HP 8340b User Manual

HP
8340B/41B
Assembly-Level
Service
Calibration
Constants
Three
sets
of
calibration
constants
containing
calibration
data,
serial
number,
option,
HP-IB
address,
and
checksum information,
are
maintained
by
the
instrument:
•
Working
Data
This
data contains
the calibration information
that
is
required
for
optimum instrument perfor¬
mance.
This
is
the
only set
of
calibration
constants accessed
during
normal
operation.
Working
data
is
stored
in
RAM
on
the
A60
processor assembly,
and
is
maintained
by
a
battery
with
enough
energy
to
support
RAM
for three
full
years
when
the
instrument
is
disconnected from
ac
mains.
•
Protected
Data
This
data resides
in
EEPROM
and
contains
calibration information
that
is
essentially
the
same
as
in
the
working
data.
(PEAK
and
SHIFT
PEAK
auto
tracking functions
change
noncritical
calibration
constants
in
working
data
to
optimize
performance.
This
is the
one area
where
working
and
protected
data
can
normally
differ.)
If
any
unacceptable
difference
occurs
between working
and
protected
data,
the
instrument copies
the
protected
data
values
into
working
data
RAM
memory.
You
can
view
or
update
this
data.
•
Default
Data
This
data
resides
in
UVEPROM, and
differs
from
the
working
and
protected
data.
ROM-based
default
data has immunity to
improper
value
changes.
The
data,
however
is
not
for
a
specific
instrument,
rather,
it
is
data
representing
the
typical
instrument.
When
using
default calibration
constants,
instrument performance
is
good,
but
not
optimized
for
peak
performance.
To
return
the
instrument
to
peak
performance,
manually
enter
into
protected
and
working
memory
the
instrument-optimized
calibration
constants from
the printed
copy
of
calibration
constants
shipped
with
your instruments (see
HOW TO
RESTORE
FACTORY-OPTIMIZED
CALIBRATION
CON¬
STANTS,
in
this
section).
The instrument
only selects
default
data
if
a
problem exists
in
both
working and protected
data.
If
this
occurs,
the
CAL DEFAULTED
message appears
in
the
ENTRY
DISPLAY
and
the
FAULT
indicator
lights.
INSTRUMENT
ACCESS
During
normal
operation,
the
instrument
accesses
working
data
to
obtain
the
calibration
information
required for
optimum
operation.
In
addition,
the
instrument
accesses
working
data
after
an
instrument
preset,
but
only
to
verify
that
the
CHECKSUM
(cat
constant
#99) is
accurate
(see
Figure
A-2).
When
you press
[INSTR
PRESET], the
working
data
cal
constants
1
through
98
are
summed
and then
complemented.
The result
is
compared
with
the
CHECKSUM.
If
the
two numbers
agree,
the
instru¬
ment
continues
normal
operation.
If
not,
protected data
is
written
into
the
working
data
memory
location
and
the
CHECKSUM
test
is
repeated.
If
the
checksum
test
passes,
the
data
in
protected data
is
stored
as
working
data.
CALIBRATION
RESTORED
appears
in
the
ENTRY
DISPLAY.
If
the
CHECKSUMS
do
not
agree,
default
data
is
written to
the
working
data.
Working data
now
contains
the
default
values,
the
front
panel
FAULT
light
lights,
and
CAL
DEFAULTED
is
displayed.
Press
[SHIFT]
[MANUAL]
to display the
FAULT
diagnostics
in
the
ENTRY
DISPLAY;
the
CAL
light
flashes
(note
that
the
protected
data
was
not
changed.
For
troubleshooting,
this
data
can
be
written
into
the
working data and
viewed
—
see
USER
ACCESS).
HP 8340B/41B
Assembly-Level
Service
Calibration
Constants
A-ll

HP 8340b Specifications

General

Brand	HP
Model	8340b
Category	Inverter
Language	English