Pneumatic Servo Systems

The Enfield S2 positioning system is a servo pneumatic proportional control valve offering all in one positioning of varying loads at high speeds for lower cost than competing electric drives and hydraulic systems.

Enfield Technologies has introduced the S2 Servo Pneumatic Proportional Control System for variable positioning of air cylinders. The compelling aspect of the S2 is tight integration of control algorithms, electronics and mechanical components in one package. Focused on simplifying setup and attaining superior performance, Enfield designed the S2 as a directional control valve with an on-board closed-loop controller, high efficiency valve driver, and sensors to measure differential pressure in the cylinder. Inputs are simply power, cylinder position set-point signal, and cylinder position sensor feedback signal.

Enfield has provided the end user with ultimate flexibility in their design process. Instead of being locked into one brand, the S2 can be paired with any air cylinder brand and standard analog position sensors. This allows the customer to deploy best-of-breed components for their application. Designers can tackle high speed and high force applications with less cost and less space than electric drives for the same load capacity.

The innovative algorithm uses a cascaded control system with both position and pressure feedback. The result rivals electric drives while retaining the advantages of pneumatics for moving and holding high loads, space efficiency, and low cost. Their website shows a video of an application using 40 mm (1.5”) bore cylinder following a PLC command to move 25 kg (55 lb) to various positions at 1200 mm/s (50 in/s) with positional accuracy of 0.5%. Customers have also used the system for even more precise control. For example, a laboratory automation process was developed to provide 5 mm indexing with better than 0.25 mm accuracy for a tray of small samples moved by a 300 mm low friction guided cylinder with feedback. That’s better than 0.1% accuracy

Valve

Flow Capacity (approx.)
(80 psig to atmosphere)
Max. Valve Coefficient (Cv)
Ports
Shifting Time