Datron 4708 User Handbook Manual page 102

Resistance
Verification
Procedure
Calibrated Values (10Q
to
100MQ)
Record
results
on Report Sheet 4708
RS
1
(Page
7-36).
4-Wire
Ohms
Verification Routine:
Measurement
of the values of internal
resistors.
Verification
Sequence
This
routine
assumes
that a
DMM
is
used
to
measure
the
Verify the
resistors in
the value sequences of
RSI
Table
6,
resistance values.
It
also
assumes
that if
a
DMM
is
not
using the Verification
Routine below. Refer
to the
diagrams
employed,
users will
have
all
the information required
to
for
connections
to the
measuring equipment,
operate
their
own
resistance-measuring equipment.
Routine
for
RSI
Table
6(a):
a.
4707
i.
Ensure
OUTPUT
is
OFF.
ii.
Select
O.
iii. Select
Remote
Sense.
b.
Connect
the
DMM
as
shown
in the
above
diagram,
for
direct
4-wire measurement
of the value of
the internal
resistor only.
c.
4707
i.
Press the designated
resistor
(RANGE)
key:
The
previously
calibrated value
appears
on
the
OUTPUT
display
i i
.
Record on
Table
6(a) as
'OUTPUT
Display Reading
(Rd)'
e.
DMM
i
.
Measure
the value of
the internal
resistor.
i i
.
Record on
Table
6(a) as
'Measured Value
(Qm)'.
f.
4708
Set
OUTPUT
OFF
g.
Repeat
(c) to
(f)
for
each value of Table
6(a).
h.
Report Sheet RSI:
i
.
Sum
the setup uncertainties
in
ppm,
and
record
in
the ±Us(abs)
column
(Refer
to
Appendix
2).
i i
.
Enter any
additional uncertaint
due
to
Is<I<Im
in the
±Ua(ppm)
column.
iii
.Calculate
and
enter the Total
Uncertainty
in
the
Ut(ppm)
column.
i
V
.
Calculate
and
enter the
Upper
and
Lower
Validity Tolerance Limits.
d.4707
Press
OUTPUT
ON+.
7-27
The 4708
verifies if
each of
the
Measured
Values
(Om)
is
at
or
between
its
Validity
Tolerance
Limits.