Datron 1062 - Page 11

4
1.3
OHMS
CALIBRATION
1.3.1
General
The
procedure
in the
table
opposite is
all
that is
necessary
to
completely
'AUTOCAL'
the
Ohms
function.
If
just
the Ohms
or just
one
range
of
the
Ohms
is to
be
calibrated, then
steps 1 and
2 in
the DC
Voltage
Calibration
table should be
carried
out first.
Then
on each
Ohms
range
just
a 'Zero' and
'Gain'
calibration
is
required.
If the 'DVM
Reading
After
Calibration'
is not
in
accordance
with the
table,
repeat
operations
of the same
'CALIBRATE'
key is
permissible to
improve the
reading.
Where no
tolerance is
shown in
this column,
only the
exact
reading quoted
with an
occasional
least
significant
digit
showing is to be
expected.
1.3.2
'Zero'
Resistance
Source
For
accurate
'Zero'
calibration
on
Ohms
it is
ESSENTIAL
that a
correctly
connected
zero
source
is used.
Two
arrangements
are
necessary
as
shown
in Fig.
1.1;
it
can be
seen
that
'4
wire
J2'
selection
is
recommended
on
all
ranges.
1.3.3
Equipment
Required
A
set
of
resistance
standards
from
lOfil
to
lOMO
in
decades;
it is
essential
that
10J2
to
lOOkfi
standards
are
4
terminal
devices,
e.g.
Datron
4000/4000A
Autocal
Standard
with
Option
20.
1.3.4
Checking
Accuracy
after
'AUTOCAL'
To
check the
accuracy
after
'AUTOCAL'
the
'Speci-
fication
Verification'
section
of the
Operating
Handbook
will be
useful.
It
provides
tables
for
quick
reference
of
accuracy on
all
ranges and
functions
in
displayed
digits.