11
Therefore,
10000 10 1000
10 2160
21600
pulses pulses
watt -seconds
watt -seconds
=×
21600 watt-seconds is the theoretical energy required to produce exactly 10000 pulses. If the SC-10
is in error, it will take more or less energy to produce 10000 pulses. The 811A calculates the amount
of energy actually required to produce 10000 pulses and displays that value in the watt-seconds
display. With this value, the registration error is readily determined. For example a reading of 21610
pulses causes registration error of
%Error %
%Registration %Error
=
×=
=− =
21610 21600
21600
100 0 046
100 99 964
.
.%
Similarly, a reading of 21590 pulses causes a registration error of,
% Error
Registration %Error
=
×=−
=− =
21590 21600
21600
100 0 046
100 100 046
.%
%.%
This test would last approximately 36 seconds.
To configure the 811A for this test the voltage and current outputs of the 811A are attached
to the voltage and current connections of the SC-10. The "HI" pulse output of the SC-10 is connected
to pin D of J48 on the rear panel of the 811A. Switch S-3 on the inside Rear Panel assembly must be
set as shown in the cutaway on Figure 2-4. This switch is set to this position at the factory. The
movable mini jumper must be moved so that the 4.7 kOhm resistor to +5 VDC is connected. When
S-3 is in the correct position the EVENT/GATE mode LED is illuminated whenever a pulse occurs.
Reset the 811A, then enter 120 volts. Then key 600 volt-amperes and press enter to set
120 volts, 5 amperes, and 600V-A. Ensure that the Power Factor control is set to unity. Connect the
SC-10 to the voltage and current outputs of the Model 811A. Next enter the number of events or
pulses to be counted, which is 10000 in this instance. Press Operate to apply power to the SC-10.
When the SC-10 has stabilized, the Event Count button is pressed to begin the test. The pulses are
counted and the event count display will indicate the number of pulses left to be counted. When
10000 pulses have occurred, the event count display will contain a value which is the energy
delivered in units of watt-seconds. This test is conducted "on the fly" and can be repeated by
pressing enter, then keying the desired count of 10000 again, etc. Other voltages, power levels,
pulse counts and power factor may be employed as necessary. The maximum input pulse rate is
4000 pulses per second.
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