Industrial Sensors Explained: Proximity, Photoelectric, Ultrasonic and Smart Sensors

Quick overview: This guide explains industrial sensors and the practical checks that help you understand and plan an installation. Use the contents below to go directly to the relevant section.

Industrial automation begins with information. Before a PLC can start a conveyor, stop a machine, count a product, confirm a cylinder position or determine whether material is present, something needs to detect what is happening in the physical process.

That job is performed by industrial sensors.

Sensors can detect metal, objects, distance, position, liquid, material presence and many other conditions. Selecting the correct sensor involves considerably more than choosing one that physically fits the machine. The sensing principle, target material, sensing distance, output type, supply voltage, connector, mounting arrangement and environment all affect whether the sensor will work correctly with the application and control system.

This guide focuses primarily on industrial machine and discrete sensing technologies and complements Softcore Group Industrial Solutions's separate instrumentation guide, which covers continuous process measurements such as 4–20 mA pressure, temperature, flow and level signals.

What Is an Industrial Sensor?

An industrial sensor detects a physical condition and converts it into an electrical or digital signal that a PLC, remote I/O system, controller or other automation device can use.

Typical sensing tasks include:

• Detecting whether an object is present
• Confirming machine position
• Counting products
• Detecting metal components
• Monitoring material presence
• Measuring distance
• Confirming cylinder or actuator position
• Detecting a product on a conveyor
• Providing machine limit information

Sensor vs Switch vs Transmitter

A sensor can provide either a discrete switching output or a continuously variable measurement depending on its design.

A proximity sensor commonly provides a simple ON/OFF signal when a target enters its sensing area.

A process transmitter commonly provides a continuous signal such as 4–20 mA representing pressure, level or another measured variable.

Understanding whether the control system requires a discrete input or analogue measurement is an important first step in product selection.

Common Industrial Sensor Types

Industrial sensing technologies include:

• Inductive proximity sensors
• Capacitive proximity sensors
• Photoelectric sensors
• Ultrasonic sensors
• Magnetic cylinder sensors
• Mechanical limit switches
• Pressure switches
• Level switches
• Temperature switches
• Smart sensors with IO-Link or other digital interfaces

Each technology is suited to different targets and environments.

What Is an Inductive Proximity Sensor?

An inductive proximity sensor detects metallic targets without requiring physical contact.

It generates an electromagnetic field at the sensing face. When a suitable metal target enters that field, the sensor detects the resulting change and switches its output.

Inductive sensors are widely used for machine position detection because they are robust, compact and do not require mechanical contact with the target.

What Can an Inductive Sensor Detect?

Inductive sensors detect electrically conductive metal targets.

Common targets include:

• Steel
• Stainless steel
• Aluminium
• Brass
• Copper

The effective sensing distance can differ according to the target material and sensor design.

A nominal sensing distance stated for a standard steel target should not automatically be assumed to apply equally to every metal.

Inductive Sensor Applications

Typical applications include:

• Detecting machine components
• Confirming actuator positions
• Counting metal parts
• Detecting gear teeth
• Confirming fixtures are present
• Machine limit detection

What Is a Capacitive Proximity Sensor?

A capacitive sensor detects changes in capacitance caused by material entering its sensing field.

Unlike an inductive sensor, it can detect many non-metallic materials as well as metals.

Depending on the sensor and application, targets can include:

• Plastic
• Glass
• Wood
• Paper
• Powders
• Granules
• Liquids
• Metal

Capacitive Sensor Applications

Capacitive sensing can be useful for detecting material where inductive sensing cannot be used.

Applications can include:

• Material presence in containers
• Powder or granule detection
• Plastic component detection
• Liquid presence through suitable non-metallic vessel walls
• Packaging machinery

Performance depends strongly on the dielectric properties of the target and surrounding environment.

Capacitive Sensors and Moisture

Because capacitive sensors respond to changes in dielectric conditions, moisture, product buildup and environmental changes can influence operation.

Sensitivity adjustment and correct installation are therefore particularly important in challenging applications.

Inductive vs Capacitive Proximity Sensors

The correct technology depends on the target material and installation rather than one sensor type being universally better.

What Is a Photoelectric Sensor?

A photoelectric sensor uses light to detect an object.

Photoelectric sensing can provide significantly longer detection distances than many proximity sensors and can detect a wide range of materials.

Common arrangements include:

• Through-beam
• Retroreflective
• Diffuse reflective

Through-Beam Photoelectric Sensors

A through-beam system uses a separate emitter and receiver positioned opposite one another.

