PERFORMANCE TESTS
5-2
2. Self Tests
The internal self tests verify the functionality of the SR715/720.
1) Turn on the unit. The ROM firmware version and serial number will be displayed for about 3 seconds.
Next the message 'tESt.....' will be displayed while the unit performs its self tests. After the tests are
completed the unit should display 'tESt PASS' to indicate that the tests were successful. If not, an
error message will appear. See the TROUBLESHOOTING section for a description of the error
messages.
3. Output Voltage
This checks the SR715/720 output voltage for the correct frequency and amplitude.
1) Set the SR715/720 to 1 kHz, 1.0V and constant voltage. Set the scope to 1 V/div vertical and
0.5 ms/div horizontal. Connect a X10 probe to the scope.
2) Place the tip of the probe into the "+" side of the fixture and connect the ground clip to the center
guard ground.
3) The scope should display a sine wave that occupies 2 divisions horizontally and about 5.5 divisions
peak to peak vertically (1.0 VRMS = 2.83 V peak to peak). There should be no irregularities in the
wave form.
4) Change the amplitude setting of the SR715/720 to 0.25 and 0.10 V and verify that the output is within
2% of nominal.
5) Set the amplitude back to 1.0 V. Change the SR715/720 and scope settings to verify that the output at
100 Hz, 120 Hz, 10 kHz and 100 kHz (SR720 only) is within 2% of nominal.
4. Resistance Measurement
This verifies that the SR715/720 operates and is able to measure a component in each of its ranges. The
readings obtained should be within ± (tolerance of the com tolerance of the SR715/720).
1) Press [Recall] [0] [ENTER] to put the unit in its default setup.
2) Perform open & short circuit cal for the fixture configuration to be used. See the operation section for
details on this.
3) Set the unit to R+Q, series equivalent circuit and 1 kHz test frequency. Install the 24.9
Ω
resistor.
Verify that it reads within ±0.15% (SR720) or ±0.3% (SR715). Verify that Q is a small value, about
+.0001 or smaller.
4) Install the 402
Ω
resistor. Verify that it reads within ±0.15% (SR720) or ±0.3% (SR715). Verify that Q
is a small value, about +.0001 or smaller.
5) Change the equivalent circuit to parallel. Install the 6.34 k
Ω
resistor. Verify that it reads within ±0.15%
(SR720) or ±0.3% (SR715). Verify that Q is a small value, about -.0001 or smaller.
6) Install the 100 k
Ω
resistor. Verify that it reads within ±0.15% (SR720) or ±0.3% (SR715). Verify that Q
is a small value, about -.0002 or smaller.
