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Basic Principles

Instructions for Use

Technical Term

Notes

Basic Principles

Before purchasing or during the process of using QWIFM products, different problems may meet depending on the application environment of the product. We organize and classify the problems you may encounter, making it convenient for you to quickly find and solve them online. You can also contact us through online messages or email.

BASIC CONCEPT OF INDUCTIVE PROXIMITY SENSORS

The inductive sensor is the use of metallic conductors and the mutual inductance of the alternating electromagnetic field principle. At the front end of the sensor detection coil generates a high frequency magnetic field, when metal objects are close to the magnetic field, eddy current metal objects internal product, leading to the decay of the magnetic field energy, energy is absorbed when the metal special body constantly gets close to the sensor sensing face and cause decay. when the attenuation reached a certain extent, the trigger sensor sensors the output signal, so as to achieve the purpose of the non-contact type of detection.

BASIC CONCEPT OF CAPACITANCE PROXIMITY SENSORS

The sensing surface of the capacitive sensor is constituted by two coaxial metal electrode, the two electrodes form a capacitor, in series with the RC oscillation circuit. When the power is turned on, the RC oscillator does not oscillate, when a target is closer toward the sensor sensing surface, the increase in capacitance, and the oscillator starts to oscillate. Is converted into a switching signal by the processing of the post-stage circuit, and thus play the purpose of detecting the presence of the object exists. Capacitive sensors can detect metal objects, can also detect non-metallic objects, metal objects can get maximum distance of the action, and non-metallic objects action distance determines the dielectric constant of the material, the larger the dielectric constant of the material, available action the greater the distance.

PHOTOELECTRIC SENSOR CONCEPT

Photoelectric sensor is a sensor that uses light to detect objects collectively, the light signal emitted by the sensor by detecting objects it shot, block and absorb longer accepted part of the detected and converted into corresponding electrical signal to the control device.

BASIC CONCEPT OF DIFFUSE PHOTOELECTRIC SENSOR

Diffuse reflection type photoelectric sensor is the transmitter and the receiver is placed integrally under normal circumstances, the receiver received less than the optical signal sent by the transmitter; when detection purified by blocking the light, and the light portion is reflected back, the receiver receives optical signal, and outputs a switch control signal.

BASIC CONCEPT OF RETRO-REFLECTIVE PHOTOELECTRIC TRANSFER DEVICE

Retro-reflective photoelectric sensor is the transmitter and the receiver is loaded into the same apparatus, and a reflective plate mounted in front thereof, and the completion of the principle of reflection of the photoelectric control role. Under normal circumstances, the light emitted by the transmitter is reflection plate reflected back is received by the receiver, blocker once the optical path of the object to be detected, the receiver detects the optical signal changes, the operation of the photoelectric sensor, outputs a switch control signal.

BASIC CONCEPT OF THROUGH BEAM TYPE PHOTOELECTRIC SENSOR

Beam photoelectric sensor is composed by an independent transmitter and receiver of the photoelectric sensor. Since the separation of the transmitter and receiver, the detection distance of the sensor to increase. Detection distance of up to a few meters or even tens of meters. To use the transmitter and receiver are mounted in the test object through the sides of the path, and must be aligned to create an optical path, when the subject was purified by blocking the light path, the receiver operation outputs a switching control signal.

Basic concepts of Hall sensors

Hall sensor is a magnetic sensor composed of voltage regulator, Hall voltage generator, differential amplifier, Schmidt trigger and output stage of Open collector. Its input is Magnetic flux density and its output is a voltage signal.

PROXIMITY SENSOR CHARACTERISTICS

● No Institutions contact detection, difficult to damage, wear, small errors
● Not influenced by ambient environment, Work normally under harsh environment
● High accuracy of repeated detection, accurate objects positioning
● Rapid reaction frequency, suitable for fast moving object detection

CHARACTERISTICS OF PHOTOELECTRIC SENSORS

● Non-contact detection, long sensing life, no damage to the objects to be detected.
● Suitable for long-distance detection of a wide range of uses.
● Applicable to a variety of subjects, also suitable to the objects which may affect ray propagating.
● High frequency response, suitable for the use of the high speed line detection.
● high detection precision, different colors can be used to distinguish.
● Use IC of independent research and development, Anti-glare interference, Anti-electromagnetic interference.