The emitter sends light toward the receiver. An object is detected when it interrupts the beam.

Through-beam systems can provide long sensing distances and reliable detection because the receiver normally sees the light source directly.

They require equipment and wiring on both sides of the detection path.

Retroreflective Photoelectric Sensors

A retroreflective sensor contains the emitter and receiver in one housing and uses a reflector positioned opposite the sensor.

The sensor detects an object when the returned beam is interrupted.

This can simplify wiring compared with a through-beam arrangement because only the sensor side requires electrical connection.

Polarised Retroreflective Sensors

Reflective or shiny objects can sometimes return enough light to cause detection difficulties in conventional retroreflective applications.

Polarised retroreflective sensors use optical polarisation to help distinguish the intended reflector from certain reflections off the target.

Suitability still depends on the target and sensor specification.

Diffuse Photoelectric Sensors

A diffuse sensor contains both emitter and receiver in the same housing and detects light reflected directly from the target.

No separate reflector is required.

The amount of reflected light depends on the target's colour, surface, angle and material, so effective sensing distance can vary considerably between objects.

Background Suppression

Photoelectric sensors with background suppression are designed to detect objects within a defined range while reducing detection of objects or surfaces farther away.

This can be useful where a conveyor, machine frame or wall sits behind the target.

Exact performance depends on the sensor technology and target characteristics.

Foreground Suppression

Some specialised photoelectric sensors can also suppress objects within a foreground region while detecting targets beyond it.

This is useful in selected machine arrangements where nearby structures would otherwise interfere with detection.

Detecting Transparent Objects

Transparent bottles, films and glass can be difficult for ordinary photoelectric sensors because much of the emitted light passes through the target.

Specialised transparent-object sensors can detect small changes in returned light and are designed for these applications.

A standard diffuse sensor should not automatically be expected to detect clear products reliably.

Detecting Dark Objects

Dark or matte targets reflect less light than bright targets and can reduce the sensing distance of diffuse photoelectric sensors.

Sensor selection should therefore consider the actual target rather than testing only with a convenient sample of a different colour.

What Is an Ultrasonic Sensor?

An ultrasonic sensor uses high-frequency sound waves to detect an object or measure distance.

The sensor emits an ultrasonic pulse and evaluates the returning echo from the target.

Because the sensing principle does not rely on visible light, ultrasonic sensing can be useful for targets that are difficult for optical sensors.

What Can Ultrasonic Sensors Detect?

Depending on the application, ultrasonic sensors can detect:

• Solid objects
• Liquids
• Transparent materials
• Dark objects
• Some bulk materials

Target shape, angle, surface texture, environmental conditions and sensing distance still influence performance.

Ultrasonic Sensor Applications

Typical applications include:

• Distance measurement
• Object presence
• Web or roll monitoring
• Tank level measurement in suitable applications
• Detecting transparent products
• Position monitoring

Ultrasonic Blind Zone

Ultrasonic sensors commonly have a minimum sensing distance close to the sensing face where reliable measurement is not possible.

This region is often called the blind zone.

The target must remain within the specified usable measurement range.

Temperature and Ultrasonic Measurement

The speed of sound in air changes with temperature.

Ultrasonic sensors can incorporate temperature compensation, but significant environmental variation can still affect measurement performance.

The manufacturer's specifications should be checked where high accuracy is required.

Photoelectric vs Ultrasonic Sensors

Photoelectric sensors can provide fast detection and long sensing distances, while ultrasonic sensors can be advantageous where target colour, transparency or optical characteristics create difficulties.

Neither technology is universally superior.

Selection should consider:

• Target material
• Target colour
• Transparency
• Required range
• Response time
• Environment
• Mounting geometry

What Is a Magnetic Cylinder Sensor?

Pneumatic cylinders often contain a magnet in the piston. A magnetic sensor mounted in a groove or bracket on the cylinder detects the piston as it reaches a particular position.

These sensors can provide end-of-stroke or intermediate position feedback without external mechanical limit switches.

Cylinder profile and sensor mounting compatibility should be checked carefully.

Mechanical Limit Switches

A mechanical limit switch uses physical contact to operate electrical contacts.

Although non-contact sensors are common, limit switches remain useful in industrial machinery because they can provide positive mechanical actuation and are available in many actuator styles.

Selection can involve:

• Roller lever
• Plunger
• Rotary lever
• Adjustable lever
• Contact configuration
• Environmental enclosure

Non-Contact Sensor vs Mechanical Limit Switch

A non-contact sensor avoids mechanical wear from repeated actuation and can support high cycle rates.

