Shiva Electronics Panchavati, Nashik, Maharashtra

Slot Sensors also called as Fork Switches because of their forked shape, detect objects that pass between the two arms one is the Transmitter & the other is the Receiver. These sensors operate on a through beam design, they combine the transmitter & receiver into a fixed housing so alignment is never an issue. The transmitter emits pulsed light in the infrared wavelength range. The receiver detects the light beam and immediately converts a beam interruption caused by an object in the sensing zone into a switched signal. Fork Width is defined as the height between the transmitter & receiver. Depth is defined as the distance between the transmitter & receiver area and back of the opening.

Ultrasonic sensors operate with a piezoelectric transducer as the sound emitter and receiver. A patented de-coupling layer in special material is used to decouple the ultra-Sonics to the air - an acoustically thin medium. This ultrasonic transducer is embedded, watertight, into the sensor housing, in polyurethane foam..The transducer transmits a packet of sonic pulses and converts the echo pulse into a voltage. The integrated controller computes the distance from the echo time and the velocity of sound. The transmitted pulse duration ∆t and the decay time of the sonic transducer result in an unusable area in which the ultrasonic sensor cannot detect an object. The ultrasonic frequency lies between 65kHz and 400kHz, depending on the sensor type; the pulse repetition frequency is between 14Hzand 140Hz.The active range of the ultrasonic sensor is referred to as the sensing range sd. This range is bounded by the lowest and highest sensing distances, whose values depend on the characteristics of the transducer. The highest sensing distance is given in the type code. The ultrasonic sensor detects objects within its sensing range, regardless of whether these objects approach the sensor axially or move through the sound cone laterally. Ultrasonic sensors are available with switching outputs and/or analog outputs, various output functions are available ac-cording to type. The ultrasonic beam has an opening angle of around ±5°. The sound pressure level outside of this cone is less than half (-6dB) that of the value on the sensor axis. The opening angle defines the spatially dimension of the sound cone. 

Slot Sensors also called as Fork Switches because of their forked shape, detect objects that pass between the two arms one is the Transmitter & the other is the Receiver. These sensors operate on a through beam design, they combine the transmitter & receiver into a fixed housing so alignment is never an issue. The transmitter emits pulsed light in the infrared wavelength range. The receiver detects the light beam and immediately converts a beam interruption caused by an object in the sensing zone into a switched signal. Fork Width is defined as the height between the transmitter & receiver. Depth is defined as the distance between the transmitter & receiver area and back of the opening. The primary benefits of using fork sensors are easy installation, high immunity to ambient light & ability to detect different kinds of material. Sensors with different fork widths are available. They are typically used in labeling applications to detect the presence of the label compared to the carrier material. By adjusting the sensitivity with the help of a potentiometer or teach-in button, even slight differences in the light attenuation are detected. There are many applications beyond the packaging industry for fork sensors that include conveyors, small parts detection and general manufacturing. 

For a retro-reflective sensor the transmitter and receiver are incorporated into one housing. By means of a reflector the transmitted light is returned to the receiver. An object in the beam path interrupts the beam and triggers a switching operation. Features Transparent objects such as bottles or foils can be detected better than with a through beam sensor because the light beam must pass the object twice and is thus weakened twice as much as with the through beam sensor. Since the transmitter and receiver are integrated into one housing only one voltage supply and thus only one cable are necessary. Compared to a through beam sensor, a retro-reflective sensor has an average excess gain. An object must have the size of the optics directly in front of the optics and the size of the reflector directly in front of the reflector. 

In all automated processes sensors are absolutely necessary to provide the PLC with information. They supply the necessary signals on positions, limits or serve as pulse pick-ups for counting tasks or for monitoring rotational speed. Inductive & Capacitive Proximity Switches are useful in industries for non-contact operation free from any wear & tear with high switching frequencies and accuracy. They are insensitive to vibration, dust & moisture. Inductive Sensors detect all metals without contact. Capacitive Sensors detect almost all solid and liquid media such as metal, glass, wood, plastic, water, oil etc. Inductive Proximity Switches take advantage of the physical effect of the change in the quality factor in a resonant circuit caused by eddy current losses in conductive materials. This is how it works: ALC tuned circuit generates a high frequency electromagnetic field. This field is radiated from the active face of the oscillator. This reduce the oscillation amplitude. The change is converted into a switching signal. The operating principle permits detection of all metals irrespective of whether they are moving or not. Important: the high frequency field causes no measurable heat in the object nor is there any magnetic interference. The operation of the sensors is without interaction. The distance to the active face at which an electrically conductive material causes a change of signal in the sensor is called sensing range. The sensing range of an Inductive Proximity Switch is defined by means of a target of mild steel (Fe 360). If the switch is damped by other metals, e.g. aluminium or copper, this is reduced. Using correction factors for every kind of metal the user can calculate the attainable sensing ranges.

