Level of a counter input

[Olivier B.]

Hi there,
I'd like to measure a level (high or low) of a counter input with a 6624. My problem is that when i am performing a duty cycle read with a counter input and the signal i am measuring hang on 100% or 0% duty cycle, i get a timeout error. When i get this timeout error, how can i get the level of the signal?

Olivier.

[Kevin_Price]

Olivier,

A few potential ideas:

1. Wire the same signal to an available digital input that you can read. I just looked at the spec sheet and it appears the 6624 doesn't have its own DIO. If you don't have any DIO available on another DAQ card, can you use one of the input PFI lines of the 6624? I don't know if they can be queried for high/low state.

2. Use the duty cycling signal as a pause trigger for another counter that counts edges of an internal clock. When your first counter times out, you can then detect whether the second counter is incrementing or not to determine whether your signal is low or high.

3. I'm not at a LabVIEW PC now to check -- maybe there's a DAQmx property node that can be queried directly to detect the state of the signal in question? I kinda don't think so though.

Good luck,

-Kevin P.

[Olivier B.]

Thanks for your ideas. But:
1-Wiring the signal to a digital input : the problem is that the 6624 enables to use non-ttl signal, and our signals are 0-13V levels.
2-Using another counter: we already use all of our counters (and it s a bit expensive to use two counters to get the duty cycle of a single PWM signal).
3-A daqmx property to get the level: i looked for but did not find anything. Any tip welcome!

Finally, we decided to use digital inputs of another card in our configuration (and an home made signal conditionning) to get the level.

Any more better ideas?

Olivier.