VP-ITC MicroCalorimeter User’s Manual
5.3 Y-axis Calibration
All necessary calibrations of your VP-ITC are carried out at MicroCal prior to shipment. Still, it
is a good idea that the user performs a y-axis calibration check every 2-3 months. Y-axis
calibration is achieved by dissipating a known power through a resistive heater located on the cell
wall, and by then adjusting the software coefficient for DP. When setting up an ITC calibration
experiment, it is best to enter calibration heat Pulse Sizes (power is in uCal/sec.) on the order of 1
uCal/sec. or larger, in order to negate any effects from baseline drift. Users must enter Pulse
Durations for at least 4 minutes to allow enough time to establish a flat deflected baseline.
Finally, users will want to allow enough time after the heat pulse has been turned off to allow the
DP to return to it’s original baseline position. Entering a value for Pulse Spacing which is at
least 4 minutes longer than the Pulse Duration will allow the deflected baseline to return to it’s
original value. Users are encouraged to use the default parameters for y-axis calibration runs. The
following procedure uses the default parameters.
To initiate a y-axis calibration procedure select ITC/Start ITC Calibration Run/Y Axis.
Once the menu has been selected, the Calibration Pulse Setup Window will appear. This window
will serve as the pulse parameter editing window where users will define the calibration pulses to
be entered. 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). This window is pictured below:
The parameters shown in the above window will allow for setting of all relevant y-axis
calibration parameters with the exception of the delay period prior to the first pulse. This variable
72
To Next Page
Loading...