Instructions for Use

SETTING A POSITION OF THE DETECTING BODY

The sensing distance of the sensor will be changed slightly due to changes of ambient temperature, voltage changes surrounding conditions. Therefore, in order to make the sensor steady work, the maximum approach position of the detecting body is required to be less than the sensing distance. Using standard detection, the setting the actual sensor distance should be 80% of the operation distance or less of the distance. In addition, when the sample detecting the shape of the body is less than the standard sample or use detected body with other material, the sensing distance is shortened, the actual sensing distance is set must also be reduced.

Advantages of QWIFM Long distance Proximity Sensor

① The detection distance of long distance proximity sensors is twice that of ordinary sensors with the same diameter.
② It has various protection circuits such as polarity protection, over current protection, surge protection, etc.
③ QWIFM long distance proximity sensors have stronger resistance to electromagnetic interference through internal processing compared to other brands' long-distance products.

Installation method of proximity sensors

Proximity sensor installation methods can be divided into flush and non-flush. The difference is that the flush can be used to sense inside the metal, and the non-flush can’t. But the sensing distance is longer when compared with the flush.

SENSOR CONNECTION

About way of leads Cable leads
About way of terminals Terminal block
About connection Connecting through socket

Differences between PNP and NPN proximity sensors

From the perspective of output level, the high and low levels of PNP and NPN output signals are different. From the meaning represented by PNP and NPN, the PNP type indicates that the signal output terminal outputs a high level output, and the internal switch is connected between the signal terminal and the positive electrode; The NPN type indicates that the signal output terminal outputs a low-level output, and the internal switch is connected between the signal terminal and the negative electrode.
From the perspective of load connection, PNP type sensors are used when the load is connected to the negative electrode, and NPN type sensors are used when the load is connected to the positive electrode.

Wiring method for relay output

Wiring method for two wire sensors

When wiring two wire sensors, they must be connected in series with the load to the power supply (excluding the emission of photoelectric sensors).

Technical Term

SENSING DISTANCE

Sensing distance of the proximity sensor detects the size of the body.

Attenuation Coefficient

Detect body factors affect the sensing distance of the sensor. The nature of the material of the detecting body plays an important role, which can be described attenuation coefficient. Attenuation coefficient refers to a movement distance of a material with respect to reducing the number of iron (ST37). The attenuation coefficient is smaller, the smaller a distance for the operation of certain materials. The characteristic parameters of the capacitive sensor is the relative permittivity.

VOLTAGE DROP

The voltage drop is when the sensor is working, the voltage obtained from the ends of the sensor or the output end.

CURRENT CONSUMPTION

The needde current of the sensor in working state.

BACKLASH

The difference between the distances of proximity sensors detect body sensing surface, triggering the sensor action sensing distance away from the sensor detects body movements reversion reversion.

REPEATABILITY

Repeated accuracy is in the housing temperature(23±5)℃，the relative humidity is random,the supply voltage for rated measuring voltage ±5, the effective distance measuring the resulting amount of change in the range of 8 hours.

SWITCHING FREQUENCY

The switching frequency is the maximum times of sensor operation per second.

IP PROTECTION CLASS SYSTEM

IP PROTECTION CLASS SYSTEM was drafted by IEC (International Electrotechnical Commission).Classify electrical appliances according to their dust and moisture resistance characteristics. The external objects referred to here, including tools, and human fingers, should not come into contact with the live parts inside the electrical appliance to avoid electric shock. The IP protection level is composed of two numbers. The first number represents the level of dust separation and prevention of foreign object intrusion of the product, the second number represents the degree of airtightness of the product against moisture and water intrusion, and the larger the number, the higher the protection level.

LIGHT SOURCE

The emitter of the photoelectric sensors typically use the following light sources: Red LED-visible, can be easily adjusted. Infrared LED-high-energy unvisivle light.
Red laser-visible light, its physical characteristics are the ideal choice for small detected body and a wide range of detection. The Vanguard IFM brand photoelectric sensor using infrared LED as a light source.

LOAD CURRENT

The load current is in the normal case, the working current through the sensor.

LEAKAGE CURRENT

When the sensor is not turned on, the residual current in its load, is called leakage current.

