Abstract
Described in this paper are dynamic characteristics of the pneumatic micrometer with both hybrid pressure cascade connection and feedback. The dynamic behavior of the measuring system is analogically presented as a 2nd order linear system, ie, both input and output circuits have time constants and transfer gains which change values as a function of the operating point. Damping ratio, natural frequency and equivalent time constant of the system are shown as a function of the output operating pressure and are further studied on an example how they are effected by the circuit parameters, such as the initial operating pressure, the coupling transducer gain, the feedback transducer gain, loading volume and compliances between the gauging nozzle and its counter-face. Means of adjusting the device to obtain required dynamic performance is discussed and it is demonstrated that measurements can be achieved with nearly constant and short response times, throughout the operating range, despite changes in output loading volume.