A mechanical switch can be useful where positive physical actuation is desired or where the target is unsuitable for a particular electronic sensing technology.

Machine design and safety requirements determine the appropriate approach.

What Is PNP?

PNP is a common transistor output configuration used by DC industrial sensors.

In a typical PNP arrangement, the sensor switches positive voltage to the PLC input when active.

The PLC input circuit must be compatible with this sourcing output arrangement.

What Is NPN?

NPN is another common transistor output configuration.

In a typical NPN arrangement, the sensor switches the output toward 0 V when active.

The receiving PLC or controller input must be compatible with this sinking output arrangement.

PNP vs NPN

PNP and NPN describe the electrical behaviour of the transistor output, not the sensing technology.

An inductive, photoelectric or ultrasonic sensor can potentially be available with either output type.

When replacing a sensor, matching the sensing function but ordering the wrong PNP/NPN output can prevent the PLC input from operating correctly.

Sourcing and Sinking

The terms sourcing and sinking describe the direction of conventional current in a DC input/output circuit.

PNP sensors are commonly described as sourcing outputs, while NPN sensors are commonly described as sinking outputs.

Terminology around PLC input modules can sometimes be confusing, so the manufacturer's wiring diagram should always be checked.

Normally Open vs Normally Closed

A sensor output can be configured or manufactured as normally open or normally closed.

For a typical normally open proximity sensor, the output becomes active when the target is detected.

For a normally closed configuration, the output is active in the normal no-target condition and changes state when the target is detected.

Some sensors provide complementary outputs or programmable switching logic.

Why NO and NC Matter

The PLC program and machine wiring expect a particular signal behaviour.

Replacing an NC sensor with an NO sensor without adjusting the control logic can invert the machine's interpretation of the condition.

The required switching function should therefore be confirmed during purchasing.

Two-Wire Sensors

Two-wire electronic sensors use the same pair of conductors for power and switched load current.

They can be useful in applications replacing mechanical switches but can have characteristics such as residual current and voltage drop that need to be compatible with the receiving input.

Two-wire DC and AC sensor variants exist, so the exact specification must be checked.

Three-Wire Sensors

Three-wire DC sensors commonly have separate supply positive, supply negative and switched output conductors.

A typical arrangement uses:

• Brown: positive supply
• Blue: 0 V
• Black: switching output

This colour convention is common but should not replace checking the wiring diagram for the exact sensor.

Four-Wire Sensors

Four-wire sensors can provide additional functionality such as complementary NO and NC outputs, teach inputs or other functions depending on the model.

Do not assume the purpose of the fourth conductor without checking the product documentation.

Sensor Supply Voltage

24 VDC is common in industrial automation, and many sensors support a DC range around this nominal voltage.

Other sensors are designed for AC supplies or wider voltage ranges.

Always verify the permitted supply voltage before replacing a sensor.

Sensor Output Current

Transistor sensor outputs have a maximum permitted load current.

A PLC digital input normally requires very little current, but directly switching larger loads such as solenoids or lamps can exceed the sensor rating.

Where necessary, an interface relay or suitable output device should be used according to the system design.

Short-Circuit Protection

Many modern electronic sensors provide output short-circuit or overload protection.

The exact protective behaviour is product-specific and should not be assumed without checking the datasheet.

What Is Sensing Distance?

Sensing distance is the distance at which the sensor can detect the specified target under defined conditions.

Nominal sensing distance should not be treated as a guaranteed operating point in every installation.

Target size, material, mounting, temperature and manufacturing tolerances can influence the reliable operating distance.

Rated Operating Distance

Industrial sensor standards and manufacturers can distinguish between nominal, effective, usable and assured operating distances.

For reliable machine design, the target should operate within the sensor's guaranteed switching region rather than exactly at its theoretical maximum distance.

Hysteresis

Hysteresis is the difference between the point where a sensor switches as a target approaches and the point where it resets as the target moves away.

This prevents unstable switching when the target sits near the detection threshold.

Repeatability

Repeatability describes how consistently a sensor switches at the same position under the same conditions.

It is particularly important in applications where the sensor contributes to repeatable machine positioning.

Repeatability should not be confused with absolute measurement accuracy.

Switching Frequency

Switching frequency indicates how rapidly a sensor can respond to repeated targets.

A sensor used to count high-speed products or gear teeth requires sufficient switching frequency for the target rate.

A sensor that works perfectly during slow manual testing can miss objects when the production line reaches full speed if its response is too slow.

