Functional safety supplement L B. SiGNUM angle and linear analogue encoder systems

Transcription

1 L B SiGNUM angle and linear analogue encoder systems

2 Contents: 1 Introduction 3 2 Safety function definition Monitoring of the safety function and action required when limits are exceeded 3 3 Hardware failure data (in accordance with EN ISO :2008) 4 4 Environmental limits 5 5 Fault exclusions 5 6 Installation Rotary scale - all types Linear scale retained using clips Linear scale retained using self adhesive tape Readhead Interface Cables 7 7 Maintenance requirements Cleaning Security of mechanical fastenings 8 8 Repair constraints 8 9 The Renishaw plc quality management system 9 10 EC Declaration of conformity 10 2

3 1 Introduction This Safety Manual details the actions required for the integration of the SiGNUM analogue encoder system into a safety related control system. It is to be used in conjunction with the relevant installation guides referred to by this safety manual. The SiGNUM system as defined below is suitable for use in a Category 3 Performance Level d (PLd) application in compliance with ISO :2008 when installed and operated in accordance with the instructions defined by this safety manual. Failure to follow the instructions and environmental limits contained in this safety manual may result in the performance level not being achieved. Products assessed for PLd safety related use: SiGNUM angle encoder system comprising the SiGNUM analogue readhead series identified by the product name SR-XXX-A, SiGNUM standard, analogue and low noise analogue interface series identified by the product name Si-NN and the encoder ring series identified by the product name prefix RES and defined by installation guide number M titled SiGNUM RESM angle encoder system. SiGNUM linear encoder system comprising the SiGNUM analogue series readhead identified by the product name SR-XXX-A, SiGNUM standard, analogue and low noise analogue interface series identified by the product name Si-NN and the linear encoder series identified by the product name prefix REL or RSL as defined by installation guide number M titled SiGNUM RSLM/RELM high accuracy linear encoder system. Products not assessed for PLd safety related use: The SiGNUM REXM/REXT ultra high accuracy angle encoder system has not been assessed for safety related applications but may be used for non safety related control applications. Functions assessed for PLd safety related use: The sine and cosine analogue outputs as defined by the safety function. Functions not assessed for PLd safety related use: The IN-TRAC reference mark signal function, position limits signals, the digital signals and status LEDs have not been assessed for safety related applications but may be used to check the correct operation of the SiGNUM system for non safety related control applications. For functionally safe end of travel limit operation an alternative method should be used. 2. Safety function definition The SiGNUM encoder system safety function is defined as: The provision of 1 Vpp (nominal) sine and cosine outputs where the cosine output leads the sine output by 90 (or lags by 90 for the opposite direction) in order for the control system to perform incremental counting and thereby confirm machine position is within safe limits. 2.1 Monitoring of the safety function and action required when limits are exceeded To achieve full system integrity to the specified safety performance levels the control system must continuously monitor the condition of the analogue output from the Signum interface as follows: u u The sum of the squares of the differential analogue incremental signals must be monitored for variation from the nominal value of 1, indicating full signal strength where sin 2 + cos 2 = 1. The control system must be programmed to respond by placing the machine into the safe state to changes beyond the limits of sin 2 + cos 2 <0.49 V and >1.69 V. 3

