Although the trend analysis of all vibrations occurring is an excellent tool for assessing the condition of rotating machinery, it is only of limited use for monitoring piston engines. Since bumps generally result in only minimal changes in the overall vibration level signal, many errors are not detected at an early stage. Thus, irregularities are often diagnosed only when damage has been caused and it is too late for rapid relief. There are several flaws in piston engines that only marginally increase the overall vibration level signal before causing serious damage. The IMI Sensors' patented RMP transmitter, model PCB- (M) 649A01, is very sensitive to these faults early in their development.