3-Axis Digital Accelerometer

Model EADA-350F Overview

Encardio-rite model EADA-350F is a digital, force feedback, triaxial accelerometer with digitizer and data acquisition system integrated in a single unit, designed for specific applications in seismology, hazard mitigation and civil & earthquake engineering to study the response of mega structures like dams, barrages, underground caverns & tunnels etc., in case of any seismic activity. It’s extremely large dynamic range exceeding 145 dB makes it ideal equipment for the applications in the open field and to study the ambient ground accelerations. The unit is manufactured by Encardio-rite in India under license from Gaiacode, UK.


  • An isolated dc-dc converter ensures galvanic isolation of the system and operates from +9VDC to +36VDC.
  • The analogue feedback accelerometer has a vast dynamic range, and the 8-channel 24-bit acquisition system is incorporated to exploit the full dynamic range of the sensor as high gain and low gain digital outputs.
  • The low and high gain outputs are set digitally using the (PGA) Programmable Gain Amplifiers of the 8-channel Acquisition system.
  • Nominally the high gain outputs are set to have a 12 times larger output than the low gain outputs.
  • The sensor's analogue differential outputs are interfaced to the differential inputs of the digitiser. The digital part of the circuity is optically isolated from the front end analogue to digital converter circuitry.
  • Figure 1 shows the sensor's connector turret, allowing easy connection to the sensor. All the connectors are waterproof with O ring seals to a depth of 2 meters of water. The display provides the state of health information of the feedback sensor and the digitiser.
  • Full-scale low and high gain sensitivity is digitally user-adjustable from ±4.0 g to ±0.33 g on individual channels of the digitiser.
  • The standard frequency passband is flat to acceleration from DC to 350 Hz.
  • Detailed sensor calibration information is provided with every sensor, including sensor dc calibration levels, the frequency response of the instrument and the transfer function in poles/zeros notation. The digitiser calibration values are also provided and the calibration values are stored within the digitiser.
  • It is extremely simple to install the digital sensor, a single point slotted base bolt point ensures that the sensor can be fixed firmly to the installation point. Three levelling feet ensure that the sensor is levelled and locked to the installation bolt.
  • The North/South ordination points are machined on the sensor base and the sensor component fixing screws are fixed with dowel pins to achieve the highest possible orientation accuracy. Any errors in the pointer to sensor orientation are less than ± 0.1 degrees.
  • After installation, the sensor output offsets are nulled electronically, without needing to expose the inside of the accelerometer.
  • The digital sensor noise performance is better than 0.15 µm/s2 or 0.15 µm/√ Hz. The sensor dynamic range exceeds 145 dB.