Responding to a field Digital Input immediatley..

[MogaRaghu]

In a code for a a test rig ( LV7.1 + Win XP ) I am scanning all digital inputs once every 50ms inside a timed loop. But there is one input from a proximity switch that I need to be able to respond to immediatley as it changes state.

 Any delay  of even a few ms, will add on to the reversal error of a servo drive motor.

 Ideally what I am looking for is a kind off  Interrupt or  Event Structure for an external field input.  I know this is not there in LV, but would be ineterested in achieving the same functionality by some other means.

Thanks

Raghunathan

[MogaRaghu]

Going by the silence and lack of any responses, looks like LV does have a problem when it comes to handling interrupts like a microcontroller does, so easily.

Raghunathan

[ChrisJ]

Hello Raghunathan,

It LabVIEW if you are polling your device every 50ms for data, you will only get updates from your device every 50ms. It sounds like you are looking for some sort of change notification or change detection from your board. It is likely that you will get a much better and faster response to this question on the Multifunction DAQ or Digital I/O discussion forums since this is primarily a hardware question. If you decide to post to the hardware discussion boards, it may also be a good idea to list the specific hardware you are using so that people with similar setups can share their experience.

Best of luck,

Chris J

Multifunction DAQ board

http://forums.ni.com/ni/board?board.id=250

Digital I/O board

http://forums.ni.com/ni/board?board.id=70

[Dynamik]

Hi Raghunathan,

      If you happen to be using a 652X device... then an edge-detection event is available in LabVIEW - actually, it's an "occurrance".

See "DIO Change Occurrance Config.vi".

I know it's a long-shot, but it is on-topic!

Cheers

[MogaRaghu]

Hi Chris,

Thank you so much for  the links. Just didn't strike me in the first place. Will try to post there.

reagrds

Raghunathan

[MogaRaghu]

Hello,

I am using a PCI- 6229  card from the M-Series.

Regards

Raghunathan

[AlanArmstead]

Please refer to this thread.

-Alan A.