Introduction
When looking at a conveyor system, most of the equipment is easy to see.
There are rollers, belts, motors, frames and the products moving from one area to another.
What is less visible is the system controlling how all of those components work together.
A conveyor control system manages the operation of a powered conveyor, using components such as sensors, programmable logic controllers (PLCs) and motor controls to determine when and how products should move.
Depending on the application, controls can be relatively straightforward or form part of a much larger automated warehouse system.
So, what does a conveyor control system actually do, and when does a conveyor need one?
What Is a Conveyor Control System?
A conveyor control system is the combination of electrical hardware and programming used to control the operation of a powered conveyor system.
At its simplest, this could involve starting and stopping a conveyor.
In a more advanced system, the controls may manage multiple conveyor sections, detect products, control accumulation, communicate with other equipment and respond automatically to different operating conditions.
A typical conveyor control system can include:
- PLCs
- Sensors
- Motor controls
- Variable speed drives
- Emergency stops
- Operator controls
- Human-machine interfaces (HMIs)
- Electrical control panels
These components work together to turn a physical conveyor layout into a controlled material handling process.
Why Can’t a Powered Conveyor Just Run Continuously?
For some simple applications, a conveyor may operate continuously.
However, this is not always the most practical way to move products.
Imagine a conveyor connecting several areas of a warehouse.
If the downstream process temporarily stops but the conveyor continues delivering products, cartons could begin building up at the end of the line.
Similarly, there may be no reason to run every section of conveyor when there are no products present.
A conveyor control system allows the equipment to respond to what is actually happening within the operation.
Instead of simply moving constantly, different parts of the system can start, stop or react according to product flow and operational requirements.
How Do Conveyor Systems Know Where Products Are?
Sensors are an important part of many conveyor control systems.
They can be positioned at different points along the conveyor to detect whether a product is present.
For example, a sensor may detect a carton entering a conveyor zone and send that information to the control system.
The PLC can then use that signal to determine what should happen next.
Depending on the system, this might mean:
- Starting a conveyor section
- Stopping a product
- Releasing the next product
- Preventing another carton entering an occupied zone
- Activating another piece of equipment
This allows the conveyor to respond automatically as products move through the system.
What Does a PLC Do on a Conveyor?
A programmable logic controller, or PLC, can be thought of as one of the main decision-making components within a conveyor control system.
It receives information from devices such as sensors and uses programmed logic to determine what the conveyor should do.
For example:
A sensor detects that a carton has reached a particular position.
The PLC receives that signal.
Based on its programming, it may tell a motor to stop, start another conveyor section or wait until the next area becomes available.
This process happens automatically and repeatedly as products move through the conveyor system.
The complexity of the PLC programming depends on the application. A relatively straightforward conveyor may only require simple control logic, while a larger automated system can involve many different inputs, outputs and operating conditions.
What Is Conveyor Zoning?
Rather than treating an entire conveyor line as one continuous system, powered conveyors can be divided into individual sections or zones.
Each zone can then be controlled separately.
For example, if a carton enters an empty zone, the conveyor can move it forwards. If the next zone is already occupied, the carton can be held until space becomes available.
Once the downstream product moves away, the next carton can be released.
This allows products to accumulate along the conveyor in a controlled way rather than simply running into one another.
Zoning can be particularly useful where products need to queue before packing, processing, sorting or another automated stage. Typically these zoned sections use 24-volt motor rollers, one on each zone. This design of roller conveyor system is typically referred to a zero line pressure (ZLP) accumulation.
Can Conveyor Controls Prevent Product Build-Up?
They can help manage it.
Product accumulation is common in operations where different processes run at different speeds.
For example, products may arrive faster than operators can pack them, or one piece of equipment may temporarily stop while the rest of the system remains operational.
Without suitable control, products could continue moving towards the blocked area.
A controlled conveyor can respond by holding products further upstream.
This creates a managed buffer within the system and helps prevent uncontrolled build-up at a single point.
Once the downstream process becomes available again, products can continue moving.
Can Conveyor Controls Change the Speed of a Conveyor?
Depending on the system, yes.
Variable speed drives can be used to control motor speed, allowing conveyor speed to be adjusted for the application.
