Page 1
KUKA Roboter GmbH Controller KR C2 edition2005 Operating Instructions Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en...
Page 2
Subject to technical alterations without an effect on the function. Translation of the original documentation KIM-PS5-DOC Publication: Pub BA KR C2 ed05 en Bookstructure: BA KR C2 ed05 V8.1 Label: BA KR C2 ed05 V5 en Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 2 / 215...
Description of the power unit ..................3.7.1 Fuses ........................3.7.2 Power supply unit KPS 600 .................. 3.7.3 Low-voltage power supply KPS-27 ............... 3.7.4 KUKA Servo Drive (KSD) ..................3.7.5 Mains filter ......................Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 3 / 215...
Page 4
5.6.2 Software limit switches ..................5.6.3 Mechanical end stops ................... 5.6.4 Mechanical axis range limitation (optional) ............5.6.5 Axis range monitoring (optional) ................5.6.6 Release device (optional) ..................Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 4 / 215...
Page 5
Installing the robot controller ..................Connecting the connecting cables ................Connecting the KCP ....................Connecting the PE equipotential bonding ..............Connecting the robot controller to the power supply ..........Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 5 / 215...
Page 6
Display and operator control elements of the KCP coupler (optional) ....... 9.1.1 Uncoupling the KCP ..................... 9.1.2 Coupling the KCP ....................Booting the robot controller from a KUKA USB stick ..........Maintenance ....................10.1 Cleaning the robot controller ..................Repair ......................11.1 Wiring example X11 ....................
Page 7
12.18.11 Selecting the display for signals ................12.18.12 Selecting the properties of the ESC node ............. 12.18.13 Assigning ESC nodes to a controller ..............12.18.14 Error messages and troubleshooting ..............KUKA Service ....................Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 7 / 215...
Page 8
KR C2 edition2005 13.1 Requesting support ....................13.2 KUKA Customer Support ................... Index ......................Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 8 / 215...
Electromagnetic compatibility Electronic Safety Circuit Teach pendant (KUKA Control Panel) KUKA Guiding KUKA Robot Language Force sensor card KVGA KUKA Video Graphics Array LPDN DeviceNet card Fiber-optic cable Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 9 / 215...
Page 10
Load voltage (24 V) not switched Load voltage (24 V) switched. Deactivates actu- ators, for example, when the drives are deacti- vated. KUKA System Software VxWorks Real-time operating system Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 10 / 215...
For optimal use of our products, we recommend that our customers take part in a course of training at KUKA College. Information about the training pro- gram can be found at www.kuka.com or can be obtained directly from our subsidiaries.
Page 12
KR C2 edition2005 Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 12 / 215...
The robot controller consists of the following components: Control PC Power unit KCP teach pendant Safety logic ESC KCP coupler (optional) Service socket (optional) Connection panel Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 13 / 215...
Motherboard with interfaces Processor and main memory Hard drive MFC3 KVGA DSE-IBS-C33 Batteries Optional modules, e.g. field bus cards Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 14 / 215...
3.3.2 "PCI slot assign- ment" Page 16) AGP PRO slot Mouse connection USB (2x) X961 power supply DC 24 V X804 Ethernet ST5 serial real-time inter- face COM 3 Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 15 / 215...
Profibus master/slave card (optional) LIBO-2PCI card (optional) KUKA modem card (optional) free 3.3.3 Motherboard The following components are located on the motherboard: Configuration Processor Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 16 / 215...
Page 17
Fan 2 Fan 3 FireWire (IEEE 1394) Housing monitoring USB G/H Serial AT A1 Serial AT A2 USB E/F Additional +3 V power supply Additional +12 V power supply Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 17 / 215...
KR C2 edition2005 The KUKA Robot Group has assembled, tested and supplied the mother- board with an optimum configuration. No liability will be accepted for modifi- cations to the configuration that have not been carried out by the KUKA Robot Group. 3.3.4 Hard drive The hard drive is partitioned into 2 “logical”...
Error and situation information read from the servo modules is also processed. If more than 8 axes are used in the robot system, the MFC3 must additionally be fitted with a DSE-IBS-C33-AUX board. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 19 / 215...
The RDC has a Digital Signal Processor and converts analog signals to digital Description signals and is mounted in an RDC box on the base frame of the robot. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 20 / 215...
Page 21
Saving of the following data: Operating hours meter Absolute position Resolver position Adjustment data (offset, symmetry) RDC connections Fig. 3-10: Connections on the RDC board Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 21 / 215...
Fig. 3-12: Force sensor card Electrical isolation of the reset signal for the force sensor Functions Filtering of the force sensor signal Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 22 / 215...
The Fast Measurement function is a function for recording robot position data Description via fast measuring inputs and digital sensors to measure components and subsequently correct application programs. This option can be retrofitted. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 24 / 215...