Notes

一、Photoelectric sensors are suitable for various applications. However, when using photoelectric sensors, attention should also be paid to environmental conditions to ensure that the photoelectric sensors can operate normally and reliably:
1. Our photoelectric sensor can resist strong light interference, but the environmental illumination should not exceed 11000lux (natural light) and 5000lux (non natural light), and the interference source should avoid aligning with the sensor axis.
2. Mirror angle: When the tested object has luster or encounters a smooth metal surface, the reflectivity is generally high and has a similar effect to a mirror. In this case, the photoelectric sensor should be installed at an angle of 10-20 ° with the tested object to prevent its optical axis from being perpendicular to the tested object and prevent malfunction.
3. Background: Using a diffuse reflective photoelectric sensor may result in unstable detection due to the fact that the detected object is close to the background and the background is a smooth object with high reflectivity. Therefore, distance limited photoelectric sensors can be used instead, or methods such as moving away from the background, removing the background, painting the background as matte black, or trying to make the background rough or dark can be used to eliminate it.
4. Table top impact: When the photoelectric sensor is installed close to the table top, some of the reflected beams from the table top may illuminate the receiver, causing unstable operation. This can be achieved by placing the light receiver and projector at a certain distance from the countertop and installing a sunshade.
5. It is strictly prohibited to use diluents and other chemical substances to avoid damaging the optical lenses.
6. The wiring of high-voltage lines, power lines, and photoelectric sensors should not be placed in the same wiring tube or slot, otherwise it may cause (sometimes) malfunction or damage of photoelectric sensors due to induction. Therefore, in principle, separate wiring should be used. 7.When connecting the output terminal to inductive loads such as DC relays, please use diodes or rheostats to eliminate surges.
8. If the sensor wiring is too long, surges, etc., it may cause sensor malfunction. Please try to shorten the wiring as much as possible.
9.When using two or more transparent photoelectric sensors at close range, mutual interference may occur due to the influence of one projector. When installing, please switch the positions of the projector and receiver to ensure that they are not affected by each other.
10.When using two or more direct reflection photoelectric sensors at close range, the reflected light on the surface of the detected object can affect one photoelectric sensor and cause malfunction.

二．Attention for use of proximity sensors：
1. It cannot be used in environments beyond the temperature range.
2. When pulling the cable close to the sensor, its tensile strength should not be exceeded.
3. Do not use the same conduit and label the same electrical control and power lines to prevent errors.
4. Do not tighten with excessive force, and use washers when tightening.
5. The fluctuation of power supply voltage should not exceed its range.
6. This product cannot be used at the moment of power on (80ms).
7. This product cannot use Autotransformer, but isolation transformer.
8.Try to use a shorter cable size as much as possible to reduce interference.
9. The cable can be extended when needed, with a cable specification of 0.3 square millimeters and a maximum length of up to 200m.
10.If the target is metal, the detection distance varies depending on the material.
11.The impact of metal particles may cause malfunction of this product.
12. This product is used in the surrounding environment when using the following devices (such as bulbs, motors, etc.). As these devices can cause voltage and current fluctuations, surge absorbing devices must be connected to protect this product.
13.When the load is a relay, diodes for protection should be connected externally at both ends of the load.
14.When connecting a load with a high current, the initial resistance will decrease due to the impact of the current. When the current continues to increase, the load resistance value will increase and the current will return to normal. In this case, the current impact will damage the proximity sensor. If using a light bulb, please connect a relay or resistor to protect this product.
15. Stay away from radio equipment, otherwise it may cause malfunctions.

三．Precautions for intelligent three phase Solid-state relay:
When selecting products, allowance should be made in the current level based on the nature of the load. (For resistive loads, 50% of the load current can be selected. For inductive or capacitive loads, one-third of the load current can be selected).
According to the relationship between load current and ambient temperature, when the ambient temperature is high or the heat dissipation conditions are poor. Current capacity should be increased, radiator volume should be increased, or forced air cooling should be strengthened if necessary. To prevent load short circuits during use, it is required to connect the corresponding fast disconnect switch or fast fuse in series in the load circuit of this product.
When installing, it is required that the contact surface between the radiator and this product be flat and smooth, and a layer of thermal conductive silicone grease should be evenly applied to its surface. Then, the fasteners attached to the product should be symmetrically tightened and fixed to achieve the best heat dissipation effect.