Micromeritics Gemini VII 2390a, Руководство оператора, Страница: 298 / 426

Appendix C Gemini VII
C-4 239-42828-01 - Dec 2012
Equilibration
P
AVG
36
P
11
P
1
+
 
– 9
P
10
P
2
+
 
44
P
9
P
3
+
 
69
P
8
P
4
+
 
84
P
7
P
5
+
 
89
P
6
 
+ + + + +
429
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
=
P
CHG
5
P
11
P
1
–
 
4
P
10
P
2
–
 
3
P
9
P
3
–
 
2
P
8
P
4
–
 
P
7
P
5
–
 
+ + + +
110
----------------------------------------------------------------------------------------------------------------------------------------------------------------
=
P
PCPI
100%
P
CHG
P
AVG
--------------
=
Equilibration is reached when the pressure change per equilibration time interval (first derivative) is
less than 0.01% of the average pressure during the interval. Both the first derivative and average pres-
sure are calculated using the Savitzky-Golay
1
convolution method for polynomial functions. The
equations below are those used to compute weighted average and first derivative, respectively, for the
6th point of an 11-point window.
where the numerical constants are from the Savitzky-Golay convolution arrays, and
P
AVG
= average pressure (mmHg)
P
CHG
= change in pressure (mmHg)
P
PCPI
= percent change per interval
P
I
= I
th
pressure reading taken at equilibrium intervals (mmHg)
If a non-zero value that is too small is entered for the maximum equilibration time, the
points are collected before equilibration is reached.
If P
AVG
is greater than 0.995 times the current Po, equilibration will not take place until
the Minimum equilibration delay for P/Po 0.995 has expired, in addition to the standard
equilibration criteria.