Proceq Pundit Lab - Correction Factors and Units

© 2013 by Proceq SA
7
Rx Gain 200x, 500x, 1000x
This feature is available in Pundit Lab
+
only and replaces the need for an external amplifier (325
40 059) when using long cables or exponential transducers. When such high gain stages are
selected it is highly recommended to use manual triggering with the waveform display.
Pulse Width
The pulse width is automatically set to the optimum value for the selected transducer frequency
and typically requires no adjustment. For certain applications, it may however be adjusted if
desired. (Refer to ASTM D 2845
- Standard T
est Method for Laboratory Determination of Pulse
V
elocities and Ultrasonic Elastic Constants of Rock.)
It also allows non-standard transducers up to 500 kHz to be used with Pundit Lab:
Pulse width “p” in microseconds (µs) to be entered here is calculated from the formula
p = 1'000/(2*f) , wher
e f
= transducer frequency in
kHz
If a non standard value is set manually it is indicated
by an asterisk.
Continuous/Burst
T
ransmission
Continuous transmission continues transmitting until the “Stop” button is pressed.
Burst transmission sends out packets of pulses until a stable reading is obtained
then stops
automatically.
Correction Factor
Pulse velocity measurements are affected by several factors. These are well described in BS
1881 : Part 203 and it is recommended that the user refers to this document. Two key factors
are the moisture content of the concrete and the temperature. The table below shows the
correction factor that should be keyed in based on the recommendations made in the above
standard.
T
e
m
p
e
r
a
t
u
r
e
D
r
y
c
o
n
c
r
e
t
e
W
e
t
c
o
n
c
r
e
t
e
1
0
°
C
–
3
0
°
C
1
.
0
(
N
o
c
o
r
r
e
c
t
i
o
n
)
1
.
0
(
N
o
c
o
r
r
e
c
t
i
o
n
)
6
0
°
C
1
.
0
5
1
.
0
4
4
0
°
C
1
.
0
2
1
.
0
2
0
°
C
0
.
9
9
0
.
9
9
-
4
°
C
0
.
9
8
0
.
9
2
Units (Pundit Lab
+
only)
Selecting units opens a second screen where
the user may select a compressive strength unit
in addition to the imperial or metric units.
Date and Time (Pundit Lab
+
only)
Used to provide measurements with a time
stamp.
Use the left and right keys to move between
settings. Use the up and down keys to adjust
the settings. Press enter to save, or cancel to
return without saving.