1. No category

GeoSIG Ltd
Ahornweg 5A
5504 Othmarsingen
Switzerland
Tel :
+41 44 810 2150
Fax : +41 44 810 2350
Email : info@geosig.com
www.geosig.com
AC-63 / AC-62 / AC-61-DH Downhole Accelerometer
Features
ˆ Full Scale ± 2 g (± 0.5, ± 1, ± 3 g optional)
ˆ Bandwidth DC to 50 or 100 Hz
ˆ Dynamic range >120 dB
ˆ Digital Sensor Control (DSC)
ˆ No field adjustment required
ˆ Temperature and drift compensation
ˆ Robust suspension system
ˆ Fits in 4'' (102 mm) borehole
ˆ Same basic specifications as AC-63
Outline
The AC-63-DH accelerometer is based on a force balance
servo accelerometer concept having a new innovative and
rugged mass suspension system designed for borehole
applications regarding Strong Motion earthquake survey
and monitoring.
A Digital Sensor Control (DSC) is used to provide the AC63 with exceptional user-friendly features. At turn on the
DSC nulls all outputs including the vertical channel. This
powerful feature allows the users to install the AC-63 and
turn it on. Time consuming offset adjustment and
instrument levelling are not necessary.
The DC response allows the sensor to be easily repaired,
tilt tested or recalibrated in the field. With the help of the
TEST LINE the AC-63 accelerometer can be completely
tested assuring proper operation and accurate
acceleration measurement.
The downhole casing contains the entire sensor system.
The sensor is connected through Overvoltage Protection
stage to the recorder at the surface with a cable.
Using inclinometer tubes and the provided guiding wheels,
the sensor can be inserted in the borehole with a defined
orientation.
The AC-63-DH accelerometer is directly compatible with
the GeoSIG recorders.
Typical 100 mm casing or hole diameter
Surface
Borehole with or
without casing
Soft
material
Sand
Sand
CABLE
Inclinometer
tube
SENSOR
Hard
rock
Concrete
Concrete
Sand
GUIDE
Sand
Specifications AC-63 / AC-62 / AC-61-DH Downhole Accelerometer
Strong Motion earthquake survey &
industrial applications requiring rugged
sensors
AC-63:
AC-62-H:
AC-62-V:
AC-61-H:
AC-61-V:
Biaxial
Triaxial
Configurations:
Uniaxial
General Characteristics
Application:
Axes
Alignment**
X–Y–Z
H–H–V
■
X–Y
H–H
■
X (or Y) – Z
H–V
■
X (or Y)
H
■
Z
V
■
** H: Horizontal, V: Vertical
Full Scale Range:
±2g
optional ± 0.5, ± 1, ± 3 g
for ± 10 V diff at output
Damping:
Full Scale Output:
Measurement Range:
10
6
10
5
10
4
10
3
10
2
Connector
Type
Mating:
Surge Protection:
12 poles metallic, shielded, male
Binder / Coninvers type RC
All pins are protected by ™Transzorb
Connector Pin Configuration
Pin 1-6
Signal output for axis X, Y, Z
Pin 7,8
Test Input
Pin 9-10
+ 12 VDC power supply
Case
Shielded Ground
Environment/Housing
Housing Type:
Housing Size:
Weight:
Force Balance Accelerometer
>120 dB effective at ± 3 g full scale
± 0.2 %
< 0.01 %
< 0.2 %
From DC to 100 Hz
optional DC to 50 Hz
0.7 critical
standard ± 10 V differential
0 ± 5 V single ended
See Plot
Aluminium cylinder, fully sealed
Diameter 55 mm, length 420 mm
3.5 kg
420 mm
Index of Protection:
Temperature Range:
Humidity:
Orientation:
3
IP 68, up to 10 bars water pressure
- 40 to 85 °C (operating)
- 40 to 85 °C (non-operating)
0 to 100 %
Using 3” inclinometer casing (Figure 1)
with included guidewheels (Figure 2).
10
2
Standard AC-63-DH
10
]
[g
1
D
isp
la
ce
m
en
t[
n
tio
ra
le
ce
Ac
m
m
]
10
10
9.5 to 15 VDC, single supply
70 mA @12 VDC (average)
∅ 55 mm
Sensor Element
Type:
Dynamic Range:
Nonlinearity:
Hysteresis:
Cross Axis
Bandwidth:
7
Power
Supply Voltage:
Consumption:
10
-1
10
VE-1x
VE-2x
VE-3x
VE-5x
VE-5x-BB
VE-5x-DIN
AC-2x
AC-4x
AC-6x
AC-7x
Accessories
DH-TUBE
1
-2
10
Installation kit:
10
-1
-3
10
DH-BALL
Full scale 2 g, sensor mating connector
and user manual on CD.
Borehole cable length to be defined.
10
Ordering Information
Specify:
10
-3
-5
10
Type of AC-6x-DH, acceleration full
scale, depth of borehole and total cable
length.
1
10
-4
-6
10
10 -1
10
-5
-7
10
10 -2
10
-6
-8
10
10 -3
10
-7
-9
10
10 -4
10
-8
0
-1
10
10 -5
3
10
2
10
10
1
10 -1
10
10 -2
10
-9
1
-1
10
10 -6
-3
Velocity [mm/s]
10
-2
-4
10
3” inclinometer casing as in figure 1 in
sections of 3 meters with coupling
elements.
All required tools and fixation
consumables for up to 100 meters of
casing.
Glass Balls for settlement of downhole
sensor (25 kg bag)
Frequency [Hz]
Figure 1
Figure 2
Specifications subject to change without notice
Copyright © GeoSIG Ltd, 11.11.2010/ GS_AC-63-DH_Leaflet_V03.doc