Modern factories generate an enormous amount of operational information. Every machine may have dozens of sensors, alarms, control parameters and production states. Although much of this information is displayed on control panels and human-machine interfaces, operators still need a fast and simple way to understand what is happening across the production floor.

C'est là que feux de cheminée play an important role.

Stack lights transform machine signals into highly visible colored indications. A green light may show that a machine is operating normally, a yellow light may indicate that attention is required, and a red light may warn that production has stopped. Additional colors and audible modules can communicate material requests, maintenance calls, quality inspections and other production conditions.

Because stack lights are easy to recognize from a distance, they are widely used on CNC machines, packaging equipment, robotic cells, conveyors, assembly stations, testing systems and industrial control panels.

However, selecting the right industrial stack light involves more than choosing a few colors. Machine builders must consider the number of layers, operating voltage, visibility distance, mounting method, light mode, environmental protection and audible alarm requirements.

This guide explains how industrial stack lights work, what their colors commonly mean and how to choose an appropriate LED signal tower for an industrial application.

Qu'est-ce qu'un feu de cheminée ?

A stack light is an industrial signaling device made from one or more illuminated modules arranged vertically. Each module usually has a different color and can be activated independently.

A traditional stack light may include three sections:

• Rouge
• Jaune ou ambre
• Vert

More advanced signal towers may include blue, white or clear modules. Some models also contain an audible buzzer or alarm module at the top of the tower.

Each section is connected to a control system such as:

• A programmable logic controller
• A relay output
• A push button
• A limit switch
• A machine sensor
• An industrial computer
• An Andon call station
• A production monitoring system

When the condition of the machine changes, the controller activates the corresponding light module.

For example, a packaging machine may activate the green module during normal production. When packaging material becomes low, the yellow module may turn on. If the machine detects a serious fault, the red module and buzzer may be activated.

This simple communication method allows employees to recognize equipment conditions without approaching the machine or reading a control panel.

Different Names Used for Stack Lights

Stack lights are known by several names depending on the manufacturer, industry and country.

Common terms include:

• Feux de signalisation
• Feux de signalisation industriels
• Feux lumineux en colonne
• Feux de signalisation empilables
• Voyants d'état de la machine
• Indicator tower lights
• Feux Andon
• Warning tower lights
• Feux de signalisation industriels
• Machine signal towers

The words stacklight, stacklights et stack light are also used interchangeably.

Although these terms may describe slightly different product configurations, they generally refer to the same type of industrial signaling device: a vertical tower that communicates machine or process conditions through colored lights.

An Andon light is usually a stack light used as part of a visual management system. In this type of application, an operator can activate a specific light to request maintenance, materials, supervision or quality support.

A machine status light, on the other hand, may operate automatically according to signals generated by the machine controller.

The hardware can be similar, but the operational purpose may be different.

Pourquoi les feux lumineux industriels sont-ils importants ?

Industrial facilities are often large, noisy and visually complex environments. Employees may supervise several machines at the same time, and maintenance personnel may be responsible for equipment located across multiple production areas.

Without a clear visual signaling system, employees must repeatedly approach each machine to determine whether it is running, waiting or experiencing a fault.

Industrial stack lights help reduce this problem by making basic machine information visible from a distance.

Faster Recognition of Machine Faults

A red or flashing stack light helps maintenance personnel locate stopped equipment quickly.

Instead of checking every machine individually, a technician can identify the affected machine by looking across the production floor.

Improved Production Visibility

Supervisors can use signal tower lights to understand the general condition of a production area.

A line with mostly green lights may be operating normally, while several yellow or red lights may indicate delays, shortages or technical problems.

Clearer Communication

Stack lights create a shared visual language between operators, technicians and supervisors.

When the color meanings are standardized, employees can understand equipment conditions without requiring detailed explanations.

Reduced Unnecessary Movement

Operators do not need to walk to every control panel to check the basic status of a machine.

This can be particularly useful in facilities where one employee monitors multiple machines.

Better Maintenance Response

A blue or white light can be assigned to maintenance, material or quality requests.

The signal allows support teams to identify where assistance is needed.

Support for Visual Management

Stack lights are commonly used in Lean Manufacturing and Andon systems because they make abnormalities visible at the point where they occur.

The light itself does not solve the problem, but it initiates a communication and response process.

How Does a Stack Light Work?

The operating principle of a stack light is relatively simple.

Each light module contains an LED circuit or another light source. The modules receive electrical signals from the machine controller.