Response Time

Response time is the time required for the sensor output to react to a change in target condition.

The complete control-system response also includes PLC input filtering, program scan time, communications delays and output response.

Flush vs Non-Flush Inductive Sensors

Inductive proximity sensors can have different mounting requirements.

A flush or shielded sensor can generally be mounted with its sensing face surrounded by metal according to the manufacturer's specified installation.

A non-flush or unshielded sensor typically requires free space around the sensing face but can provide a longer sensing distance for a comparable body size.

The required mounting clearances should be followed to prevent false operation or reduced range.

Mutual Interference

Sensors mounted too close to one another can sometimes interfere with each other's sensing fields or optical/acoustic signals.

Minimum spacing, synchronisation functions or different operating modes can be required depending on the sensor technology.

Sensor Body Sizes

Cylindrical proximity sensors are commonly available in metric body sizes such as M8, M12, M18 and M30.

Body diameter does not define the complete sensor specification.

Two M18 sensors can differ in sensing range, output type, mounting style, connector, supply voltage and switching function.

Rectangular Sensors

Industrial sensors are also available in rectangular and miniature housings for machine spaces where cylindrical threaded bodies are unsuitable.

Mounting hole position and sensing-face orientation can become important when replacing these products.

M8 and M12 Connectors

M8 and M12 circular connectors are widely used for industrial sensors.

They allow sensors to be replaced without rewiring field terminals and support pre-moulded cordsets and distribution boxes.

The connector size alone does not establish pinout, coding or electrical function.

M12 Connector Coding

M12 connectors are available in different coding arrangements for sensors, Ethernet, power and other industrial functions.

An M12 connector should therefore not be ordered simply by diameter.

Pin count, coding, gender and intended interface all need to match.

Pre-Wired Sensors vs Connector Sensors

A pre-wired sensor has a permanently attached cable.

A connector version uses a detachable cordset.

Connector versions can simplify replacement and machine assembly, while pre-wired versions can be convenient where a direct cable run is preferred.

Sensor Cordsets

Industrial sensor cordsets should be selected for the connector, pinout, cable length and environment.

Cable jacket materials differ in resistance to oils, chemicals, flexing and other conditions.

Repeated-motion applications can require cable specifically rated for continuous flexing.

IP Ratings

Ingress Protection ratings describe defined levels of protection against solid objects and water.

Industrial sensors commonly carry ratings such as IP65, IP67, IP68 or IP69K depending on their design and certification.

The exact meaning of the rating should be considered against the real installation conditions rather than assuming that a higher number makes a sensor suitable for every environment.

Washdown Environments

Food, beverage and other washdown applications can expose sensors to high-pressure water, cleaning chemicals and temperature cycling.

Suitable housing materials, seals, connectors and approvals can be required.

A standard machine sensor should not automatically be used in hygienic or aggressive washdown environments.

High-Temperature Applications

Electronic sensors have defined operating temperature ranges.

Applications near ovens, furnaces or hot processes can require specialised high-temperature sensors or remote sensing arrangements.

Ambient temperature at the sensor body should be considered rather than only the target temperature.

Outdoor Applications

Outdoor sensors can be exposed to sunlight, rain, condensation, temperature variation and UV radiation.

The environmental rating, housing and cable should be suitable for the installation.

Optical sensors can also be affected by intense ambient light depending on the application and design.

Oil, Coolant and Chemicals

Machine tools and industrial processes can expose sensors and cables to oils, coolants and chemicals.

Material compatibility should be checked for the sensor housing, sensing face, cable and connector.

Sensor Mounting

Correct sensor mounting is essential for reliable detection.

Installation should consider:

• Target path
• Mechanical protection
• Sensing distance
• Mounting clearances
• Vibration
• Cable routing
• Accessibility for replacement

A sensor positioned where it is repeatedly struck by the target is likely to fail regardless of its electrical specification.

Target Size

Published sensing distances are usually based on defined standard targets.

A smaller real-world target can reduce effective sensing distance.

When the target is small, narrow or irregular, confirm sensor performance for the actual geometry.

Target Speed

Fast-moving targets remain within the sensing zone for a shorter time.

The sensor response time and PLC input response must be fast enough to register the object reliably.

Detecting Products on Conveyors

Photoelectric sensors are commonly used to detect products on conveyors because they can detect many materials without contact.

The best photoelectric arrangement depends on the product.

