PCI-6220 generate a digital output pulse signal while monitoring analog input signal

[cbh]

What is the best way to set up the PCI-6220 for a digital output signal of 0.2 sec pulse width(single shot) , while simultaneously  capturing  a analog input pulse train of 2.5 seconds.  I need to analysis the return analog pulse signal.

[CKap]

Hello Cbh,

The best way to generate a single digital pulse (of specific period) is to use the onboard counters. You could generate this digital pulse based off some hardware trigger, or have these VIs to execute an a Case Structure. I have attached two VI that could be used for this purpose. The first example does not use any triggering and would only generate a single pulse. The second example does the same thing, but it waits for a specified trigger to file.

Regards,

Chetan K

Appplication Engineer

National Instruments

[metumu]

Hello,
I was searching on the internet about generating digital pulses, and
found your answer to CKap. I guess I will also make use of this VI.
Thank you very much for this. However, I have a very big problem with
running my stepper motor by LabVIEW 7.1.1, and a USB-DAQ Device. If you
know how to do this, Could you help me please? Thank you.

CKap wrote:
> Hello Cbh,
> The best way to generate a single digital pulse (of specific period) is to use the onboard counters. You could generate this digital pulse based off some hardware trigger, or have these VIs to execute an a Case Structure. I have attached two VI that could be used for this purpose. The first example does not use any triggering and would only generate a single pulse. The second example does the same thing, but it waits for a specified trigger to file.
> Regards,
> Chetan K
> Appplication Engineer
> National Instruments
>  
>  
>
>
> Gen Dig Pulse.vi:
> http://forums.ni.com/attachments/ni/70/4855/1/Gen Dig Pulse.vi
>
>
> Gen Dig Pulse-Dig Start.vi:
> http://forums.ni.com/attachments/ni/70/4855/2/Gen Dig Pulse-Dig Start.vi

[CKap]

Hello metumu,

What are the specifications of your stepper motor? Specifically, how much current would you need to drive this motor?

Usually stepper motors demand higher currents than what the DAQ device can supply. For this reason, stepper motors are associated with external drives.

You can find another similar discussion forum by following this link

Chetan K

Application Engineer

NI

[MeghanM]

Could you provide an example that uses an express VI? I don't fully understand how to use DAQmx items, and my current VIs use Express VIs and I'm not sure how to integrate them.

I am using a rotary encoder on a motor shaft, and want to send out a pulse train to trigger a camera. The rotary encoder outputs a relatively clean digital signal, at 1000 pulses / rotation. However, I would only like to send the trigger to the camera 25 times per rotation (so a decimating factor of 40).

I am using LabVIEW 8.5 with a PCI-6251 and BNC-2110. There are two BNC connections under "Trigger/Counter": PFI0/AI START and CTR 0 OUT, and I was wondering if/how I should be using these connections, instead of analog input or digital input for the encoder signal, or where to send the output.

Also, if you can provide any insight to how much, if any, of a delay will result from decimating the signal, or a way that I could measure that.

Thanks!