A typical wired stack light may contain:

• One common connection
• One wire for the red module
• One wire for the yellow module
• One wire for the green module
• Additional wires for blue or white modules
• One wire for the audible alarm

When voltage is applied to a specific control wire, the corresponding light turns on.

Depending on the product design, the stack light may use:

• Common-positive wiring
• Common-negative wiring
• Relay contact control
• PNP transistor outputs
• NPN transistor outputs
• AC control voltage
• DC control voltage
• Multipin connectors
• M12 industrial connectors

Some stack lights include built-in flashing or strobe circuits. Other models depend on the PLC program to create the flashing pattern.

Modular stack lights may allow light modules to be added, removed or rearranged. Fixed stack lights are supplied with a predefined number and order of layers.

Stack Light Color Meaning

One of the most common questions about industrial signal towers is: What do stack light colors mean?

There is no universal color arrangement that automatically applies to every machine. The machine manufacturer and facility operator must define the meaning of each color according to the application, risk assessment and relevant standards.

IEC 60073 provides general coding principles for indicators and actuators, including visual, acoustic and tactile indications. It is intended to support recognition, monitoring, control and maintenance of equipment and processes.

Nevertheless, several common color conventions are widely used.

Red Stack Light

Red normally communicates a serious, dangerous or abnormal condition.

Typical meanings include:

• Machine fault
• Emergency condition
• Safety circuit activation
• Production stopped
• Critical process alarm
• Guard open
• Excessive temperature
• Motor overload

A red light may be steady or flashing. Flashing red is often used to attract greater attention, but its meaning should be clearly documented.

Yellow or Amber Stack Light

Yellow generally indicates a warning, developing problem or condition requiring attention.

Typical examples include:

• Les stocks de matériel sont presque épuisés
• Machine waiting
• Maintenance approaching
• Temperature increasing
• Production delay
• Minor fault
• Manual intervention required
• Setup or changeover condition

A yellow condition may not require an immediate stop, but it usually indicates that action should be taken before the condition becomes more serious.

Green Stack Light

Green commonly indicates a normal, safe or satisfactory operating condition.

Typical meanings include:

• Machine running normally
• Equipment ready
• Automatic operation active
• Production cycle in progress
• System available
• Normal process condition

A steady green light is one of the most frequently used signals on industrial machinery.

Blue Stack Light

Blue often indicates that a specific action is required.

Common uses include:

• Maintenance requested
• Operator assistance required
• Material replenishment requested
• Supervisor requested
• Mandatory action
• Technical support call

In an Andon system, blue may be assigned to maintenance or material handling personnel.

White or Clear Stack Light

White is commonly used for neutral or user-defined information.

Typical examples include:

• Quality inspection required
• Machine setup mode
• Cleaning process active
• Product changeover
• Custom production condition
• General information
• Communication active

Because white has fewer universally recognized industrial meanings, its purpose should be explained clearly to personnel.

Creating a Standard Color Policy

The effectiveness of stack lights depends on consistency.

If red means “machine fault” on one production line but “material required” on another, employees may hesitate or respond incorrectly.

A factory-wide signal tower policy should define:

• La signification de chaque couleur
• Whether the light is steady or flashing
• Si plusieurs couleurs peuvent fonctionner simultanément
• When the audible alarm is activated
• Qui est chargé d'y répondre ?
• How the condition is acknowledged
• Comment le signal est réinitialisé
• How the event is recorded

The goal is not simply to install more lights. The goal is to create a visual language that employees can understand immediately.

How Many Stack Light Layers Are Needed?

Industrial stack lights are commonly available with one to five illuminated layers.

The correct number of layers depends on how many separate conditions must be communicated.

Feux d'alerte à une rangée

A one-layer stack light is appropriate when only one important condition needs to be displayed.

For example:

• Red for machine fault
• Green for equipment available
• Yellow for attention required
• Blue for assistance requested

One-layer stack lights are often used on compact machinery, laboratory equipment, control panels and test systems.

They may also be used as simple warning indicators where a traditional signal beacon would otherwise be installed.

Feux d'avertissement à deux rangées

A two-layer stack light can communicate two major conditions.

Common combinations include:

• Vert pour « en marche » et rouge pour « à l'arrêt »
• Green for available and yellow for waiting
• Yellow for warning and red for critical alarm
• Blue for assistance and red for fault

Two-layer configurations are useful when space is limited or when the machine has a simple operating sequence.

Feux d'alerte à trois niveaux

The red-yellow-green configuration is one of the most widely recognized industrial signal arrangements.

