Appendix F. Model 4200Ht-T High Temperature Strain Gage; Figure 13 - Model 4200Ht-T - Geokon 4200 Series Instruction Manual

APPENDIX F. MODEL 4200HT-T HIGH TEMPERATURE STRAIN GAGE

Geokon Model 4200HT-T High Temperature Embedment Strain Gage is similar to the Model
4200, but is constructed using components that can withstand temperatures up to 220 °C. It is
particularly useful for measurements in autoclaved spun concrete piles.
Data Interpretation is the same as that outlined in Section 6, with the exception of the
Temperature Coefficient, which for the 4200HT-T is 17.3µε/°C. Coil resistance for Model
4200HT-T is 50 ohms.
The thermistor included with the gage is a high temperature thermistor, which uses the resistance
to temperature conversion table shown in Appendix D (Table 10). When using a readout box, it
is not necessary to connect the green and white wires to the readout as the temperature shown on
the readout will be incorrect. Instead, use a digital ohmmeter.
To read temperatures using an ohmmeter:
1) Connect an ohmmeter to the green and white thermistor leads coming from the strain gage.
(Since the resistance changes with temperature are large, the effect of cable resistance is
usually insignificant.)
2) Look up the temperature for the measured resistance in Appendix D, Table 10.

Figure 13 - Model 4200HT-T

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