Through-beam sensing can be highly reliable where both sides of the conveyor are accessible. Retroreflective sensing simplifies wiring. Diffuse sensing can avoid a separate reflector but depends more strongly on target reflectivity.

Counting Products

For counting applications, the sensor must reliably distinguish individual products at maximum production speed.

Consider:

• Minimum product spacing
• Conveyor speed
• Sensor response time
• PLC input filtering
• Target size
• Potential double detection

Detecting Metal Machine Position

An inductive proximity sensor is often a strong starting point where a steel machine component needs to be detected over a short distance.

It provides non-contact operation and avoids dependence on optical target colour or ambient light.

Detecting Plastic Components

Inductive sensors will not detect ordinary plastic.

Depending on the application, suitable technologies can include photoelectric, capacitive or ultrasonic sensing.

The best choice depends on distance, target size, colour, background and environment.

Detecting Liquids

Liquid presence can be detected using multiple technologies including capacitive, ultrasonic, optical and dedicated level-switch technologies.

The correct choice depends on whether the sensor contacts the liquid, whether detection is through a vessel wall, the liquid properties and whether point or continuous measurement is required.

Continuous tank measurement is covered more fully in Softcore Group Industrial Solutions's industrial instrumentation guidance.

Detecting Powders and Granules

Bulk solids can present challenges such as dust, buildup, changing density and uneven surfaces.

Capacitive, ultrasonic and specialised level technologies can be suitable depending on the material and vessel.

Actual process conditions should be considered rather than selecting by material name alone.

What Is IO-Link?

IO-Link is a standardised point-to-point digital communication technology used with compatible sensors and actuators.

An IO-Link device connects to an IO-Link master, which exchanges process data, parameters and diagnostic information with the device.

The master then communicates with the PLC through the industrial network supported by the master.

IO-Link Sensor vs Conventional Sensor

A conventional sensor can provide a simple switching or analogue signal.

An IO-Link-capable sensor can additionally provide digital data such as:

• Process value
• Device identification
• Parameters
• Diagnostics
• Status information

Many IO-Link devices can also operate in a conventional switching mode depending on the model.

Benefits of IO-Link

Potential benefits include:

• Remote parameter setting
• Additional diagnostics
• Automatic parameter restoration after replacement where supported
• Reduced manual sensor adjustment
• Additional process data
• Device identification

The value depends on the machine architecture and maintenance strategy.

IO-Link Masters

An IO-Link master provides one or more ports for IO-Link devices and interfaces them to the higher-level control system.

Masters are available for different industrial networks and mounting environments.

The PLC protocol and master network interface must therefore be compatible.

IO-Link Is Not the Same as the PLC Network

IO-Link is a device-level point-to-point connection between a field device and master.

The master might then communicate to the PLC using PROFINET, EtherNet/IP, EtherCAT or another supported industrial network.

These are different communication layers.

Sensor Diagnostics

Traditional discrete sensors provide limited information beyond ON or OFF.

Smart sensors can provide additional diagnostics such as signal quality, contamination warnings, device temperature or operating status depending on the product.

This information can support predictive maintenance and troubleshooting.

Teach Functions

Some photoelectric, ultrasonic and smart sensors provide teach functions that allow the switching point or detection conditions to be configured for the application.

Teaching can be performed using buttons, a teach wire or digital configuration depending on the sensor.

The commissioning procedure should follow the manufacturer instructions.

Adjustable Sensitivity

Some sensors allow sensitivity or sensing range to be adjusted.

Setting sensitivity excessively high can cause background objects or buildup to be detected, while setting it too low can cause unreliable target detection.

The sensor should be adjusted using the actual target and operating environment.

Light-On vs Dark-On

Photoelectric sensor switching behaviour can be described as light-on or dark-on.

These terms refer to whether the output is active when the receiver sees sufficient light or when the light path is interrupted.

The relationship to NO and NC terminology can depend on the sensor and application, so the exact output logic should be checked.

Sensor LEDs

Many sensors include status LEDs for power, output and sometimes signal quality.

These indicators are useful during installation and troubleshooting but should be interpreted according to the product documentation.

Sensor Integration With PLCs

Discrete sensors commonly connect to PLC digital input modules.

A typical path is:

Target → Sensor → PLC digital input → Control logic

The sensor voltage, PNP/NPN output and input-module characteristics must be compatible.

Sensor Integration With Remote I/O

Remote I/O allows sensors to connect near the machine or process and sends their states back to the PLC over an industrial network.

This can reduce large bundles of individual field cables returning to a central panel.

The remote I/O module must still support the electrical sensor type.