A typical three-layer stack light may represent:

• Green: normal operation
• Yellow: warning or waiting
• Red: fault or stop

Three-layer signal towers are commonly installed on:

• CNC machines
• Packaging equipment
• Conveyors
• Assembly machines
• Robotic cells
• Filling machines
• Production test systems

For many standard industrial machines, a three-layer tower provides enough information without creating unnecessary complexity.

Feux d'alerte à quatre rangées

A fourth layer allows the machine to display an additional condition.

For example:

• Red: machine stopped
• Yellow: warning
• Green: machine running
• Blue: maintenance requested

Another configuration may use white for quality inspection or setup mode.

Four-layer stack lights are frequently used in Andon systems and production cells where employees need to distinguish between machine status and assistance requests.

Feux d'alerte à cinq rangées

Five-layer stack lights provide the greatest number of independently controlled visual states.

A five-color arrangement may include:

• Rouge
• Jaune
• Vert
• Bleu
• Blanc

These systems are suitable for complex machinery and production lines with several different support or operating conditions.

However, adding more colors does not automatically improve communication. Each color should have a clear purpose.

If employees cannot remember the meanings, the signal tower becomes confusing rather than helpful.

Modular Stack Lights vs Fixed Stack Lights

Stack lights can be divided into two general construction types: modular and fixed.

Lampes à pile modulaire

A modular stack light is assembled from separate components.

These may include:

• Light modules
• Audible modules
• Base units
• Extension tubes
• Connection modules
• Wall brackets
• Foldable mounting bases
• Connector components

A modular system allows machine builders to create different configurations using a common product family.

For example, one machine may require red, yellow and green, while another may require red, green, blue and an audible buzzer.

Modular stack lights are particularly useful when:

• Different machines require different colors
• Une expansion future est prévue
• Individual modules may need replacement
• Spare-part standardization is important
• Multiple mounting methods are required
• The same design platform will be used globally

Machine manufacturers and system integrators can explore a broad range of industrial stack lights that includes modular products, standard tower lights and Andon configurations. Mucco’s category currently includes modular stack light and Andon-related product groups for industrial applications.

Fixed Stack Lights

Fixed or preconfigured stack lights are supplied with a predefined number of layers and color arrangement.

These products can be suitable when:

• The machine design is standardized
• The color sequence will not change
• A straightforward product selection is preferred
• Large numbers of identical machines are produced
• Future reconfiguration is unlikely

Fixed stack lights may reduce configuration decisions for repetitive production projects.

The best option depends on the machine lifecycle. Modular products provide flexibility, while fixed products provide simplicity.

LED Stack Lights and Their Advantages

Most modern industrial stack lights use LED technology.

LED stack lights offer several practical advantages compared with older incandescent signaling products.

Long Operating Life

Industrial machines may operate for thousands of hours each year. LEDs can reduce the need for routine lamp replacement, especially when the stack light is mounted high above the machine.

Low Power Consumption

LED modules generally require relatively little electrical power, making them suitable for PLC-controlled and low-voltage systems.

Fast Response

LEDs switch on and off quickly. This is useful for flashing, pulsed and strobe-style signals.

Strong Color Visibility

LEDs can generate clear, saturated colors without relying only on colored lenses.

Resistance to Frequent Switching

Unlike some older light sources, LEDs are well suited to applications involving repeated on-and-off cycles.

Compact Construction

LED technology allows manufacturers to produce compact signal towers with high visibility.

Steady, Flashing, Rotary and Strobe Modes

Stack lights can provide different visual signaling modes.

The correct mode depends on the urgency and duration of the condition.

Steady Light

A steady light is suitable for stable machine states such as:

• Running
• Ready
• Waiting
• Setup mode
• Maintenance request

Steady lights are easy to understand and create less visual distraction.

Flashing Light

A flashing light attracts more attention than a steady light.

It may be used for:

• Developing faults
• Material shortages
• Process warnings
• Operator requests
• Temporary abnormal conditions

The flashing frequency should be selected carefully. Several different flashing rates operating in the same area can become confusing.

Strobe Light

Strobe effects are highly noticeable and are generally reserved for conditions that require urgent attention.

They should not be used for every routine event because excessive strobing can reduce the perceived importance of the signal.

Rotary-Style Light

Some LED stack lights simulate the appearance of a rotating beacon without using a mechanical motor.

This effect can provide a recognizable warning pattern while benefiting from LED construction.

