Synch counter

[Kiebach]

Here is the measurment I am Trying to make.

I need to generate a pulse train of 40 pulses (15uS width 1mS period) then I need to monitor a signal from the uut and determine if it went high after 6 pulses and low after receiveing 35 pulses.

I was able to generate the input pulse train which I then wrapped around to another counter input which I have setup as a Semi-period input counter. This gives me the timing for all the input clock edges.

Now I would like to connect the monitor signal from the uut to another counter input and perform a semi period measurment on this signal as well.

My question is how to I syncronize the two semi-period counters to start counting at the same time?  

Another question is can I connect the output pulse train to another counter input without hardwiring externally? I did try to make the souce for the 1st Semi-period counter the same as the output counter using the channel properties vi but was unsuccessfull. Kept getting error that the resource was already reserved...

[Kevin_Price]

First let me make sure I understand your app properly.  Since this is the timer/counter forum, I'll assume you're looking for a counter/timer solution.

You want to generate a finite pulse train of 40 pulses at 1 kHz.  This will require the use of 2 counters.

You want to perform semi-period measurement on that generated pulsetrain.  This requires 1 counter.  (Seems redundant though, since you are generating that pulsetrain with the same board).

You want to perform semi-period measurement on your uut's response.  This requires 1 counter.

You want to synchronize the start time of the 2 semi-period measurements.  This requires use of the "Arm Start" trigger, available only through a DAQmx Trigger Property node.

Since you need 4 (probably really only 3) counters, you'd need something like a 6602 board.

Re: "resource reserved" error.  I'd guess you're probably trying to configure a counter for semi-period measurement that was already reserved for the finite pulsetrain generation.  If you generate a finite pulsetrain on counter 0, then under the hood counter 1 is reserved as a helper.  And vice versa.  Same for other pairings (2,3), (4,5), (6,7).   In general, under DAQmx you should be able to fairly easily perform the necessary routings via software calls without screwdriver work.

If you have an M-series board rather than a 6602, you only have 2 counters but can still handle this app using "correlated DIO."

-Kevin P.

[Kiebach]

Thank YOu. The "Arm start" trigger was the missing link for me.