GeoSIG AC-4x-DH Accelerometer
Key Features
- Full Scale ± 2 g (± 0.625, 1, 4, 5 g optional)
- Bandwidth DC to 100 Hz
- MEMS Inertial Sensor
- High shock survivability
- Wide operational temperature range
- High lifetime stability
- Cost effective sensor
- Low power consumption
- Simple test and calibration
- Strong mechanical design
- Fits in 3 inch casing
The AC-4x-DH sensor package, now a legacy product, was a triaxial accelerometer designed for borehole applications regarding strong motion earthquake survey and monitoring. The AC-4x accelerometer was based on the modern MEMS (Micro Electro-Mechanical Systems) technology, consisting of sensing cells assembled in a way that optimises their performances. This combined with the state of the art proprietary circuit design yielded this cost effective and reliable accelerometer.
MEMS cells include linear accelerometer sensing elements which measured the capacitance variation in response to any movement or inclination and a factory trimmed interface chip that converted the capacitance variations into analog or digital signal proportional to the motion. The DC response allowed the sensor to be easily repaired, tilt tested or recalibrated in the field. With the help of the TEST LINE the AC-4x accelerometer could be completely tested assuring proper operation.
The downhole casing contained the entire sensor system. The sensor was connected through Overvoltage Protection stage to the recorder at the surface with a cable.
Using inclinometer tubes and the provided guiding wheels, the sensor could be oriented before insertion in the tube.
MEMS cells include linear accelerometer sensing elements which measured the capacitance variation in response to any movement or inclination and a factory trimmed interface chip that converted the capacitance variations into analog or digital signal proportional to the motion. The DC response allowed the sensor to be easily repaired, tilt tested or recalibrated in the field. With the help of the TEST LINE the AC-4x accelerometer could be completely tested assuring proper operation.
The downhole casing contained the entire sensor system. The sensor was connected through Overvoltage Protection stage to the recorder at the surface with a cable.
Using inclinometer tubes and the provided guiding wheels, the sensor could be oriented before insertion in the tube.
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General Characteristics
- Application
- Strong Motion earthquake recording Vibration monitoring Alarm / Switch Systems
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Configurations: Triaxial Biaxial Uniaxial Axes Alignment** AC-43 X X – Y – Z H – H – V AC-42-H X X – Y H – H AC-42-HV X X (or Y) – Z H – V AC-41-H X X (or Y) H AC-41-V X Z V - * i : Internal sensor ** H: Horizontal, V: Vertical
- Full Scale Range:
- ± 2G std, optional ± 0.625, ± 1, ± 4 or ± 5G
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Sensor Element
- Sensor Element Type:
- MEMS Inertial Sensor
- Dynamic Range:
- > 88.5 DB at 2G FS (0.1 to 30Hz), 96.5 DB at 5G FS
- Noise:
- 50 ugRMS
- Nonlinearity:
- <0.3% typ, <0.6% for vertical
- Cross Axis Sensitivity:
- <2%typ
- Bandwidth:
- DC to 100Hz
- Span Drift:
- 100 ppm/°C
- Offset Drift
- ± 0.8 mg / °C
- Full Scale output:
- 0 ±10 V differential (20 Vpp)optional 2.5 ± 2.5 V single-end (5 Vpp)0 to 20 mA current loop
- Measuring Range
- See Plot
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Power
- Supply Voltage:
- 7 to 15 VDC, single supply, optional, 7 to 30 VDC
- Consumption:
- 9 mA @12 VDC
- Connector:
- Metallic, Shielded, IP67, 12 pins, male. optional MIL, Bendix PT07A 14-19P.
- Mating:
- Binder / Coninvers type RC
- Overvoltage Protection:
- All pins are protected
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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
- Pin 11-12:
- not used)
- Case:
- Shielded Ground
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Environment/Housing
- Housing Type:
- Aluminium cylinder, fully sealed
- Housing Size:
- Diameter 55 mm, length 420 mm
- Weight:
- 3.5 kg
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- Index of Protection:
- IP 68, up to 10 bars water pressure
- Temperature Range:
- - 40 to 85 °C (operating)
- 40 to 85 °C (non-operating) - Humidity:
- 0 to 100 %
- Orientation:
- Using 3” inclinometer casing (Figure 1) with included guidewheels (Figure 2).
- Standard AC-43-DH
- Full scale ± 2 g, Sensor mating connector and user manual
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Optional Accessories
- DH-TUBE:
- 3” inclinometer casing as in figure 1 in sections of 3 meters with coupling elements.
- Installation kit:
- All required tools and fixation consumables for up to 100 meters of casing.
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DH-Ball
- Glass Balls for settlement of downhole sensor (25 kg bag)
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Ordering Information
- Specify:
- Type of AC-4x-DH, acceleration full scale, depth of borehole and total cable length.
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**Specifications subject to change without notice