Stack Lights With Sound

Visual signals only work when someone can see them.

In a large factory, an employee may be facing away from the machine, working behind an enclosure or moving between several production areas.

A stack light with sound combines a visual signal with an audible alarm.

Audible modules are commonly used for:

• Critical machine faults
• Cycle-complete notifications
• Material requests
• Maintenance calls
• Process timeouts
• Operator assistance
• Production line stops

Selecting the Correct Sound Level

The audible signal must be evaluated against the background noise of the installation area.

A buzzer that is clearly audible in a quiet workshop may be difficult to hear beside compressors, presses or machining equipment.

However, unnecessarily loud alarms can create discomfort and alarm fatigue.

Machine designers should consider:

• Ambient sound level
• Distance from the operator
• Number of machines in the area
• Duration of the alarm
• Continuous or intermittent sound
• Tone frequency
• Whether personnel can identify the source
• Whether acknowledgment is available

In extremely noisy environments, a separate industrial horn or siren may be more suitable than a small integrated buzzer.

Choosing the Correct Voltage

Stack lights are available with several operating voltage options.

Common voltage ranges include:

• 12V DC
• 12–24V AC/DC
• 24V DC
• 24V AC
• 48V
• 110V AC
• 120V AC
• 220V AC
• 230V AC
• Wide-range AC/DC inputs

24V Stack Lights

A 24V stack light is a common choice for industrial automation because many PLCs, sensors and control systems operate at 24V DC.

A 24V DC signal tower may be suitable when:

• The control cabinet includes a 24V power supply
• The PLC uses 24V transistor outputs
• The machine has low-voltage control wiring
• Direct PLC integration is required
• The builder wants a common industrial control voltage

Before connecting the tower directly to a PLC output, verify the current consumption and output capacity.

Mains-Voltage Stack Lights

110V, 120V, 220V and 230V stack lights may be used when the machine control circuit is based on mains-voltage relay outputs.

They may also be useful for retrofit installations where a low-voltage supply is not available near the signal tower.

However, installation and servicing must be performed by qualified personnel, and all wiring components must be rated for the selected voltage.

Wide-Range Stack Lights

A wide-range input can simplify inventory for machine builders exporting equipment to multiple countries.

For example, a product supporting a broad AC/DC voltage range may reduce the need to purchase separate stack light models for every destination.

The exact input range, current consumption and connection method must always be confirmed in the product documentation.

Mounting Options

The position of a stack light is as important as its brightness.

A signal tower should be visible from the locations where operators, technicians and supervisors normally work.

Direct Surface Mounting

The stack light is mounted directly on top of the machine or control cabinet.

This provides a compact installation and is suitable when the mounting surface is already high and clearly visible.

Extension Tube Mounting

An extension tube raises the signal tower above the machine.

This is useful when:

• Machine guards block visibility
• The cabinet is low
• The signal must be seen across a large area
• Nearby equipment may obstruct the view

Different extension lengths can be selected according to machine height.

Wall Mounting

A wall bracket allows the tower to be installed on the side of a cabinet, column or machine frame.

Wall mounting is useful when there is no suitable horizontal surface.

Foldable-Base Mounting

A foldable base may help protect the stack light during machine transportation.

It can also reduce the risk of damage in areas where the tower may be hit by equipment or materials.

Environmental Protection

Industrial environments can expose stack lights to dust, moisture, vibration, oil mist, cleaning chemicals and temperature changes.

Before selecting a product, evaluate:

• Required IP protection
• Indoor or outdoor use
• Ambient temperature
• Humidity
• Water spray
• Dust concentration
• Chemical exposure
• UV exposure
• Mechanical vibration
• Risk of impact

The product’s IP rating should be reviewed according to the actual installation conditions.

A stack light installed inside a clean control room does not require the same protection as a product mounted on food-processing machinery or outdoor equipment.

Common Industrial Applications

CNC and Machine Tools

CNC machines use stack lights to indicate:

• Cycle running
• Program complete
• Tool change required
• Machine waiting
• Alarm condition
• Guard open
• Maintenance required

A technician can identify a stopped CNC machine without checking every control screen.

Packaging Machinery

Packaging lines may use signal towers for:

• Low packaging material
• Conveyor jam
• Product rejection
• Batch complete
• Guard fault
• Emergency stop
• Operator assistance

Audible alarms can be added when immediate action is required.

