KUKA KR C5 Controller Assembly and Troubleshooting

KUKA KR C5 Controller Assembly and Troubleshooting

In the field application of industrial robot controllers, the KR C5 Controller is no longer a single "control cabinet" concept, but a modular platform composed of control units, power units, safety logic, interface boards, cooling systems, and UPS. It is designed for KUKA industrial robots, supporting up to 7 servo axes, with a protection level of IP20 and a weight of approximately 25 kg. It is available in KR C5 S6/S7, M6/M7, L6/L7 and other specifications, and comes in both AC and DC versions. For engineers in the search solution phase, the most important concerns are how to identify critical components, configure safety chains, wire connections, power on, replace modules, and where to start checking after an alarm. This article revolves around these practical issues.

System architecture: First distinguish between control unit and power unit

The KR C5 Controller consists of a control unit and a power unit. The control unit, also known as the control box, contains mini CSP, SSD hard drive, button battery, SYBperf system board, IFBstd standard interface board, IFBsafe safety interface board, IFBsafext safety expansion interface board, and internal fan. Mini CSP is a status display component that provides feedback on operating mode, operating status, errors, and sleep status through LEDs and soft power buttons. The system board is responsible for graphical interface, program creation and modification, path planning, sequence control, driver circuit control, monitoring, and communication of safety devices. The interface board provides non secure digital I/O, secure I/O, and secure extended I/O required for SafeOperation.

The power unit, also known as the drive box, includes an external fan, a heat sink, and a KSP-600 drive controller. The internal components consist of FCU-600 and SCU-7-1L. It is responsible for generating intermediate circuit voltage and system voltage, controlling motors, controlling brakes, and checking intermediate circuit voltage in braking mode. It should be noted that the power unit is not allowed to be opened arbitrarily, otherwise it may cause serious injury or property damage.

KR C5 also supports the Customer Kinematics variant, which can use KUKA motors to control non KUKA industrial robots. In terms of cabinets, KR C5 dualcab provides 2 rack units, triple cab provides 3, and quad cab provides 4. DualCab SR is designed for single robot applications, with a maximum of one robot controller and one device board. The control unit and power unit are connected through a vertically installed connection board, which must be used with extra caution when replacing system boards or power unit related components.

Security Chain: STOP 0, STOP 1, STOP 2 and Security Interface

The safety functions of KR C5 comply with Category 3 and Performance Level d of EN ISO 13849-1, and the PFH value is usually less than 1 × 10 ⁻⁷. 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: The safety controller immediately cuts off the driving and braking power supply; STOP 1 is executed by the non safety part for braking, monitored by the safety controller. At T1, all axes come to a standstill or cut off the braking power supply no later than 680 ms, followed by a delay of 200 ms to cut off the drive. At T2/OUT/OUT EXT, the drive is cut off after 1.5 seconds by default; After STOP 2 braking, the driver remains activated, the brake is released, and it switches to safe stationary monitoring. Safety stop 1 DRS is used for safety options with BBRA, and after braking, the brake power is cut off according to the configured time plus 500 ms oscillation time.

The safety interface is a key point for on-site wiring. XG11.1 provides 2 safety inputs and 1 safety output for external emergency stop and operational safety. XG11.3 provides more secure inputs and outputs, including operation safety confirmation, peripheral enablement, safe operation stop, safe stop 1/2, safe stop 2, etc. XG13.1 and XG13.2 are used for options such as SafeRangeMonitoring, SafeOperation, SafeSingleBrake, etc. XG58 is used for external enable switches and additional emergency stops. When not connected, it needs to be short circuited according to the instructions. The Ethernet safety interface supports PROFIsafe, CIP Safety, and FSoE, with input bytes including external emergency stop, operational safety, operational safety confirmation, and safety stop 1/2 US2、 Signal to stop safe operation.

The external enable switch has three positions: not pressed, middle position, and fully pressed. Only the middle position can move the axis; Releasing or fully pressing will trigger Safety Stop 2 or Safety Stop 1. The enable switch must not be fixed with tape, otherwise it will lose its safety significance. In T1 mode, the default limit for axis specific speed is 30 °/s for the rotating axis, 250 mm/s for the linear axis, and 250 mm/s for the Cartesian speed. Exceeding the limit triggers a safety stop of 0.