Page 25
Connector X33 of the first RDC box Connector X33 of the second RDC box Connector X33.1 of the second RDC box Connection of the two RDC boxes Cable to the Fast Measurement sensors Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 25 / 215...
Safe disconnection of the drives Communication with the robot controller Pulsing of the safe inputs and outputs The inputs for the “Fast Measurement” option are not supported. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 26 / 215...
Page 27
The contact to the SafeRDC box is established using a screw. LEDs indicate the operating state of the SafeRDC. (>>> 12.16 "LEDs on the LEDs SafeRDC board" Page 170) Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 27 / 215...
X902 Connections for safe inputs and outputs Not used X905 Connection for enabling KUKA Guiding Device (KGD) X904 Connection for reference switch input X901 Connection for SafeRDC board Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 28 / 215...
This option can be retrofitted. Connector pin allocation for X33 Fig. 3-24: Connector pin allocation for X33 Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 29 / 215...
(16 or 256) are set automatically during installation. There are 2 KCP connections on the KVGA card. A normal VGA monitor can also be connected in parallel. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 30 / 215...
They are backed up by the KPS600. Fig. 3-27: Batteries Description of the KUKA Control Panel (KCP) The KCP (KUKA Control Panel) is the teach pendant for the robot system. The Function KCP has all the control and display functions required for operating and pro- gramming the robot system.
In the operating modes Automatic and Automatic Exter- nal, the enabling switch has no function. KCP coupler (optional) The KCP coupler allows the KCP to be connected and disconnected with the Description robot controller running. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 33 / 215...
Page 34
CAN bus to the KCP Debug connector B Debug connector A The LEDs on the KCP coupler card indicate the operating status. (>>> 12.14 "KCP coupler LED display (optional)" Page 167) Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 34 / 215...
The node in the KCP is the master and is initialized from here. Node in the KCP The node receives dual-channel signals from: EMERGENCY STOP pushbutton Enabling switches Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 35 / 215...
External E-STOP Input for external E-STOP (dual-channel). If the signal is interrupted, the drives contac- tor drops out after a delay. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 36 / 215...
The CI3 board links the individual nodes of the ESC system with the customer Description interface being used. Various different boards are used in the robot controller according to the spe- cific customer requirements: Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 37 / 215...
It connects the nodes that are present in the ESC circuit and distributes the signals to the individual interfaces. The “Local E-STOP” state is indicated via a relay. The ESC circuit can be reset using the reset button. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 38 / 215...
Page 39
Connection of external controllers, E-STOP button on control cabinet Internal interface Peripheral interface, outputs > 500 mA Connection: robot controller, internal fan Relays Item Designation Description Message: Local E-STOP Message: Local E-STOP Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 39 / 215...
RDC power supply Connection of external mode selector switches (optional) CAN connection, I/O board Internal/external power supply and ESC cir- cuit KCP connection KCP power supply and KCP CAN Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 40 / 215...
The ESC circuit can be reset using the reset button. Further information is contained in the "ESC Safety System with SafetyBUS p Gateway" documentation. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 41 / 215...
Page 42
Internal interface Peripheral interface, outputs > 500 mA Connection: robot controller, internal fan SafetyBUS Gateway interface (optional) Reset Item Designation Description ESC Reset button Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 42 / 215...
Description of the power unit The power unit includes the following components: Overview Power supply units Servo drive modules (KSD) Fuse elements Fans Main switch Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 44 / 215...
KSDs for 2 external axes (option) KSDs for 6 robot axes Fuse elements (24 V with battery back-up) 3.7.1 Fuses The fuses protect the components of the robot controller. Overview Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 45 / 215...
Ballast circuit, including short-circuit braking relays Brake switches (in common for all 6 robot axes and separate for 2 external axes) Interface to DSE-IBS and KUKA Servo Drive Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 46 / 215...
Page 47
The KPS 600 supplies the energy to the intermediate circuit and includes: Intermediate circuit Rectifier circuit Charging circuit Ballast circuit Discharging circuit Main contactor K1 Fig. 3-40: Connections on the KPS 600 Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 47 / 215...
The KPS-27 is a 24 V power supply which provides power to the following Description components: Motor brake Periphery Control PC Servo drive module Batteries Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 48 / 215...
Monitoring of the motor current and short-circuit protection Heat sink temperature monitoring Communication monitoring Fig. 3-42: Servo drive module 2 sizes are used: Sizes Size 1 (BG 1) KSD-08/16/32 Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 49 / 215...
Size 2 (BG 2) KSD-48/64 The designations 08 to 64 give the max. current in amps. Connections Fig. 3-43: Connections for KUKA Servo Drive, size 1 and size 2 X1 Connection X2 Motor connection X13 Interbus IN X3 Additional motor connec-...
The robot controller can optionally be equipped with an additional cooling unit. Optional cooling Description of interfaces The connection panel of the control cabinet consists as standard of connec- Overview tions for the following cables: Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 51 / 215...
