Ha0193T_21_Scanning Galvo System GVSM001 M Manual
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GVS001 GVS101 GVS201 GVS301 and and and and GVS002 GVS102 GVS202 GVS302 Scanning Galvo Systems User Guide Original Instructions Contents Chapter 1 For Your Safety ............................................................................. 3 1.1 Safety Information .................................................................................. 3 1.2 Warnings ................................................................................................ 3 Chapter 2 Overview......................................................................................... 4 2.1 Introduction ............................................................................................. 4 2.2 System Description ................................................................................ 5 Chapter 3 Installation & Initial Set Up .......................................................... 8 3.1 Dimensions ............................................................................................. 8 3.2 Mechanical Installation ......................................................................... 12 3.3 Electrical Installation ............................................................................. 15 Chapter 4 Operation ..................................................................................... 20 4.1 General Operation ................................................................................ 20 4.2 External Enabling of the driver board ................................................... 20 4.3 Using a DAQ Card ................................................................................ 20 Chapter 5 Troubleshooting ......................................................................... 21 5.1 Common Problems ............................................................................... 21 5.2 Galvanometer Faults ............................................................................ 24 Appendices Appendix A Specifications and Associated Products .............................. 25 1.1 Specifications ....................................................................................... 25 1.2 Associated Products ............................................................................. 26 Appendix B Calculating the Power Dissipation ........................................ 27 Appendix C Reasons For Image Distortion ............................................... 28 Appendix D Regulatory................................................................................. 30 2 HA0193T Rev 21 Jan 2018 Chapter 1 Safety 1.1 Safety Information For the continuing safety of the operators of this equipment, and the protection of the equipment itself, the operator should take note of the Warnings, Cautions and Notes throughout this handbook and, where visible, on the product itself. The following safety symbols may be used throughout the ha ndbook and on the equipment itself. Shock Warning Given when there is a risk of injury from electrical shock. Warning Given when there is a risk of injury to users. Caution Given when there is a risk of damage to the product. Note Clarification of an instruction or additional information. 1.2 General Warnings Warnings If this equipment is used in a manner not specified by the manufacturer, the protection provided by the equipment may be impaired. In particular, excessive moisture may impair operation. Spillage of fluid, such as sample solutions, should be avoided. If spillage does occur, clean up immediately using absorbant tissue. Do not allow spilled fluid to enter the internal mechanism. Although the unit does not emit radiation, it does redirect laser radiation emitted from other devices. Operators must follow all safety precautions provided by the manufacturer of any associated laser devices. 3 Chapter 2 Overview 2.1 Introduction The GVS series scanning galvo systems are board level, mirror positioning systems, designed for integration into OEM or custom laser beam steering applications. The single axis systems consists of a motor and mirror assembly, a mounting bracket, a tuned driver card and a heat sink. The dual axis systems comprises two mirror and motor assemblies, an X-Y mounting bracket, two driver cards and two heat sinks. The driver cards feature a small footprint, fixings for easy mounting to a heatsink and a simple analog command signal interface. A choice of mirror coating is available as follows: GVS001 and GVS002: Single- and Dual-Axis Systems with Protected Silver Mirrors GVS101 and GVS102: Single- and Dual-Axis Systems with Protected Gold Mirrors GVS201 and GVS202: Single- and Dual-Axis Systems with 400-750 nm Broadband Dielectric Mirrors GVS301 and GVS302: Single- and Dual-Axis Systems with High Power Dual Band (532 and 1064 nm) Nd: YAG Mirrors Typical applications include laser scanning, laser microscopy, and laser marking. Fig. 2.1 GVS002 2-Axis Galvo System (Post Adapter and post not included) 4 Single- and Dual-Axis Scanning Galvo Systems for Small Beam Diameters 2.2 System Description 2.2.1 Introduction Galvo Scanners are widely used in a pplications such as l aser etching, confocal microscopy, and laser imaging. A galvanometer is a precision motor with a limited travel, usually much less than 360 degrees, whose acceleration is directly proportional to the current applied to the motor coils. When current is applied, the motor shaft rotates through an arc. Mo tion is stopped by applying a current of reverse polarity. If the current is removed, the motor comes to rest under friction. Typically, the term ' Galvo' refers only to the motor assembl y, whereas a 'Galvo Scanner' would include the motor, tog ether with a mirror, mirro r mount and driver electronics. A description of each component in the system is contained in the following sections. 