PDA - Pocket PC 2002 (7.01f) - DAQCard 6062E Minimum Scan Rate 200 Hz?

[RevaD]

On doing an acquire waveforms (buffered finite samples) on 8 channels. I'm getting a PDA lockup if I select a scan rate lower than 200Hz.
I'm on Pocket PC 2002 with the 7.01f PDA module on Labview 7.0. (eg 100Hz 1000 samples, approx 10 seconds of data)

I might be missing something but all I can find on the web is that I should be able to get down to 1.21 Hz.

Any help much appreciated.

Thanks,

Dave.

[SachaE]

Hi,

When you say you get PDA lockup - at what point in the code? during configuration or read?

If it's during the read, then since it's finite, it will only return to the rest of the program after the read completes, so the front panel will be un-responsive during this time. Also since there's no DMA on the pcmcia slot every transfer has to be on irq so the cpu is always involved in the transfer. (i.e. are you saying your lockup last 10 seconds if it's at 100Hz, 1000 samples)

Working continuously instead of finite, you could read chunks of data, but the maximum speed will be lower than running in finite mode due to the cpu involvement, so it will depend on the spec of you PDA and what extra code you're running as to whether you can get back to the read fast enough that the onboard FIFO hasn't overflown (on the 6062 that's 8k Samples which is one of the best for this)

Otherwise, can you attach your code please?

Thanks

Sacha Emery
National Instruments (UK)

[RevaD]

Thanks Sacha,
I'll have to get back to you when I can get back on the PDA. My perception is that I'm getting an indefinite lockup; which is broken by disconnecting the expansion jacket although I'll have to investigate if it's just the vi or the whole PDA. Raising the sample rate to 200Hz and doubling the No of samples to 2000 cures the problem and the acquire function finishes after about 10 seconds.
Mainly though I'm still curious to get to the bottom of it.
Interesting that you mention the front panel being unresponsive as I'm also trying to update a string indicator just before I go into the state that calls the acquire but it only updates after the acquire. Also tried adding a 0.5 second delay between updating the indicator and calling the acquire state but the indicator still remains unresponsive. Is there a function to force a PDA screen update?
Regards,

Dave.