Page 52
All contactor, relay and valve coils that are connected to the robot controller by the user must be equipped with suitable suppressor diodes. RC elements and VCR resistors are not suitable. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 52 / 215...
The robot controller must only be connected to a power system with a clock- wise rotating field. Only then is the correct direction of rotation of the fan mo- tors ensured. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 53 / 215...
Data cable X21, axes 1 to 8 Connector pin allocation Fig. 3-51: Connector pin allocation for X21 3.9.6 SafeRobot X21.1 The SafeRDC signals are routed via connector X21.1. Description Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 57 / 215...
Page 58
Safe input, test 1 channel A (24 V level) E_T1_B_24V Safe input, test 1 channel B (24 V level) Not assigned Not assigned Not assigned Not assigned Connector coding Not assigned Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 58 / 215...
The voltage supplied via pins b5 and b6 is present at the safe outputs. The safe outputs have a max. load rating of 100 mA per output. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 59 / 215...
Overview of the door which can be fitted as an option for integrating external customer equipment. Fig. 3-56: Mounting plate for customer components Mounting plate for customer components Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 61 / 215...
Page 62
5 kg Power dissipation of installed components max. 20 W Depth of installed components 180 mm Width of mounting plate 400 mm Height of mounting plate 340 mm Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 62 / 215...
Brake control 25-26 V DC Output voltage Max. 6 A Output current, brake Open circuit and short circuit Monitoring Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 63 / 215...
Page 64
Half-sine/11 ms in X/Y/Z direction) If more severe mechanical stress is expected, the controller must be installed on anti-vibration components. Control unit 25.8 to 27.3 V DC Supply voltage Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 64 / 215...
Vibration resistance 100 Hz Immunity from interference with Electromagnetic compatibility mains filter to EN 61800-3 (EMC) Degree of fouling 2 to VDE 0110 Degree of fouling part 2 Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 65 / 215...
The dimensions of the robot controller are indicated in the diagram (>>> Fig. 4-1 ). Fig. 4-1: Dimensions (in mm) 1 Cooling unit (optional) 3 Side view 2 Front view 4 Top view Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 66 / 215...
If the side or rear panels are not accessible, it must be possible to move the robot controller into a position in which the work can be carried out. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 67 / 215...
Dimensions of boreholes for floor mounting The dimensions of the boreholes for floor mounting are indicated in the dia- gram (>>> Fig. 4-4 ). Fig. 4-4: Boreholes for floor mounting View from below Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 68 / 215...
The following plates and labels are attached to the robot controller. They must Overview not be removed or rendered illegible. Illegible plates and labels must be re- placed. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 69 / 215...
Page 70
KR C2 edition2005 Fig. 4-6: Locations of plates and labels Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 70 / 215...
Page 71
Hot surface warning sign Hand injury warning sign Rating plate on the controller Warning: read manual PC rating plate Fuse ratings Warning: ≤ 780 VDC / wait 5 minutes Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 71 / 215...
Page 72
KR C2 edition2005 Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 72 / 215...
No modifications may be carried out to the industrial robot without the autho- rization of KUKA Roboter GmbH. Additional components (tools, software, etc.), not supplied by KUKA Roboter GmbH, may be integrated into the indus- trial robot. The user is liable for any damage these components may cause to the industrial robot or to other material property.
Annex II A. The declaration of incorporation, together with its annexes, remains with the system integrator as an integral part of the technical documentation of the complete machinery. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 74 / 215...
Danger zone The danger zone consists of the workspace and the stopping distances. The KCP (KUKA Control Panel) teach pendant has all the operator con- trol and display functions required for operating and programming the industrial robot.
Page 76
The tasks can be distributed as shown in the following table. Example System Tasks Operator Programmer integrator Switch robot controller on/off Start program Select program Select operating mode Calibration (tool, base) Master the manipulator Configuration Programming Start-up Maintenance Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 76 / 215...
The follow- ing table shows the different stop reactions according to the operating mode that has been set. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 77 / 215...
Number of switching cycles of the main contactors: max. 100 per day Warning! If these conditions are not met, KUKA Roboter GmbH must be contacted. Danger! In the absence of functional safety functions and safeguards, the industrial robot can cause personal injury or material damage. If safety functions or safeguards are dismantled or deactivated, the industrial robot may not be op- erated.
If the operating mode is changed during operation, the drives are immediately switched off. The manipulator and any external axes (optional) are stopped with a STOP 0. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 79 / 215...
The operator safety input is used for interlocking physical safeguards. Safety equipment, such as safety gates, can be connected to the dual-channel input. If nothing is connected to this input, operation in Automatic mode is not possi- Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 80 / 215...
Before operation can be resumed, the EMERGENCY STOP button must be turned to release it and the stop message must be acknowledged. Fig. 5-3: EMERGENCY STOP button on the KCP EMERGENCY STOP button Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 81 / 215...
