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Block Mode Setup Time

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Block Mode Setup Time

Postby Armin_T. » Thu Mar 31, 2011 8:25 am

Hello,

I'am using PicoScope 4224 with LabView 2010 on a notebook and have a question about the Setup Time, whitch takes according to the Programmers's Guide up to 50ms, before collecting each block of data. Is it possible to avoid these 50ms between collecting samples? I have an application that needs to collect data every 3ms and I can not use rapid block mode for my application.

If this setup time can not be avoided with PS4224, is there any other scope that could collect data every 3ms or faster in block mode?

Thanks for your help.
Regards,
Armin
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Re: Block Mode Setup Time

Postby Chris » Fri Apr 01, 2011 3:08 pm

This time is PC dependant, and will also vary depending on what else the PC is doing, hence the guide states up to 50mS.

The time can be reduced by setting the DataBuffer prior to calling RunBlock.

Using Rapid Block mode will enable multiple captures, for each data retrieval, so reducing the retrieval overhead time.
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Re: Block Mode Setup Time

Postby Armin_T. » Mon Apr 04, 2011 12:27 pm

Could you explain "setting DataBuffer prior to calling RunBlock" ?
Is this the execution priority, adjustable in the VI properties?
Thanks for your help. :)
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Re: Block Mode Setup Time

Postby Chris » Mon Apr 04, 2011 4:10 pm

In the ps4000pg.en.pdf programmers guide, section 4.6.1.1 (Using block mode) shows 'Use ps4000SetDataBuffer' as step 7, after ps4000RunBlock is called, and ps4000BlockReady callback function has indicated that data is ready.

If you loop back to the ps4000RunBlock call, you will call ps4000SetDataBuffer again.

If you put this ps4000SetDataBuffer call before the ps4000RunBlock call, you take it out of the loop, and only call it once.
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