Rationale: This document will be updated to include a chapter about measurement of vibrations in engines equipped with FADEC. The proposed new chapter is:
Vibration Measurement in Engine Equipped With FADEC Systems
In modern engines, equipped with FADEC systems, accelerometers are supplied with the engine by the OEM. They are connected to the engine control unit (or protection and monitoring unit) that is the one that performs the conditioning of the signal, obtaining the relevant data: broadband acceleration in RMS for monitoring and FFTs (frequency analysis) for engine life management and potential troubleshooting.
The engine control unit is able to protect it in case high vibration levels are reached, overcoming the limits.
The communication of the control units with the test bed is usually performed by means of avionic buses like Arinc-429, mil-std-1553B, AFDX or similar and requires OEM special test equipment to implement it. To record and visualize the parameters on the test facility the data acquisition system should be able to communicate with the commented equipment.
If troubleshooting is required, it is always possible to install a small accelerometer next to or even on the engine accelerometer to perform the checks required.