The enabling switches must not be held down by adhesive tape or other means or manipulated in any other way. Death, serious physical injuries or major damage to property may result. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 82 / 215...
Software limit switches The axis ranges of all manipulator and positioner axes are limited by means of adjustable software limit switches. These software limit switches only serve as Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 83 / 215...
If a manipulator (or external axis) collides with a buffer at more than 250 mm/s, the manipulator (or external ax- is) must be exchanged or recommissioning must be carried out by KUKA Ro- boter GmbH.
They must not be modified or removed. Labeling on the industrial robot consists of: Rating plates Warning labels Safety symbols Designation labels Cable markings Identification plates Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 85 / 215...
EMERGENCY STOP active active active active device active active Enabling device Reduced velocity during active program verification active active Jog mode active active active active Software limit switches Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 86 / 215...
The KCP must not be used as long as an external keyboard and/or external mouse are connected. The external keyboard and/or external mouse must be removed as soon as the start-up or maintenance work is completed or the KCP is connected. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 87 / 215...
Avoid vibrations and impacts during transportation in order to prevent damage to the robot controller. Transportation must be carried out in accordance with the operating instruc- tions or assembly instructions of the robot controller. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 88 / 215...
Warning! If additional components (e.g. cables), that are not part of the scope of supply of KUKA Roboter GmbH, are integrated into the industrial robot, the user is responsible for ensuring that these components do not adversely affect or disable safety functions.
Page 90
All other safety-relevant inputs and outputs used Test of reduced velocity control: This test is to be carried out as follows: 1. Program a straight path with the maximum possible velocity. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 90 / 215...
New or modified programs must always be tested first in Manual Reduced Velocity mode (T1). The manipulator, tooling or external axes (optional) must never touch or project beyond the safety fence. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 91 / 215...
The purpose of maintenance and repair work is to ensure that the system is kept operational or, in the event of a fault, to return the system to an operation- Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 92 / 215...
Page 93
Faulty components must be replaced using new components with the same article numbers or equivalent components approved by KUKA Roboter GmbH for this purpose. Cleaning and preventive maintenance work is to be carried out in accordance with the operating instructions.
These components can be used with write access to modify programs, outputs OPC server, or other parameters of the robot controller, without this being noticed by any remote control persons located inside the system. tools Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 94 / 215...
5 Safety Safety measures: KUKA stipulates that these components are to be used exclusively for di- agnosis and visualization. Programs, outputs or other parameters of the robot controller must not be modified using these components. These components can be used to modify programs, outputs or other param-...
Page 96
2007 EN 61000-6-4 Part 6-4: Generic standards; Emission standard for indus- trial environments Safety of machinery: 2006 EN 60204-1 Electrical equipment of machines - Part 1: General requirements Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 96 / 215...
The cable shield must be connected with maximum surface area to the PE rail in the cabinet using shield terminals (screw-type, no clamps). The robot controller may only be operated in an industrial environment. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 97 / 215...
Cooling unit (optional) Warning! If the minimum clearances are not maintained, this can result in damage to the robot controller. The specified minimum clearances must always be ob- served. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 98 / 215...
Page 99
Swing range for door Fig. 6-4: Swing range for cabinet door Swing range, standalone cabinet: Door with computer frame approx. 180° Swing range, butt-mounted cabinets: Door approx. 155° Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 99 / 215...
XS1 CEE connector; the cable is led out of the robot controller (optional) Overview Fig. 6-6: Power supply connection * The N-conductor is only necessary for the service socket option with a 400 V power supply. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 101 / 215...
CEE connector EMERGENCY STOP circuit and safeguard The following examples show how the EMERGENCY STOP circuit and safe- guard of the robot system can be connected to the periphery. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 102 / 215...
Page 103
6 Planning Example Fig. 6-9: Robot with periphery Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 103 / 215...
Page 104
KR C2 edition2005 Example Fig. 6-10: Robot with periphery and external power supply Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 104 / 215...
PST3 manufactured by Pilz Interface X11 Interface X11 EMERGENCY STOP devices must be connected via interface X11 or linked Description together by means of higher-level controllers (e.g. PLC). Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 105 / 215...
Page 106
3.6.2 "Overview of CI3 boards" Page 37) Detailed information about integration into higher-level controllers is con- tained in the Operating and Programming Instructions for System Integra- tors, in the chapter “Automatic External signal diagrams”. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 106 / 215...
Page 108
Is closed if the “Drives ON” nel B signal “Drives ON”. contactor is energized. These contacts are only avail- able if a CI3 Extended or CI3 Tech board is used. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 108 / 215...
controller. An additional PE conductor between the central PE rail of the supply cab- inet and the PE bolt of the robot controller. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 109 / 215...
