Pneumatic control system, control means therefor and method of making the same

In a control means for a pneumatic control system that has a pneumatic source and a pneumatically operated device that produces an output, said control means being adapted to interconnect said source to said device and having an input means adapted to be interconnected to said source and an output means adapted to be interconnected to said device, said control means having set point means for selecting a desired output of said device, said control means having valve means for controlling the interconnection between said input means and said output means so as to regulate the pressure value in said output means, said control means having regulating means for operating said valve means to tend to produce an output of said device that corresponds to said selected otuput of said set point means, the improvement wherein said regulating means has a silicon transverse voltage strain gauge means that is adapted to sense said pressure value in said output means and operate said valve means so as to produce a pressure value in said output means that is substantially equal to a pressure value that will cause said device to produce said selected output, said control means comprising a relay means having said input means and said output means, said relay means having a pilot input and a valve unit for interconnecting said input means to said output means in relation to the pressure value in said pilot input at said valve unit, said valve means being adapted to be interconnected to said source and to said pilot input whereby said regulating means is adapted to operate said valve means to create said pressure value in said pilot input at said valve unit in relation to the sensed pressure value in said output means, said regulating means also having another silicon transverse voltage strain gauge means that is adapted to sense the pressure value in said pilot input at said valve unit thereof.