Correction on Pt-104 input

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perbackstrom
Newbie
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Joined: Tue Oct 13, 2020 9:01 am

Correction on Pt-104 input

Post by perbackstrom »

Hi saw you can use probe scaling and a table for making a correction on the Pt100 input. But I could also see that you use equation scaling. Is it possible to make correction on the IEC scaling, just as you mention on your homepage: "The linearization equation is: Rt = R0 * (1 + A* t + B*t2 + C*(t-100)* t3)" and put in values for A, B and C? This would make the correction even better on the Pt-104

Gerry
PICO STAFF
PICO STAFF
Posts: 734
Joined: Mon Aug 11, 2014 11:14 am

Re: Correction on Pt-104 input

Post by Gerry »

Hi perbackstrom

Yes, you should be able to get the PT100 calibrated for correction, using temperature points to determine the actual coefficients for the sensor (rather than the standard) used in the Callendar-Van Dusen equation, and then use the coefficients provided by the Cal Lab to apply your own calculation of the measured resistance values. This is likely to improve the accuracy (and would be particularly useful where, for instance, you are using a PT100 sensor that is not based upon Alpha 385 coefficients). You could apply the calculation using a Scaling Equation in PicoLog 6, and, because of the conversion time of the PT-104 Data Logger, you shouldn't have any issues with real-time display while the Math channel applies a conversion for every sample value on each Channel.

However, bear in mind that when the calibration is done you would need to use an acquisition device (to complete the measurement) and its uncertainties would need to be factored into the accuracy of the coefficients used for correction. Those should be based upon the Device, i.e. PT-104 (and Channel) that you intend to use to perform the measurements.

Regards,

Gerry
Gerry
Technical Specialist

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