It is not possible to generate a trigger on PXI Trigger bus programmatically. While you can reserve and route different trigger bus lines through NI-VISA driver, MAX, or with some drivers in LabVIEW, the idea of trying to set the trigger bus high or low cannot be implemented. The PXI Trigger bus is simply a bus used to route triggers through the backplane. However, there are other ways to get this desired feature depending on the hardware in your chassis:
If you have access to a timing card, we have examples to help accomplish this task.
- If you are using a signal-based timing card (for ex., PXI 6651/6652/6653, PXIe 6672/6674/6674T), then you can modify the Route Software Trigger LabVIEW shipping example.
- If you are using a time-based timing card (for ex., PCI 1588, PXI 6682/6682H/6683/6683H), then you can modify the Generate Digital Pulse LabVIEW shipping example. As a note for the Generate Digital Pulse example, if you remove the time parameter input to the niSync Create Future Time Event function, then the VI defaults to sending it immediately.
- If you are using a DAQ or similar device, you will need to write to any given trigger line from one of the chassis slots with a card (for example, a multifunction DAQ device), or provide an external trigger source to drive the line.
There aren't any VISA commands to programmatically set the PXI trig lines high or low at any given time.