|
Campbell Scientific data acquisition systems' versatile capabilities make them ideal for structural and seismic monitoring. Our data loggers have been used in applications ranging from simple beam fatigue analysis, to structural mechanics research, to continuous monitoring of large, complex structures.
Highway overpasses, roads, buildings, retaining walls, bridges, and amusement park rides are the types of structures for which our systems provide remote, unattended, and portable monitoring. Our data acquisition systems make reliable structural measurements, even in harsh environments.
System Benefits
- Processing for rainflow & level crossing algorithms can accommodate a large number of cycles.
- On-board, programmable, excitation is provided for ratiometric bridge measurements.
- Systems provide triggered output with pretrigger data capture capability.
- Most sensors and communications options can be used, allowing systems to be customised to meet exact needs.
- Systems operate reliably in harsh environments.
- Scan rates range from a few hours to 100,000 times per second.
- Systems can report conditions by calling out to pagers, radios, or phones.
- Systems support long-term, unattended data storage and transfer.
- Pick-and-click software facilitates programming.
Monitoring and Control
The versatility of our systems allows them to be customised for each application. We offer a range of data loggers from the most basic system with just a few channels, to expandable systems that measure hundreds of channels. Scan rates can be programmed from a few hours to 100,000 times per second, depending on the data logger model. Measurement types, recording intervals, and processing algorithms are also programmable. Data Loggers not only provide advanced measurement capabilities, but can also control external devices.
On-board processing instruction sets contain programmed algorithms that process measurements and output results in the desired units of measure. For example, data can be displayed as rainflow or level crossing histograms. These rainflow and level crossing algorithms allow processing for extended periods of time, not just a limited number of cycles. The instruction sets also allow for triggered output with pretrigger data capture capability. Triggers can be based on sensor output, time, and/or user control. For example, if an overpass is being monitored, data collection can be triggered by a sensor detecting the approach of a car, an earthquake, pre-programmed times, or by pushing a button.
The control functions of our data loggers combined with their programmability allow them to sound alarms, actuate electrical devices, or shut down equipment based on time or measured conditions. Systems can also call out to phones, pagers, radios, and other devices to report site conditions. Voice-synthesized modems are available, so the system can actually call and tell you what is happening.
Sensors
Because our data loggers are compatible with nearly every commercially available sensor, you can use the sensors that best meet your application. Typical sensors used for structural and seismic monitoring by our systems include:
- Carlson strain meters
- vibrating wire strain gauges
- foil strain gauges (set up in quarter, half, or full bridge strain configurations)
- inclinometers
- crack and joint sensors
- tilt sensors
- piezoresistive accelerometers
- piezoelectric accelerometers
- capacitive accelerometers
- borehole accelerometers
- servo force balance accelerometers
Because our data loggers have many channel types and programmable inputs, all these sensor types can be measured by one data logger. Channel types include analog (single-ended and differential), pulse counters, switched excitation, continuous analog output, digital I/O, and anti-aliasing filter. Using switched or continuous excitation channels, our data loggers provide excitation for ratiometric bridge measurements.
Our configurable data logger models, the CR9000X and CR9000XC, allow you to customise a system with the channel types that best fit your application. The number and type of channels on most of our data loggers are expandable using multiplexers and other measurement peripherals. Our data loggers have input resolutions to 0.33 microvolts, allowing strain measurements with a resolution of a single micro-strain.
Communications
The availability of multiple communications options for retrieving, storing, and displaying data also allows systems to be customised to meet exact needs. On-site communication options include direct connection to a PC or laptop, PC cards, storage modules, and data logger keyboard/display. Telecommunication options include short-haul, telephone (including voice-synthesized and cellular), radio frequency, multidrop, and satellite.
Software
Our Windows-based software simplifies data logger programming, data retrieval, and report generation. The data logger program can be modified at any time to accommodate different sensor configurations or new data processing requirements.
Example Application: Monitoring an Overpass
Campbell Scientific's monitoring systems are used for a variety of structural and seismic applications. Monitoring possibilities on an overpass include:
