How do you use the counters on board

[Gian]

I am involved in the development of a LabVIEW VI for the acquisition and processing of signals generated by a chip under test; my application provides two signals having the waveforms sketched in the attached figure.
With reference to this figure, I should generate a digital pulse just after a pulse on signal 1, also in case of no pulses on signal 2.
I am using the board PCI 6110 with LabVIEW 6i: I tryed to use the counters implemented on the board to generate my signal. My idea is to count the pulses of signal 1 with a counter and, if it is possible, to reset the counter on a rising edge of the signal 2. By so doing, when the counter assumes the value “2”, it must generate an impulse. Unfortunately I have not su
cceeded to implement this procedure.
Please, could you suggest me how to implement this solution, or, if this is not possible, any other procedure to accomplish the required task?
Thank you very much for your attention.

[Russell]

Hello Gian,

I've tried to think of a method to implement this for a while, but the one fundamental obstacle I keep coming across is that it seems the system must have a deterministic output. (It has to identify the gaps and generate the pulse while on the fly.) It is easy to acquire the two signals and even determining when the gaps occur. The problem is getting your software to recognize this and generate the output fast enough. You could possibly do this with a LabVIEW RT system.

On the other hand, I have thought of a way you could do this with a 660x counter/timer board using quadrature encoder position measurement mode. The problem with the 6110 is that it's counter/timers do not support this mode. With the 660x board in encoder position measurement m
ode, you can wire signal 1 to the source (which increments the counter) and signal 2 to the z-index (which resets the counter to a specified value). You would have this specified value set to be 2 less than the terminal count. If you recieved two signal 1 pulses without any signal 2 pulses, the counter would reach terminal count which triggers a short pulse to be generated on the output and this could be your output signal.

If you do decide to go this route, our technical support can assist you further with this after you have the hardware.

I hope this helps.

Russell

Applications Engineer
National Instruments
http://www.ni.com/support