Control Enclosure
General
The electrical control enclosure of a forklift AGV includes all controls of the AGV. Normally there are a control board with an I/O board, chopper units for drive, steer and lift motors. The design of the enclosure makes it very easy to access all the components, which makes it easier to service and troubleshoot. Another advantage is that the control enclosure can be prefabricated as a standard unit, which lowers the cost of the AGV and shortens the lead time during manufacturing.
CB12 Control board
The AGV has a control board which is special designed for AGV applications.
Features of the Control Board:
- Modular design
- For use in 24V or 48V systems
- LED indications of digital inputs and digital outputs
- Battery voltage monitoring
- Integrated safety part with relay outputs
- Parallel bus for expansion of digital I/O's and other I/O modules
- Flexible due to software controlled functions
- 16-bit micro-processor
- 12-bit A/D converter
- 12-bit D/A converter
- Chopper interface
- Encoder interface
- Flexible analog signal interface
- Download of program over serial communication link
- Rugged design
- Small dimensions
- Multiple navigation principles
DIS20 Control Terminal
On the front part of the control enclosure is the control terminal (DIS20) located. It is used for entering information when inserting an AGV to an AGV traffic control system. It is also used for all kind of trouble shooting on the vehicle.
Control Terminal display features
- Current error messages
- A history of the 16 latest error messages
- Status of all on-board software
- Status of all digital I/O's
- Guidance status
- Hour counters for power, drive and lift motors
- Battery voltage
- ACE status (commands to control an AGV Electronics AGV)
- Memory content, may also be changed from the keypad
The DIS20 control terminal has also eight large square LED's which are easy to identify on a distance showing main information of the vehicle.
SM20 Safety Control
A separate safety control module is located in the enclosure. All safety signals from bumpers, E-stop's etc. are connected to the safety control module. The SM20 supervise the safety parts of the AGV making sure all safety equipment is in function at all times. The safety functions can be tested during AGV operation making the vehicle very safe.
The SM20 has doubled safety circuits and safety relay outputs. SM20 detects single faults in safety components and safety circuits. The principle of operation is that both safety circuits must have the same status. If only one circuit is opened up, the SM20 can not be restarted.
The safety module features:
- Doubled safety circuits
- Single fault detection
- Safety relay outputs
- LED indications
- Emergency stop functions
- Bumper stop functions
- Bumper photocell test
- Bumper bypass function
- Restart function
- Feedback loop from the drive motor contactors
- Isolation meter, Chassis - 0V.
Key Switch and E-stop's
On the side of the control enclosure are normally a key switch used to select OFF / AUTOMATIC / MANUAL mode. In the OFF status is the power turned off. The AUTOMATIC mode is the normal mode for the AGV when used automatically in the system. The MANUAL mode is only used for manual operation when inserting an AGV to a system, or for moving the AGV manually. Loads may also be loaded and unloaded manually.
The control enclosure has an E-stop push button on each side. The E-stop will stop all functions of the AGV by disconnecting power to motors and contactors as well as giving an E-stop signal to the microprocessor.
Manual Control Unit
The manual control unit (MCU) is located on the side of the control enclosure. To each AGV is normally one MCU included. It is used for manually controlling all functions of the AGV.
The standard manual control unit features:
- Semiauto/manual function
- Speed control
- Forward/reverse control
- Steering control
- Lift or conveyor control
- Bumper bypass function