Using the fp-ctr502 for timing

[Jason Stallard]

I need to use the ctr502 for timing.
Ex: In a 30sec frame the front X amount will be idle time, the rest will be divided into on/off time. This on/off time doesn't have to be equal, but can be done in any number of "shots". This on/off time will send an enable/disable signal to an injector. So I need to configure on counter for 30-(period*shots)...at the end of this counter it will trigger the "on time" which will trigger the "off time" (period - on time).

All the examples I manage to find deal with measuring frequency and not timing. I have an idea of what to do...just not HOW to use the module.

???

[Cyril]

I'm going to try to answer that post as I understand it.

The way I understand it is that:
1) you first need to generate a pulse train of period 30 seconds of duty cycle (30-X)/30
2) you also need to generate a pulse train of period "on.off" time of duty cycle On/of
3) the first train would be the gate of a counter while the second train would be the source and by counting the pulses generated by the second train while the gate is high, you would get, I think the signal you're looking for

But there will be a problem with that because the CTR Module cannot generate pulse train of variable duty cycle(i.e Refer to http://zone.ni.com/devzone/conceptd.nsf/2d17d611efb58b22862567a9006ffe76/b3e3a26bbbbf9e1586256af00059b86e?OpenDocument) and you would need a PWM module
in order to accomplish that.

Let me know if I understood the question properly and if not try to rephrase the question (with a drawing perhaps?)

Regards,

Cyril Bouton
Applications Engineer
National Instruments