Product category:
Pneumatic Valves and Controls
News Release from: Enfield Technologies | Subject: LS system
Edited by the Engineeringtalk Editorial
Team on 07 June 2004
Speedy response for servo-pneumatic
controller
The LS high-speed, advanced servo-pneumatic control system helps automation designers control position, pressure, force, flow or velocity in either open- or closed-loop applications.
The LS high-speed, advanced servo-pneumatic control system helps automation designers control position, pressure, force, flow or velocity in either open- or closed-loop applications The LS system comprises a dedicated device controller and a five-port three-position closed-centre directional valve for a unique yet simple and easy-to-use package
The system's multiple feedback design gives the designer more control over the application.
The device controller requires a minimum +/-12V DC at 25W or 1.0A power source, and accepts a 4-20mA, 0-10V DC or +/-10V DC command signal input from a variety of sources including PLCs and computers.
Its convergent controller circuitry provides real-time command and feedback signal monitoring with a sub-100ms response time.
It has active valve current feedback, which monitors the linear force motor's position and immediately corrects external disturbances at the valve before the system sees them.
It is rated for operating temperatures from -25 to +85C.
Optional sensor signal conditioners are available.
The sensor signal conditioner provides amplification and linearisation for either two individual or one differential low voltage level pressure or force sensors.
For example, with differential pressure measurement an additional feedback path can be provided for those applications requiring more stability under varying load conditions.
The command signal ramp conditioner modifies the characteristics of the command signal by changing the up and down slopes of the command signal for gradually opening and closing of the servo-valve.
This allows the system to be tuned to avoid overshoot, and it is ideal for helping conserve energy (electricity and compressed air) by matching the servo-pneumatic control system to the mechanical system dynamics.
The servo-pneumatic valve uses a directly coupled linear force motor and lapped-spool-and-sleeve construction for fast, smooth, quiet, stiction-free operation.
This patented design provides infinitely variable and truly linear proportionality with almost zero hysteresis.
The valve's response time from closed-centre to fully open in either direction is 2.5ms, and it consumes less than 1A to complete this operation.
The valve is available in three sizes 10-32 UNF, 0.125in NPT and 0.25in NPT with a flow capacity up to 985 litre/min.
The valves are capable of controlling pneumatic actuators up to 125mm bore.
The LS System is rated for use with clean, dry, non-lubricated air or inert gases up from vacuum to 10bar, and ambient temperatures from -23 to +46C.
The valve receives it command signal through a 3-pin pico M8 female, 24AWG cable.
Although the system is designed for proportional pneumatic control it can be used in speed applications with a total cycle time of 5ms for a complete open and close of one port.
That's four to seven times faster then the typical solenoid operated valve.
Its trapezoidal command curve eliminates the end of stroke shock typically associated with high-speed - bang-bang - applications.
The LS system is being used in a wide variety of applications and is well suited for industrial automation, product testing and animation.
• Enfield Technologies: contact details and other news
• Email this article to a colleague
• Register for the free Engineeringtalk email newsletter
• Engineeringtalk Home Page
