Today, the applications for automating hydraulic powered equipment are growing by leaps and bounds. As manufacturers strive to increase their competitive edge through Precision, Efficiency, Reliability, and Safety, they look to automation as the solution. CPI's new SL720 Sensor will play a key role in this new direction for heavy machinery. With the SL720, manufacturers of both mobile and stationary equipment can now deploy advanced motion control with reliable and accurate hydraulic cylinder position sensing. If you're serious about automation, CPI's SL720 is the enabling technology that can get your ideas off the drawing board and into the field.

Telescoping cylinders? No problem... only the SL720 can do it. The unique design of the SL720 Sensor establishes accurate position with up to a 72" extension. Until the introduction of CPI's SL Series, internal position sensing in a telescoping cylinder was impossible.

Plus, the SL720 is a logistical lifesaver. Since one sensor works for any stroke length (within the maximum range), there is no need to inventory multiple models or a multitude of parts to accommodate different cylinders.

Worried about the real world challenges? Relax. The SL720 is virtually indestructible. It resides safely and securely inside the hydraulic cylinder -- immune to shock and vibration, impervious to the elements, and safe from even the harshest environments. The SL720 will live a long life with no degradation in performance.

The SL720 at a glance:

• Sensor resides completely inside of cylinder
• No core drilling of rod required
• Non-contacting Linear Variable Inductive Transformer sensor technology
• No end-of-stroke dead zone
• No lower limit to cylinder bore size
• Virtually immune to shock and vibration, regardless of stroke
• One part can be used for any stroke length -- same low cost and simplified inventory
• Hammer-proof high pressure electrical connection
• The only internal sensor that can be used in telescoping cylinders
• Easily integrated into high-volume hydraulic cylinder production

How it works
At the heart of the SL720 is a Linear Variable Inductive Transformer (LVIT). Because LVITs are non-contacting, submersible, and unaffected by pressure and temperature, they are ideal for hydraulic cylinder applications. And as a mature technology, LVITs are well known throughout the industry for being reliable, accurate, and tough.

An integrated precision mechanism couples the long translation of the hydraulic cylinder to the short translation of the LVIT via a micrometer-like threaded element. The LVIT/micrometer assembly forms the axis of a recoil spool mechanism (fig. A). The spool uses a flexible polymer-coated stainless steel cable to form a reliable, repeatable coupling between the piston and sensor. The cable is drawn off the recoil reel as the piston moves away from the sensor, and vice-versa. The entire unit is about the size of a large proximity sensor and mounts securely on the inside face of the cylinder end-plug, replacing the hydraulic cushion (fig. B).

Fig. A	Fig. B

Features
In addition to being reliable and repeatable, the SL720 is easy to install and extremely durable. Here's how we did it.

	Snap-in-place mounting flange Made from a high-endurance elastomer, the mounting flange snaps onto the prepared piston quickly, easily, and securely. By snapping the SL720 onto the piston, the sensor and piston can be installed into the cylinder as a single unit. (NOTE: For small ID cylinders, the SL720 cannot be installed in this manner. Please see our Installation Details for further information.)
	Flexible connection A nylon-insulated stainless steel cable translates the movement of the piston to the LVIT mechanism. Why nylon? Flexibility. Because the cable is flexible, it can be wound around a spool to save space. A non-binding bolt securely attaches the cable to the piston rod.
	Self-guiding bolt mounts A precise lineup every time. Two bolts hold the sensor in place, and generous lead-ins allow for an approximate lineup of the bolt holes during installation. Once the sensor is roughly in place within the cylinder, the lead-ins guide the sensor into proper position, in alignment with the high-pressure connector.
	3/4 round shape The unique shape of the SL Sensor allows for free passage of hydraulic fluid should a fluid port be located even with the sensor.
	High-Pressure Connector and Signal Conditioner All the signal-conditioning electronics are integral with the high-pressure connector assembly. A standard vehicle bus voltage (12-24VDC) powers the sensor through the SC450 signal conditioner, which provides the 0-5VDC output. Housed in a stainless steel casting, the SC450 is completely sealed from the environment and comes standard with a 24" shielded cable (interconnect to be specified by customer).

SL720 Sensor & Signal Conditioner specifications

Download the complete SL720 set of drawings (PDF, 224kb)

Applications / Markets

CPI's SL Series is the right choice
You may have heard about (or even tried) other internal position sensing technologies, but none of them work as well as CPI's SL720 Sensor. Other technologies available today are much harder to implement, they're much more expensive to implement, they're not as robust, and they are much more susceptible to damage. Plus, they absolutely cannot be used with telescoping cylinders.

Talk to us today
Got automation on your drawing board? We want to help. Talk to us today... we'll send you an SL720 Evaluation Kit containing the sensor, signal conditioner, cable, high pressure connector, mounting screws, and instructions. Aluminum piston adapters are also available for mounting the sensor to a piston head. See for yourself how easy it is to implement SL720 position sensing and bring Precision, Efficiency, Reliability, and Safety to your most demanding applications.
Call 973-887-9400; or e-mail sales@cpi-nj.com

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Control Products, Inc • 280 Ridgedale Ave. • E. Hanover, NJ 07936 • (973) 887-9400 • E-mail: sales@cpi-nj.com
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