wiring hardware for pulse width measurement

[astroboy]

I am in difficulty.even with so simple pulse width measurement.

I am using labview 7.1, DAQmx, MAX, PCI - 6220.

I cannot find help document as to how to measure PW measurement and I find no connection diagram in MAX for using pulse width measurement.

I connect to PFI 9 (Gate) to 5V via switch. What about timebase counter as source? Ok I wanted to use internal clock from PCI-6220. But I cannot get to measure PW.

I want to MAX to measure. Once it is ok, then I will build a simple vi to understand its working better.

Pls help.

[astroboy]

In addition to my previous post, I would like to know how to wire hardware so that PW measurement can be achieved.

 Clement

[samantham]

Hello,

LabVIEW has examples that are located in the Example Finder under the Help menu inside of LabVIEW.  The examples specific to pulse width measurement are organized and located under the Browse tab of the Example Finder under the folders <Hardware Input & Output> <DAQmx> <Counter Measurements> <Period & Pulse Width>.  The Example Finder has an information section that has information on the Description, Instructions for Running, Block Diagram Steps, and I/O Connections Overview.  The last section will help with the connections.  The input for the example titled Meas Pulse Width – Buffered –Cont.vi will be the gate of the counter specified in the “Counter(s)” control on the front panel … such as Dev1/Ctr0.  So on your device the 6220, counter 0 gate is PFI 9 as you mentioned.

I understand that you are interested in getting started with the Test Panel in MAX first.  The Test Panels are limited to Pulse Train Generation for counter output and Count Edges for counter input.  Please use the Count Edges if you are interested in testing the device with a counter input task.  However, the Count Edges will just be counting edges of the signal specified in “Edge Source”. 

I also understand you are interested in using the internal clock from the 6220.  The example I previously suggested uses a DAQmx Timing.vi to configure the duration of the task … for example finite or continuous.  The Timing is set to implicit, since the signal wired into the gate of the counter is in fact controlling the timing.  The source of the counter task for pulse width is the internal timebase when using DAQmx Timing (Implicit). 

“Create a Counter Input channel to Pulse Width.  It is important to set the Maximum and Minimum Values of your unknown pulse width as accurately as possible so the best internal timebase can be chosen to minimize measurement error.  The default values specify a range that can be measured by the counter using the 20MhzTimebase.” - from the description of the Block Diagram notes on the example.  I also link helpful KnowledgeBase below.

AE KB 2X6CMDDS: What Does Implicit Mean in the DAQmx Timing VI?

http://digital.ni.com/public.nsf/allkb/2B6477E3A9B7C07386256D1F0066FBDD?OpenDocument