Reed Relays and
Electronics India Limited
Manufacturer of Reed Switches, Reed Sensors and Reed-based products
Reed Relays and Electronics India Limited Incorporated in 1971
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Pulse Counting Type

Electricity Meter panel

When an application requires the volume of a fluid, or a distance, or the RPM of a machine tool measured, such an application can be classified as a pulse counting application.

The basic principle of pulse counting is to use a reed switch or a reed sensor on a fixed surface, with a multi-pole ring magnet attached or embedded to the center of the wheel or counter. The best practice is to use ring magnets with two poles for high speed applications and to use ring magnets with 4 or more poles for low speed applications, for better accuracy. When the sensing circuit is low in the range of milli-amperes, the basic reed switch does the job for up to a billion operations.

Reed Switches works so well in pulse counting type applications as they have a very high operating frequency. The Reed Switches used generate a square wave that can then be translated to the actual consumption of fluid, or energy, or the measurement of wheel speeds. As the wheel rotates, the multi-pole magnet’s alternating North and South poles turn the reed switch on and off continuously and this generates the square wave pulse. This pulse output is used by control circuits to display the actual measurement. The translation of number of pulses to the actual unit of measurement is achieved initially, by conducting various trials. More information regarding magnet actuation of reed switches is available here.

For pulse counting applications using larger wheels, where the diameter of the magnet is more and the pole moves away far enough to open the reed switch, any standard reed switch with a differential of 40-50% can be used. But for very tiny wheels in water and gas meters, it is important the reed switches with a close differential or 70% minimum differential are used. This is to ensure that the reed switch opens immediately as the magnetic pole moves away, so that the reed switch does not remain closed at any point.

Reed Switches are hermetically sealed, they are immune to dust and moisture, and can safely be used in environments with extreme dirt and moisture. Pulse counting for applications can also be achieved by using active devices like Hall effect sensors, but Reed Switches and Reed Sensors, are passive, have more advantage as no power is consumed for operation, and have no leakage current across the contacts, that need to be compensated for. Some of the pulse counting applications are listed below.

Example Applications

Dialysis Machine Flow Rate Sensing Using Reed Sensors

Dialysis machine flow rate sensing Dialysis machines are life-saving devices used to filter waste and excess fluids from the blood when the kidneys are unable to function Continue reading ->

Oct 26, 2024

Automatic Gates Use Magnet Sensors for Motor Control

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Sep 11, 2024

Valve Position Sensing Using Reed Sensors

Valve position sensing In industries such as water purification, gas, and chemicals, precise control over the cleaning and filtering processes is critical. Continue reading ->

Sep 3, 2024

Layering during Coil Winding Using Reed Sensors

Coil Winding for Buzzing A coil winder is an essential machine in the manufacturing of bobbins, inductors, transformers, motors, and other electromagnetic Continue reading ->

Sep 3, 2024

Surveyor’s Wheel Uses Reed Switches for Distance Measurement

surveyor wheel A Surveyor's Wheel, also known as a Trundle Wheel, serves as a fundamental tool for measuring distances efficiently. Designed with Continue reading ->

Sep 3, 2024

Sun-shade Shutter Control Applications Using Reed Sensors

window shutter Sun-shade shutter control systems in Smart Homes are revolutionizing the way we manage light and privacy within living spaces. These Continue reading ->

Sep 3, 2024

Reed Sensors in Automobile Power windows

Car power window In modern automobiles, the convenience of raising or lowering power windows is facilitated by buttons located near the seats or on the Continue reading ->

Sep 3, 2024

Control of Automobile Sunroofs Using Reed Switches

automotive sunroof An automotive sunroofs, typically constructed from tinted glass, serve as a movable panel that offers the flexibility to be fully or Continue reading ->

Sep 3, 2024

Fuel Pumps Use Reed Switches to measure Volume of fuel

Reed switches in petrol and disel pumps Fuel pumps represent inherently hazardous environments where even the slightest error can precipitate a catastrophic fire. Given this Continue reading ->

Sep 3, 2024

Bicycle and E-bike Speedometers Use Magnet Sensors

Reed switches in bicycle speedometer Fitness enthusiasts rely on accurate feedback to track their progress and performance metrics, whether it's calorie burn, distance Continue reading ->

Sep 3, 2024

Treadmills Use Magnet Sensors for Belt Speed Sensing

Reed switches in treadmill Magnet Sensors find a few applications in treadmills for speed and gradient sensing. The speed of the belt is determined by positioning a Continue reading ->

Sep 3, 2024

Fishing Reels Sense “Bites” Using Reed Sensors

Reed switch usage in electric fishing reel Electric Fishing reels represent a technological leap forward from traditional fishing gear, offering enhanced functionality and Continue reading ->

Sep 3, 2024

Reed sensors for Tamper-proofing Electricity Meters

Electricity Meter panel Electric companies rely on electricity meters calibrated to measure one kilowatt-hour and determine maximum demand, representing the peak Continue reading ->

Sep 3, 2024

Anemometers Use Magnet Sensors record Data

Reed switches in anemometer Anemometers serve as indispensable tools for measuring wind speed, pivotal in a wide array of applications including weather forecasting Continue reading ->

Sep 3, 2024

Underwater currents in Lakes measured using Flow Meters

Reed switches in flow_meter The dynamics of underwater currents in lakes and other aquatic ecosystems are influenced by a multitude of factors, ranging from Continue reading ->

Sep 3, 2024

Anti-lock braking system (ABS) Use Reed Sensors

Reed switches in ABS control system The Anti-lock Braking System (ABS) represents a pivotal safety feature utilized not only in vehicles but also in aircraft. In the realm Continue reading ->

Sep 3, 2024

Cruise Control Systems use Reed Switches

Reed switches in cruise control Cruise Control is an automated feature designed to regulate the speed of a motor vehicle, alleviating the need for the driver to maintain Continue reading ->

Sep 3, 2024

Magnet sensors in Satellite dish position sensing in the DTH industry

Satellite dish A satellite dish is a concave device used to transmit and receive information and is used primarily in the direct-to-home (DTH) TV Continue reading ->

Sep 3, 2024

A Spirometer Use Reed Sensors to Assess Lung Function

Spirometer A Lung function test or Pulmonary Function test, PFT for short, is a system to evaluate the respiration system of a patient. It uses a Continue reading ->

Sep 3, 2024

Fluid Metering Using Reed Sensors

fluid metering using pulse counting application In many major cities, utility companies or gated communities manage the distribution of piped water and Liquefied Petroleum Gas (LPG) to Continue reading ->

Sep 3, 2024

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