M. Harada, O. Oyama
IFAC Proceedings Volumes
Abstract To reduce the probability distribution width of switching delay, it is necessary to use steep rise signals to the pneumatic devices. It is said conventional pneumatic delay of restrictor and capacitor combination causes ± 5 to 7 % errors, because signals rise slowly. To make the pneumatic delay accurate, the signals must rise steeply after the delayed time. A simple model for calculation shows one tenth reduction of error by using a soft flexible volume installed in a chamber. A new type inflating film capacitor was developed. The original film type can obtain ± 0.4 to 0.7 % errors, and a combination of film and pneumatic sensor gives ± 0.1 to 0.2 % in accuracy.