Pallet dispensers are used in some automated warehouses to supply empty pallets to a defined location. When an AGV forklift needs to collect pallets from or deliver pallets to a dispenser, the physical interface and control logic must be clearly defined.

The challenge is not simply getting the AGV to the dispenser. The two systems must coordinate pallet availability, vehicle positioning, transfer completion, and exceptions.

What Is a Pallet Dispenser?

A pallet dispenser automatically supplies pallets from a stack or storage mechanism to a designated pickup position.

Depending on the equipment, the dispenser may:

• Separate one pallet from a stack

• Present a pallet at a pickup position

• Receive an empty pallet

• Maintain a defined pallet stack

The exact mechanism depends on the dispenser design.

Where Can AGVs Be Used?

An automated forklift can support several workflows.

• Collecting an empty pallet from the dispenser

• Delivering pallets to the dispenser

• Moving pallets between the dispenser and storage

• Supplying pallets to a downstream process

The correct workflow depends on whether the dispenser is acting as a pallet source, pallet destination, or both.

What Does the AGV Need to Know?

The AGV needs a defined pickup or drop-off position and a clear indication that the pallet is ready.

Possible signals include:

• Pallet available

• Dispenser ready

• AGV ready

• Pickup position clear

• Transfer complete

• Dispenser fault

The actual signal list should be agreed between the AGV supplier and dispenser supplier.

How Can the Systems Communicate?

Depending on the equipment, the interface may use:

• PLC signals

• Digital I/O

• Industrial Ethernet

• TCP/IP

• API-based communication

The integration should define both commands and feedback states.

For example, an AGV should not interpret a "request received" signal as proof that a pallet is physically ready for pickup.

How Should the Physical Handover Be Designed?

The dispenser and AGV need a repeatable physical interface.

Important factors include:

• Pallet dimensions

• Pallet entry direction

• Fork access

• Pickup height

• Vehicle alignment

• Available clearance

• Sensor positions

• Safety separation

These dimensions should be reviewed using the actual AGV and dispenser specifications.

What Happens if No Pallet Is Available?

The AGV should not repeatedly approach a dispenser that cannot provide a pallet.

The control system should define what happens when:

• Pallet stock is empty

• Dispenser is faulted

• Pallet is misaligned

• Pickup position is blocked

• Communication is lost

Possible responses include waiting, generating an alarm, assigning another task, or requesting operator intervention.

How Should Safety Be Tested?

Because the AGV and dispenser operate in the same physical area, their safety functions should be considered together.

Test scenarios can include:

• AGV approaching while dispenser is operating

• Dispenser stopping during pallet transfer

• AGV stopping during pickup

• Obstacle entering the area

• Emergency stop

• Communication interruption

• Recovery after fault reset

How Does WMS Integration Fit Into the Process?

The WMS may generate the business requirement, while the WCS, RCS, PLC, or other control layer coordinates the physical equipment.

A typical flow could be:

1. WMS creates a pallet movement requirement.

2. Control software requests a pallet from the dispenser.

3. Dispenser prepares the pallet.

4. Dispenser confirms pallet availability.

5. AGV receives the transport task.

6. AGV collects the pallet.

7. Transfer completion is confirmed.

8. Inventory status is updated.

The exact architecture depends on the warehouse automation system.

What Should Be Tested Before Go-Live?

• Normal pallet dispensing

• Empty dispenser

• Misaligned pallet

• AGV positioning error

• Communication loss

• Dispenser fault

• AGV fault

• Emergency stop

• Task cancellation

• System restart

Testing should verify the complete sequence from the software task to the physical pallet transfer.

What Information Should Be Given to the AGV Supplier?

• Dispenser model and layout

• Pallet dimensions

• Pallet weight

• Pickup height

• Transfer direction

• Required throughput

• Communication interface

• PLC signal list

• Safety devices

• WMS/WCS architecture

Early coordination between the AGV supplier and pallet-equipment supplier can prevent interface problems from appearing during commissioning.