This can be useful where different parts of a process require different product speeds.
However, faster is not always better.
The correct conveyor speed should reflect factors such as:
- Product type
- Required throughput
- Operator interaction
- Transfer points
- Downstream equipment
- Safety requirements
A well-designed control system focuses on maintaining appropriate product flow rather than simply running every conveyor as quickly as possible.
What Is an HMI?
An HMI, or human-machine interface, provides operators with a way to interact with the conveyor control system.
This will often take the form of a touchscreen or control panel.
Depending on the system, an HMI may allow operators to:
- Start and stop equipment
- Select operating modes
- View conveyor status
- Identify faults
- Monitor sensors
- Reset certain alarms
- View different areas of the system
The aim is to make the automation easier to understand and operate.
Rather than requiring employees to understand the underlying PLC programming, the HMI presents relevant information in a more accessible format.
What Happens When Something Goes Wrong?
Controls are also important for identifying faults.
If a sensor does not detect an expected product, a motor develops a fault or another part of the system stops responding correctly, the conveyor control system can detect certain conditions and respond accordingly.
Depending on the system, it may:
- Stop the affected conveyor
- Prevent additional products entering the area
- Display an alarm
- Identify the affected zone
- Provide information through the HMI
This can make troubleshooting easier because operators or maintenance teams have more information about where the issue has occurred.
Rather than simply knowing that “the conveyor has stopped”, they may be able to identify which part of the system requires attention.
How Do Conveyor Controls Support Safety?
Safety is another important part of conveyor control design.
Powered conveyor systems may incorporate devices such as:
- Emergency stops
- Safety switches
- Guards
- Interlocks
- Safety sensors
If an emergency stop is activated, for example, the control system should respond according to the system’s designed safety function.
The precise safety requirements will depend on the conveyor, application and surrounding environment.
Safety should therefore be considered as part of the complete system design rather than added after the conveyor has been installed.
Can Conveyor Controls Connect to Other Equipment?
Yes, and this is where conveyor controls become particularly important within wider warehouse automation.
A conveyor may need to interact with:
- Packaging equipment
- Barcode scanners
- Printers and labellers
- Sortation equipment
- Warehouse robots
- Lifts and vertical conveyors
- Production machinery
- Warehouse management systems
For example, a product may need to be detected before another machine begins its process.
Alternatively, a conveyor may need confirmation that a downstream area is ready before releasing the next product.
Controls allow these different pieces of equipment to communicate and coordinate their actions.
This is often what turns several individual machines into one connected automation system.
Do All Conveyor Systems Need Complex Controls?
No.
The level of control should match the application.
A straightforward conveyor moving products between two fixed points may require relatively simple controls.
A large system handling high volumes across multiple conveyor routes may require considerably more sophisticated programming.
Adding unnecessary complexity can increase cost and make a system more difficult to maintain.
Equally, using controls that are too basic for the application can limit performance and flexibility.
The objective should be to provide the level of automation the process actually requires.
Why Should Controls Be Considered During Conveyor Design?
It can be easy to focus primarily on the physical conveyor layout during the early stages of a project.
However, how the system will operate is just as important as where the conveyor will go.
Control requirements can affect:
- Conveyor zoning
- Sensor positions
- Motor selection
- Electrical requirements
- Operator stations
- Product accumulation
- Integration with other equipment
- Safety design
Considering these factors from the beginning helps ensure the mechanical and electrical parts of the conveyor system work together properly.
It also creates opportunities to design the system around how products genuinely move through the operation rather than simply creating a physical route between two locations.
Conclusion
A conveyor control system is what allows a powered conveyor to do more than simply move products from one end to the other.
Using components such as sensors, PLCs, motor controls and HMIs, the system can detect products, manage conveyor zones, control movement, identify certain faults and coordinate with other automated equipment.
The level of control required depends entirely on the application. Some conveyor systems need only straightforward start and stop functionality, while others form part of a much larger automated process.
The important thing is that the controls are designed around the operation and the way products need to move.
If you’re considering a new conveyor system and would like to understand what level of control or automation your application requires, feel free to contact the team. You can also explore more articles across the Knowledge Hub for practical guidance on conveyor systems, controls and warehouse automation.