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.

The operating modes include T1, T2, Auto, Remote, and Servo Free. T1 speed not exceeding 250 mm/s; T2 can exceed 250 mm/s; Auto is used for program execution; Remote executes commands through I/O; Servo Free allows operators to manually grasp the moving axis of the robotic arm. J1 and J2 brakes can be released through software, while J3 and J4 brakes can be released through the release button on the robotic arm. The priority of emergency stop related control equipment is the highest, including external emergency stop, teaching pendant emergency stop, and safety door sensor; Teaching pendant, control PC, confirmation button, enable switch, remote PLC, and Ethernet remote operation have lower priority. Whoever connects to the teaching pendant and controls the PC first gains exclusive control.

Interfaces and wiring: Emergency, I/O, EtherCAT, LAN, and USB

The Emergency interface is 25 pins and includes system automatic mode indication, safety door status indication, emergency stop status indication, external enable test pulse, safety sensor test pulse, confirm button output, external emergency stop test pulse, external enable input, safety sensor input, confirm button input, and external emergency stop input. Safety related outputs can be connected to indicator lights or LEDs, requiring external 24V power supply and a load not exceeding 100 mA. Shielded cables must be used for safety circuits, with a recommended wire diameter of AWG 22, and measures must be taken to prevent cross connections between channels.

The EtherCAT interface uses RJ45, with pins defined as 1 TX+, 2 TX -, 3 RX+, 6 RX -, and 8 PE. The maximum wire diameter is AWG 22, and Cat5 shielded cables are recommended. The LAN interface provides a 100 Mbps service channel for KUKA. ControlStudio on PC, and Cat5 shielded cables are also recommended. The USB Memory interface is USB 2.0 Type A, used for data backup and recovery, and is used in conjunction with the Trigger button. The I/O interface is 50 pins, providing 24 digital inputs and 16 digital outputs. The input voltage range is DC 20.4 V to 26.4 V, the input impedance is 5.4 k Ω, and the typical operating current is 4.2 mA. The output is a solid-state relay, with NPN from 0 to 7 and PNP from 8 to 15. The operating voltage is DC 20.4 V to 30 V, with a maximum single point of 200 mA. The input common terminal can be connected to 0 V or 24 V, and NPN or PNP connections are supported. When connecting the output to a relay or inductive load, a freewheeling diode must be added, otherwise it may damage the output. PE protection equipotential connection requires the use of a 4 mm ² cable to connect the robotic arm and controller, and connect them to the central PE row along the shortest path. Finally, perform grounding inspection according to EN 60204-1.

Installation, power on, and initial debugging

The dimensions of KR CS Box-2 are approximately 280 mm × 310 mm × 120 mm, with a minimum spacing requirement of front 100 mm, back 60 mm, left 60 mm, and right 60 mm to ensure heat dissipation. The controller can be placed horizontally or installed vertically through a bracket. When installing vertically, first remove the 4 M3 TORX feet, then install the bracket and use 4 M4 × 8 self tapping internal TORX screws with a tightening torque of 1.7 to 1.8 Nm. The power supply must use a grounded neutral system for independent protection, and it is recommended to use a 16 A, 30 mA B-type residual current protector for each robot; When multiple robots share the same total protection, it is recommended that the total remaining operating current for 1 to 7 robots be no less than 100 mA and the rated current be no less than 32 A; for 7 to 25 robots, it is recommended to be no less than 300 mA and 100 A; It is recommended to use no less than 500 mA and 160 A for 25 to 40 units. Before powering on, confirm that there is no condensation, all connections are correct, the casing is closed, and there is no one in the danger zone. Release the teach pendant emergency stop, turn on the main switch, log in with the default username admin and password ADMIN after system startup, and then change the default password. If the teaching pendant is not used, a bypass connector must be inserted into the TP interface to simulate emergency stop not being pressed and enable disconnection, and the teaching pendant must be removed to prevent the mistaken belief that its emergency stop is still valid.

Maintenance: Wait for 10 minutes, clean the filter and ventilation holes

Before maintenance, the controller must be turned off and locked with a tag, the power cable must be unplugged, and wait for at least 10 minutes, as there may be residual voltage of 60 to 450 V in the intermediate circuit. Clean the filter screen every 3 months, clean the ventilation holes every 12 months, and conduct cyclic functional tests on all safety equipment and emergency stop devices annually. Check if the fuses, plugs, and boards are securely fastened, and inspect the potential of cables, PE, and system components for wear or damage. During cleaning, it is prohibited to use compressed air, spray water, use solvent-free, water-soluble, non flammable, and non corrosive cleaning agents, and do not allow cleaning agents to enter electrical components.

Troubleshooting: Display panel and alarm codes

The display panel has 2 red LEDs (Error, E Stop) and 2 green LEDs (Auto, Manual), as well as a four digit 7-segment digital display. C-3 indicates that the system is normal; 800 indicates an error, and the digital display scrolls to show the error code; E-SP indicates emergency stop, both red LEDs are on; E-CC may indicate system startup, communication failure between display panel and controller, system disabled but emergency stop not pressed, or backup in progress; UPOK indicates that the update is in progress. Insert a USB flash drive during backup, press the Trigger button, wait for the display of "----", and after successful backup, the file name format will be bckp_date time. zip, bckp_ip_date time. txt, and bckp_date time MD5。

Common alarms and handling: 65 motion element errors, check limit, tracking errors, and drive errors; 66 CPU overload, reduce loops, decrease page refresh, restart controller; The 3006 element has been attached to the task. Stop the attached task before starting a new motion task; 3016 envelope errors, check Pemax and collision; 3017 axis tracking error, reduce speed, check for collision; 3022 return to zero over distance, check the limit switch; 3058 driver not enabled, click the system enable button; 3082 feedback speed exceeds limit, reduce command speed, check encoder; 3115 enters the following mode to check for mechanical arm interference, zeroing, and motion errors; 3117 is too close, reset the target point; 3121 target unreachable, modify Pmin/Pmax; 3154 reaches the maximum position, jog in the opposite direction; 3192 not attached, add Attach Group before exercise; 3204 inverse matrix cannot be calculated, modify the starting or ending point of the arc; 3245 zeroing error, reduce zeroing speed; Follow the error when stopping 3253, check the PEMax, enable the robot, and check the joint limit; 3335 limit switch triggered, check for return to zero and sensor; 5034 cannot accept host connections, check IP and network segment; Port 5043 is already open, please close the occupied port first; 5055 connection rejected or timed out, check IP and cable; 13102 additional torque exceeds the limit, check the load, speed, and acceleration; 13132 singular point, modify path; 19015 EtherCAT topology change, restart the system, check cables, and perform I/O remapping; 19020 driver short circuit, check U/V/W and grounding; 19021 to 19023 U phase continuous overcurrent, check U phase cable, reduce load, check insulation; 19024 hardware overcurrent, check mechanical card resistance, encoder wiring, and braking circuit; 19026 DC bus overvoltage, adjust input voltage, check braking resistance; 19027 DC bus undervoltage, adjust input, check power cable; 19028 power module overheating, reduce load, replace driver, improve heat dissipation; 19031 Regenerative resistor overload, avoid frequent and rapid stops; 19043 encoder data abnormality, check the encoder cable and replace the encoder; 19045 encoder communication timeout, check the encoder wiring; The 19051 driver is continuously overloaded. Check the encoder wiring and replace the encoder; 19053 drive output phase loss, check the motor and brake wiring; 19054 motor stalling, check encoder wiring, strengthen anti-interference; 19055 current tracking error is too large, check for mechanical jamming; 19059 motor brake abnormality, check the brake circuit; 19061 STO1 trigger, check the STO1 cable and circuit; The speed following error of 19068 is too large. Check for mechanical jamming, reduce acceleration, and optimize the regulator; Instantaneous overload of motor 19079 to 19081, reduce load, check for jamming and braking; 19087 encoder overheating, reduce ambient temperature, replace driver; 19088 encoder battery undervoltage, check battery wiring, set current value, replace battery; The power on position error of 19090 is too large. Check the encoder battery and battery voltage; 19096 brake control abnormality, check brake wiring, 24V and drive; 19113 axis 0 secondary velocity tracking error, reduce speed, check interference; The 20005 system is not enabled. Check the safety board contact, fan, parameter consistency, and zero return; 20007 unable to enable group, check emergency stop, drive error, confirm button; From 2009 to 20104, if the target exceeds X/Y/Z, reverse jog or modify the target point, increase Pmax/Pmin; 20123 SDO error, check driver and I/O cables, restart; 20140 singular point, move J2 away by ± 15 °, modify the path; 20151 STO signal, check I/O and drive cables; Unable to allocate tools and bases in September 2016, please check the coordinate system; 20217 Exceeding UserFrame, restricting or modifying targets; 20273 update failed, check firmware, cables, and replace drivers; 20285 unable to load application, check compilation, tool coordinates, APP status; 20310 unable to run remote tasks, check communication parameters; Execute Stop 1 on 20488 as the fan speed is below the threshold, check the fan cable; 20507 safety board is not in the enabled state, check for short circuit between deadman and safety board; 20537 joint coordinates are out of range, modify coordinates; 20562 EtherCAT topology change, perform I/O remapping; The maintenance of A3/A4 belts, splines, and encoder batteries from 20791 to 20793 has expired. Replace the components and enter a new lifespan; 20830 cannot set displacement, disable or separate motion group; Data recovery failed from 20840 to 20844. Check the controller serial number, cable, and restart; 20907 Invalid signal name, check the I/O module and old I/O; 20939 The safety door opens on Auto/Remote and continues to close; 20954 unable to open communication channel, check port, network, cable, restart; 20978 motor cannot be activated due to overheating, waiting for the motor to cool down; 21105 Topology changes update data, waiting or refreshing; 21108 reboot failed, check I/O module, redo I/O remapping; 21112 to 21115 cannot run/load, execute I/O remapping; 21136 remapping with topology changes, re execute; 21138 failed to obtain topology, restart the system; 21139 EtherCAT master station status change, execute I/O remapping.

In the servo drive debugging software DriveMasterMA, short circuit 0x2250, output overcurrent 0x2310/0x2311/0x2312, hardware overcurrent 0x2320, encoder data abnormality 0xFF06, encoder communication abnormality 0xFF07, encoder communication timeout 0xFF08, encoder internal abnormality 0xFF09, control encoder overspeed 0xFF14, continuous drive overload 0xFF15, drive output phase loss 0xFF17, motor speed loss control 0xFF18, position target abnormality 0xFF22, motor braking abnormality 0xFF25, control power undervoltage 0xFF26, STO1 triggering 0xFF27, motor overspeed 0xFF31, EtherCAT abnormality 0xFF51, encoder resolution change 0xFF52, encoder overheating 0xFF53, encoder battery Undervoltage 0xFF54, excessive power on position deviation 0xFF58, abnormal encoder acceleration 0xFF59, motor stalling 0xFF60, abnormal brake control 0xFF66, servo not ready 0xFF77, STO Abnormal wiring of 0xFF8F can be handled by checking the cable, reducing the load, optimizing parameters, or replacing the encoder or driver.