Section 5: Instrument Maintenance
comes from the Standard ITC setup menu as the Initial Delay value. This value should be at least
60 seconds.
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.
After the final equilibration phase has completed, the initial delay will begin and the pulses will
be applied as entered. As each pulse completes, VPViewer will analyze the pulse region and
determine the deflection of the baseline as well as the energy (area) of the pulse. The requested
power and energy will also be displayed as will a percent error for both power and energy. It is
sufficient for users to gauge the accuracy of their y-axis calibration by the results supplied by
VPViewer, in the script window. An example of these results, is shown below:
In general, users can anticipate that the reported error in deflection or energy will be less than
1%. If the error is reported as higher than 1%, please call MicroCal and speak to a Service
Representative. If a more thorough analysis of y-axis calibration results is desired, the calibration
data file can be read into Origin just as a titration data file can for detailed analysis.
Also, it is important that users realize that the data displayed in VPViewer, in real time, will
change in it’s appearance after each pulse analysis is carried out. After each pulse is turned off
and the DP signal has re-equilibrated to it’s original baseline, the data is operated on within
VPViewer. The pulse region will have a linear baseline subtracted from it resulting in the
baseline portion of the pulse region to be offset very close to zero. After this subtraction it is easy
to gauge the actual deflection of the pulses from the graph. Also, it need be mentioned that only
the data within VPViewer will be operated on in this way and that the *.itk data file will contain
only raw data.
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