cable assembly

miniature jets, and two setting rings. By rotating the component through 360 ° and halving the maximum deflection reading, centreline bow and hence degree of straightness may be read directly from the gauging equipment. To achieve the required accuracy, particularly when gauging to less than 1 /~m, units are normally used with an air-electronic gauging unit, This converts readings into electrical signals which are then measured by an electronic gauging system. The inherent high accuracy of air gauging may therefore be combined with all the optional advantages of microprocessor-based statistical process control. Thomas Mercer Ltd, Eywood Road, St Albans, Hertfordshire, ALl 2ND, UK

Gauging transducer has replaceable coil/cable

assembly In the AGZ 1 precision gauging transducer, which provides for + 1.00 mm maximum calibration range, the cable and coil assembly is threaded and can be withdrawn from the transducer body for replacement. This design also facilitates fine adjustment of pre-travel. The transducer body can be mounted approximately at the null position and the fine zero calibration adjustment made easily by screwing the coil further into or out of the body. A

Interferometric fringe counter from F T Technologies locking nut secures the adjustment. The core of the Schlumberger transducer is attached to an actuator, which runs in a selectively assembled ball sleeve bearing, resulting in a repeatability of better than 0.15/~m. Schlumberger Transducer Division (Sangamo), Steyning Way, Southern Cross Industrial Estate, Bognor Regis, West Sussex, PO22 9ST, UK

Interferometer fringe counters for distance measurement Designed for use in a wide range of

AGZ 1 gauging transducer from Schlumberger shown with threaded coil and cable assembly removed from body

PRECISION ENGINEERING

mterferometric distance measurement applications, the FT610AS and FT61 2AS from F T Technologies are microprocessor-based counters. When used in conjunction with a HeNe laser interferometer, they can accommodate a total measurement range of over _+ 300 m with a resolution of 0.08 Ibm (FT610AS) or 0.32 nm (FT612AS) and provide a target tracking capability of either 6000mms 1 o r l 0 0 0 m m s 1 The measurement resolution is achieved by the use of fringe interpolation techniques. The FT612AS incorporates a true ratiometric x 1000 interpolator which gives a measurement resolution of 2/2000. The FT610AS has x 4 interpolation providing it with an effective 80 MHz counting rate at 2/8 resolution. The counters require sine and cosine (phase quadrature) compatible inputs and are easily connected to many types of distance measuring interferometers. Other features include an external trigger input for precise synchronizing of the counter with other equipment, display markers facility and over-speed and overrange indication. Both models include a GPIB (IEEE-488) interface as standard and an optional RS232 serial interface can be supplied. Application areas include high accuracy interferometric length measurement, integrated circuit manufacture and surface profiling. F T Technologies Ltd, Church Lane, Teddington, Middlesex, TWl 1 8PA, UK

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