Syscomp CTR-201, Руководство пользователя

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The curve tracer is supplied in calibrated form. It shouldn’t be necessary to do a re-calibration, but we supply the
information in this section.
The curve tracer
should not
be operated in the uncalibrated state. It will generate incorrect results and may
cause damage.
You will need a digital multimeter with voltage and current ranges and an alligator clip lead. The multimeter
should have voltage resolution of 1mV or better and 0.01mA or better.
•
Remove rear panel of the curve tracer.
•
In the right corner, next to the USB connector, there is a square area marked on the PC board, shown in
figure 21(a) on page 21. This is the ground point for the instrument. Attach an alligator clip lead to that
point as shown in figure 21(b).
•
Plug in the power adaptor and the USB cable to the instrument. Start the curve tracer software.
•
Select the menu item Tools -> Calibration . The Calibration panel appears, similar to figure 22.
Figure 22: Calibration Panel
The Curve Tracer software assumes that the output voltages and currents, and the feedback voltages and
currents, can be corrected by a straight line equation
y = M x + B . The calibration procedure establishes
the values of slope
M
and y offset
B
. It does this by outputting an assumed value (eg, 10 volts). The
operator then enters the actual output voltage. Doing this twice provides two equations in two unknowns,
so that the actual values of slope
M
and y offset
B
can be determined. In general, the values of slope will
be fairly close to unity, and y offset less than unity though there can be exceptions.
•
Select Reset Calibration Values . This wipes the existing calibration and you must then enter
new calibration values.
•
The software has been designed as a Wizard to guide the operator through the entire calibration process.
To begin with, click on
Calibrate Collector Voltage
and follow the on-screen instructions. The
software outputs a voltage (eg, 10 volts) and asks for the operator to enter the actual voltage reading (which
might be 9.7 volts). When the software has done this twice it has enough information to calculate the slope
and y offset for the collector voltage function.
Then the software outputs a test value, such as 10 volts. The meter reading should be very close to 10 volts.
•
Continue with the other calibrations in a similar manner. Some of the calibration steps will require current
measurement.
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