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Tachometer using open collector square wave

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#1 martinmathias

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Posted 25 May 2014 - 04:18 AM

Morning, Apologies if cross posting or missed something obvious but very new labjack and DAQFactory.  Any pointers to existing files, posts, and comments warmly received


I have just picked a half completed test rig that I have been asked to finish within the next 48hrs so as to allow some testing that will affect the use of some equipment on a big sporting event.

Are there any examples of a tachometer using open collector square wave?


I need to get the RPM of a shaft, the problem is that the hardware gives 360 counts per rev, believe it’s really meant for angle measurement not tacho.  With a shaft of up to 125 rpm that’s 750 pulses per second.  An update of the rpm once a second would be fine, but don’t know if I can count fast enough.  I’m very very new to labjack and when I did something similar before it was with NI kit and think did it in hardware.    Maybe I’m over simplifying it but count how many pulses in a second, do the math then send results to DAQFactory.  Really looking forward to learning the full potential but if there is an example i can learn from it would be a great help


Apologies if cross posted but desperate to get this working or at least find out if possible and work out a plan B if not


Kind regards



#2 LabJack Support

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Posted 26 May 2014 - 10:25 AM

We responded on AzeoTech's forum:



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