Endress+Hauser Gammapilot FMG50 - Page 70

Commissioning Gammapilot FMG50
70 Endress+Hauser
The procedure varies depending on the type of table that is selected.
• For the "Normalized pulse rate" type of table
• For the "Semi-automatic" type of table
Normalized pulse rate
A0042183
N C I I
N
1 100 2431 1000
2 92 1935 792
3 83 1283 519
4 65 642 250
5 35 231 77
6 0 46 0
Normalized pulse rate
Note that the normalized pulse rate is entered in the linearization table. The normalized
pulse rate is not identical to the pulse rate actually measured. The correlation between
these two variables is defined by:
I
N
= (I - I
0
) / (I
MAX
- I
0
) x 1000
Where:
• I
0
is the minimum pulse rate (i.e. the pulse rate for full calibration)
• I
MAX
is the maximum pulse rate (i.e. the pulse rate for empty calibration)
• I: the measured pulse rate
• I
N
: the normalized pulse rate
The normalized pulse rate is used because it does not depend on the activity of the
radiation source used:
• For L = 0 % (empty vessel), I
N
always = 1000
• For L = 100 % (full vessel) I
N
always = 0
The individual linearization values can be entered via the input screen or via a separate
linearization module. The linearization table consists of up to 32 "normalized pulse rate :
concentration" value pairs.