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How to sync Encoder Z signal with TDC (engine Top dean center)?

Hello guys,

I am trying to set up DAQ system for engine testing to measure pressure, temp, torque and etc.

I am currently using NI-6211, 6212(pressure and engine parameter), and 9213 (for temperature).

So far, I am able to measure mean values over cycle such as pressure and temperature. 

Then, I want to see instantaneous value by crank angle rotation (let's say every 1 CAD or 0.5 CAD). 

I have encoder installed at the free end of the crank shaft which has 1024 ppr.

So, theoretically, I can measure it every 0.35 CAD.

Then, I need reference signal to define exact crank rotation angle that is TDC.

So, how to sync TDC with Encoder Z signal?

Is there any simple and accurate way to sync TDC with encoder Z signal?

Thank you for assistance in advance.

 

 

 

 

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There have been a number of similar threads on the forums here.  I only have time for a brief recap on what I'd do, more details can be found with more searching.

 

  • use the z index of the encoder as a Start Trigger for your AI task(s)
  • use the A or B channel of the encoder as an external sample clock for pressure AI.  Maybe also for temp, not sure if your device is speed limited.
  • do some upfront prep work to figure out the separation between the encoder Z index and TDC.   You can ignore this many samples at the front end of your acquisition so that what's left starts at TDC.

 

-Kevin P

CAUTION! New LabVIEW adopters -- it's too late for me, but you *can* save yourself. The new subscription policy for LabVIEW puts NI's hand in your wallet for the rest of your working life. Are you sure you're *that* dedicated to LabVIEW? (Summary of my reasons in this post, part of a voluminous thread of mostly complaints starting here).
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