14 Verification
CV Load Effect
This test measures the change in output voltage resulting from a change in output current from full load to no load.
a. Turn off the supply and connect the output as shown in Figure 2-1 with the DVM connected between the +S and -S
terminals.
b. Turn on the supply and program the current to the maximum programmable value and the voltage to the full-scale value
(see Table 2-3).
c. Adjust the load for the full-scale current (see Table 2-3) as indicated on the front panel display. The CV annunciator on
the front panel must be on. If it is not, adjust the load so that the output current drops slightly.
d. Record the output voltage reading on the DVM connected to +S and -S.
e. Open the load and again record the DVM voltage reading.
The difference between the DVM readings in steps (d) and (e) is the load effect voltage, and should not exceed the value
listed in the Performance Test Record Form for the appropriate model under CV LOAD EFFECT.
CV Source Effect
This test measures the change in output voltage that results from a change in AC line voltage from the minimum to
maximum value within the line voltage specifications.
a. Turn off the supply and connect the AC power line through a variable voltage transformer.
b. Connect the output as shown in Figure 2-1 with the DVM connected between the +S and the -S terminals. Set the
transformer to nominal line voltage.
c. Turn on the supply and program the current to the maximum programmable value and the output voltage to the
full-scale value (see Table 2-3).
d. Adjust the load for the full-scale current value (see Table 2-3) as indicated on the front panel display. The CV
annunciator on the front panel must be on. If it is not, adjust the load so that the output current drops slightly.
e. Adjust the transformer to 13% below the nominal line voltage (e.g., l04.4 Vac for a 120 Vac nominal line voltage
input).
f. Record the output voltage reading on the DVM.
g. Adjust the transformer to 6% above the nominal line voltage (e.g., 127.2 Vac for 120 Vac nominal line voltage input).
h. Record the output voltage reading on the DVM.
The difference between the DVM reading in steps (f) and (h) is the source effect voltage and should not exceed the value
listed in the Performance Test Record Form for the appropriate model under CV SOURCE EFFECT.
CV Noise (PARD)
Periodic and random deviations (PARD) in the output (ripple and noise) combine to produce a residual AC voltage
superimposed on the DC output voltage. CV PARD is specified as the rms or peak-to-peak output voltage in a frequency
range from 20 Hz to 20 MHz.
a. Turn off the supply and connect the output as shown in Figure 2-1 to an oscilloscope (AC coupled) between the (+) and
the (-) terminals. Set the oscilloscope’s bandwidth limit to 20 MHz and use an RF tip on the oscilloscope probe.
b. Turn on the supply and program the current to the maximum programmable value and the output voltage to the
full-scale value (see Table 2-3).
c. Adjust the load for the full-scale current value (see Table 2-3) as indicated on the front panel display.
d. Note that the waveform on the oscilloscope should not exceed the peak-to-peak limits in the Performance Test Record
Form for the appropriate model under CV NOISE (PARD).
e. Disconnect the oscilloscope and connect an AC rms voltmeter in its place. The rms voltage reading should not exceed
the RMS limits in the Performance Test Record Form for the appropriate model under CV NOISE (PARD).
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