Chauvin Arnoux C.A 1875, User Manual

Page: 95 / 100

Français
94
To be sure of making a valid measurement, the following value must not be
exceeded:
d
Cable
= 3 x ∆ s
2
In addition, based on the IFOV of the camera:
at 1 m ∆ s
1
= 2.2 mm
at d
1
m ∆ s
2
= d
Cable
/ 3
It follows that:
d
1
= ∆ s
2 /
2.2
= (d
Cable
/3) / 2.2
= (((4 x P)/ π )
1/2/
3 ) / 2.2
Whence:
d
1
= 0.21m = 21 cm
For a valid measurement to be made, the camera must be between 10 cm and
21cm from the target.
Question b
To be sure of making a valid measurement, the following value must not be
exceeded:
d
Cable
= 3 x ∆ s
2
In addition, based on the IFOV of the camera:
at 1 m ∆ s
1
= 4.1 mm
at d
1
m ∆ s
2
= d
Cable
/ 3
It follows that:
d
1
= ∆ s
2 /
2.2
= (d
Cable
/3) / 2.2
= (((4 x P)/ π )
1/2/
3) / 4.1
Whence:
d
1
= 0.11 m = 11 cm
It is possible to use a wide-angle lens.
For a valid measurement to be made, the camera must be between 1 cm and
11 cm from the target
Solution 10
Thermogram 1
From the temperatures of the cursors, let us determine the difference of
temperature between P01 and P02:
∆ T = T
P01
– T
P02
= 52.8 – 45.5
∆ T = 7.3°C
Whence a degree of criticality of level 0, requiring surveillance.
Thermogram 2
English