Calibration For Density And Concentration Measurements - Endress+Hauser PROFIBUS Gammapilot M FMG60 Operating Instructions Manual

Commissioning
1) I is the pulse rate for the tube being empty. Generally, its value is significantly higher than any real pulse rate occuring during the measurement.
0
70
6.5 Calibration for density and concentration measure-
ments
6.5.1 Basic principles
The calibration points for the measurement are entered in the "calibration" (*1) function group.
Each calibration point consists of a density value and the associated pulse rate.
Calibration points for density and concentration measurements
Function of the calibration points
For density and concentration measurements the Gammapilot M needs (apart from the length of the
irradiated measuring path) the following two parameters:
• the absorption coefficient µ of the material measured
• the reference pulse rate I
It calculates these parameters automatically from the following calibration points:
• background calibration
• up to nine calibration points for samples of various known densities.
0
OFF
Calibration points for density and concentration measurements; 0 0 0 0 : background calibration; 1 ... 9
various densities
One-point calibration
For many applications a one-point calibration is sufficient. That means, that apart from the
background calibration only one further calibration point is used. This calibration point should be
located as near as possible to the operating point. Densities in the proximity of this operating point
are measured fairly precisely, whereas the precision may decrease with increasing distance to the
operating point.
In the case of an one-point calibration the Gammapilot M calculates the reference pulse rate I
For the absorption coefficient it uses a standard value of µ = 7,7 mm
Multiple-point calibration
If high accuracy is required over the complete measuring range, two (or more - up to nine)
calibration points should be applied. The calibration points should be located as far from each other
as possible and should be uniformly distributed over the measuring range. After the calibration
points have been entered, the Gammapilot M automatically calculates the parameters I
Multiple-point calibration is especially advisable for measurement in a wide range of densities or for
especially precise measurements.
1
.
0
1
ON
Gammapilot M FMG 60 - PROFIBUS PA
9
ON
L00-FMG60xxx-05-00-00-xx-003
1 ... 9: calibration points for
1 ... 9 1 ... 9
2
/g.
, only.
0
und µ.
0