Endevco introduces new variable capacitance accelerometer featuring onboard, microprocessor-based temperature compensation

Patented by Endevco, typical applications for the new model 7290D require measurement of whole body motion immediately after the accelerometer is subjected to a shock motion and in the presence of severe vibration inputs. Gas damping and internal over-range stops enable its anisotropically etched, silicon sensing element to withstand high shock and acceleration loads. The use of gas damping in the sensing element also results in very small thermally induced changes in frequency response.

With its onboard, microprocessor-based temperature compensation, the model 7290D delivers 2.5% total dynamic accuracy over the entire military spec temperature range of -55ºC to +125 ºC. Total dynamic accuracy is defined as the root of the sum of the squares of thermal sensitivity shift, non-linearity and hysteresis, and transverse sensitivity.

Custom signal conditioning enables the model 7290D to operate with a nominal excitation of 8.0 Vdc to 30.0 Vdc and provides a high-level, low-impedance output. The ±2.25 V differential output (single-ended output optional) is DC coupled at a DC bias of approximately 2.5 V.

In order to maintain stringent thermal characteristics and high accuracy, a custom ASIC provides factory programmable temperature compensation. All compensation and adjustments are incorporated within the accelerometer and no post-processing is required. The compensation is accomplished via a five-point, piecewise, linear fit algorithm for both thermal sensitivity shift (TSS) and thermal zero shift (TZS). A Transducer Electronic Data Sheet (TEDS) conforming to IEEE 1451.4 has been included to store serial number and calibration information.