Sensor Distribution Boxes

Passive sensor distribution boxes can collect multiple M8 or M12 sensor connections into a multicore home-run cable.

Active field I/O blocks can instead convert sensor signals into industrial network data near the machine.

These approaches can simplify machine wiring when selected appropriately.

Replacing an Existing Sensor

The safest starting point for a failed sensor is the exact manufacturer and model number.

If an exact replacement is unavailable, identify:

• Sensing technology
• Body size
• Sensing distance
• Flush or non-flush mounting
• Supply voltage
• PNP or NPN output
• NO, NC or complementary output
• Number of wires
• Cable or connector type
• Connector pinout
• Switching frequency
• Environmental rating

A physically identical-looking sensor can have completely different electrical behaviour.

Do Not Replace Sensors by Appearance Alone

M12 and M18 cylindrical sensors from different product families can look nearly identical.

One may be PNP normally open with a 4 mm sensing range while another is NPN normally closed with an 8 mm range.

The nameplate or part number is therefore far more useful than appearance alone.

Common Industrial Sensor Selection Mistakes

• Ordering an inductive sensor for a non-metallic target
• Matching only the sensor body diameter
• Ordering NPN when the PLC requires PNP
• Ordering NO when the machine expects NC
• Ignoring sensing distance
• Ignoring flush vs non-flush mounting
• Assuming nominal sensing distance is guaranteed for every target material
• Using a diffuse photoelectric sensor without considering target colour
• Using a standard photoelectric sensor for transparent products without testing suitability
• Ignoring response time in high-speed counting
• Ordering the correct M12 connector size with the wrong pinout or coding
• Ignoring cable material in oil or continuous-flex applications
• Ignoring environmental and washdown requirements
• Assuming IO-Link connects directly to an ordinary PLC digital input as a communication network
• Replacing a sensor by appearance instead of part number and specification

A Practical Planning Checklist

For an accurate sensor quotation, provide as much of the following information as possible:

• Application: ___
• What needs to be detected? ___
• Target material: metal, plastic, glass, liquid, powder or other
• Target colour/finish if optical: ___
• Required sensing distance: ___ mm
• Sensor technology if known: inductive, capacitive, photoelectric, ultrasonic, magnetic or other
• Body style/size: M8, M12, M18, M30, rectangular or other
• Flush or non-flush mounting: ___
• Supply voltage: ___
• Output: PNP, NPN, relay, analogue, IO-Link or unknown
• Switching function: NO, NC, complementary or programmable
• Number of wires: ___
• Connection: fixed cable, M8, M12 or other
• Cable length: ___
• Required switching speed: ___
• Operating temperature: ___
• Environment: indoor, outdoor, dusty, wet, washdown, oily or other
• Required IP rating: ___
• PLC/remote I/O model if relevant: ___
• Existing manufacturer: ___
• Existing model number: ___
• Quantity: ___

For replacement enquiries, clear photographs of the sensor label, connector, sensing face and installed mounting arrangement can help identify a suitable replacement.

How Sensors Fit Into a Complete Automation System

Sensors form the field-detection layer of industrial automation. They tell the control system what is happening physically on the machine or process.

A simple automation path can look like:

Target or process condition → Sensor → PLC or remote I/O → Control logic → Output device

The output device might then be a contactor, solenoid valve, VSD, servo system, alarm or another machine function.

Sensors therefore connect directly with many of the technologies covered elsewhere in Softcore Group Industrial Solutions's Knowledge Centre, including PLCs, remote I/O, industrial communications, VSDs, servo drives and process instrumentation.

Products listed in our active online catalogue can be purchased or quoted through the Softcore Group Industrial Solutions store. Other brands, models and project-specific sensor requirements can be quoted on request, with pricing, availability and lead time confirmed separately.

For replacement enquiries, provide the existing sensor manufacturer and exact model number wherever possible. For new applications, information about the target, sensing distance, required output, environment, mounting and PLC interface helps narrow the appropriate sensing technology before quotation.

Technical Note

This article provides general industrial automation information. Sensor selection, machine design, wiring, environmental suitability, functional safety and control-system configuration must be assessed for the specific application. Manufacturer documentation, applicable standards, machine risk assessments and site requirements take precedence. Sensors used for safety-related functions require appropriately rated safety devices and safety-system design rather than ordinary automation sensors unless specifically certified and applied for that purpose.

Related catalogue examples: PLCs & Programmable Controllers. For an equipment enquiry, contact Softcore Group Industrial Solutions at info@softcoregroup.co.za.