Serial HD In-Place Inclinometers
Applications
A real-time alternative to the traversing probe type of inclinometer, the in-place inclinometer employs a fixed chain of sensors and does not require an on-site operator. In-Place Inclinometers are ideal for data logging and real-time, remote monitoring for critical applications such as construction control.
Typical applications include:
- Monitoring landslide areas above dams, highways, and railroads to provide early warning of slope failure.
- Monitoring ground movements induced by tunnel construction and excavation.
- Monitoring deformations of embankments and retaining walls.
Operation
The in-place inclinometer system consists of inclinometer casing and a chain of inclinometer sensors. The inclinometer casing is installed in a vertical borehole that passes through a suspected zone of movement. The chain of sensors is positioned inside the casing to span the zone of movement.
The sensors measure the inclination of the casing. Changes in the inclination readings indicate that the casing has been displaced by ground movement. The amount of displacement is calculated by finding the difference between the current inclination reading and the initial reading and then converting the result to a lateral distance.
In most applications, sensors are connected to a data acquisition system that continuously monitors movements and can trigger an alarm when it detects a change, or rate of change, that exceeds a preset value.
positioned inside the casing to span the zone of movement.
The sensors measure the inclination of the casing. Changes in the inclination readings indicate that the casing has been displaced by ground movement. The amount of displacement is calculated by finding the difference between the current inclination reading and the initial reading and then converting the result to a lateral distance.
In most applications, sensors are connected to a data acquisition system that continuously monitors movements and can trigger an alarm when it detects a change, or rate of change, that exceeds a preset value.
Advantages
Ideal for Critical Applications: In-place inclinometers are ideal for continuous, unattended monitoring and can delivery readings in near-real time.
Single Cable Installation: Each sensor is supplied with cable so that it can be connected to the sensors above and below, effectively reducing the number of signal cables to just one. This eases installation, simplifies connections to the logger, eliminates the need for multiplexers, and greatly decreases cable costs.
Durable and Reusable: Strong wheels make it practical to install and remove these sensors as needed. Assuming that displacements have not closed off the inclinometer casing, the sensors can be recovered and reinstalled at another project site.
Configurable Gauge Lengths: The use of varied gauges lengths can provide better measurements while reducing the total number of sensors needed for complete coverage. Use short gauge lengths to obtain detailed measurements within the zone of interest; use long gauge lengths to monitor adjacent zones.
High Performance: The MEMS sensor has a range of +/- 10 degrees and a resolution of 9 arc seconds (0.04 mm/m) with a CR1000 or M-Logger.
Complete Solution: Slope Indicator offers complete monitoring solutions that include data loggers and software such as Atlas Web-Based Monitoring , which can present profile plots and trend plots of inclinometer data just minutes after the readings are obtained.
For More Information
Please see the datasheet for Inclinometer Casing or the datasheet for In-Place Inclinometer Sensors.
