RGH25F encoder system

Transcription

1 L A The Renishaw RGH25F series is a non-contact optical encoder system, providing highly-reliable position feedback. This system consists of an ultra-compact RGH25F readhead that reads a graduated scale, and an REF interface that outputs a choice of industry standard 1Vpp analogue or RS422 digital signals down to 5 nm resolution. It offers the benefits of Renishaw s established encoder series, such as a set-up LED indicator for easy installation, and unique filtering optics for excellent dirt immunity. Additionally, the low profile of RGH25F and the flexible remote mounting options of the REF interface allow for easy integration into all but the most restricted spaces. The automatic gain control and unique self-tuning adaptive electronics within the REF interface improve the already excellent signal integrity, and gives even lower cyclic errors. The RGH25F reads the 20 µm pitch RGS20 gold tape-scale. RGS20 is suitable for mounting to most common engineering materials including metals, granites, ceramics and composites. The scale can be mastered to the axis substrate by means of specially formulated pre-applied adhesive and epoxy fastened end clamps. This method ensures the differential movement between the scale and the substrate is close to zero, even with significant temperature swings. Common applications include optical fibre alignment, semiconductor manufacturing, inspection, precision stages and other systems requiring high resolution where space is at a premium. For vacuum applications, Renishaw also offers an ultra-high vacuum (UHV) compatible RGH25F. It is specially constructed from clean UHV compatible materials and adhesives to give low outgassing rates. RGH25F readhead and REF interface: Customer selectable AGC operational at all speeds Digital and analogue output options Resolutions from 5 µm to 5 nm Low cyclic error (<50 nm) Self-tuning adaptive electronics give reliability and high accuracy Low mass readhead Tri-coloured set-up LED indicating signal strength RGS20 scale: Cut-to-length flexibility Lengths from 100 mm to over 50 m Protective lacquer or tough polyester coating option for applications using harsh solvents Efficient, accurate installation Affixes to most common engineering materials Self-adhesive backing tape Applicator tool allows scale to be installed using the motion of the axis

2 RGH25F readhead installation drawing Fixing screws M3 x 0.5 x 8 Alternative mounting face Arrow indicates forward direction of readhead relative to scale 8 6 (RGS20-S) 6.3 (RGS20-P) Dimensions and tolerances in mm ( ) See note 11.5* mounting holes M3 x 0.5 through (Yaw tol. ± 0.5 ) Mounting face > 4 R>20 dynamic bend radius R>10 static bend radius (Extent of mounting faces) (Roll tol. ± 1 ) 0.09 Reference mark actuator (A ) Ø4.4 max (Pitch tol. ± 1 ) A * 4* 8* Detail A Optical centreline Reference mark sensor position Scale surface Scale thickness 0.2 (RGS20-S) 0.3 (RGS20-P) * Dimensions measured from substrate. Required nominal 0.8 gap can be set using blue readhead spacer (supplied) positioned between readhead and actuator when positioning/fixing the actuator. Readhead to scale clearance 0.8 ± 0.1 Rideheight REF installation drawing Dimensions and tolerances in mm Optional mounting brackets (A ) NOTE: Remove washers when installing brackets Max. screw size M Input 15 way D type socket Calibrate button Set up LED CAL /AGC LED Output 15 way D type plug Nm torque

3 General specifications Power supply (system) 5 V -5 % +10 % 200 ma maximum NOTE: Current consumption figures refer to unterminated interfaces For digital outputs a further 25 ma per channel pair (e.g. A+, A-) will be Ripple drawn when terminated with 120 Ω. For analogue outputs a further 20 ma will be drawn when terminated with 120 Ω. Power from a 5 V dc supply complying with the requirements for SELV of standard IEC BS EN Temperature (system) Storage -20 C to +70 C Operating 0 C to +55 C The interface will be fully active <300 ms after power is applied. The readhead and interface are protected from reverse voltage and over voltage up to 12 V. 200 mvpp@frequency up to 500 khz maximum. Humidity (system) 95% relative humidity (non-condensing) to EN Sealing Readhead IP40 Interface IP20 Acceleration (system) Operating 500 m/s 2, 3 axes Shock (system) Non-operating 1000 m/s 2, 6 ms, ½ sine, 3 axes Vibration (system) Operating 100 m/s 2 55 Hz to 2000 Hz, 3 axes Mass Readhead 9 g Readhead cable 34 g/m Interface 100 g Readhead cable Double shielded, maximum diameter 4.4 mm. Flex life >20 x 10 6 cycles at 20 mm bend radius. Maximum cable lengths Readhead 5 m Interface to receiving electronics: Analogue output Digital output 100 m Recommended clock frequency (MHz) Maximum cable length (m)