4 NOTES: A. Perform monitoring of the sin 2 + cos 2 function either constantly or at a time interval required by the specific application and risk assessment as conducted by the machine builder/installer. A persistent negative result of this check may indicate a hardware failure of the SiGNUM system or an installation problem. B. For safety related applications, such as for the determination of speed, position or direction of rotation, direct evaluation of the sine and cosine signals must be conducted. Position values which are obtained by interpolation must not be used for safety related functions. C. The evaluation of sine and cosine signals must be done separately and the results must be compared with each other. Unacceptable deviations should be interpreted as a fault condition. D. The size of the allowable deviation must be specified with regard to the possible hazards of the particular application. For fault condition detection described by notes A to C a suitable error response must be initiated, resulting in the machine being placed into a safe state. E. In case of failure, the safe state of the application must be reached before a hazardous situation can occur. Therefore, the sum of the maximum time required for error detection and corresponding error response, must be smaller than the application-specific time required to reach a safe state. The maximum time required for error detection is the time interval within which the diagnostic measures defined by notes A to C 3 can be fully repeated. F. Improper setting of the switching thresholds and hysteresis in signal evaluation can result in incorrect identification of incorrect switching edges or incorrect identification of correct switching edges. This can, for example, lead to the incorrect determination of direction of rotation, position or speed. 3 Hardware failure data (in accordance with EN ISO : 2008) The failure data below is with respect to the SiGNUM safety function as defined above. MTTFd: Environmental limits: Lifetime/replacement limits: Diagnostic coverage: Category: Performance Level (PL): 60 years (high) See section 3 of this safety manual 20 years 99% (low) 3 d 4

5 4 Environmental limits The limits as shown below override those shown by the installation guides M SiGNUM RESM angle encoder system and M SiGNUM RSLM/RELM high accuracy linear encoder system and the data sheets L SiGNUM encoder system and L SiGNUM with FANUC serial interface. Power supply 5 V ±10% <250 ma (typical for system). Readhead 60 ma max. Interface 180 ma max. NOTE: Current consumption figures refer to un-terminated SiGNUM systems. For digital outputs a further 25 ma per channel pair (e.g. A+, A-) will be drawn when terminated with 120R. For analogue outputs a further 20 ma will be drawn when terminated with a 120R resistor. Power supply 5 V dc supply complying with the requirements for PELV of standard EN Ripple 200 mvpp frequency up to 500 khz maximum. Short circuit current: Readhead to interface cable 5 A maximum. Interface to controller cable 5A maximum. The fitment of an external fuse rated at 5A for circuit and fire-protection is recommended. Temperature (system) Storage -20 C to +70 C (readhead) Operating 0 C to +70 C (interface) Operating 0 C to +70 C Humidity Rated up to +40 C, 95% maximum relative humidity (non-condensing) Sealing (readhead) IP64 (interface) IP30 Acceleration (readhead) Operating 500 m/s² EN :1993 Shock (system) Non-operating 1000 m/s², 6 ms, ½ sine EN :2009 Vibration (system) Operating 100 m/s² 55 Hz to 2000 Hz EN :2008 Mass Readhead 15 g with no cable Interface 205 g with no cable Readhead to interface cable 35 g/m EMC compliance (system) BS EN :2008 Readhead cable Double-shielded, outside diameter 4.7 ±0.1 mm maximum Flex life >20 x 10 6 cycles at 20 mm bend radius UL recognised component Pollution degree Readhead 1. Interface 2. 5 Fault exclusions The use of non approved cables to extend the readhead to interface cable. Cutting and reconnecting the read head to interface cable. 6 Installation The information relating to all scale types and mounting options is listed. The machine builder/installer must apply the instructions for the product being installed as defined by the installations guides as shown. The following general conditions must be observed during installation: u ESD handling precautions. u Cleaning mating surfaces before mounting the rotary or linear scales. 5