Robotic Cells

Robot cells can display:

• Automatic mode
• Manual mode
• Robot running
• Cycle paused
• Safety stop
• Fault condition
• Setup in progress

The color logic should be integrated into the overall safety and operating documentation.

Systèmes de convoyage

Conveyor stack lights may indicate:

• Running
• Stopped
• Blocked
• Overloaded
• Waiting for product
• Emergency condition

Signal towers positioned along long conveyor lines can help maintenance teams locate problems quickly.

Assembly Stations

Assembly stations commonly use Andon lights.

Operators can request:

• New materials
• Maintenance support
• Quality inspection
• Supervisor assistance
• Tool replacement

The call may be activated using buttons, switches or production software.

Injection Molding Machines

Stack lights may communicate:

• Heating
• Machine ready
• Production cycle
• Cooling
• Material shortage
• Mold fault
• Alarm condition

Warehouses and Logistics

Warehouses can use signal tower lights on:

• Sorting systems
• Picking stations
• Automated storage systems
• Loading areas
• Pallet handling equipment
• Inspection stations

Testing and Laboratory Equipment

Compact or miniature stack lights can display the status of:

• Electrical test equipment
• Quality control systems
• Environmental chambers
• Laboratory instruments
• Product inspection machines

Stack Lights in Andon Systems

The term Andon comes from visual management practices associated with production systems.

An Andon system makes abnormalities visible and allows employees to request help without leaving their workstation.

A basic Andon tower may use:

• Green for normal production
• Yellow for developing problems
• Red for stopped production
• Blue for material or maintenance requests
• White for quality support

The success of an Andon system depends on more than the light itself.

A complete response process should define:

• Who receives the signal
• How quickly they should respond
• Which department is responsible
• When production should stop
• How the issue is escalated
• How the signal is acknowledged
• How the root cause is recorded
• How recurring problems are reviewed

Without a response procedure, employees may eventually ignore the lights.

Stack Lights and Industry 4.0

Stack lights are relatively simple devices, but they can support modern production monitoring.

The same PLC outputs used to control a signal tower can also be recorded in a database.

This allows factories to analyze:

• Machine operating time
• Waiting time
• Fault duration
• Maintenance response
• Material shortages
• Production interruptions
• Frequency of Andon calls

Older machines may not include a modern communication interface, but their operating status is often already represented by signal lights.

Research has explored the use of camera systems to detect and classify industrial signal lights on factory floors. One published study demonstrated more than 99% accuracy under its specified test conditions, while noting that broader data would be needed for reliable generalization.

This approach can help connect older machines to digital monitoring systems without modifying every internal control circuit.

The tower light continues to provide information to employees while the monitoring system records machine status for analysis.

How to Choose the Right Industrial Stack Light

Use the following process when selecting a stack light.

1. Define the Required Machine States

List the conditions that need to be communicated.

Examples include:

• Running
• Ready
• Waiting
• Warning
• Fault
• Material required
• Maintenance required
• Quality inspection
• Setup mode

2. Assign a Meaning to Each Color

Create a consistent color policy.

Avoid using the same color for unrelated conditions on different machines.

3. Select the Number of Layers

Choose one to five layers according to the number of necessary conditions.

Do not add unnecessary colors.

4. Choose Modular or Fixed Construction

Select modular stack lights when flexibility, replaceable components and future expansion are important.

Choose fixed configurations for standardized machine designs.

5. Confirm the Supply Voltage

Verify:

• AC or DC
• Nominal voltage
• Permitted voltage range
• Current consumption
• Polarity
• PLC output compatibility
• Need for an interface relay

6. Select the Light Mode

Determine whether each condition requires:

• Steady light
• Flashing light
• Strobe effect
• Rotary-style effect

Use high-attention modes only when necessary.

7. Evaluate Audible Requirements

Determine whether employees can always see the tower.

If not, consider an integrated buzzer or separate warning horn.

8. Select the Mounting Method

Consider:

• Machine height
• Viewing distance
• Obstructions
• Available mounting surfaces
• Risk of impact
• Transportation requirements

9. Review Environmental Conditions

Check the IP rating, temperature range, material construction and resistance to environmental exposure.

10. Review Documentation

Before purchasing, examine:

• Datasheet
• Wiring diagram
• Mechanical dimensions
• Certifications
• Current consumption
• Voltage specifications
• Connector pinout
• Mounting instructions

Common Stack Light Selection Mistakes

Using Too Many Colors

A five-layer tower is not automatically better than a three-layer tower.

Too many colors can make the system difficult to understand.

