Micromeritics ASAP 2460 Operator's Manual page 330

Appendix C
Equilibration
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
following equations are those used to compute weighted average and first derivative, respectively, for
the 6th point of an 11-point window.

– 36 P +
11
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- -
P =
avg

5 P
-------------------------------------------------------------------------------------------------------------------------------------------------------------- -
P =
chg
P = 100%
pcp i 
where the numerical constants are from the Savitzky-Golay convolution arrays, and
P =
avg
P =
chg
P =
pcp,i
P =
i
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 is greater than 0.995 times the current Po, equilibration will not take place until
avg
the Minimum equilibration delay for P/Po 0.995 has expired, in addition to the standard
equilibration criteria.
C-6
1
  
P + 9 P + P + 44 P
1 10 2
 
– P + 4 P – P
11 1 10 2
P
chg
----------
P
avg
average pressure
change in pressure
percent change per interval
th
i pressure reading taken at equilibrium intervals
convolution method for polynomial functions. The
  
+ P + 69 P + P
9 3 8
429
   
+ 3 P – P + 2 P
9 3 8
110
ASAP 2460 Operator's Manual
   
+ 84 P + P + 89 P
4 7 5
  
– P + P – P
4 7 5
246-42800-01 - Aug 2013

6