phiellaep

OK, thanks. What I have now is one Digital I/O output physically wired directly to the gate input, which when it goes high starts the retriggerable pulse. It does work, and fast, but it seems a little silly. Possibly this is the best way however. If anyone has any other ideas I'd be happy to hear them. Thanks again.

Do you mean one of the Digital I/O lines? To specify a 15 us pulse I need to use proper pulse generation, the default pin for which is CTR0. What I wanted to do was set up the pulse channel, and have it triggered whenever, for example, a boolean variable went HIGH. What it seems I will have to do (although I not sure why) is use a Digital I/O channel to gate the trigger (PFI9) to start the 15 us pulse. So I'm having to physically wire a Digital I/O line to PFI9 to gate the pulse, which seems daft - why can't I just do it in software?

Here is my VI. It is basically a repeating sequence, but the hold-up lies with the start-stop of the pulse in every iteration. Switch_1x2.vi

Argh! I must not have clicked 'attach'. I will add it when I get back into the office. Thank you!

Hi all, this is my first post. Like most people I am requesting help with something! Sorry! I am trying to implement TTL control of a device using LabVIEW and my 6052e PXI. The control is pretty simple, and completely TTL. It's just 4 pins for setting the new switch status, then a 5th pin to be pulsed (high to low) to initiate the switching. My VI for this (attached) does work. However, it works slowly. I can't get it to update at more than 5 Hz, and I have identified the hold-up as being the Start and Stop for the pulse. Without this, the loop runs very fast indeed. Clearly, I am not retriggering the pulse efficiently by Starting and Stopping it every iteration, and there must be a better way of doing it. However, having looked at the 'Retriggerable pulse' example VIs, it seems I would need to use a hardware trigger to start the pulsing. Ideally, what I want is to set up the pulsing channel, and for it to pulse only when I request it. But without using a hardware trigger! Surely this can be done? If not, why? And if so, how? Many thanks for any advice. Philip