measurement digial input or analog input

[daadmaster@gmail.com]

Hello,

I am trying to measure frequency using NI DAQmx task and then convert this to an RPM if at all possible.

I have the following hardware .

I have NI DAQ-9174 with the DI (NI 9421) modules  (8 channels) 

I have wired the proximity sensor and tachometer to ai0 and ai1 respectively which is PFI 1 and PFI 5  among these 8 channels in order to measure (pulse ,frequency , or periods) .  

What I am trying to do is to somehow convert this digital measurement into a RPM by using the DI module.

If not possible using the DI module, can I use AI module (NI 9229) in order to convert this analog measurement into a RPM.

Any help would be appreciated.

Mola

Test Engineer

[Izzzzz]

Hello Mola,

I would utilize your 9421 in order to get access to the counters on the backplane of your 9174 in order to create a frequency task. In software this would look like the DAQ assistant setup below

 

or the DAQmx Shipping Example LabVIEW 2011  https://decibel.ni.com/content/docs/DOC-11753 , and LabVIEW 2012 https://decibel.ni.com/content/docs/DOC-25244 . Then apply a scaling factor in order to convert the frequency into RPM. Please post back if you have additional questions. 

Best Regards,

Izzy O.

Applications Engineer

National Instruments

www.ni.com/support

[daadmaster@gmail.com]

Dear Izzy O.,

I already did the DAQ assis as you explained and U got for the proximity 72 s and for tachometer 163s . and to convert it to RPM I use this folmula : RPM = Hz *60 but still not logic because the two wheel move together in same speed.

Hope I was clear enough and hope to get your advice regard that