Page 110
PE to central PE rail of the supply cabinet Connection panel on robot controller Equipotential bonding from the robot controller to the robot Equipotential bonding connection on the robot Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 110 / 215...
RDC power supply for Fast Measurement (option) The figure (>>> Fig. 6-15 ) illustrates the power supply for one RDC. Power supply for one RDC Fig. 6-15: Fast Measurement power supply for one RDC Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 111 / 215...
Sensor 2 6.12 SafeRDC power supply for Fast Measurement (option) The figure (>>> Fig. 6-17 ) illustrates the power supply for one SafeRDC. Power supply for one SafeRDC Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 112 / 215...
Page 113
Fig. 6-18 ) illustrates the power supply for one RDC and one Power supply for SafeRDC. RDC and SafeRDC Fig. 6-18: Fast Measurement power supply for RDC and SafeRDC Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 113 / 215...
1 x 10 (V)KR C2 (edition2005) with 2 top-mounted cabinets 1 x 10 (V)KR C2 (edition2005) with KCP coupler 1 x 10 (V)KR C2 edition2005 with KUKA.SafeOperation 1 x 10 Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 114 / 215...
Page 115
3 x 10 KR C2 edition2005 titan with SafetyBUS Gateway and 3 x 10 KCP coupler For controller variants that are not listed here, please contact KUKA Roboter GmbH. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 115 / 215...
Page 116
KR C2 edition2005 Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 116 / 215...
Lifting tackle with or without lifting frame Necessary equipment 1. Attach the lifting tackle with or without a lifting frame to all 4 transport eye- Procedure bolts on the robot controller. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 117 / 215...
The door of the robot controller must be closed. The robot controller must be upright. The anti-toppling bracket must be fastened to the robot controller. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 118 / 215...
The anti-toppling bracket must be fastened to the robot controller. Procedure Fig. 7-4: Transportation by fork lift truck Robot controller with fork slots Robot controller with transformer installation kit Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 119 / 215...
Page 120
KR C2 edition2005 Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 120 / 215...
8.10 "Switching on the robot controller" Page 125) Check the direction of rotation of the fans. (>>> 8.11 "Checking the direction of rotation of the external fan" Page 125) Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 121 / 215...
Page 122
Optional: install and adjust external energy supply system, Detailed information can be found taking the programming into consideration. in the energy supply system docu- mentation. Positionally accurate robot option: check data. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 122 / 215...
2. Route the control cables to the manipulator junction box separately from the motor cable. Plug in connector X21. 3. Connect the peripheral cables. Fig. 8-1: Example: Installing the cables in the cable duct Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 123 / 215...
X7 dis- connected from the KPS600. Plug connector X7 (1) into the KPS600. Procedure Fig. 8-2: Reversing the battery discharge protection measures Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 124 / 215...
3. Switch on the main switch. The control PC begins to run up the operating system and the control software. Information about operator control of the robot using the KCP can be found in the operating and programming instructions for the KUKA System Soft- ware (KSS). 8.11 Checking the direction of rotation of the external fan Check outlet (2) on the rear of the robot controller.
Page 126
KR C2 edition2005 Fig. 8-3: Checking the direction of rotation of the fan 1 Air inlet 2 Air outlet Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 126 / 215...
This serves to prevent operational and non-operational EMERGEN- CY STOP facilities from becoming interchanged. Failure to observe this precaution may result in death, severe physical inju- ries or considerable damage to property. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 127 / 215...
Failure to observe this precaution may result in severe physical injuries or considerable damage to property. 1. Connect bootable KUKA USB stick. Procedure 2. Switch on the robot controller. 3. Press F10 during the boot procedure. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 128 / 215...
White cables remain under mains voltage even with the main switch turned off! This mains voltage can cause life-threatening injuries. The power cable is de-energized. Observe the ESD guidelines. Fig. 10-1: Maintenance points Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 129 / 215...
2. Clean robot controller with a cloth soaked with a mild cleaning agent. 3. Clean cables, plastic parts and hoses with a solvent-free cleaning agent. 4. Replace damaged, illegible or missing inscriptions, labels and plates. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 130 / 215...
Connector pin allocation Fig. 11-1: Wiring example X11 Caution! If wiring example X11 is used for start-up or troubleshooting, the connected safety components of the robot system are disabled. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 131 / 215...
8. Screw on the new fan. Observe correct installation position (direction of ro- tation). 9. Insert the tab end of the fan plate into the slot. Fig. 11-3 Fan fastening screws Tab end Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 132 / 215...
9. Mount the rear cabinet panel and fasten. Fig. 11-4: Exchanging the external fan Fastening screws and trans- Cable inlet port safeguard Holder with fan Cable to fan connector Fan holder fastening Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 133 / 215...
The power cable is de-energized. Warning! White cables remain under mains voltage even with the main switch turned off! This mains voltage can cause life-threatening injuries. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 134 / 215...