6 The maximum velocity for the scale relative to the readhead is defined by the SiGNUM RESM angle encoder system installation guide M or the SiGNUM RSLM/RELM high accuracy linear encoder system installation guide M NOTE: These values are only achievable when the readhead is set to it s optimum performance as shown by the blue signal LED. Non optimum settings will reduce the signal strength and hence the maximum operating speed. The fitment of an external fuse rated at 5 A for circuit and fire-protection is recommended. 6.1 Rotary scale - all types The mounting details defined by the SiGNUM RESM angle encoder system installation guide M must be adhered to. The mounting screws are supplied by the customer based on their installation details e.g. thread length of the tapped holes in the mating part. The recommended screw type is M3 x 0.5 and must comply with: ISO 4762/DIN 912 grade 10.9 minimum/ansi B18.3.1M. A minimum thread engagement of 6 mm is required. Comply with the torque settings defined by the SiGNUM RESM angle encoder system installation guide M Linear scale retained using clips The mounting details defined by the SiGNUM RSLM/RELM high accuracy linear encoder system installation guide M must be followed. Only use the screws supplied with the mounting kit. Do not use other types of screws as the screw heads will foul the readhead. Tighten to Nm. 6.3 Linear scale retained using self adhesive tape The mounting details defined by the SiGNUM RSLM/RELM high accuracy linear encoder system installation guide M must be followed. Ensure the surfaces are cleaned and the scale is applied as defined by this installation guide. Do not attempt to move the scale after bonding as damage to the adhesive bond will occur. 6.4 Readhead The mounting details defined by the SiGNUM RESM angle encoder system installation guide M or the SiGNUM RSLM/RELM high accuracy linear encoder system installation guide M must be followed. Additionally: The mounting screws are supplied by the customer based on their installation details e.g. thread length. The recommended screw type is M3 x 0.5 and must comply with: ISO 4762/DIN 912 grade 8.8 minimum/ansi B18.3.1M. A minimum thread engagement of 6 mm is required. Tighten to Nm. No washer is required under the screw head. 6

7 6.5 Interface The mounting details defined by the SiGNUM RESM angle encoder system installation guide M or the SiGNUM RSLM/RELM high accuracy linear encoder system installation guide M must be followed. Additionally: The mounting screws are supplied by the customer based on their installation details e.g. thread length. The recommended screw type is M3 x 0.5 and must comply with: ISO 4762/DIN 912 grade 8.8 minimum/ansi B18.3.1M. A minimum thread engagement of 6 mm is required. Tighten to Nm. No washer is required under the screw head. The DIN rail mounting where used must comply with EN Cables The mounting details defined by the SiGNUM RESM angle encoder system installation guide M or the SiGNUM RSLM/RELM high accuracy linear encoder system installation guide M must be followed. Additionally: The readhead to interface cable must be secured to a part that does not move relative to the readhead using a suitable clip within 50 mm of exiting the readhead with a minimum bend radius >10 mm. Cable rolling radius must be >25 mm when the cable is routed through moving trunking/a cable chain. Route the cable away from operating environments that will exceed the EMC limits defined EN Ensure the readhead to interface connector screws are correctly tightened. To maintain the safety function under all conditions use only Renishaw approved cables between the readhead and the interface. Do not cut and re-terminate the readhead to interface cable as this may result in failure to operate correctly in the EMC environment defined by EN Maintenance requirements The maintenance check intervals will be as defined by the machine builder/installer according to their risk assessment. There are no user serviceable parts within the readhead. The readhead lid must not be removed as it will break the IP64 seal. Do not adjust or remove the encoder ring screws. Remove readhead, clean optical window and mounting surface, re-install as per installation guide M

8 7.1 Cleaning All scale types - wipe the calibrated surface of scale using a lint free cloth wetted only with IPA or N-Heptane. Do not soak adhesive backed scale with solvent. When cleaning the linear scale retained by the mounting clips ensure the cleaning cloth does not catch on and bend the clips. Readhead wipe the glass window using a dry lint free cloth. Do not use a solvent. Interface and cables no cleaning is required. 7.2 Security of mechanical fastenings The failure of the readhead, ring or linear scale mounting will be detected by the safety function. No checks of the fastenings for these parts are required to maintain the safety function. It is recommended that the ring retaining screws are not checked for tightness as this may result in the ring setting being changed. This will not affect the safety function but may affect the signal level and hence cause the safety function to be implemented. The following periodic checks are recommended. The check interval will be as defined by the machine builder/installer: u u u Linear scale check clip retaining screws are correctly tightened using a torque wrench as defined in installation guide M Readhead and interface check mounting screws are correctly tightened. Cables check connector screws are correctly tightened using a torque wrench as defined in installation guide M check for insulation damage/cuts. Replace any damaged cables with a Renishaw approved cable. 8 Repair constraints There are no user serviceable parts contained in the readhead or interface. Repair is limited to replacement of the SiGNUM system parts as required. Removal of the parts is the reverse of the installation process with the exception that for the linear scale retained using the double-sided tape option the mounting face will need to be cleaned with N-Heptane or IPA to remove all traces of adhesive prior to fitting a new length of scale. The instructions in this installation guide are to be followed when installing, adjusting and commissioning the replacement parts. 8

