Fluke 8506A Instruction Manual page 281

The
8505
A
and 8506
A
use a nonvolatile, read /write
memory
for
microprocessor-
controlled
calibration of
each range
in
each
function.
The
Calibration
Memory
is
a
standard part of the Controller
module
with these multimeters.
Extended
intervals
between hardware
calibration are possible.
The
scale factor for
each range can be
calibrated
using
any
reference input value
from 60%
of range to
full scale.
The
following
paragraphs
first
discuss the
general
procedure used
in
software calibration,
then
detail
the
procedure used
for
each
function.
CAUTION
Interruption
of
input
power
could
affect Calibration
Memory
entries
when
the
multimeter
Is in
Calibration
mode.
Do
not cycle Input
power
to the
multimeter
when
Calibration
mod©
Is
activated.
If
power
Is
ON,
locally verify
that the
AVG/(CAL)
annunciator
is
not flashing or remotely
verify that
Calibration
mode
is
off
(G5 response
=
0)
before cycling
power
to
OFF.
If
power
Is
OFF,
verify that
the rear panel Calibration
switch
is
off
before cycling
power
to
ON.
Software
calibration entails
a
combination
of zero
offset
and
gain corrections.
The
Calibration
mode
must be
activated
when making
calibration entries
from
either a local
or
remote
location.
This
mode
can only be entered by accessing the Calibration switch
on
the
multimeter
rear panel.
The
calibration sticker
must
be
removed and
the
slide
switch
positioned
to
ON
when
the multimeter
is
in local (front
panel) control.
The
front
panel
AVG/(CAL)
annunciator
flashes to
denote
activation of Calibration
mode. Zero
correction values can then be entered
for
each range
in
dc voltage
(VDC)
and
resistance
(OHMS)
functions
only.
Gain
correction factors
can be
stored for
each range
in
each
function
by
applying a reference input
and
entering
a
numeric
string
representing that
reference value.
The multimeter then computes
the gain correction factor necessary
to
read the reference value.
Depending on
the function being
calibrated,
gain corrections
are
made
once
or twice for
each
range.
A
number
representing the calibration date or
identifying the
multimeter can
also
be entered
when
the Calibration
mode
is
activated.
The
zero
offset
correction values are applied
to the
reading
whenever
the
Zero
mode
is
on
(ZERO
annunciator
lit).
The
gain correction
factors are applied to the
reading
as
soon
as
they are entered
and continue
to
be applied
whether
Calibration
mode
is
on
or
off.
NOTE
In Calibration
mode,
the
multimeter uses the
"permanent" zero
offset
corrections stored
in
Calibration
Memory;
it
does not use
the
"temporary
zeros" that
can be stored
when
Calibration
mode
is off
Locally, application of zero correction values can be interrupted
by turning the
Zero
mode
off.
Remotely, both
zero correction values
and gain correction factors
can
be
inhibited or enabled with the following
commands: