KUKA KR C5 micro KSS troubleshooting

KUKA KR C5 micro KSS troubleshooting

KUKA KR C5 micro is a controller platform designed for small robots, compact workstations, and limited installation spaces. When equipped with KUKA System Software (KSS) or VW System Software (VSS), it supports up to 6 servo axes, weighs approximately 9.8 kg, has a protection level of IP20, noise level below 54 dB (A), power supply from AC 1 × 200 V to 240 V, allowable deviation ± 10%, rated connection power of 1.30 kVA, main power side fuse 1 × 16 A slow melting C-type, and maximum thermal output of 250 W. Unlike the iiQKA.OS version, the KSS/VSS version uses KUKA smartPAD-2, with its own operating mode, safety rules, and fault diagnosis path. The on-site engineers are most concerned about how to distinguish between the control box and the drive box, how to configure the safety chain, how to wire the interface, how to verify the first power on, how to replace the module, and how to quickly locate the KSP alarm and CSP LED. This article revolves around these practical issues.

System Architecture: Control Box, Drive Box, and Cooling

The KR C5 micro consists of a control unit and a power unit. The control unit, also known as the control box, contains a mini CSP, button battery, SSD hard drive, system board, IFBstd interface board, internal SSD storage, and fan. The system board is responsible for controlling the computer, including graphical interfaces, program creation and modification, path planning, sequence control, drive loop control, monitoring, safety equipment communication, and external device communication. The IFBstd interface board provides non secure digital I/O and is connected to the system board through a ribbon cable; The system board is connected to KSP through ICT plug and is powered by KSP. Mini CSP is a status display component that provides feedback on operating mode, operating status, errors, and sleep status through LED1 to LED4 and a soft power button.

The drive box, also known as the drive box, includes a fan, main filter, braking resistor, radiator, and KSP-300 drive controller. KSP-300 consists of FCU-300 and SCU-6-1S, used for up to 6 servo axes; KSP-300-4 consists of FCU-300-4 and SCU-6-1S and is used for up to 4 servo axes. The drive box is responsible for generating intermediate circuit voltage and system voltage, controlling the motor, controlling the brake, and checking the intermediate circuit voltage in braking mode. The power unit is not allowed to be opened arbitrarily, otherwise it may cause serious injury or property damage. The KR C5 micro also supports the Customer Kinematics variant, which can use KUKA motors to control non KUKA industrial robots. Cooling is achieved by two fans, with air entering through the inlet and exiting through the outlet. The front and rear surfaces must be kept in contact with the cooling air.

Safety Chain: STOP 0/1/2, Operational Safety and Enabling Devices

The safety features of KR C5 micro comply with Category 3 and Performance Level d of EN ISO 13849-1. The premise is that each emergency stop device should be pressed at least once every 12 months, each enabling device should be checked at least once every 12 months, and the USS 2 peripheral contactor should also be tested regularly. Safe stop is divided into STOP 0, STOP 1, and STOP 2. STOP 0 immediately cuts off the drive and applies the brake, and the robot stops in a path guided manner. STOP 1 is executed by the non safety part for braking, monitored by the safety controller. At T1, the braking power is cut off after all axes come to a standstill or at the latest 680 ms, and the drive is cut off after 200 ms; Under T2, AUT, and AUT EXT, the drive is cut off by default after 1.5 seconds, and the brake power is cut off 200 ms in advance. STOP 1 DRS is used for safety options with BBRA. After braking, the brake power is cut off according to the configured time plus 500 ms oscillation time. STOP 2 does not cut off the drive, does not apply the brake, and maintains a braking ramp deceleration path.

The operating modes of KSS are T1, T2, AUT, AUT EXT; VSS is T1, T2, EXT. T1 is used for testing, programming, and teaching, with a maximum program validation speed of 250 mm/s and a maximum jog speed of 250 mm/s. T2 is used for testing, and the program verification speed is set according to the program settings. Jogging is not available. AUT and AUT EXT are used for program execution and jogging is not available. The operation safety signal is used to monitor physical protection such as safety doors. Without this signal, it cannot operate in automatic mode; Opening the safety door during operation will trigger safety stop 1. Operation safety is not activated under T1 and T2. Under VSS, T1 can be operated safely with E2/E22 key bypass, T2 can be operated with E2/E22+E7 bypass, but no one is allowed in the danger zone under T2.

The emergency stop device includes local emergency stop and external emergency stop on smartPAD. Pressing the smartPAD emergency stop will trigger safety stop 1, which must be rotated and released before it can be restored. The system must have at least one external emergency stop so that it can still be stopped when the smartPAD is disconnected. The enabling device consists of four enabling switches on the smartPAD-2, with three positions: not pressed, middle position, and fully pressed. Under T1/T2, only the middle position can move the axis; Release all intermediate position enable switches to trigger safety stop 2, and fully press one enable switch to trigger safety stop 1. The enable switch must not be fixed with tape and must undergo regular functional testing: move the robot in testing mode, press the enable switch to the panic position and hold it for 3 seconds. The robot must stop and no enable device errors must be displayed. The external enabling device is connected through XG58, with a maximum switching frequency of 20000 times, and must use the KUKA specified model.

T1 speed monitoring is divided into axis specific and Cartesian monitoring. Axis specific monitoring defaults to a rotation axis of 30 °/s and a linear axis of 250 mm/s. Exceeding the limit triggers a safety stop of 0. Descartes monitoring defaults to 250 mm/s, which can be configured using options such as SafeOperation, but can only be reduced and cannot be increased. The Drives ready light must be tested before entering the danger zone: press and hold the enable switch at T1, and the light should turn on; Press to the panic position, the light should turn off.

Interface Layout: Safety, Communication, and Power Supply

The KR C5 micro front panel interface includes: XFUSB1 and XFUSB2 for USB 3.0; XF1 to XF8 are Ethernet and EtherCAT interfaces, and the specific allocation depends on the system software; XGDP is DisplayPort DP 1.2; XGSD is used for microSD cards; XG19 is used for smartPAD; XD12 and XD12.1 are 24V power supplies; XG12 provides 16 digital inputs and 16 digital outputs; XD20.1 is used for motor interfaces of axes A1 to A3; XD20.2 is used for axes A4 to A6; XG33 provides 3 fast measurement inputs and 1 Drive ready light output; XF21 is used for RDC or TPC; XG58 is a secure interface; XG11.1 is a secure interface. The rear panel includes device switches, fuses F1 and F2, power connections XD1 and XD2 for UPS 24V power supply and daisy chain connection.

In XF1 to XF8, XF1 is the KSI service interface, XF2 is the KLI IT, XF3 and XF4 are daisy chains, XF5 and XF6 are the KLI OT, XF7 is KONI, and XF8 is KEI. The KSI interface is used for diagnosis, WorkVisual configuration, and updates, and must not be connected to IT networks with a maximum cable length of 100 m. The KLI interface can be connected to OT or IT networks for PLC, terminals, update services, and diagnostics with a maximum cable length of 100 m. The KEI interface is used to connect external EtherCAT slaves, and EtherCAT devices must be configured with WorkVisual. The maximum cable length for XGDP is 5 meters. The maximum cable length for the Drive ready light output of XG33 is 50 meters. The maximum cable length for the RDC/TPC connection of XF21 is 50 meters.

The security interface XG11.1 provides 2 security inputs and 1 security output. The default configuration is: security output 1 is for local emergency stop, security input 1 is for external emergency stop, and security input 2 is for operational safety. XG58 provides 2 safety inputs for external enable switches and additional emergency stops, as well as for reference switches. The secure input adopts a dual channel design with external testing and loop detection shutdown capability. The test outputs TA_S and TA_S are alternately turned off, with a turn off pulse length of 600 μ s, a single channel turn off period of less than 1 second, and a 50 ms offset between the two channels. The input channel N_A [x] must be powered by TA_S, and N_B [x] must be powered by TA_S, and no other power sources must be used. Only sensors that can access test signals and provide floating contacts are allowed to be connected.

