUE, no new command will be accepted at the inputs.
bError	BOOL	This output is switched to TRUE as soon as an error occurs during the execution of a command. The command-specific error code is contained in ‘nErrorId’. If the function block has a timeout error, 'bError' is TRUE and 'nErrorId' is 1861 (hexadecimal 0x745). Is reset to FALSE by the execution of a command at the inputs.
nErrorId	UDINT	Contains the ADS error code or the command-specific error code of the last executed command. Is reset to 0 by the execution of a command at the inputs.

Further information

	Open camera Control Channel needed! The Control Channel of the GigE Vision camera must be open in order to be able to use this function block. In addition, some camera parameters can only be changed if the image acquisition is stopped. It is therefore recommended to place the camera in the state TCVN_CS_OPENED first.

Parameter

nAddress

The register address identifies the camera register to be addressed. It is of the type GVCP_REGISTER_ADDRESS, which is an alias of the type UDINT. Thus, all register addresses have a size of 4 bytes. The register address of a camera parameter can be seen at the respective point in the configuration tree of the GigE Vision camera instance:

nEndian

Endianess describes the order in which the bytes of a camera register are arranged. This does not need to be considered any further in terms of the application and can be adopted as a property of the respective parameter of the configuration tree of the GigE Vision camera instance:

A Big Endian is represented by nEndian := 0 and a Small Endian by nEndian := 1. Big Endian is the default.

Examples

Reading/writing a register

Required License

TC3 Vision Base

System Requirements

Development environment	Target platform	PLC libraries to include
TwinCAT V3.1.4024.54 or later	PC or CX (x64) with PL50, e.g. Intel 4-core Atom CPU	Tc3_Vision