Hioki RM3545, Инструкция по эксплуатации, Страница: 119 / 364

5.3 Performing Statistical Calculations on Measured Values
111
5
Statistical calculations can be performed on up to 30,000 measured values, with results dis-
played. Printing is also available (p. 245).
Calculation types: average, maximum and minimum values, population standard deviation,
sample standard deviation, process compatibility indices
Deleting Statistical Calculation Results
Stored data is automatically erased at the following times:
5.3 Performing Statistical Calculations on
Measured Values
Maximum value Xmax = MAX (x
1
, ....., x
n
)
In these formulas, n represents the number
of valid data samples.
* Process capability index
• The process capability indices repre-
sent the quality achievement capability
created by a process, which is the
breadth of the dispersion and bias of
the process' quality. Generally,
depending on the values of
Cp
and
Cpk , process capability is evaluated as
follows:
Cp
,
Cpk
>1.33 ............Process capabil-
ity is ideal
1.33
≥
Cp
,
Cpk
>1.00 .Process capabil-
ity is adequate
1.00
≥
Cp , Cpk ...........Process capabil-
ity is inadequate
•
UPP
and
LOW
are the upper and
lower thresholds of the comparator.
• When the BIN function is on, the pro-
cess capability index will not be calcu-
lated.
Minimum value
Xmin = MIN (x
1
, ....., x
n
)
Average
Population
standard
deviation
Standard
deviation
of sample
Process
capability index
(dispersion) *
Process
capability
index (bias)*
n
x
x

=
σ
n
x
2
nx
2
–

n
--------------------------- =
σ
n 1 –
x
2
nx
2
–

n 1 –
--------------------------- =
Cp =
UPP
−
LOW
6
σ
n
−
1
Cpk =
UPP
−
LOW UPP
+
LOW
−
2x
−
6
σ
n
−
1
−
•
When only one valid data sample exists, standard deviation of sample and process capa-
bility indices are not displayed.
•
When
σ
n-1
= 0,
Cp
and
Cpk
are 99.99.
•
The upper limit of
Cp
and
Cpk
is 99.99. If
Cp
or
Cpk
exceeds 99.99, the value 99.99 is dis-
played
•
Negative values of
Cpk
are handled as
Cpk
= 0.
•
If statistical calculation is turned off and then back on without first clearing calculation
results, calculation resumes from the point when it was turned off.
•
Measurement speed is restricted when statistical calculation is enabled.
•
Turning on
Δ
T or setting the measurement terminal to multiplexer automatically turns off
the statistical calculation function.
•
when changing measurement conditions (low-power, measurement current, OVC,
100 M
Ω
range high-precision mode, TC, non-offset scaling settings)
•
when changing comparator settings (p.98)
•
when changing BIN measurement function settings (p.108)
•
when printing the statistical calculations (p. 245) (you can select whether to delete
results after printing
(
p.246))
•
upon system reset (p. 134)
•
when turning off the instrument