The robot controller must be switched off and secured to prevent unau- Preconditions thorized persons from switching it on again. The controller is shut down. The power cable is de-energized. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 135 / 215...
2. Open the PC chassis. 3. Unplug the connections to the KVGA card. 4. Release the fastenings of the card and pull the card out of the slot. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 136 / 215...
The power cable is de-energized. Warning! White cables remain under mains voltage even with the main switch turned off! This mains voltage can cause life-threatening injuries. Observe the ESD guidelines. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 137 / 215...
7. Place the hard drive on the holder and fasten it with the retaining clip. 8. Close the PC housing and the control cabinet door. 9. Install the operating system and the KUKA System Software (KSS). Fig. 11-8: Exchanging the hard drive...
The power cable is de-energized. Warning! White cables remain under mains voltage even with the main switch turned off! This mains voltage can cause life-threatening injuries. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 139 / 215...
Page 140
5. Carefully pull the RDC board out of the RDC box without tilting it. 6. Insert and fasten the new RDC board. 7. Connect all cables. 8. Close cover of RDC box and screw it firmly in place. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 140 / 215...
This mains voltage can cause life-threatening injuries. Observe the ESD guidelines. 1. Unscrew the 4 screws on the lid of the SafeRDC box. (>>> Fig. 11-13 ) Procedure Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 141 / 215...
Page 142
9. Switch on the robot controller and let it run up. 10. Accept the safety parameters with the correct robot-specific ID. Description Fig. 11-13: SafeRDC box lid fastening Fastening screws on the lid Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 142 / 215...
3. Remove the force sensor card from the SafeRDC board. 4. Plug the new force sensor card onto the SafeRDC board and fasten it. 5. Install SafeRDC board. (>>> 11.15 "Exchanging the SafeRDC board" Page 141) Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 143 / 215...
4. Plug the new I/O Print board onto the SafeRDC board and fasten it with hexagon screws. Tightening torque M =0.9 Nm 5. Install SafeRDC board. (>>> 11.15 "Exchanging the SafeRDC board" Page 141) Description Fig. 11-16: Exchanging the I/O Print board Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 144 / 215...
KPS600 and the low-voltage power supply unit. Fig. 11-17: Battery connection example Spring clamp Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 145 / 215...
5. Insert the new KPS600 into the lower holder, hook it on at the top and tight- en the fastening screws. 6. Plug in all the connections. Fig. 11-18: Exchanging the KPS600 Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 146 / 215...
5. Insert the new KSD evenly and straight into the opening until the upper and lower retaining clips snap in. 6. Plug in all connectors. Fig. 11-19: Exchanging the KSD Retaining clip Locking device Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 147 / 215...
This mains voltage can cause life-threatening injuries. Observe the ESD guidelines. 1. Open the control cabinet door. Procedure 2. Unplug all connectors on the KCP coupler card. 3. Remove the fastening screws. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 148 / 215...
1. Open the control cabinet door. Procedure 2. Remove the foam ring. 3. Exchange the filter insert. 4. Insert the foam ring so that it is flush with the pressure relief plug. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 149 / 215...
Foam ring Filter insert 11.22 Installing the KUKA System Software (KSS) Further information is contained in the operating and programming instruc- tions for the KUKA System Software (KSS). Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 150 / 215...
Troubleshooting 12.1 Repair and procurement of spare parts Repairs to the robot controller may only be carried out by KUKA customer sup- Repair port personnel or by customers who have taken part in a relevant course of training held by KUKA Roboter GmbH.
Power supply to connector X5 Check power supply for KCP missing KCP cable or connector faulty Replace KCP KVGA card defective Exchange KVGA card Defective motherboard Exchange the control PC. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 152 / 215...
KCP status window has a green background. Panic position: Intermediate circuit is rapidly discharged, the “I” in the KCP status window has a red background. Press the Drives ON/OFF buttons. 3. CAN bus Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 153 / 215...
24 V DC interface VCC 24 V DC interface VCC 24 V DC VCC-ESC RDC supply LEDs Item Designation Description LED16 (red) Fuse monitoring for F2 LED5 (red) Fuse monitoring for F16 Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 154 / 215...
Fig. 12-2: CI3 Extended board fuses and LEDs Fuses Item Designation Value in A Description 24 V DC fan monitoring 24 V DC interface VCC 24 V DC interface VCC 24 V DC interface VCC Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 155 / 215...
Page 156
LED22 (red) ESC bus, local ESC node error LED21 (green) ESC bus, local ESC node OK LED19 (red) ESC bus KPS error LED20 (green) ESC bus KPS OK Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 156 / 215...
Fuse monitoring for F15 LED14 (green) 24 V without battery back-up LED9 (green) 24 V with battery back-up LED1 (red) Fuse monitoring for F10 LED12 (red) Fuse monitoring for F23 Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 157 / 215...
