VISA Assert Trigger Function

Owning Palette: VISA VIs and Functions

Requires: Base Development System

Asserts a software or hardware trigger, depending on the interface type. For software triggers, Default (0) is the only valid protocol. For VXI hardware triggers, Default (0) is equivalent to Sync (5). For PXI triggers, PXI: Reserve (6) and PXI: Unreserve (7) are the only valid protocols.

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	VISA resource name specifies the resource to be opened. The VISA resource name control also specifies the session and class.
	protocol is the trigger protocol to use during assertion. This input accepts the following values. 0 Default 1 On 2 Off 5 Sync 6 PXI: Reserve 7 PXI: Unreserve
	error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
	VISA resource name out is a copy of the VISA resource name that VISA functions return.
	error out contains error information. This output provides standard error out functionality.

VISA Assert Trigger Details

Software Triggers for 488.2 Instruments (GPIB, VXI, TCP/IP, USB)

This function sends an IEEE-488.2 software trigger to the addressed device, with the following bus-specific details:

• GPIB—VISA addresses the device to listen and sends the GPIB Group Execute Trigger (GET) message.
• VXI—VISA sends the Word Serial Trigger command.
• USB—VISA sends the trigger message ID on the bulk-out pipe.

Software Triggers for Non-488.2 Instruments (Serial Instr, TCP/IP Socket, USB Raw)

If the property IO Protocol is set to Serial-TCPIP-USB/488 Strings (4), this function sends the string "*TRG\n" to the device. Otherwise, this operation is not valid.

Hardware Triggers for VXI

For hardware triggers to VXI instruments, you must first set the property Trigger Identifier to the desired trigger line. This function performs the specified trigger operation on the line identified by the Trigger Identifier property.

Trigger Reservation for PXI

For PXI instruments, this function reserves or unreserves (releases) a trigger line for use in external triggering.

Example

Refer to the PXI - Reserve Trigger VI in the labview\examples\Instrument IO\VISA\PXI directory for an example of using the VISA Assert Trigger function.

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