In-Place Inclinometers Sensors Specifications
| SERIAL SYSTEM CONFIGURATION | |
|---|---|
| A serial IPI system requires inclinometer casing, serial sensors with wheels and gauge tubes, a suspension kit, and a jumper cable | |
| Inclinometer Casing | Choose 70 mm or 85 mm (2.75 or 3.34 in) diameter inclinometer casing |
| Uniaxial or Biaxial Sensors | Uniaxial sensors measure tilt in the plane of the wheels. Biaxial sensors include a second sensor that measures tilt in the plane perpendicular to that of the wheels |
| Wheels | Choose wheels to fit 70 mm or 85 mm casing. Order sensor wheels for each sensor, and one top wheel for each chain of sensors. Top wheels can be provided for suspension by cable or tubing |
| Tubing for Gauge Lengths | Order gauge tubing for each sensor. Tubing is sized to make exact gauge lengths of 1, 2, or 3 m. Custom gauge lengths can be special-ordered (3 m max) |
| Signal Cable | Serial sensors include signal cable sufficient for gauge lengths up to 3m. Cables have connectors that allow them to be joined into a bus. A bottom plug is required for the bottom of the bus. A jumper cable connects the top of the bus to the data logger |
| Top Suspension Kit | Order one top suspension kit for each installation. Suspension kits can be provided for tubing or cable suspension |
| In-Line Suspension Kit | The in-line suspension kit is used to suspend an independent chain of sensors from the chain above. This allows monitoring of two or more widely separated zones. The kit includes cable thimbles and clamps. Requires stainless steel cable, not included |
| Data Logger | The Slope Indicator M-Logger is specifically designed to read MEMS sensors. It can operate a single chain of up to 16 sensors. The M-Logger can also be used to verify operation of the sensors at installation time. The Campbell Scientific CR1000 data logger can operate 6 chains of serial sensors and the CR800 logger can operate 3 chains of serial sensors |
| Data Reduction Software | Readings retrieved from the logger can be processed manually by spreadsheet or automatically by the Atlas webbased monitoring system |
| SERIAL HD IPI SENSORS | |
|---|---|
| Serial HD IPI Sensor, Uniaxial | 57804721 |
| Serial HD IPI Sensor, Biaxial | 57804722 |
| Sensor Wheels for 70 mm Casing | 57805342 |
| Sensor Wheels for 85 mm Casing | 57805343 |
| Tubing for 1 m Gauge Length | 57805321 |
| Tubing for 2 m Gauge Length | 57805322 |
| Tubing for 3 m Gauge Length | 57805333 |
| Tubing for 3 ft Gauge Length | 57805331 |
| Tubing for 5 ft Gauge Length | 57805332 |
| Tubing for 10 ft Gauge Length | 57805333 |
| Bottom Plug | 57804510 |
| Jumper Cable, 25 m | 57804525 |
| IPI SENSOR SPECIFICATIONS | |
|---|---|
| Sensor Type | MEMS (Micro Electro-Mechanical Systems) tilt sensor for inclination readings. Biaxial model has two sensors. Thermistor for temperature readings |
| Requirements | Accepts power input between 8 to 15 Vdc. Outputs ±2.5 volt differential signal. Biaxial version contains two tilt sensors |
| Calibrated Range | ±10 degrees |
| Resolution | 9 arc seconds or 0.04 mm/m using the CR1000 data logger |
| Repeatability | ±22 arc seconds or ±0.1 mm/m |
| Calibration | 11 angles at temperatures from 4 to 20°C. Other temperature ranges available |
| Required Casing | 70 or 85mm (2.75 or 3.34") diameter casing |
| Housing | Stainless steel, 32 mm (1.25") diameter, waterproof to 2 MPa (300 psi) |
| Weight | 4.01 kg with 2m gauge length |
| Signal Cable | Cable for 3m gauge length supplied with each sensor. Connectors are rated to 70 MPa (10,000 psi) |
| DISCRETE HD IPI SENSORS | |
|---|---|
| Discrete HD IPI Sensor, Uniaxial | 57804711 |
| Discrete HD IPI Sensor, Biaxial | 57804712 |
| Signal Cable | 50613527 |
| SUSPENSION KITS | |
|---|---|
| 2.75" Casing, Tubing Suspension Top Wheel Kit | 57805328 |
| 3.34" Casing, Tubing Suspension Top Wheel Kit | 57805338 |
| 2.75" Casing, Tubing Suspension Top Cap | 57805352 |
| 3.34" Casing, Tubing Suspension Top Cap | 57805355 |
| 2.75"/70mm IPI Cable Suspension Kit | 57804452 |
| HD IPI 70mm Top Wheel (for Cable Suspension) | 57805324 |
| 3.34"/85mm IPI Cable Suspension Kit | 57804453 |
| HD IPI 85mm Top Wheel (for Cable Suspension) | 57805334 |
| 3mm Stainless Steel Cable | 50402310M |
| 1/8" Stainless Steel Cable | 50402310F |
| 1/8" SS Cable In-Line Suspension Kit | 57804320 |
