INSTRUCTIONAL MANUAL
2750L-P/4500L-P/6000L-P
August, 2001
Rev. K
-109-
the output parameters of the power source. Data from measurement circuits are accepted and reported to the display
and GPIB. Measurement calibration coefficients are stored in a memory backed up by a battery. The battery has a 10
year life expectancy.
Measurement circuits on the CPU/GPIB board monitor voltage, current, power, frequency, and phase angle. Voltage
from the rear panel sense connector is scaled, converted to a DC voltage by a true-rms-converter, and sent to the
microprocessor by the analog-to-digital converter.
Current sensed by internal current transformers is scaled, converted to a DC voltage by a true-rms-converter, and sent
to the microprocessor by the analog-to-digital converter.
The scaled voltage and current waveforms are applied to the inputs of a multiplier. The multiplier output is filtered to a
DC level and digitized by the analog-to-digital converter.
Frequency is computed from the measured time intervals between zero crossings of the Phase A waveform. Phase is
computed from the differences of measured zero crossings between the Phase A signal and the Phase B or Phase C
signal.
A digital-to-analog converter on the CPU/GPIB board sets the DC voltages that are used for the programmable current
limit function.
5.11 PHASE
A/REF
BOARD
The Phase A/Ref Board, A11A5, serves several purposes. A programmable clock sets the output frequency of the
power source. Digital-to-analog converters program references to set the output amplitude of Phases A, B and C. A
sine wave generator creates a 1024 step waveform which is filtered to provide the Phase A oscillator signal. A external
sense amplifier controls the Phase A output amplitude.
5.12
PHASE B/C BOARD
The Phase B/C Board, A11A4, uses the DC voltage references and programmable clock from the Phase A/Ref board
to generate the Phase B and C oscillator waveforms. External sense circuits control the Phase B and C output
amplitudes.
5.13 DISPLAY
MODULE
The Display Board, A11A13, is held to the power source by a small panel and is connected through a short ribbon
cable. It holds the 20 button keyboard and a 32 character LCD display. A knob on the board allows the display viewing
angle to be adjusted.
Summary of Contents for 12000L-1P
Page 119: ...INSTRUCTIONAL MANUAL 2750L P 4500L P 6000L P August 2001 Rev K 115 Figure 6 1 MODULE LOCATION...
Page 138: ...INSTRUCTIONAL MANUAL 2750L P 4500L P 6000L P August 2001 Rev K 134 Figure 14 EMERGENCY VOLTAGE...
Page 148: ...INSTRUCTIONAL MANUAL 2750L P 4500L P 6000L P August 2001 Rev K 144 FIGURE 2...