LabVIEW™ VIs

The TwinCAT 3 Interface for LabVIEW™ provides controls and VIs for use in LabVIEW™.

The VIs are located in the block diagram in the functions palette: Functions > User Libraries > Beckhoff-LabVIEW-Interface.

The main folder contains the basic VIs that can be used to build a program for reading via ADS, writing via ADS, TypeResolving and releasing the ADS client. In addition, the main folder contains the subfolders: Low-Level, With TypeResolving and Utilities.

Low-Level

The Low-Level subfolder contains Low-Level-VIs. The low-level VIs operate based the same principle as the basic VIs. The low-level VIs involve a little more programming effort but offer higher performance (in terms of data throughput) than the basic VIs and more flexibility for realizing complex programs. Reading data continuously is an example that uses the Low-Level-VIs for fast reading via ADS. Writing data continuously is a similar example. Not only reading and writing can be accelerated in this way, but also TypeResolving, see Continous Read, for example.

The table describes the subfolders and their contents and function:

Subfolder	VIs	Function
Init	Base Init	Initializes the ADS client.
	Get List of ReadWrite Symbols	Creates a list of ADS read and write symbols.
	Get List of Registered Targets	Creates a list of registered ADS target systems.
Read	Init Reader	Initializes the ADS Reader.
	Send Reader-Request	Sends a request to the ADS server.
	Register Notification	Registers the notification on the ADS server.
	TryReadData	Checks the response from the server and reads the data stream.
	Release Reader	Releases the reader from memory.
Write	Init Writer	Initializes the ADS Writer.
	Send Writer Request	Sends a request to the ADS server.
	CheckWriteStatus	Checks for the response from the ADS server to ascertain whether the data packet was received.
	Release Writer	Releases the writer from memory.
TypeResolver	Init Type	Initializes the TypeResolver.
	Resolve From TC Type	Converts the TC3 data type to a LabVIEW™ data type variant.
	Resolve To TC Type	Converts the LabVIEW™ data type variant to TC3 data type.
	Release Type	Releases the TypeResolver from memory.

With TypeResolving

The With TypeResolving subfolder contains two VIs for reading and writing via ADS with integrated TypeResolver block.

Utilities

The Utilities subfolder contains additional VIs for the following purposes:

Subfolder	VIs	Function
Notification	ADS To LabVIEW Timestamp	Converts ADS timestamps to LabVIEW™ timestamps.
	Notification Data To Variant Array	Builds an array of LabVIEW™Variant from the notification data stream.
	Stop Notification	Stops the ADS notifications.
	Start Notification	Starts the ADS notifications.
	Unregister Notification	Unregisters the notification on the server.
	Check License	Checks the license state on a given target system.
	Set Device State, Get Device State	Reads or changes the state of an ADS device.
	Get Version Info	Provides information regarding the product version.

Operating elements

The controls are located in the front panel in the controls palette under: User Controls > Beckhoff-LabVIEW-Interface.

The Notification subfolder contains controls that are required when initializing the LabVIEW™ event for ADS notifications.

Furthermore, the subfolder "TypeGenerator" contains TypeGenerator class objects to convert TwinCAT types into LabVIEW™ types (see Basic examples).

The following table describes the function of the controls:

Subfolder	Controls	Function
Notification	Single User-Event Data	Control for initializing a LabVIEW™ event for Single ADS notifications.
Notification	Buffered User-Event Data	Control for initializing a LabVIEW™ event for Buffered ADS notifications.
TypeGenerator	CBase	Class object; base class of the TypeGenerator
	CBool	Class object; Boolean class of the TypeGenerator.
	CNumeric	Class object; numeric class of the TypeGenerator.
	CString	Class object; LabVIEW™ string class of the TypeGenerator.
	CArray	Class object; array class of the TypeGenerator.
	CTimestamp	Class object; LabVIEW™ timestamp class of the TypeGenerator.
	CCluster	Class object; LabVIEW™ cluster class of the TypeGenerator.

Further Information