4 RGS20 scale installation drawing Dimensions and tolerances in mm Measuring length (ML) >5 >5 Bolted reference mark actuator shown (A ) Reference mark/limit switch actuator position range >15 < F 0.2/100 F = axis of motion 13 6 (RGS20-S) 6.3 (RGS20-P) Scale length (ML + 40) Overall length (ML + 70) NOTE: The surface roughness of the scale mounting surface must be 3.2 Ra. The parallelism of the scale surface to the axis of motion (readhead rideheight variation) must be within 0.05 mm. Scale specifications Scale type RGS20-S Reflective gold plated steel tape with protective lacquer coating. Adhesive backing tape allows direct mounting to the machine substrate. RGS20-P Reflective gold plated steel tape with tough polyester coating for applications using harsh solvents. Adhesive backing tape allows direct mounting to the machine substrate. Scale period 20 µm Linearity RGS20-S ±3 µm/m RGS20-P ±5 µm/m Scale length Up to 50 m (>50 m by special order) Form (H x W) RGS20-S 0.2 mm x 6 mm (includes adhesive) RGS20-P 0.3 mm x 6.3 mm (includes adhesive) Substrate materials Expansion coefficient End fixing Metals, ceramics and composites with expansion coefficients between 0 and 22 µm/m/ C (steel, aluminium, Invar, granite, ceramic etc.) Matches that of substrate material when scale ends are fixed by epoxy mounted end clamps Epoxy mounted end clamps (A ) using 2 part epoxy adhesive (A ) Scale end movement <1 µm over temperature range -20 C to +50 C Temperature Operating -10 C to +120 C. Minimum installation 10 C Storage -20 C to +70 C. Humidity 95% relative humidity (non-condensing) to EN

5 REF interface features Self-tuning active correction The REF interface actively corrects for input signal imperfections to optimise system accuracy. Corrections are made for the following: Automatic Offset Control (AOC) adjusts offset independently for the sine and cosine signals Automatic Gain Control (AGC) ensures consistent 1 Vpp signal amplitude Automatic Balance Control (ABC) adjusts the gain to equalise the sine and cosine signals These correction mechanisms operate over the full working speed range of the readhead. The user can disable/enable the AGC by depressing the CALIBRATE button for greater than 3 seconds. LED indicators The REF interface SETUP LED provides visual feedback of signal strength, error condition and reference mark phasing, for setup and diagnostic use. Flashing Purple indicates high signal alarm condition >135% Purple indicates high signal >110% and <135% Blue indicates optimum signal >90% and <110% Green indicates acceptable signal >70% and <90% Orange indicates low signal >50% and <70% Red indicates unacceptable signal >20% and <50% Flashing Red indicates unacceptable signal alarm condition <20% Flashing Blue indicates overspeed alarm condition Red flash when traversing reference mark indicates good phasing* Orange flash when traversing reference mark indicates poor phasing* Blank flash when traversing reference mark indicates phasing unacceptable* The Yellow CAL/AGC LED indicates when the REF is in a calibration routine and whether or not AGC is active LED on indicates AGC active LED off indicates AGC inactive LED slow flashing indicates calibration routine LED fast flashing indicates calibration failure Alarm output The REF interface asserts the alarm output (E) for the following conditions:- Incremental signal level below 20% Incremental signal level above 135% Readhead speed in excess of specification Signal offset compensation of sine and cosine excessive Signal balance compensation excessive *Reference mark flashes only occur up to 100 mm/s traverse speed. 5

