Logr Temperature Technology; Logr Temperature Accuracy - Thermo Scientific Orion Versa Star Pro User Manual

Thermo Scientific

LogR Temperature Technology

The Versa Star Pro meter with pH/LogR measurement module allows direct temperature
measurement and temperature compensation using most standard glass-bulb pH electrodes
and patented digital LogR technology.
LogR technology is based on using the electrical resistance of the pH-sensing glass-bulb as the
temperature source. The logarithm of the resistance of the bulb varies almost linearly with the
reciprocal of the absolute temperature. Almost all standard glass-bulb pH electrodes exhibit a
similar decrease in resistance with increasing temperature. To maximize LogR performance
and accuracy, a ROSS Ultra or ROSS pH electrode is recommended.
LogR Resistance vs. Temperature Graph

LogR Temperature Accuracy

Table 1 – Two Point LogR Temperature Calibration, Average Error at pH 3 and pH 11
Average
Temp. Error
Electrode
0 to 25 °C
(°C)
8202BN 0.36
8203BN 0.13
8235BN 0.04
8256BN 0.22
8272BN 0.23
9202BN 0.21
9203BN 0.20
9206BN 0.29
9207BN 0.16
9256BN 0.27
9272BN 0.22
* For 20 °C temperature compensation spans
Appendix A
Average Average Temperature
Temp. Error Compensation Error
Above 20 °C * 0 to 25 ºC
(°C) (pH Units)
0.10 0.004
0.02 0.002
0.14 0.000
0.06 0.003
0.06 0.003
0.06 0.003
0.10 0.002
0.06 0.003
0.07 0.002
0.07 0.003
0.06 0.003
Orion Versa Star Pro Meter User Manual

Channel Specific Settings and Features
Average Temperature
Compensation Error
Above 20 °C *
(°C)
0.001
0.000
0.002
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001

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