XG12 digital I/O can be configured in high side or low side mode. Jumpers 1 to 2 switch inputs 1 to 8 to low side, jumpers 3 to 4 switch inputs 9 to 16 to low side, jumpers 5 to 6 switch outputs 1 to 8 to low side, and jumpers 7 to 8 switch outputs 9 to 16 to low side. Default high side. The power supply is provided through XD12 and must use a safely isolated PELV/SELV power supply, rated at 24 V ± 10%, with a maximum insurance of 10 A. XD2 is used for UPS, with a maximum of 6.5 A for the first 60 seconds after power failure, and a maximum of 4 A until complete shutdown; without UPS, the controller should not operate, otherwise data loss may occur. XD55.1 to XD55.4 provide a 27 V power supply on the external shaft drive box and are internally protected by a 3A fuse.

Installation, power on, and initial debugging

The KR C5 micro can be installed horizontally or vertically, with or without a bracket, stackable, can be installed in a 19 inch rack, wall mounted, or as a panel mounted variant. The minimum distance must be observed during installation: at least 150 mm between the front (air inlet) of the robot controller and the housing, and at least 100 mm between the rear (air outlet) and the housing. If wall mounted, additional fire protection measures must be taken and can only be used or equipped with drip protection inside the fireproof housing. The front and rear must always be able to come into contact with cooling air. Stacking up to 3 controllers, the lower controller should be fixed on the ground, and the upper controller should be installed diagonally using 4 brackets. 19 inch rack installation requires the use of an installation frame with a minimum insertion depth of 700 mm. When installing the bracket, M5 screws are used for horizontal installation and M6 screws are used for vertical installation.

The equipotential connection must be completed before power on: a 4 mm ² cable is used between the robotic arm and the controller; An additional PE conductor of 4 mm ² is recommended to be used between the central PE row of the power supply cabinet and the PE connection of the controller. The connecting cable must be laid separately from the data cable, with a fixed installation bending radius of 3 to 5 times the cable diameter, and a drag chain installation radius of 7 to 10 times. The length of motor cables and data cables between the controller and the robot must not exceed 25 meters. After replacing the data cables, it is necessary to re master or perform master tests on all axes.

Pre power on inspection: visually inspect for no condensation or damage; Install strain relief plates; Connect equipotential; Connect motor cables, data cables, and power cables; Insert smartPAD; Configure and connect security interfaces XG11.1 and XG58 (must be plugged in and out when the controller is turned off); Connect Ethernet and EtherCAT interfaces; Connect optional interfaces. Power on steps: Release the emergency stop on the smartPAD, turn on the device switch, and control the PC to start. The startup sequence is recovery stick, external hard drive, and internal hard drive; If an external hard drive is detected, the internal hard drive will be disabled; If no external hard drive is detected, it will not automatically switch to an internal hard drive. The robot controller can only run with the connected smartPAD-2.

Functional testing must be performed: after all connected emergency stop devices are pressed, smartPAD displays that the emergency stop has been triggered and does not display any emergency stop device errors; After all enable switches are released in test mode, the robot stops without displaying any enable device errors; Press and hold the panic function of all enable switches for 3 seconds, and the robot will stop without any errors; Safety output shutdown capability test, after turning off and then turning on the controller, smartPAD does not display safety output errors; The brake test is performed on each axis during initial start-up and re commissioning, and every 48 hours during operation, unless otherwise specified in the risk assessment.

Maintenance and module replacement

Maintenance work must be carried out after the controller is turned off, tagged and locked, and the power cable is unplugged. After a power outage, there may be residual voltage of 60 to 800 V in the intermediate circuit for up to 5 minutes, and at least 5 minutes must be waited for. KSP、 Motor connectors and connected motor cables may remain energized. The homework must comply with ESD regulations. Maintenance table requirement: Conduct annual cyclic functional testing on operational safety and all emergency stop devices; Test all enable switches; Test external enabling devices; Test the Drives ready light before entering the danger zone each time; Clean the fan protective grille according to the degree of pollution; Replace the system board battery every 10 years. Check if the plug connection is secure and inspect all system components for wear or damage.

