Datron 4708 User Handbook Manual page 111

Validity
Tolerance
Limit Calculations
Appendix
1
lo:
4708
User's
Handbook
Section 7
This appendix
lists
the calculations
necessary
to
determine
the Validity Tolerance Limits
for
each of
the verification
procedures. Reference
to
the
appropriate calculation
is
given
in
each procedure.
1
.
Verification
at Full
Range
Values
(where
Upper and
Lower
Relative
Accuracy
Limits are
given
on
the
Report
Sheet).
The
abbreviations
have
the
following meanings, expressed
directly as voltages or
currents.
Lr = Lower Wideband
Accuracy
Tolerance Limit,
relative
to Cal.
Standards;
Ur =
Upper Wideband
Accuracy Tolerance Limit,
relative
to Cal. Standards;
Ud
= Ud(Abs) =
Datron
Cal.
Standard Uncertainty.
Us =
Us(Abs)
=
User's Cal. Standard Uncertainty-
A.
On
Receipt
from
Datron:
For each 4708
OUTPUT
Value/Frequency
selection calcu-
late
the
Validity Tolerance Limits
as follows;
Lower
Limit
= Lr
-
Ud
-
Us
Upper
Limit
= Ur +
Ud
+
Us
Enter the
results
as
Lower
and Upper
Validity Tolerance
Limits respectively.
B. Following User
Calibration:
For each 4708
OUTPUT
Value/Frequency
selection calcu-
late
the Validity
Tolerance Limits
as follows:
Lower
Limit
=
Lr
-
Us
Upper
Limit
=
Ur + Us
Enter the
results
as
Lower
and Upper
Validity
Tolerance
Limits respectively.
2.
Post-Calibration Verification Calculation
(using the instrument Spec.
Mode
'ppm' or Readout).
This
calculation
can be used
to
verify the instrument
after
calibration,
with
the
CALIBRATION INTERVAL
switch
on
the rear
panel
set
as detailed
below.
(The
instrument provides
a
24-hour
'Stability'
readout
in
Spec
Mode,
under
the
same
conditions
used
for calibration.
At
this interval,
Datron's
uncertainty
is
not included
in the readout.)
Convert any readout
figures into
ppm
tolerance values
before
performing
the calculation:
Ur
= Ur(ppm) =
Tolerance
in
ppm =
10
x
Readout
in
%
Other abbreviations used for these calculations:
Us = Us(ppm) =
User's Cal.
Standard Uncertainty
Ud = Ud(ppm) =
Datron's Cal.
Standard Uncertainty
(as
quoted
in
the specifications
of Section
6
).
Ut = Ut(ppm) =
Calculated Validity Tolerance
in
ppm.
V
=
Required instrument output
Value
of
voltage or current.
A.
For
CAL.
INTERVAL
24Hr
Ut = Ur
+ Us
B. For
CAL.
INTERVAL
90Dy
or
lYr
Ut = Ur + Us
-
Ud
C. Obtain Ut from
(A) or (B)
and
calculate the Validity
Tolerance
Limits:
Lower
Limit
=
V
-
(V
x Ut)
10~^
Upper
Limit
=
V
+ (V
x Ut)
7-A1-1