Microcontroller based Power Pack Module is used to generate On and Off delay in the output set by user after any input changed is sensed by sensor interfaced to module. User can adjust delay (Range from 0-9 seconds) using switches S1 and S2 provided on board, corresponding delay also be seen on seven segment display. PNP and NPN both type of sensor can be connected to module, depending on the user set delay value Thyristorised output is generated which can be used to control AC load connected to module

It is a microprocessor based tuning (vibrating) fork for liquids. It works well for level detection of fluids in extreme plant conditions such as high temperature and high pressure. It's compact and power saving.

A diffuse reflection sensor is used for the direct detection of objects. As with a retro-reflective sensor transmitter and receiver are incorporated into one housing. The transmitter emits light which is reflected by the object to be detected and seen by the receiver. This system does not evaluate the interruption of the light beam but the reflected light of an object. In the use of these photo sensors, it is important to bear in mind the color and the type of surface of the object. With opaque surfaces, the sensing distance is affected by the color of the object. Light colors correspond to the maximum distances and vice-a-versa. In the case of shiny objects, the effect of the surface is more important than the color. The sensing distance in the technical data is related to matte white paper. The switching function referred to light-on (NO) dark-on (NC) mode is therefore reversed. The transmitted light of this system is also pulsed. Since transmitter and receiver are integrated into one housing only one voltage supply and thus only one cable are necessary in contrast to through beam sensors. The sensitivity of a diffuse reflection sensor is very high.

Capacitive Proximity Switches are used for the non-contact detection of any objects. In contrast to inductive switches, which only detect metallic objects, capacitive sensors can also detect non-metallic materials. Typical application are in the wood, paper, glass, plastic, food and chemical industries. Capacitive Sensors for example monitor that the contents of a cardboard box are complete or check the presence of the non-metallic caps. Another application is to monitor the conveying of sheets of glass on a roller conveyor. The capacitance between the active electrode of the sensor and the electrical earth potential is measured. An approaching object influences the electrical alternating field between these two " Capacitor Plates". This applies to metallic and non-metallic objects. In principle, capacitive sensors work with an RC oscillator. A very small change in capacitance is enough to influence the oscillation amplitude. The evaluation electronics converts this into switched signal. The user can set the sensitivity with a potentiometer. 

The system consists of two separate components, a transmitter & receiver. The transmitter emits pulsed light in the infrared wavelength range. The receiver detects the light beam and immediately converts a beam interruption caused by an object in the sensing zone into a switched signal. Features The light only travels one way (from the transmitter to the receiver). Adverse effects in the applications, such as dust in the air, dirt on the lenses, steam or mist do not immediately interfere with the system. A through beam sensor is distinguished by a long range. The characteristics of the sensing zone can be described easily. An object must have at least the size of the optical axis, i.e. the size of the sensing surface or the lens to enable safe detection. Since the transmitted light only travels one way it is very difficult to detect transparent objects. The light beam is not sufficiently interrupted. 

An "absolute" encoder maintains position information when power is removed from the system. The position of the encoder is available immediately on applying power. The relationship between the encoder value and the physical position of the controlled machinery is set at assembly; the system does not need to return to a calibration point to maintain position accuracy. An "incremental" encoder accurately records changes in position, but does not power up with a fixed relation between encoder state and physical position. Devices controlled by incremental encoders may have to "go home" to a fixed reference point to initialize the position measurement. A multi-turn absolute rotary encoder includes additional code wheels and gears. A high-resolution wheel measures the fractional rotation, and lower-resolution geared code wheels record the number of whole revolutions of the shaft.  An incremental rotary encoder provides cyclical outputs (only) when the encoder is rotated. They can be either mechanical, optical or magnetic. The mechanical type requires denouncing and is typically used as digital potentiometers on equipment including consumer devices. Most modern home and car stereos use mechanical rotary encoders for volume control. Due to the fact the mechanical switches require denouncing, the mechanical type are limited in the rotational speeds they can handle. The incremental rotary encoder is the most widely used of all rotary encoders due to its low cost and ability to provide signals that can be easily interpreted to provide motion related information such as velocity. The fact that incremental encoders use only two sensors does not compromise their resolution. One can find in the market incremental encoders with up to 10,000 counts per revolution, or more. There can be an optional third output: reference or "index", which happens once every turn. This is used when there is the need of an absolute reference, such as positioning systems. The index output is usually labelled Z. The optical type is used when higher speeds are encountered or a higher degree of precision is required. Incremental encoders are used to track motion and can be used to determine position and velocity. This can be either linear or rotary motion. Because the direction can be determined, very accurate measurements can be made.