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4.2.7 4.2.7 Fractional Divider Tests
Set the Series 800 to 120V, 600VA, 50Hz, 1.0 PF. Use MSB-001A Watt converter as in
Paragraph 4.2.5, connecting to the 5 Amp current input range.
4.3 Calibration Procedure
The following paragraphs list the steps required to calibrate the Series 800. All internal
calibration measurements are made with respect to Signal Ground, which is located at the left hand
test point on the Reference module; refer to Figure 4-7. Voltage output measurements are made
between the Sense High terminal and the Sense Low terminal with the Series 800 in the INTERNAL
SENSE MODE. A four wire system may also be employed by placing S20, located on the rear panel,
in the EXTERNAL SENSE mode. Current output is measured by the procedure of Paragraph 4.2.2.
Power is measured by the procedure of Paragraph 4.2.5. The temperature should be maintained at
23 ±1°C. All adjustments are made with the Calibrator in the Operate condition and the Deviation
control 'OFF', unless otherwise specified. The calibration is performed at the nominal line voltage
±1%, 50-60 Hertz with the top cover of the instrument and the inner cover guard in place. The cover
is momentarily removed to make adjustments or measurements. Adjustments are identified on the
guard cover, inside the top cover. Use caution in making connections to test points underneath the
guard. The guard is at the ground potential. Accidental shorting between test points and the guard
or between the guard and circuit elements on the modular plug-in assemblies could destroy
components. Paragraph 4.3.3 lists the factory adjustments and the procedures for adjusting each
one.
4.3.1 Model 800A/811A Calibration Procedure
Be sure the following conditions are established before beginning calibration.
• Deviation - OFF
• Power Factor - 1.0 Lagging
• Fractional Divider - OFF
• Vernier - OFF
• Current Waveshape - SINE WAVE
• Line Synchronization - OFF
Step 1 - Power Up
a. Turn power on and set the Series 800 to l20V, 600VA, 5 Amps, 50Hz. Use 50Hz where line
frequency is 60Hz. Where line frequency is 50Hz use 60Hz setting throughout. Put the
calibrator in Operate, placing a short on the current output terminals, and allow the unit to
operate for 2 hours.
Step 2 - Reference Module, Reference adjustment
a. Using a Digital Multimeter, and the black TP located on the left side of the Reference Module
as ground, adjust R16 for 10.0000V ±20µVDC at TP3. Move Lead to TP4 and adjust R32 for
10.0000V ±20µVDC.
Step 3 - Oscillator Module, DC Offset adjustment
a. Using a Keithley Model 155 Null Detector Micro voltmeter, with a 1 megohm resistor in series
with the high lead, and a 1.0 µF capacitor across the meter terminals, and using TP13 as
ground, adjust R53 for 0V ±20µVDC at TP11. The arrangement of the null detector with
series resistor and shunt capacitor is referred to below as "the meter with filter".
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