KUKA KR CS Box-2 Compact Controller for Four Axis SCARA Robot

KUKA KR CS Box-2 Troubleshooting and Maintenance

KUKA KR CS Box-2 is a compact controller designed for KR SCARA CS series robotic arms. Compared with the previous generation product, it adopts a stronger CPU, with a performance improvement of about 40%, smaller size, richer communication interfaces, and more stable system operation. It supports a maximum of 4 servo axes, weighs about 7 kg, has a protection level of IP20, noise level below 60 dB (A), power supply from AC 1 × 200 V to 240 V, maximum input power of 3.50 kVA, frequency of 50/60 Hz. It is recommended to use a protection device with not less than 16 A on the main power supply side, and a B-type full current sensitive residual current protector with a rated residual operating current of not less than 30 mA. The system impedance is not greater than 100 m Ω, and the ground leakage current is not greater than 10 mA. The controller provides 24 digital inputs, 16 digital outputs, 2 Ethernet interfaces, and 1 EtherCAT interface, with safety performance in accordance with ISO 13849-1 Performance Level d, Category 3, and PFH value less than 1.724 × 10. ⁻⁷. For on-site engineers, the troubleshooting focus of KR CS Box-2 is not on whether it can be powered on, but on the quick positioning of safety chains, servo drives, EtherCAT communication, I/O wiring, and display panel alarm codes.

System architecture: Control board, servo drive, power protection board, and safety board

The front panel of KR CS Box-2 integrates Emergency interface, Encoder interface, display panel, Motor Power interface, power switch, power socket, PE grounding, TP interface, LAN1, LAN2, EtherCAT, Trigger button, Memory USB interface, and I/O interface. The control board is the core, responsible for user interface, program creation and modification, archiving and maintenance, sequence control, path planning, servo drive control, monitoring, and communication with external controllers, upper computers, PCs, and networks. The control board is equipped with ECAT M, safety board status feedback, ECAT O, SD card, display interface, fan control, 24V power input, digital I/O, USB, trigger button, ECAT output, LAN1, LAN2, TP interface, TP power supply, and TP safety interface. The servo drive consists of a servo power board and a servo control board, responsible for driving and controlling the mechanical arm axis. The LED on the board can indicate the operating status. The power protection board is used for power filtering and overcurrent protection. The input L/N, output L/N, PE, and two series fuses form the main protection circuit. The safety board is a component of the safety interface, providing external safety interfaces, control power, STO interfaces, and internal safety interfaces. It is responsible for collecting external safety device inputs and activating Safe Torque Off.

The servo drive interface includes J1 to J4 encoder interface, RS485 debugging interface, IO interface (including STO), EtherCAT input/output, J1 to J4 brake interface, J1 to J4 motor power output, power input and regeneration resistor interface, and control power input. The motor power interface is 20 pins, including U, V, W, PE for four axis motors, as well as 24 V, 0 V, 24 V Brake+, and 24 V Brake com. The encoder interface is 26 pins, including positive and negative data from a four axis encoder, a 5V power supply, and GND. The TP interface is 12 pins, including teach pendant emergency stop, enable, data transmission and reception, 24V and GND, and has a foolproof structure. When inserting and unplugging, it must be aligned with the foolproof port to avoid damaging the pins.

Safety Chain: Emergency Stop, Safety Gate, Enable and Confirm

The safety function response time of KR CS Box-2 is 20 ms. After the emergency stop device is pressed, the robotic arm stops with safety stop 1, and the system automatically cuts off the motor, stops moving, and disables the axis; The emergency stop button is self-locking and must be rotated to release before pressing the confirm button to clear the emergency stop status. The safety door signal, also known as the "operation safety" signal, cannot operate in automatic mode without this signal; Opening the safety door during automatic operation will trigger safety stop 1. The system supports two safety door sensors. If only one is used, the 6th and 18th pins of the Emergency interface must be short circuited, and the 7th and 19th pins must be short circuited. After the safety gate is closed, it cannot be restored to automatic operation solely by closing the door. It must be confirmed through the confirmation button outside the safety fence.

The enabling device is located on the smartPAD touch, with only one enabling switch in three positions: not pressed, middle position, and fully pressed. In manual mode, only the middle position can move the robotic arm; Release or fully press will trigger safety stop 1. If an external enabling device is used, the external enabling and the teaching pendant enabling are in an AND relationship; If external enablement is not used, pins 4 and 16 must be short circuited, and pins 5 and 17 must be short circuited. The confirmation button must be installed outside the safety fence, normally open, and automatically reset when pressed. It needs to be continuously pressed for more than 0.5 seconds to take effect. Automatic mode output SAFETY-OUT1-A, safety door status output SAFETY-OUT3-A, emergency stop status output SAFETY-OUT2-A, all can be connected to indicator lights, external 24V power supply, single load not exceeding 100 mA.