Module replacement includes: replacement of strain relief board, replacement of 19 inch mounting frame, replacement of SSD hard drive, replacement of system board battery, replacement of input fuse F1/F2, replacement of system board, replacement of interface board, replacement of TCA-OUT interface board, replacement of KSP-STA interface card. General steps: Turn off the device switch and unplug the power cable; Wait for 5 minutes; Open the shell cover; Disconnect the plug connection; Replace components; Install the housing cover and tighten with a torque of 0.6 Nm; perform a power on inspection. When replacing the system board, be careful not to damage it by connecting it to the power unit through a vertically installed connection board. When replacing the interface board, disconnect the ribbon cable X1000. After replacing the battery, you need to plug in the USB keyboard, enter the BIOS to set the date and time, load the default values, and perform a functional test. After replacing the SSD, it is necessary to check the settings and perform functional testing. Replace fuses F1/F2 with 10 A 250 V slow melting 5 × 20 mm. To replace TCA-OUT, remove 3 TX10 TORX screws. When replacing KSP-STA, it is necessary to remove 4 TX10 TORX screws and pay attention to the vertical connection plate.

Common troubleshooting: KSP alarm and CSP LED

KSP warning messages are the focus of investigation. 26103 internal error: reinitialize the driver bus, Power Off/On。 26104 IxT overload: When starting, the program load is too high. During operation, check the mechanical, temperature, and current trajectories, reduce the program speed, and check the CBS pressure and gearbox. 26105 Grounding Fault: Check the motor cable and motor. 26106 Overcurrent: Check the current trajectory, motor, and motor cable. 26107 Intermediate circuit overvoltage: Check the trajectory of the intermediate circuit, main power supply, and braking resistor to reduce the braking load. 26108 Intermediate circuit undervoltage: Check the trajectory of the intermediate circuit and the main power supply. 26112 radiator overheating: Check the fan, ambient temperature, program load, cooling circuit cleanliness, installation position, and ventilation gap. 26113 motor phase loss: Check the motor cable and motor. 26114 communication error: reinitialize the driver bus, check the EtherCAT cable and stack. 26118 Power phase loss: Check the power cord. 26119 power failure: Check the power cord and fuse. 26122 brake resistor fault: Check the brake resistor. 26123 Braking resistor overload: Reduce frequent braking overload and check the braking resistor. 26131 Intermediate circuit charging failure: Check the intermediate circuit cable, main power supply, and system impedance. 26133 brake fault: Check the motor/brake, brake cable/motor cable.

CSP LED is also an important clue. LED1 white indicates operating mode, LED2 green indicates operating status, LED3 red indicates error, and LED4 white indicates sleep/soft power. All off indicates that the controller is turned off; Irregular flashing of LED4 indicates sleep mode; LED4 flashing slowly indicates Bus Power Off. When LED1 to LED4 are all on during startup, it indicates LED testing, and then turning off indicates that BIOS POST is still running; LED2 slow flashing indicates that BIOS is OK and startup has started; LED2 lights up to indicate startup completion. When running, LED2 lights up to indicate T1/T2, and LED1 and LED2 lights up to indicate automatic mode. LED3 flash indicates PROFINET ping, slow flash indicates maintenance mode. Regarding startup errors: LED2 flashing and LED3 lit up indicate a BIOS error. You can replace the SSD or check the USB; If LED2 flashes slowly and LED3 lights up, it indicates that PMS startup has timed out and the mirror needs to be reloaded; LED2 and LED3 flash rapidly, indicating a software startup error and the need to reload the image; During operation, both LED2 and LED3 are lit, indicating a fatal error. Please check the smartPAD error message. The recovery image can be created or restored using KUKA. Recovery USB V4 or higher, in conjunction with Windows 10 64 bit PC, following the CSP status prompt to create or restore C and D drive images. If the system board LED lights up red, turn off the controller, unplug the power cord, and contact KUKA customer service.