Inconsistent Color Meanings

Using different meanings for the same color creates confusion.

Standardize the color logic across similar equipment.

Poor Mounting Location

A bright stack light provides little value when it is hidden behind a machine guard or storage rack.

Check visibility from actual working positions.

Incorrect Voltage Selection

Choosing a product based only on appearance can result in electrical incompatibility.

Always verify the voltage and output type.

Ignoring Ambient Noise

An integrated buzzer may not be loud enough for every environment.

Evaluate the real background noise level.

Treating Stack Lights as Machine Guards

Stack lights communicate conditions but do not normally prevent access to hazards.

They do not replace physical guards, interlocks, emergency-stop circuits or lockout procedures. OSHA’s machine-guarding guidance addresses the need to protect workers from hazardous machine motions and actions.

Failing to Define a Response Process

A warning light has limited value when nobody knows who should respond.

Assign responsibilities for each signal condition.

Maintenance and Inspection

Stack lights should be included in routine machine inspections.

Recommended checks include:

• Confirming that every color operates
• Testing the audible module
• Inspecting the lens for dirt or damage
• Checking mounting hardware
• Inspecting cables and connectors
• Confirming the tower remains visible
• Reviewing the color labels
• Checking for water or chemical damage
• Testing the PLC output logic
• Verifying that employees understand the signals

Even long-life LED products can become less effective if the lenses are covered with dust or the tower is moved behind new equipment.

Conclusion

Industrial stack lights remain one of the simplest and most effective ways to communicate machine status.

They convert control signals into information that operators, maintenance personnel and supervisors can understand from a distance.

A properly selected stack light can help facilities:

• Identify faults more quickly
• Improve production visibility
• Support Andon systems
• Standardize machine communication
• Reduce unnecessary movement
• Improve maintenance response
• Connect visual management with digital monitoring

The right configuration depends on the application.

A compact one-layer light may be sufficient for a test station, while a three-layer red-yellow-green stack light may suit a standard production machine. Complex assembly cells may require four or five layers, modular construction and an audible alarm.

Before choosing a product, define the machine states, assign consistent color meanings, confirm the operating voltage and evaluate mounting, visibility and environmental conditions.

Machine builders, automation companies and industrial facilities can review the Mucco modular stack light range to compare different layer configurations, mounting styles and industrial signaling options.

A stack light is a relatively small component, but when it is integrated into a clear response system, it can become an important part of factory communication and operational visibility.

Foire aux questions

Qu'est-ce qu'un feu à colonnes ?

A stack light is an industrial signaling device that uses vertically arranged colored modules to communicate machine or process conditions.

What is another name for a stack light?

Stack lights are also called signal tower lights, Andon lights, machine status lights, indicator towers and industrial tower lights.

Que signifient les couleurs des barres lumineuses ?

Red generally indicates a fault or serious condition, yellow indicates warning or attention, green indicates normal operation, blue indicates an action request and white is commonly used for custom information.

What is the most common stack light configuration?

A three-layer red-yellow-green tower is one of the most common configurations used on industrial machinery.

What is a modular stack light?

A modular stack light is assembled from separate light, buzzer, base and mounting components. The configuration can be adapted to the application.

Can stack lights connect directly to a PLC?

Many stack lights can be controlled by PLC outputs, but voltage, current, polarity and output type must be verified.

What voltage do industrial stack lights use?

Common options include 12V, 24V, 48V, 110V, 120V, 220V and 230V. Wide-range AC/DC models are also available.

Can a stack light include sound?

Yes. Many models offer an integrated buzzer or audible alarm module.

What is the difference between an Andon light and a stack light?

A stack light is the signaling device. An Andon light is normally a stack light used within a structured visual management and assistance-request system.

Are stack lights safety devices?

Stack lights can improve awareness, but they generally do not replace machine guards, safety interlocks, emergency-stop circuits or other required safety controls.

How many stack light layers should I choose?

Choose only the number of layers required to communicate clearly defined conditions. Most applications use between one and five layers.

Where should a stack light be mounted?

It should be mounted where it remains visible from the required operator and maintenance positions without being easily damaged.

Should I choose a flashing or steady stack light?

Use steady light for stable conditions and flashing or strobe modes for events that require increased attention.

What industries use stack lights?

They are used in automotive, packaging, food processing, logistics, electronics, metalworking, pharmaceuticals, robotics, warehousing and many other industrial sectors.

How often should stack lights be inspected?

They should be checked as part of the machine’s routine preventive maintenance and safety inspection schedule.