6 Speed Digital systems, maximum speed (m/s) Resolution (µm) Analogue system - RGH25F + REF Recommended minimum clock frequency (MHz) Internal clock frequency (MHz) Signal amplititude (%) Frequency (khz) Interpolation factor (period to resolution) AGC Off AGC On Speed (m/s) Output signals Input Output way D type socket 15 way D type plug Function Wire colours from readhead Analogue input Digital output Analogue output Signal Pin Signal Pin Signal Pin Power Incremental signals Red 5 V 8 5 V 7, 8 5 V 4, 5 White 0 V 9 0 V 2, 9 0 V 12,13 Green A 6 A+ 14 V Yellow B 5 A- 6 V 1-1 Blue C 4 B+ 13 V B- 5 V 2-2 Z+ / Q+ 12 V 0 + / V q + 3 Reference mark / limit Pink Hall 1 Z- / Q- 4 V 0 - / V q - 11 E+ 11 Alarm E- 3 Ired servo Brown Servo 3 External set-up V x 13 X 1 V MID Interface V MID 7 Sin monitor* outputs only Sin monitor 11 Cos monitor* Cos monitor 10 Inner 15 Shield Outer Case Outer Case Outer Case Do not connect Not connected 2, , 14, 15 * % signal amplitude centred on 1.65 V 6

7 Electrical connections Grounding and shielding RGH25F Inner shield (except UHV) REF interface Extension cable Customer electronics 5 V 0 V power Output signals Outer shield 0 V Pin 15 IMPORTANT: The outer shield should be connected to the machine earth (Field Ground). The inner shield should be connected to 0 V at customer electronics only. Care should be taken to ensure that the inner and outer shields are insulated from each other. If the inner and outer shields are connected together, this will cause a short between 0 V and earth, which could cause electrical noise issues. Recommended signal termination Digital outputs 0 V 5 V Analogue output, REF0000 only Interface A B Z Q E+ 220 pf 1k # Customer electronics V q V 0 V 1 V 2 + Cable Z 0 = 120 Ω 120 Ω 120 Ω A B Z Q E- 220 pf 1k # V q V 0 V 1 V 2-0 V 0 V # Only required on alarm channel E for fail safe operation. Standard RS422A line receiver circuitry. Capacitors recommended for improved noise immunity. 7

8 Output specifications Digital output signals - type REF digital output interfaces Form - Square wave differential line driver to EIA RS422A Incremental 2 channels A and B in quadrature (90 phase shifted) Signal period Resolution Analogue output signals - type REF0000 Form - 1 Vpp differential Incremental 2 channels V 1 and V 2 differential sinusoids in quadrature (90 phase shifted) 20 µm A B (V 1 +) -(V 1 -) (V 2 +) - (V 2 -) 90 1 Vpp (nominal) with AGC active Reference Z Wide reference (option C) Z Limit Q Repeatability <0.1 mm typical Length of actuating magnet Asynchronous pulse Q NOTE: RGH25F readheads and REF interfaces are available with reference mark or limit switch detection. Actuation device A /A Alarm E 20 ms minimum Asynchronous pulse E Set-up 1 Synchronised pulse Z, duration as resolution Synchronised pulse Z, duration as signal period Repeatability of position (uni-directional) maintained within ±10 C from installation temperature and for speed <250 mm/s Actuation device A /A NOTE: Wide reference mark option useful when using long cable lengths and/ or high speed operation to overcome effects of skew Alarm asserted when: - >20% signal amplitude >135% - Readhead exceeds specified maximum speed - Signal offset excessive NOTE: 3-state alarm option also available Reference (V 0 +) - (V 0 -) -18 Limit (V q +) - (V q -) 0 Asynchronous pulse V q V Repeatability <0.1 mm typical Length of actuating magnet Differential pulse I 0-18 to 108. Duration 126 (electrical) Repeatability of position (uni-directional) maintained within ±10 C from installation temperature and for speed <250 mm/s Actuation device A / A NOTE: RGH25F readheads and REF interfaces are available with reference mark or limit switch detection. Actuation device A /A Set-up 1 Voltage at V X 0 0 Signal level 1 V Setup signal voltage proportional to signal amplitude 100% Voltage at X 0 0 Signal level 100% Setup signal voltage proportional to signal amplitude Inverse signals not shown for clarity 8

