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XNET Blink (G Dataflow)

Last Modified: November 2, 2017

Blinks LEDs for the XNET interface to identify its physical port in the system.

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interface in

The XNET Interface I/O name.

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modifier

An input that controls LED blinking.

Disable (0) Disable blinking for identification. This option turns off both LEDs for the port.
Enable (1) Enable blinking for identification. Both LEDs of the interface’s physical port turn on and off. The hardware blinks the LEDs automatically until you disable, so there is no need to call XNET Blink repetitively.

Both LEDs blink green (not red). The blinking rate is approximately three times per second.

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error in

Error conditions that occur before this node runs.

The node responds to this input according to standard error behavior.

Standard Error Behavior

Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

error in does not contain an error error in contains an error
If no error occurred before the node runs, the node begins execution normally.

If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Default: No error

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interface out

An output that is the same as interface in, provided for use with subsequent nodes.

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error out

Error information.

The node produces this output according to standard error behavior.

Standard Error Behavior

Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

error in does not contain an error error in contains an error
If no error occurred before the node runs, the node begins execution normally.

If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Description

Each XNET device contains one or two physical ports. Each port is labeled on the hardware as Port 1 or Port 2. The XNET device also provides two LEDs per port. For a two-port board, LEDs 1 and 2 are assigned to Port 1, and LEDs 3 and 4 are assigned to physical Port 2.

When your application uses multiple XNET devices, this node helps to identify each interface to associate its software behavior (LabVIEW code) to its hardware connection (port). Prior to running your XNET sessions, you can call this node to blink the interface LEDs.

For example, if you have a system with three PCI CAN cards, each with two ports, you can use this node to blink the LEDs for interface CAN4, to identify it among the six CAN ports.

The LEDs of each port support two states:

  • Identification: Blink LEDs to identify the physical port assigned to the interface.
  • In Use: LED behavior that XNET sessions control.

Identification LED State

You can use XNET Blink only in the Identification state. If you call this node while one or more XNET sessions for the interface are open (created), it returns an error, because the port's LEDs are in the In Use state.

In Use LED State

When you create an XNET session for the interface, the LEDs for that physical port transition to the In Use state. If you called XNET Blink previously to enable blinking for identification, that LED behavior no longer applies. The In Use LED state remains until all XNET sessions are cleared. This typically occurs when all LabVIEW nodes are no longer running. The patterns that appear on the LEDs while In Use are documented in LEDs.

Where This Node Can Run:

Desktop OS: Windows

FPGA: Supported

Web Server: Not supported in VIs that run in a web application


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