TA Q Series, Руководство по началу работы, Страница: 37 / 58

TMA Q Series Getting Started Guide
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When to Calibrate:
The sample thermocouple should be calibrated in the following situations:
• When the TMA is first installed
• When the sample thermocouple is changed
• When the TMA is serviced or repaired
• Periodically (approximately once a month)
• If you are changing the temperature range of interest
• If the run data obtained seems to be inaccurate
• When the purge gas is changed.
Cell Constant
Cell constant calibration is based on a run conducted in the calibration mode in which a known standard ( e.g. ,
aluminum or copper) is heated through its transition temperature and data is gathered for analysis. The cell
constant is calculated by dividing the actual coefficient of expansion of the standard by the measured coeffi-
cient of expansion. The cell constant is then entered in the instrument control software for calibration of the
instrument.
Using the default cell constant value of 1.000 is usually adequate; however, for greatest accuracy, calibration
should be performed.
It is recommended that you follow the procedures of ASTM Standard Test Method E831 to perform the cell
constant calibration.