HP 8340b User Manual

RPG
Rotating
the
RPG
(rotary pulse generator)
increments
or decrements
a
counter,
and
generates
a
service
request,
with
the
main
instrument
microprocessor
reading
the
counter
output.
POWER STANDBY/ON
SWITCH
The front
panel
power
standby/on
switch
is
an
open
circuit
in
the
on
position.
In
standby,
a
ground
is
supplied
to
the
yellow standby
LED,
and to
the
fan
relay.
This
ground
is
also
LSBY
(low
standby).
In
standby,
the
fan
relay
is
energized,
and
the
power
to
the
fan
is
removed.
The
LSBY
signal
is fed
to
the
+20V
regulator,
which
shuts down
the
+20V
supply.
Because
the
+20V
supply
is
a
reference
for
all
other regulated
supplies,
all
regulated supplies
are
shut
down
as
well.
In
the
standby
mode,
line
power
is
still
applied
to the
power
transformer
primary and
to
the
unregulated
supplies.
A1
ALPHA DISPLAY
ASSEMBLY
The
A1
alpha
display
assembly provides
the
physical
mounting
for
the
seven
4-character
dot
matrix
display
elements.
The
assembly
is
mounted
on
the
front panel
bezel,
and interfaces
to
the
A2
display
driver
assembly
via
a
multi-pin
connector.
A2
DISPLAY DRIVER ASSEMBLY
The
A2
display driver
assembly contains
the
7-segment
displays and
the
instrument
annunciators,
and
it
pro¬
vides
an
interface
with the
A1
alpha
display
assembly.
A3 DISPLAY PROCESSOR
ASSEMBLY
The
A3
display
processor
assembly
provides
the
communication
link
for Interfacing
the
main
instrument micro¬
processor
to
the
instrument
displays.
The
instrument
microprocessor
sends
display data
to
the
A3
display
processor
via the
instrument data and
address
busses.
The
A3
display
processor
stores
the
data
in
internal
RAM
(random
access
memory),
and
processes
the
data
into
the
necessary
control
signals
to display
the
information.
The
display
processor
has
2K
of
internal
ROM
(read
only
memory)
that
contains
the
program
for
display
control.
The
A3
display
processor
assembly
outputs
control signals
to
the
A2
display
driver assembly for
the
power/
frequency
7-segment
displays,
the
entry
display
5X7
dot
matrix
displays,
and
the
instrument
LED
annunciators.
HP 8340B/41B
Front
Panel
Theory
of
Operation G-3

HP 8340b Specifications

General

Brand	HP
Model	8340b
Category	Inverter
Language	English