OAT analog tacho process VI - missing last ~3 tacho pulses of data block

[mikefoo]

Hi,

I have had the above issue when using the OAT analog tacho process VI.

I pass the VI a analog tacho signal in a waveform. The block of data sent has 10 tacho pulses.

The 'speed profile' output of time(s) and speed(rpm) only contain values for the first 7 pulses. The tacho pulse time(s) and speeds appear to be correct, however it just seems to not report the last three pulses. I don't think it is 'missing' them as the pulses are all similar and the speed is not changing over the data block.

I also passed the VI data blocks with more tacho pulses (10+) however the same problem occurred where the last 3 or so tacho pulses were missed/not reported.

I have a feeling it is possibly some buffereing issues, however there is no mention in the documentation, and it is a little difficult to determine from the subVIs inside as I can't probe any of the subVI block diagrams.

Just wondering if anyone can confirm this issue or has any ideas.

Kind regards,

Mike Foo

Labview 8.2

[Hueter]

Mikefoo

Could you please post your code so i can see what might be going on.

If you post it on the DevZone community it makes it easier to edit and share.

-Huter

[깨굴]

Hi.

I same problem ..

Example File

This problem  Order Tracking analysis delay signal.

Kind regards.

kwangho. Kim

LabVIEW 8.6, 2010

Sound Vibration 2010

[jareds]

Hi Kwangho,

Unfortunately, I don't have that toolkit, but it may help to have a little more description of what you expect to see.  Are you missing the last three pulses just as the previous poster?

[mikefoo]

Sorry to not have updated this thread, but after discussions with NI we received the following response:

R&D had gotten back to us and apparently this is an expected behaviour.
They have createda Knowledgebase in response to this question as follows:

http://digital.ni.com/public.nsf/allkb/B46B0FA276FDEE288625758400767C5D?OpenDocument

The workaround to this is to add junk pulses so that the data that is removed is not a real part of the DUT as you've implemented. Please let me know if you need more information regarding the above knowledgebase.

As they mentioned above, our work around was to extrapolate the additional (3) missing pulses.

Mike