Chroma 61501, Руководство пользователя, Страница: 79 / 134

Theory of Operation
6-1
6. Theory of Operation
6.1 General
The AC source consists of 10 print circuit boards and other components. Each of the PCB
has its specific function that will be described in the following subsection.
6.2 Description of Overall System
Figure 6-1 shows the overall system. Main power flows through the A/D, D/D, D/A power
stage converter. The A/D power stage is designated as I board, and generates DC voltage
from the line input. The DC voltage of A/D output is applied to the D/D power stage. The
G board of D/D stage takes power from the A/D output. It generates two isolated DC
outputs for D/A power stage. The H board of D/A inverter generates AC output through full
bridge controlled by B board. The D/A power stage is through G board relays in parallel or
series control to obtain more current and higher voltage.
B board is identified as DSP processor and D/A controller. The DSP processor is applied to
control output frequency and voltage, to measure voltage and current through G board, to
perform remote control through GPIB, RS-232C or EXT Vref interface on Optional E board,
to respond TTL signals through D board. A board is identified as user interface controller.
It scans front panel keys through K board, and sends settings and measurement messages
on LCD module.