Valhalla 2300, Operation Manual

Page: 73 / 115

SECTION X THEORY OF OPERATION
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10-1. General
This section gives the theory of operation of
the circuitry used in the 2300, and is divided
into two parts. The first part is a functional
description referring to the block diagram
shown in Figure 10-1. The second is a
detailed description referring to the schematic
diagrams found at the back of this manual.
10-2. Functional Descriptions
This section describes the general operation of
each section of the 2300. The paragraph titles
refer to the block diagram, Figure 10-1.
10-2-1. Current Amplifier
The current amplifier boosts the small signals
from the current shunts to workable levels.
This stage provides a DC voltage proportional
to the RMS value of the current to the isolator
stage along with an amplified version of its
input to the power multiplier stage. The gain
and input of this stage is controlled by the
control isolator stage.
10-2-2. Voltage Amplifier
The voltage amplifier attenuates the input at
the voltage terminals down to workable
levels. This stage provides a DC voltage
proportional to the RMS value of the voltage
to the isolator stage along with scaled versions
of the input to the power multiplier stage. The
gain of this stage is controlled by the control
isolator stage.
10-2-3. Power Multiplier
The power multiplier instantaneously
multiplies the current and voltage signals,
producing the watts output. This stage
provides a DC voltage
proportional to the true power to
the isolator stage.
10-2-4. Isolators
The circuitry described so far is floating from
chassis ground. The isolators pass the current,
voltage and power signals from the floating
section to the chassis-grounded section of the
2300.
10-2-5. Control Isolators
This stage isolates the signals required to
control the voltage and current amplifiers
from chassis ground through the use of opto-
isolators.
10-2-6. Receivers
This stage converts the outputs of the isolators
back into DC voltages for the watts, amps and
volts ranging sections. This stage also selects
which signal processing PCB's data will be
displayed. The receivers also sum the watts
data for three-phase displays.
10-2-7. Watts, Amps, Volts Ranging
These three stages scale the power, voltage,
and current data to provide levels usable by
the A to D converters.
10-2-8. Power Supplies
This section powers the circuitry of all other
sections of the 2300. The power supply has
four separate sections, one chassis ground-
referenced supply for the A to D's and three
fully floating supplies for the three signal
processing PCB's.