24 V DC drives ON 24 V DC drives ON 24 V DC drives ON 24 V DC VCC-ESC 24 V DC lamp CR RDC supply MPI supply Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 158 / 215...
Page 159
LED19 (red) ESC bus KPS error LED20 (green) ESC bus KPS OK LED22 (red) ESC bus, local ESC node error LED21 (green) ESC bus, local ESC node OK Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 159 / 215...
Intermediate circuit voltage 1.5 Hz below 60 V Intermediate circuit voltage above 60 V Flashes at Communication error 6 Hz Flashes at Brake error 3 Hz Main contactor K1 stuck Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 160 / 215...
Page 161
5. Press the enabling switch on the KCP, K1 and K2 on the KPS600 must pick up. 6. Observe any error messages appearing in the KCP message window. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 161 / 215...
Page 162
Brakes not connected Short circuit on brake cable Brake error Ax/PMx channel x Brake error, external axes Brakes not connected Short circuit on brake cable Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 162 / 215...
3. Check the LED status of the KPS-27. State Meaning Green LED Normal operation 12.9 Testing the KSD The operating state of the KSD is indicated by two LEDs on the front. Overview Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 163 / 215...
Check the fans Load on axis too large Parameter error Ax PR1 Checksum error in parameter Check the KSD set 1 Restart Exchange the KSD Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 164 / 215...
0.17...14 Ω 1 - 6 0.17...14 Ω 4 - 5 24...80 Ω 4. Measure the resistance of the motor cable between the KSD and the mo- tor connector. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 166 / 215...
The following LEDs are situated in the door interface: Fault LED (red), KCP coupler Request button with request LED (green) Fig. 12-9: KCP coupler LEDs and request button Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 167 / 215...
Page 168
(approx. 10 Hz) ried out automatically after 10 s. KCP coupler card Fig. 12-10: LEDs on the KCP coupler card Item State Meaning 24 V ESC Switched 24 V ESC Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 168 / 215...
Perform ESC reset. ESC communications error in KCP Check wiring, connectors and con- nections to KCP. Exchange defec- CAN communications error in KCP tive KCP or KCP cable. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 169 / 215...
If the LEDs indicate faulty operation, reboot the robot controller and force a cold start. If the error persists, exchange the SafeRDC board. Description Fig. 12-12: LEDs on the SafeRDC board Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 170 / 215...
Page 171
After boot-up of the SafeRDC board On = Faulty operation Off = Faulty operation Flashing = Normal operation (software running) H1402 Busy LED, channel A Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 171 / 215...
Page 172
On = HIGH level at output QE_B_24V Off = LOW level at output QE_B_24V H2103 Green On = HIGH level at output ENA_B_24V Off = LOW level at output ENA_B_24V Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 172 / 215...
Green Reset Sensor 1 Lights up in the case of a reset 12.16.2 LEDs on the I/O Print board Description Fig. 12-14: LEDs on the I/O Print board Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 173 / 215...
The DSE-RDW diagnostic tool indicates the current state of communication Overview between the DSE and the RDC, on the one hand, and the DSE and the drive bus, on the other. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 174 / 215...
State Operating state of the DSE module DPRAM test Result of the dual-port RAM test Type of RDC module used Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 175 / 215...
2. Select the language and confirm with OK. 12.17.3 MFC3 register display Under "System info", select MFC3 > Display register. Procedure The following parameters are displayed: Description Fig. 12-16: MFC register display Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 176 / 215...
Fig. 12-17: DSE IBS information Parameter Description Control type Type of controller (KR C2, KR C3) DSE hardware Hardware version of the DSE DSE Clock Speed Clock frequency of the DSE used Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 177 / 215...
12.17.6 RDC offset and symmetry adjustment Under "System info", select 1.RDC2 > Offset and symmetry. Procedure Adjustment of the following values is carried out automatically: Adjustment Sine offset Cosine offset Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 178 / 215...
Exchanging the RDC module Sporadic encoder errors 12.17.7 Check RDC-DSE communication Under "System info", select 1.RDC2 > Check communication. Procedure The following parameters are displayed: Description Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 179 / 215...
Page 180
Sum of all incorrect transmissions since the last “Reset comm. errors” Fig. 12-21: Encoded display of the encoder error bits and EMT signals Softkeys Softkey Description Reset comm. errors Sets errors to 0 Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 180 / 215...
Starts / stops continuous updating of the display Refresh Updates the display 12.17.9 Drive bus error list Under "System info", select 1.Drive Bus > Error list. Procedure Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 181 / 215...
Updates the display Reset cycle counter Reset Reset errors Reset Reset error list Reset 12.17.10Drive bus - KPS Under "System info", select 1.Drive Bus > 01-KPS-2. Procedure Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 182 / 215...
Page 183
Start cont. display Starts / stops continuous updating of the display Refresh Updates the display Export Code Table Saves the current code table to the hard drive (example: C:\KRC\Roboter\Log\Drivebus1-4_KSD1- 8.log) Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 183 / 215...
