Traditional 3-position valves accomplish vacuum isolation and rough pressure control via an adjustable air cylinder. Unfortunately, the single, mid-open set point is neither accurate nor repeatable. Nor-Cal Products’ 3-position throttling pendulum valve uses the patented Intellisys™ closed-loop control technology to provide much better set-point accuracy and repeatability, anywhere from 0.1 to 99.9% of stroke. Simple TTL inputs are used to trigger the controller and valve to go open, closed, or to the third position much, in the same manner, a 3-position air cylinder would be commanded using solenoid pilot valves. Alternatively, an RS-232 communications link is available for remote control and set-up to users who prefer this method of the interface over the manual local mode.
