>Dienstleistungen > FaMoS FaMoS Fast Monitoring S ystem for demanding measurements in field applications 1. FaMoS components 2. Dynamic compaction measurements at Changi Intl. Airport, Singapore FaMoS components FaMoS consists of Acquisition System (AqSys) Acquisition Box (AqBox) Apropriate Sensors (e. g. Geophones) Special Attachments (e. g. Signal Sources) The acquisition system comprises the hardware with up to 32 high-speed data acquisition channels suitable for dynamic ground measurements, accoustic measurements and surveillance of engines and plants. The measured signals are amplified and converted to digital data, transferred to the notebook PC and stored on a hard disk. Large data volumes are easily processed. The built-in manual or automatic trigger system allows precise registration of time-sensitive processes. The acquisition software operates in several modes and different channel and speed settings. Data is supplied in binary and ASCII format for further evaluation with standard software like spreadsheets and databases or customized programs. The power supply operates with 13.6VDC or 110-230VAC using a power converter. The whole system is built in an electrically shielded, robust flight-case for easy transport and fast installation on site. Up to eight acquisition boxes as input sources (see below) can be connected to the acquisition system. Availability and the high cost-benefit ratio are reached by using standard components where possible. The acquisition box is a water-resistant, die-cast aluminum case with electronics and water-resistant connectors. Up to four sensors supply their signals via a multi-purpose sensor interface (MuPSI) to the AqBox. Radio buttons allow to preset the amplification factor from 1 to 500 for each channel. The four lines are bound to one output port connector. All components of the system are connected via the same type of leads (sensors to aqboxes, aqboxes to aqsys, trigger or extension leads). Thus system installation is fast and flexible. Four different kinds of electrical sensor connections are supported by the FaMoS multi-purpose sensor interface. In this way sensors with various output specifications can be fed into the system without any further effort. According to the demands of a special measurement, we deliver a wide range of sensors to register the pressure of gases and liquids, velocity, acceleration, flow, displacement, force etc.. Sensor example:  Underground Geophone  Attachment example: Dynamic Signal Source (DSS) stored in rugged case The DSS generates pulses for ground wave propagation measurements. It is packaged in a rugged case as many other components of the FaMoS system for easy transport and fast access. Beside the system components we support our customers with planning, installing, and performing experiments. We would like to encourage people to discuss their ideas with us. Often we can help to find technical solutions. At least we will contribute to an estimate of the costs to start examinations or develop a product. Dynamic compaction measurements at Changi Intl. Airport, Singapore     Typical arrangement of sensors and FaMoS acquisition system during the experiments. In order to improve the ground conditions for the new Changi Airport in Singapore, in 1997 various construction techniques for soil compaction were used, e. g. dynamic compaction (drop of load up to 22 to from 25 m) or resonance compaction (MRC System). The vibrations in the ground due to these construction works and a special pneumatic signal source were measured by the Loster Fast Monitoring System (FaMoS). The aim was to examine the dependence of ground wave propagation on the geological conditions at that location as well as getting more information about the effectiveness of the compaction methods. A small choice of typical evaluations used for geodynamic calculations and research are shown in the following diagrams:   2 selected of 16 acquired channels show the particle speed of the ground at varying distance from the signal source. Such diagrams are used to determine the wave velocity by "1st peak" method.      Another (more precise) method to determine the wave velocityby cross correlation of phases.      Distribution of Frequency, showing transfer properties of ground waves over frequency. From this a transfer function can be derived:      Determination of the group velocity of a ground wave, corresponding to the velocity of energy transfer by the wave      A further evaluation shows dynamic properties of the ground. It can be used for predicting wave propagation and interference from vibrational sources like traffic or construction machines with structures and  humans.    Measuring ground response to vibrational sources with varying excitation frequencies (particle velocity of surface)      The more complex the experiments and measurements are, the more important is the consideration of potential sources of errors. The check of the consistency of redundant registered data can be very fruitful to this end. The following diagram shows the reliability of the taken set of measures as the correspondence between the velocity and the integrated acceleration signal is very good. This is the result of a very carefully planned and performed measurement.