Tektronix Keithley SourceMeter 2450 User Manual page 99

Model 2450 SourceMeter® Instrument User's Manual
-- Define initial values.
voltage = defbuffer1.sourcevalues
current = defbuffer1
isc = current[1]
mincurr = current[1]
imax = current[1]
voc = voltage[1]
vmax = voltage[1]
pmax = voltage[1]*current[1]
-- Calculate values.
for i = 1, num do
print(voltage[i],current[i],voltage[i]*current[i])
if (voltage[i]*current[i] < pmax) then
pmax = voltage[i]*current[i]
imax = current[i]
vmax = voltage[i]
end
if math.abs(current[i]) < math.abs(mincurr) then
voc = voltage[i]
end
end
pmax = math.abs(pmax)
imax = math.abs(imax)
print("Pmax = ", pmax, ", Imax = ", imax, ", Vmax = ", vmax, ", Isc = ", isc, ", " ..
"Voc = ", voc)
-- Display values on the front panel.
display.changescreen(display.SCREEN_USER_SWIPE)
display.settext(display.TEXT1, string.format("Pmax = %.4fW", pmax))
display.settext(display.TEXT2, string.format("Isc = %.4fA, Voc = %.2fV", isc, voc))
In the example above, the instrument is programmed to display custom text on the USER swipe
screen using the display.changescreen and display.settext commands. After the test is
finished, the display will indicate the maximum power (P
open circuit voltage (V
2450-900-01 Rev. E / August 2019
), as shown in the figure below.
OC
Figure 53: Solar cell I-V sweep results on the USER swipe screen
Section 9: Measuring I-V characteristics of solar cells
), the short circuit current (I
MAX
), and the
SC
9-9