DE2902397A1 - Proximity switch with passive RC pulse shaper - installed between oscillator and reed relay to reduce current consumption - Google Patents

Abstract

The proximity switch consists of an oscillator (with a core-type coil) a passive pulse shaping stage, and an output stage comprising a reed-relay as change-over switch driven directly by the pulse shaping stage. The passive pulse shaping stage consists of a conventional low pass filter (integrator) and a diode. The oscillator's output is connected via a capacitor to the pulse shaper's diode. The diode is coupled to the RC part of the shaper. The output of the RC part drives the reed relay directly.

Description

Proximity switch sensors with passive pulse generation level.

Technical documentation description and schemes proximity switch (Sensors) Area of application: Electronic scanning processes, controls, alarm systems.

Purpose: Extensive simplification of the scanning methods, everywhere where the electronic proximity switches have found their application.

State of the art: Currently produced sensors (their networks) consist of three stages: oscillator (active), pulse generation stage (active Schmit trigger), Output stage (power transistor active).

Criticism of the booth: Due to their structure, the sensors must be: PNP normally open or normally closed, or NPN normally open or normally closed, can be built.

Because all three stages are active, power consumption is greater than switching capacity. With alternating current there is no separation of the circuits.

Task: The invention is based on the task of eliminating all of the disadvantages that are listed in the technical documentation.

Solution: This object is achieved according to the invention in that the Sensor has only one active level instead of three active levels (oscillator). Others Stages are passive: passive pulse generation stage (subject of the invention) and as Output stage works passive reed switch.

Further embodiment of the invention: Does not apply.

Achievable advantages: 1. "Neutral" outputs 2. Lower power consumption as switching capacity 3. Galvanic isolation with alternating current 4. Area of application up to 2ovo0 C Description: According to documents provided 1. General 1.1. Capacitive proximity switches currently produced and available on the market or inductive (except light barriers), mostly consist of three main networks.

1.1.1. HF oscillator 1.1.2. Flip-flop (Schmitt trigger) 1.1.3. Output stage (Power level or switching level) All types have due to their construction the following disadvantages: 1.1.4. Nominal switching distance smaller than the diameter of the sensor 1.1.5. They are as: -PNP - normally open or -PNP- opener or -NPN- normally open or - NPN opener built 1.1.6. With alternating current, the galvanic bond always remains between the network of the sensor and the alternating current circuit to be switched.

1.1.7. Switching ratio less than 1 switching current <1 absorbed Electricity 1.2. Sensors developed on my part eliminate all the disadvantages below Point 1.1.4 to 1.1.7 are listed, and they can also be classified as sub-miniature works or build for difficult conditions (heavy industry, military purposes).

You can also use microprocessors directly with logical outputs or control IT systems.

Debounced logical H (2.7 V, 5 V) Debounced logical L (o, 7 V, 2.2 V) 2. Method of operation and description 2.1. HF - Oscilator The above 3-point oscillator (Fig. 1) without stabilization of the working point (not necessary), with core coil.

Coil with an almond core (ferrite), with a severed arm (Fig. 2).

This achieves the desired dispersion of the magnetic field Direction, and finally larger switching distance.

2.2. Passive impulse education level As a passive impulse education level Ordinary integration element (low-pass filter) works with an electronic valve.

The exact structure is shown in Figure 3. Pictures: 3 a, 3 b, 3 c clarify at the same time Working method and process of impulse formation. In the case of a proximity switch, the task frequency is much smaller than the oscillation frequency of the oscillator approx. 1; 400

As a result, the rise and fall times of the pulse are sufficiently good (even better than with the Schmitt trigger including power amplifier).

2.3. Output stage The output stage (switching stage) is a REED switch, which is driven directly by the impulse formation stage (Fig. 3).

Practical construction of an example has shown that a transistor B - 635 (Siemens) the REED switch type 200 R04 250 (company THOMSON - Munich) operates flawlessly.

3. Further developments Network for direct control of microprocessors and IT systems is shown in Figure 4, and for heavy industry in Figure 5.

Claims (1)

Claims preamble-preamble: 1. Proximity switch with passive pulse generation stage 'Characteristic Part: Passive pulse generation stage