Abstract: The system controls of a pneumatically operated valve using an electrical control signal from a controller. A pilot circuit of the system has multiple piezo valves that are subject to electrical signals from the controller to provide pneumatic output signals to a volume booster circuit of the system. Relatively small volume pneumatic pilot signals from the piezo valves are used to determine the opened or closed state of higher volume valve assemblies of the booster circuit which connect or disconnect the actuator of the valve to be operated with a source of pressurized gas. Both the piezo valves and the booster valve assemblies are subjected to gas at the same operating pressure, but the surface area of pistons in the booster valve assemblies exposed to the piezo valves is substantially larger than the surface area of the pistons exposed to operating pressure such that the pneumatic signals shift the pistons even when pressure is the same on both sides thereof.

Abstract: The system controls the position of a pneumatically operated valve using an electrical control signal from a controller. A pilot circuit of the system has multiple piezo valves that are subject to electrical signals from the controller to provide pneumatic output signals to a volume booster circuit of the system. Relatively small volume pneumatic pilot signals from the piezo valves are used to determine the opened or closed state of higher volume valve assemblies of the booster circuit which connect or disconnect the actuator of the valve to be operated with a source of pressurized gas. Both the piezo valves and the booster valve assemblies are subjected to gas at the same operating pressure, but the surface area of pistons in the booster valve assemblies exposed to the piezo valves is substantially larger than the surface area of the pistons exposed to operating pressure such that the pneumatic signals shift the pistons even when pressure is the same on both sides thereof.

Abstract: A rotary control valve includes a flow control element having a lower valve shaft rotatably received in a non-magnetic body portion. A magnet is coupled with a lower valve shaft and rotatable therewith to produce an external magnetic field that varies in accordance with the angular position of the flow control element. A magnetic field detector, positioned in the external magnetic field, is operable to detect the external magnetic field and to produce position signals representative thereof, such being indicative of the angular position of the flow control element.

Abstract: The system controls the position of a pneumatically operated valve using an electrical control signal from a controller. A pilot circuit of the system has multiple piezo valves that are subject to electrical signals from the controller to provide pneumatic output signals to a volume booster circuit of the system. Relatively small volume pneumatic pilot signals from the piezo valves are used to determine the opened or closed state of higher volume valve assemblies of the booster circuit which connect or disconnect the actuator of the valve to be operated with a source of pressurized gas. Both the piezo valves and the booster valve assemblies are subjected to gas at the same operating pressure, but the surface area of pistons in the booster valve assemblies exposed to the piezo valves is substantially larger than the surface area of the pistons exposed to operating pressure such that the pneumatic signals shift the pistons even when pressure is the same on both sides thereof.

Abstract: The system controls the position of a pneumatically operated valve using an electrical control signal from a controller. A pilot circuit of the system has multiple piezo valves that are subject to electrical signals from the controller to provide pneumatic output signals to a volume booster circuit of the system. Relatively small volume pneumatic pilot signals from the piezo valves are used to determine the opened or closed state of higher volume valve assemblies of the booster circuit which connect or disconnect the actuator of the valve to be operated with a source of pressurized gas. Both the piezo valves and the booster valve assemblies are subjected to gas at the same operating pressure, but the surface area of pistons in the booster valve assemblies exposed to the piezo valves is substantially larger than the surface area of the pistons exposed to operating pressure such that the pneumatic signals shift the pistons even when pressure is the same on both sides thereof.

Abstract: The system controls the position of a pneumatically operated valve using an electrical control signal from a controller. A pilot circuit of the system has multiple piezo valves that are subject to electrical signals from the controller to provide pneumatic output signals to a volume booster circuit of the system. Relatively small volume pneumatic pilot signals from the piezo valves are used to determine the opened or closed state of higher volume valve assemblies of the booster circuit which connect or disconnect the actuator of the valve to be operated with a source of pressurized gas. Both the piezo valves and the booster valve assemblies are subjected to gas at the same operating pressure, but the surface area of pistons in the booster valve assemblies exposed to the piezo valves is substantially larger than the surface area of the pistons exposed to operating pressure such that the pneumatic signals shift the pistons even when pressure is the same on both sides thereof.

Abstract: A rotary control valve includes a flow control element having a lower valve shaft rotatably received in a non-magnetic body portion. A magnet is coupled with a lower valve shaft and rotatable therewith to produce an external magnetic field that varies in accordance with the angular position of the flow control element. A magnetic field detector, positioned in the external magnetic field, is operable to detect the external magnetic field and to produce position signals representative thereof, such being indicative of the angular position of the flow control element.

Abstract: A rotary control valve includes a flow control element having a lower valve shaft rotatably received in a non-magnetic body portion. A magnet is coupled with a lower valve shaft and rotatable therewith to produce an external magnetic field that varies in accordance with the angular position of the flow control element. A magnetic field detector, positioned in the external magnetic field, is operable to detect the external magnetic field and to produce position signals representative thereof, such being indicative of the angular position of the flow control element.

Abstract: A signal conditioner for a linear variable differential transformer having a first amplifier which senses the differences in amplitude between secondary alternating current voltages in the two secondaries respectively, and a second amplifier which compares the phase of the difference signal from the first amplifier with the phase of one of the secondary alternating voltages. A conditioned signal A.sub.out is output by the signal conditioner according to the equation A.sub.out =K.sub.1 V.sub.s1 +K.sub.2 (V.sub.s1 -V.sub.s2) where K.sub.1 and K.sub.2 are constants, and V.sub.s1 and V.sub.s2 are instantaneous voltages across the respective secondaries.