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programming the sampling frequency for the PT104

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programming the sampling frequency for the PT104

Postby alexKP » Wed Aug 07, 2013 2:43 pm

I managed to get multiple PT104 converters to work in my code using the USBPT104.dll driver (I am using labview, by the way).Though I can call the routines like UsbPt104GetValue at any desired frequency, it appears that the driver only updates the values for each channel sequentially every second. This means that for four channels I get a sampling frequency of 0.25 Hz for each channel. This is too slow for my application, but I cannot find in the programming guide (http://www.pc-oscilloscopes.com/manuals ... g.en-2.pdf) how to specify the sampling frequency.

When using PicoLog Recorder software I can define the sampling interval down to ms, but how can I do this in my own program?

Any help or suggestions is greatly appreciated!

Alex
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Re: programming the sampling frequency for the PT104

Postby Hitesh » Thu Aug 08, 2013 11:25 am

Hi Alex,

Due to the resolution (24-bits), each channel will take around 720ms for the reading to be converted resulting in a near 3 second interval between readings on a particular channel when all 4 channels are enabled.

Although in PicoLog you can ask for a sampling interval in ms, it will return the previously converted value until a new reading is available.

I hope this helps.
Hitesh

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Re: programming the sampling frequency for the PT104

Postby alexKP » Thu Aug 08, 2013 11:33 am

Thank you for your reply! This was clarifying!
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Re: programming the sampling frequency for the PT104

Postby hans_wurst » Fri Oct 18, 2013 8:00 am

Dear all,

regarding the sampling frequency of the PT104 I would like to know if there might be a possibility (possibly in a future device version) to decrease the resolution (in bits) in order to enhance the sampling time beyond one second (at the cost of accuracy). I do not know which ADC you used and what you implemented for signal improvement (inside the PT104) but a lot of commercially available ADCs provide such a functionality.

Thanks for your reply in advance.
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Re: programming the sampling frequency for the PT104

Postby Martyn » Tue Oct 22, 2013 7:39 am

The product is designed for precision temperature measurements, hence the high accuracy ADC. Measuring temperature will also depend upon the thermal mass of the sample, the probes in use and other factors, so it is not just a case of reducing accuracy and speeding up the measurement.

What temperatures are you measuring ?
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