9 9 The Renishaw plc quality management system Renishaw plc operates an ISO9001: 2008 quality management system certified by BSI against certificate FM There are defined processes for each of the applicable clauses defined by ISO9001. A summary of the key business areas covered by the certification is: u The design and development of products and manufacturing processes. The overall process flow followed is feasibility > development > scale up > production. A stage gate process is used where each stage of work is signed off before the next stage continues. Software development is approved to TickIT. u The manufacturing, assembly, final testing and inspection of products before shipment to customers using trained staff and equipment calibrated to traceable standards. u The management of changes arising from customer feedback and from general continual improvement of the products and the manufacturing processes. u The management of quality including conducting weekly reviews of product quality, quarterly reviews of the effectiveness of the quality management system and conducting internal audits. Improvement actions are defined and implemented as required. u The management of the documentation and records that support the above. u The management of the compliance of the products with: all applicable worldwide regulations e.g. CE marking, WEEE, RoHS, FCC etc. the relevant technical standards e.g. functional safety reference IEC61508: 2010, ISO13849: 2008 etc. 3rd party approvals e.g. the CB scheme for electrical safety. 9

10 Renishaw plc New Mills, Wotton-under-Edge, Gloucestershire GL12 8JR United Kingdom T +44 (0) F +44 (0) E uk@renishaw.com 10 EC Declaration of conformity EC DECLARATION OF CONFORMITY Renishaw plc declares that the products:- Name: Description: Part nos.: Signum Encoders and Signum Interfaces Signum encoder readheads Signum analogue interface and analogue outputs from digital interfaces. For use in Category 3 PLd applications in compliance with ISO :2008 SR - all readheads Si-NN series interfaces Complies with these directives: 2004/108/EC 2006/95/EC 2006/42/EC 2011/65/EU Electromagnetic compatibility Electrical equipment designed for use within certain voltage limits Machinery The Restriction of the use of certain Hazardous Substances in electrical and electronic equipment (RoHS) Complies with these standards: BS EN :2008 BS EN 62471:2008 BS EN :2008 Electrical equipment for measurement, control and laboratory use. EMC requirements. Immunity requirements for safetyrelated systems and for equipment intended to perform safetyrelated functions (functional safety). General industrial applications Photo-biological safety of lamps and lamp systems Safety of machinery safety-related parts of controls systems, Part 1 General principles for design Person authorised to compile the technical file and issue the declaration of conformity is: Mark Acres, Regulatory Compliance Manager, Encoder Products Division, Renishaw plc. New Mills, Wotton under Edge Gloucestershire, GL12 8JR, United Kingdom Signed: Dated: 06/10/2014 Reference no. ECD Place: Wotton under Edge 10 For worldwide contact details, please visit our main website at RENISHAW HAS MADE CONSIDERABLE EFFORTS TO ENSURE THE CONTENT OF THIS DOCUMENT IS CORRECT AT THE DATE OF PUBLICATION BUT MAKES NO WARRANTIES OR REPRESENTATIONS REGARDING THE CONTENT. RENISHAW EXCLUDES LIABILITY, HOWSOEVER ARISING, FOR ANY INACCURACIES IN THIS DOCUMENT. RENISHAW and the probe symbol used in the RENISHAW logo are registered trade marks of Renishaw plc in the United Kingdom and other countries. apply innovation and names and designations of other Renishaw products and technologies are trade marks of Renishaw plc or its subsidiaries Renishaw plc All rights reserved Issued 0418 *L *