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Inductive sensors produce analogue outputs

11 December, 2007

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Pepperl+Fuchs has announced a family of inductive position and angle sensors which, in contrast to the binary outputs of most other inductive sensors, produce analogue current or voltage outputs proportional to the position of the actuator. P+F predicts that this development will open up new applications for inductive sensing.

It adds that the non-contact – and thus wear-free – devices will provide an alternative to lower-cost, contact-based (and thus wear-prone) sensors, and to more costly non-contact devices.

P&F inductive sensors

The analogue sensors (shown above) incorporate a microprocessor which evaluates their signals, compensates for any variations in temperature, and generates the analogue output signals (either 4-20mA or 0-10V). Some versions also include two switch outputs, which can be used to monitor limit values.

As well as being robust, inductive sensors are insensitive to dust, dirt and humidity. Almost any metal object – including bolts and fixing elements – can serve as a target, unlike magnetic sensing systems which need special magnets that can be costly to replace. Another attraction of inductive sensing is that the distance between the sensor and target can be quite large,

P+F is producing the PMI series of analogue inductive sensors in a variety of versions including models with:

• measuring ranges to 120mm, resolutions of 125΅m and target distances up to 3mm;

• measuring distances up to 360mm and a detection range of up to 6mm; and

• angle detectors with a 360-degree range, and capable of speeds of up to 100 rpm.

There is also a version for measuring distances up to 14mm which P+F claims is the smallest inductive measuring system available, with dimensions of just 35 x 35 x 40mm.