Proceq PROFOSCOPE - The Measuring Range; Factors Affecting the Measurement

8 © 2015 Proceq SA
3.3 The Measuring Range
The pulse induction principle used by Profoscope has defined operating ranges and accuracies.
The measuring range is dependent on the bar size. The expected accuracy of the cover measure-
ment is indicated in the graphic below. (Complies with BS1881 part 204, for a single rebar with
sufficient spacing and known diameter).
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
5 10 15 20 25 30 35 40 45 50
55
7
6
5
4
3
2
1
#2 #3 #5
#6 #8 #9
#11 #13 #14 #16 #18
[inch] [mm]
Rebar size
Cover depth
Large
range
Standard
range
±4 mm / 0.16”
±3 mm / 0.12
”
±1 mm / 0.04”
±1 mm / 0.04”
measuring accuracy
[mm]
[
1
/
16
inch]
7.5 / 185
4 / 100
2 / 50
[inch] / [mm]
0 / 0
Fig 4: Measuring ranges
3.4 Factors Affecting the Measur ement
3.4.1 Errors due to Neighboring Bars
All rebars within the sphere of influence affect the reading.
MC (4)
Sphere of influence diameter 400 mm / 16”
Any ferromagnetic material within the
sphere may have an influence on the
signal value (e.g. during a reset)
Fig 5: Influence area
NOTE! This effect can be reduced by the neighboring bar correction implemented in the
Profoscope.