Pulse Generator

[MAH2681]

We are posting a question in regard to creating a pulse generator that would:

* have Boolean logic output

* yield Boolean “high” logical level for ~ 0.2 ms at the repetition rate ~ 10 Hz

* keep Boolean “low” logical level after generating the Boolean “high” 0.2 ms pulse

* As an option, it would be great to adjust the pulse duration in a range 0.2-1000 ms, and adjust the rep. rate in a range 100 – 1 Hz.     

We would then like to use the outputted logical waveform to modulate (turn on/off) a particular pin on an external board connected to PC via USB interface.

We were thinking of using the Basic Function Generator vi, but it might be an overkill.  Also, its output is specified in volts.  Is there a simple way to convert this voltage into Boolean “high” and “low” levels?  Any better ideas or suggestions to try?

If anyone could provide some guidance on this issue, it would be greatly appreciated.

We are using Labview 2010 SP1.

Thank you.

[Jack._W]

Hello MAH2681,

I believe you will find the answer to this question in a previous discussion I posted on.

http://forums.ni.com/t5/LabVIEW/Custom-high-and-low-times-for-square-waves/m-p/1715768#M605175

One solution if you are using any sort DAQ hardware is to use the DAQmx palette VIs.

Hope this helps

[MAH2681]

Hi Jack,

Thank you for your reply.  I was looking over the topic you directed me to and will continue to do so.  I had install DAQ as it wasn't previously installed.  I had a few questions regarding that.

I setup my own vi similar to your capture in the other topic, as far as I can tell.  I was trying to create a virtual channel to use, however I am unable to do so.  This would be for the "counter" control.  It appears this needs a physical channel.  Is there something I'm missing when trying to do that (creating a virtual channel)?  I may have read the info about DAQ wrong, but I thought I could create a virtual channel and use that, but I am unable to do so right now.  I don't even see a tab for it under MAX when trying to create it (as I see in the tutorial I am reading and is mentioned in help). 

If you could provide any insight into that or what I may be doing wrong, I'd appreciate it.

Thanks.

[Kevin_F]

Hey MAH2681,

A virtual channel just corresponds to a real channel on a device you have connected to your computer.  If you don't have a device on your machine you can also use a simulated device in Measurement and Automation explorer.  Some information on using virtual channels can be found here:http://zone.ni.com/devzone/cda/tut/p/id/2835.  This article explains how to create and use simulated devices:http://zone.ni.com/devzone/cda/tut/p/id/3698.  Please post back if you have additional questions.

[MKFX]

Hi Jack, I am trying to do the same thing to make a pulse generator.

Basically I want to make an automated "timer" switch that turns off and on (boolean output) with user-set time-delay, without using a DAQ card. Basically I want a automatic boolean switch that switches off and on.

The reason for doing this is that I want the user to have an option to click to refresh, or just set an automated timer that will automatically refresh (restart averaging).

So what I am trying to do is a simple switch for the user to restart (already connected), and I would like to use an OR operation, now the next step is I am not to sure how to generate a boolean output.

How do I create a pulse generator in this manner? that automatically "clicks" with a user-set time delay?

Help would be much appreciated! Thanks!

[Jack._W]

Moved to - http://forums.ni.com/t5/LabVIEW/Auto-clicker/m-p/1838127