FERNSTEUERGERÄTE KURT OELSCH GMBH

Today potentiometric Angular Position Transmitters attain a still more status with regard to the analogue measuring technique as far as high-quality measurement tasks are concerned due to the favourable value for money. Potentiometric transmitters have either a high-resolution element of conductive plastic or a high-resolution gold or constantan wire with various resistance and angle values. They are available in various sizes as single-turn or multiple-turn potentiometers or in a multiple design. For adjustment of the measuring range almost all series can be provided with short-circuiting tracks, taps and function windings. Some models are available with incorporated Signal Converter providing current or voltage outputs in configuration of 2, 3 or 4 wires. To ensure reliability in very dirty atmospheres, oil-filled potentiometers are available.

Rope Length Transmitter with high precision analog or digital encoders The determination of measuring lengths in the range of one up to several meters is preferably carried out by using well priced and easy-tomount transducers on the basis of the draw wire measuring principle. In connection with measuring problems of industrial applications e.g. on - cranes, drilling machines and excavators - pressing, punching and injection moulding machines - weirs and lock gates - multilevel shelving rack systems and theatre stages - wood- and stone-working machines and also in - instrument engineering, high-tech medical devices etc. Rope length measuring systems series SL 3000 have proven for years to be very reliable, capable of measuring lengths up to 40 m with high accuracy and reliability even in extremely dusty and moist atmospheres.

The signals representing angle and length of a telescopic crane are important measuring data. Determination of such measuring data is performed by means of tilt angle and rope length transmitters. The determination of the jib angle is performed by a magnetically damped pendulum system, the swing of which is measured with a redundant high-resolution conductive plastic potentiometer. The output signal is provided in form either of two resistance signals or via the built-in signal converter in form of two current or voltage signals. Linear measurement is performed according to the draw wire measuring principle. One makes use of a multiwire measuring cable, which is wound multilayered on a cable reel provided with a pullback spring. A mechanical spindle lead screw nut ensures, that the rope is rewound and unwound exactly layer-by-layer. The number of drum revolutions, being proportional to the measured length is determined by a redundant potentiometer system voltage or current output.

Tilt angle values of a platform stand for important measuring data as a part of the safety and control system of machinery. Angular measurement is, for instance for equipment levelling, performed in such cases by means of dual axis pendulum systems. Transducers of that type contain inside a robust splash-proof aluminium case of protection degree IP 65 to IP 68 oil-damped pendulum systems, the tilt angle dependant swing of which is measured, depending on the application, either by a potentiometric, non-contact inductive or an optoelectronic angular encoder. For measurements relevant to safety, the pendulum swing per axis is detected with redundancy i.e. by means of two mechanically and electrically independent pendulum systems. The output signal, representing the tilt angles, is provided either in form of an analog resistance, current or voltage variation or as a digital signal - with interface bus - as well.

For measuring linear displacements on machines and converting them into electrical signals for teletransmission purposes - linear displacement transmitters of the potentiometric, inductive, incrementally or absolutely coded type can be used, depending on their application. Potentiometric linear displacement transmitters comprise high-resolution wirewound resistance elements, capable of measuring length up to 1 m with high accuracy and a linearity of ± 0,1%. For protection against mechanical damage, plunger with sintered metal bearing and pull-back spring (optional) are encapsulated in a robust aluminum casing, degree of protection IP 65. Inductive linear displacement transmitters comprise a non-contact differential inductor system providing high linearity and resolution, capable to perform reliable measuring ranges from 0 to 0.5 mm up to 0 to 500 mm even under extremely severe environmental conditions.

Hydraulically operated control equipment are to an increasing extent controlled by electronic means nowadays. This is the application range - in consideration of the extreme conditions of use which the control transmitter ST2000 is especially designed for. Corresponding to the lever displacement, it provides a direction dependent switch and control signal output for both axes X and Y. Wear-free and non-contacting inductive linear transmitters are used as primary elements of the measuring system, with respect to mode of activation and robustness their design can be compared with that of the valve system of hydraulic control transmitters. The built-in electronic circuit provides for control purposes on its output per axis either a current or a voltage signal with switchable characteristic of the linear or the progressive type. A special design offers the option to incorporate a microprocessor for individual matching of characteristics.

Wind velocity indicators are used for detecting and in connection with the appropriate indicator, monitoring a maximum wind velocity. They are used mainly in safety and monitoring systems of cranes and excavators. Two models are available. One with pendulum orientation, especially suited for the attachment on jibs of mobile cranes, and a common one, pedestal mounted or mounted on a vertical post. The output signal, being proportional to the wind velocity is taken either from a built-in tachometer generator in form of a voltage or from an optoelectronic impulse transmitter with frequency-current converter in form of a current signal in two-wire technique. For applications in the temperature range down to minus 50 °C there is optionally available for both models a mounting arrangement for a temperature controlled heating device. Cross arms feed-through sleeve and crown are splash-proof, degree of protection IP 65.

If the length or angle to be monitored shall additionally be output as a continuous electrical signal, a mounting arrangement of a remote indicating device of the analog or digital type is optional available. They contain in a robust protective casing either a backlash compensated gear or a gear with reduced backlash for matching the input angle with the switching or transducer angle. Each cam unit contains two semicircular disks, which can be adjusted against each other by means of a screwdriver via a worm drive, the switching point position encompassing a switching angle from about 10° up to 350° at maximum, and over 360° of the cam shaft. Sets of break-before-make contacts are used, each comprising one normally-closed and one normally-open contact. For positional back-indication via coupling or gear, one or two angular position transmitters can be operated on the camshaft, optionally with analog or digital output signal.

Hydraulically actuated controlling equipment, for example in - Construction and drilling vehicles - Cranes and excavators - Wheel loaders and lifting platforms - Railway Vehicles are controlled to an increasing degree electronically nowadays. Especially for these applications (under consideration of extreme operating conditions) our pedal actuated transmitters of series FS2000 were designed for. They contain wearless magnetic control systems in redundant version for security-relevant applications according to IEC 61508 (for example SIL2) with analogue or digital signal output.

Angular Position Transducers with inductive magnetoresistive or optoelectronic measuring systems. Potentiometric transmitters have either a high-resolution element of conductive plastic or a high-resolution gold or constantan wire with various resistance and angle values. For adjustment of the measuring range almost all series can be provided with short-circuiting tracks, taps and function windings. Some models are available with incorporated Signal Converter providing current or voltage outputs in configuration of 2, 3 or 4 wires. Moreover, to provide protection for all potentiometers from mechanical damage, dusty and damp industrial atmospheres a series of casings with a degree of protection IP 40 to IP 68 is available which can be equipped with gearing and limit switches.