9 RGH25F system = readhead and interface + scale + accessories Readhead part numbers Readhead series Cable length m 30-3 m 50-5 m Termination J - 15 pin D type plug for REF interface M - 15 pin D type plug for REF interface (vacuum only) Options 00 - Standard head 01 - Vacuum head and cable Reference mark / limit switch A - Standard reference mark B - Standard limit switch C - Vacuum reference mark D - Vacuum limit switch Interface part numbers (analogue output) for use with RGH25F Options A - Reference mark B - Limit switch RGH25F 15 J 00 A REF 0000 A 00 A Interface part numbers (digital output) for use with RGH25F Interface series Interpolation factor* µm µm µm µm µm nm nm nm nm Alarms Standard alarm E A - All alarms B - High and low signal alarms only 3 - state alarms E- All alarms F - High and low signal alarms only Clocked output MHz customer clock MHz customer clock MHz customer clock MHz customer clock MHz customer clock MHz customer clock 08-8 MHz customer clock 06-6 MHz customer clock 05-5 MHz customer clock 03-3 MHz customer clock 01-1 MHz customer clock Options A - Reference mark B - Limit switch C - Wide reference mark REF 0100 E 25 A * Binary interpolation factors from x4 to x4096 also available NOTE: Not all combinations are valid. Check valid options online at 9

10 Scale part numbers RGS20-S 20 µm pitch lacquered tape scale with self-adhesive backing tape. Part number Available lengths Available in increments of Ordering instructions A mm to 50,000 mm* 1 mm Ordering a quantity of 2455 will result in a length of 2455 mm (multiple orders are required for multiple lengths) A m to 50 m* 1 m Ordering a quantity of 15 will result in a length of 15 metres (multiple orders are required for multiple lengths) A xxx 10 cm to 999 cm 1 cm xxx is the length in cm (ordering A for example will result in a length of 450 cm) A xx 10 m to 50 m* 1 m xx is the length in metres (ordering A for example will result in a length of 33 metres) RGS20-P 20 µm pitch polyester coated tape scale with self-adhesive backing tape. Part number Available lengths Available in increments of Ordering instructions A mm to 50,000 mm* 1 mm Ordering a quantity of 2455 will result in a length of 2455 mm (multiple orders are required for multiple lengths) A m to 50 m* 1 m Ordering a quantity of 15 will result in a length of 15 metres (multiple orders are required for multiple lengths) * Lengths above 50 m are special order only. Please contact your local Renishaw representative. 10

11 Renishaw plc New Mills, Wotton-under-Edge, Gloucestershire GL12 8JR United Kingdom T +44 (0) F +44 (0) E uk@renishaw.com Accessory part numbers Part number Description Image A RGM245S reference mark actuator magnet screw mounted. A reference sensor within the readhead is used to determine an absolute datum within an incremental measuring system. The sensor does this by detecting the external RGM245S reference mark actuator magnet as the readhead passes it. A RGM22S reference mark actuator magnet epoxy mounted. A reference sensor within the readhead is used to determine an absolute datum within an incremental measuring system. The sensor does this by detecting the external RGM22S reference mark actuator magnet as the readhead passes it. A RGP245S 90 limit switch actuator magnet screw mounted. A limit sensor within the readhead detects end of travel by sensing the RGP245S limit switch actuator magnet. A RGP22S limit switch actuator magnet 10 mm long epoxy mounted. A limit sensor within the readhead detects end of travel by sensing the RGP22S limit switch actuator magnet. A RGC-F end clamp kit epoxy mounted. The RGC-F end clamps master the RGS scale to the substrate material to match its thermal expansion. A RGG-2 2 part epoxy adhesive. The RGG-2 epoxy is recommended for the mounting of reference marks, limit switches and end clamps. A RGA245 scale applicator guide block kit (for RGS20-S lacquered scale). The RGA245 enables efficient and accurate scale application. Fixed to the customers readhead bracket it allows the correct placement of scale relative to where the readhead will be set. A Scale applicator guide block kit (for RGS20-P polyester coated scale). The scale guide block enables efficient and accurate scale application. Fixed to the customers readhead bracket it allows the correct placement of scale relative to where the readhead will be set. 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 0118 *L *