Table Of Contents

3.5 Y-axis Calibration Check
It is recommended that the y-axis calibration be checked every few months to ensure
accurate data. The automatic calibration check routine will send a series of pulses to the cell
heaters, dissipating a known power. The offset in the DP as a result of this power is analyzed in
comparison to the correct DP offset.
Make sure the cells are clean, and fill both cells with degassed, distilled water. Load the
titration syringe with water and insert it into the sample cell. It is recommended that Origin for
real-time data be enabled.
To begin the y-axis calibration check procedure select iTC 200 software menu “ITC =>
Start ITC Calibration Run => Y Axis Check”. Once the menu has been selected, the Calibration
Pulse Setup Window will appear. This window allows the calibration pulses to be modified.
Individual pulse parameters are entered by first selecting a pulse or multiple pulses, then entering
the desired parameter value into the pulse parameter boxes (Calibration Power, Pulse Duration
and Pulse spacing). Users are encouraged to simply use the default y-axis calibration
parameters. After the run and pulse parameters are entered, clicking on the “Start Run” button
will start the run. The ITC will equilibrate in the same manner as it would during a titration
experiment.
If creating customized calibration parameters, users must be aware of the DP range limits
when setting reference power and pulse sizes. The reference power must be high enough to
allow all pulses without hitting saturation, and if a pulse size is too small, it can show abnormally
high error.
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