Triggering multiple digital lines from a single counter using PCI 6353

[JSherwood]

Hi, 

I am using a PCI 6353 to control a laser for a PIV system. The laser requires 4 pulses (F1, Q1, F2, Q2) on different channels. This would be simple using the 4 counters on the board, but I also need to trigger the camera. The card has plenty of digital outputs, so I figured I could use 2 counters and four digital outputs.

I thought that, by defining the pulse length of counter 0 to be the time between F1 and Q1 and triggering F1 from a rising edge and Q1 from a falling edge using internal output), I would be able to solve the problem. However, the system will not allow me to trigger two lines from the same internal output. I am not sure why. I have attached two vi's, one for a single channel which works fine, and one with two channels. I have also attached a rough timing diagram of my proposed solution.

I am not absolutely set on this format, so if this cannot be done and you have another solution please let me know. Accuracy is key here, the pulse widths being approx 1 microsecond and the intervals between F1 and Q1 being around 10 microseconds, so i think hardware timing is vital. However, I am not completely clear on how the digital pulses and counters interact.

Kind regards

Joe

[John_P1 · Accepted solution]

Hi Joe,

Any lines that you want to use for Clocked DO on the 6353 need to be in the same task.  Unfortunately, you can't trigger or clock multiple DO lines independently.

Having said that, I think the easiest solution would be to just build an appropriate waveform to generate all 6 signals with DO.  You should be able to clock DO up to 10 MHz which would give you 100 ns of resolution.  If you only need 1 us of resolution then you could get by clocking the DO at 1 Mhz.  While you could technically use a combination of Counters and DO to achieve what you need, it shouldn't be necessary in your case.  All you need is a single DO Task with the appropriate waveform to generate your desired signals.

Best Regards,