Polling of the current error memory and the last 3 history entries Code position: 161: current error 162: current error -1 163: current error -2 164: current error -3 Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 184 / 215...
The type and number of nodes available depend on the periphery used. The Description ESC diagnosis monitors all the robot controllers in a RoboTeam system. The arrow keys can be used to navigate in the ESC diagnosis tool. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 186 / 215...
The ESC circuit can be reset after an error. The "Reset" softkey is only avail- Description able if CI3 and MFC3 modules are being used. 12.18.4 Terminating ESC diagnosis Terminate ESC diagnosis by pressing the Close softkey. Procedure Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 187 / 215...
Qualifying input Qualifying input Not OK Not OK Drives OFF key Drives enable Green Panic Enabling switch Panic position Gray No panic Gray False AE bit Green True Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 188 / 215...
Defective KCP or KPS, defec- Exchange the defective mod- tive CI3 board, defective con- ule, carry out a visual inspec- nectors or connecting cables, tion of the bus wiring. voltage dips. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 189 / 215...
ESC circuit (e.g. 2 KPS units), the designation of the nodes should be modified in the configuration. This makes it possible to assign them precisely. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 191 / 215...
ESC circuit. A separate configuration can be defined for each structure. The ESC diagnosis loads the suitable configuration based on the structure it finds. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 192 / 215...
12.18.9 Configuring the controller properties The four property boxes of the selected controller are displayed in the Setup Description menu. The controller designations are entered and modified in the property boxes. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 193 / 215...
The contents of the Config name box are valid for all controllers. It is only necessary to enter the configuration name once. 12.18.10Configuring ESC nodes A node must be highlighted. Precondition Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 194 / 215...
The up and down arrow keys can be used to select a signal. The display of the Description signals can be activated or deactivated for the ESC diagnosis by pressing the space bar. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 195 / 215...
The four property boxes of the selected ESC node appear in the Setup menu. Description The node properties can be entered and modified in these property boxes. Fig. 12-34: Example: KPS property boxes Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 196 / 215...
General message. Hardware fault in node xx; observe other error mes- sages. PICA/PICB ESC chip from which the mes- Relevant in the case of super- sage comes. visor errors. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 197 / 215...
Page 198
Channels A-B inter- changed. Crossed connection error on: Short-circuit TA24(A) / Check wiring of the input for E2 keyswitch TA24(B). Single-channel wir- keyswitch E2. ing. Channels A-B inter- changed. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 198 / 215...
Page 199
Check wiring of the input for Activate drives or enable TA24(B). The signals "Activate Activate drives (AA) and drives drives" and "Enable drives" Drives enable (AF). have been interchanged. Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 199 / 215...
Page 200
KR C2 edition2005 Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 200 / 215...
For further assistance, please con- tact your local KUKA subsidiary. Faults leading to production downtime should be reported to the local KUKA subsidiary within one hour of their occurrence. The following information is required for processing a support request:...
Page 203
KUKA Robot Automation Korea Co. Ltd. Korea 4 Ba 806 Sihwa Ind. Complex Sung-Gok Dong, Ansan City Kyunggi Do 425-110 Korea Tel. +82 31 496-9937 or -9938 Fax +82 31 496-9939 info@kukakorea.com Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 203 / 215...
Page 204
Spółka z ograniczoną odpowiedzialnością Oddział w Polsce Ul. Porcelanowa 10 40-246 Katowice Poland Tel. +48 327 30 32 13 or -14 Fax +48 327 30 32 26 ServicePL@kuka-roboter.de Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 204 / 215...
Page 205
Spain Pol. Industrial Torrent de la Pastera Carrer del Bages s/n 08800 Vilanova i la Geltrú (Barcelona) Spain Tel. +34 93 8142-353 Fax +34 93 8142-950 Comercial@kuka-e.com www.kuka-e.com Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 205 / 215...
Page 210
Force sensor card for SafeRDC 29 KPS600, exchange 146 Force sensor card, connections 23 KRL 9 Force sensor card, description 22 KSD error message 186 Force sensor card, exchanging 143 KSD sizes 49 Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 210 / 215...
Page 211
Preventive maintenance work 93 Motherboard 16 Processor 16 Motherboard battery 135 Procurement of spare parts 151 Motor cables 52 Product description 13 Motor connector X20 55 Protective equipment 83 Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 211 / 215...
Page 212
Use, contrary to intended use 73 Signal diagrams 106 Use, improper 73 Simulation 92 User 75 Single point of control 94 User interface, DSE-RDW diagnostic tool 175 Softkeys 32 Software 13, 73 Issued: 06.10.2010 Version: BA KR C2 ed05 V5 en 212 / 215...
Need help?
Do you have a question about the KR C2 and is the answer not in the manual?
Questions and answers