2.2.2 The Galvanometer The galvanometer consists of two main components: a motor that moves the mirror and a detector that feeds back mirror position information to the system. Y-Axis Mirror X-Axis Mirror Fig. 2.2 GVS002 Dual Axis Galvo/Mirror Assembly Our galvo motor features a moving magnet, which means that the magnet is part of the rotor and the coil is part of the stator. This configuration provides faster response and higher system-resonant frequencies when compared to moving coil configurations. Mirror position information is provided by an optical position detector, which consists of two pairs of photodiodes and a light source. As the galvo and mirrors are moved, differing amounts of light are detected by the photodiodes and the current produced is relative to the galvo actuator position. 5 Chapter 2 2.2.3 The Mirror The mirror assembly is attached to the end of the actuator, and deflects the light beam over the angular range of the motor shaft. Scanning galvo applications demand high speed and frequencies of th e shaft rotation, and so the in ertia of the actuator and mirror assembly can have a profound effect on the performance of the system. High resonant frequencies and enhanced stiffness in the mirror a ssembly also add to system performance by increasing bandwidth and response times. Wavelength ranges and damage threshold of the different mirror coatings are details below: Part No Coating Wavelength Damage Threshold GVS00x Silver 500 nm - 2.0 µm 3 J/cm2 at 1064 nm, 10 ns pulse GVS10x Gold 800 nm - 20.0 µm 2 J/cm2 at 1064 nm, 10 ns pulse GVS20x E02 400 nm - 750 nm 0.25 J/cm2 at 532 nm, 10 ns pulse GVS30x K13 532 nm and 1064 nm 5 J/cm2 at 1064 nm, 10 ns pulse Fig. 2.3 Mirror Assembly Detail 6 HA0193T Rev 21 Jan 2018 Single- and Dual-Axis Scanning Galvo Systems for Small Beam Diameters 2.2.4 Servo Driver Board The servo circuit interprets the signals from the position detector, then uses positional error, speed and integral of current terms to output control vo ltages to drive the actuator to the demanded position. The scanner uses a non-integrating, Class 0 serv o, which enables higher system speeds compared to integrating servo systems, and is ideal for use i n applications that require vector positioning (e.g. la ser marking) or raster positioning (printing or scanning laser microscopy). It can also be used in some step and hold applications. Furthermore, the proportional derivative circuit gives excellent dynamic performance and includes an additional current term to ensure stability at high accelerations. The diagram below shows the architecture of the driver in more detail. Notch Filter position Jumper Differentiator Position Sensing Circuit speed error Difference Amplifier Power Amplifier Summing Amplifier Command Signal Amplifier current Integrator Current Sensing Circuit Fig. 2.4 Servo Driver Board Schematic Diagram Fig. 2.5 Servo Driver Circuit Board 7 Chapter 3 Installation & Initial Set Up 3.1 Dimensions 3.1.1 Motor Assembly Dimensions 1.49 (37.8) 0.87 (22.0) Ø 0.1 (2.5) 1.22 (31.0) Ø 0.9 (23.2) Ø 0.5 (12.6) 0.09 (2.3) 0.06 (1.5) all dimensions in inches (mm) Fig. 3.1 Motor Dimensions 3.1.2 Mirror Dimensions X-Axis Mirror 0.39 (10.0) 0.04 (1.0) 0.32 (8.0) Y-Axis Mirror 0.34 (8.5) 0.57 (14.5) 0.04 (1.0) all dimensions in inches (mm) Fig. 3.2 Mirror Dimensions 8 Single- and Dual-Axis Scanning Galvo Systems for Small Beam Diameters 3.1.3 Single Axis Mount Dimensions 1.5 (38.0) 0.75 (19.0) 0.53 (13.5) 0.59 (15.0) 0.35 (9.0) 0.33 (8.5) Ø 0.52 (13.2) M3 x 0.5 -6H 0.43 (11.0) 0.55 (14.0) 0.33 (8.5) 0.55 (14.0) 2 x Ø2.5 8.0 M3 x 0.5 -6H 6.0 0.98 (25.0) Ø 3.5 to SLOT Ø 6.0 3.0 0.17 (4.3) 0.12 (3.0) 0.39 (10.0) 0.53 (13.5) Qty 5 SLOTS 0.35 (9.0) 0.65 (16.5) 0.08 (2.0) Typ R 0.04 (1.0) 1.38 (35.0) 0.79 (20.0) 0.43 (11.0) 0.03 (0.75) 2 x Ø 2.5 8.0 M3 x 0.5 -6H 6.0 0.08 (2.0) Typ 0.06 (1.5) all dimensions in inches (mm) Fig. 3.3 Single Axis Mounting Bracket Dimensions 9 Chapter 3 3.1.4 XY Mount Dimensions 1.5 (38.0) Ø 0.52 (13.2) 0.67 (17.0) 0.06 (1.5) 0.6 (16.0) 0.07 (1.8) 0.04 (1.0) 1.58 (40.0) 0.55 (14.0) 0.2 (5.0) 0.24 (6.0) 0.2 (5.0) 0.87 (22.0) 0.75 (19.0) 1.16 (29.5) 0.39 (10.00) 0.75 (19.0) 0.06 (1.5) M3 x 6 Qty 3 0.39 0.2 (10.00) (5.0) 0.2 (5.0) M3 x 6 Qty 3 1.34 (34.0) 0.55 (14.0) Ø 0.52 (13.2) 0.02 (0.5) 0.98 (25.0) 0.39 (10.0) 0.17 (4.3) Ø 0.14 (3.5) CSK 0.24 (6.0) Qty 2 0.34 (8.5) 1.1 (28.0) 0.02 (0.5) all dimensions in inches (mm) Fig. 3.4 XY Mounting Bracket Dimensions 10 HA0193T Rev 21 Jan 2018 Single- and Dual-Axis Scanning Galvo Systems for Small Beam Diameters 3.1.5 Heatsink Dimensions GHS002 100.0 (3.94) Drill & Tap M3 Thru 97.0 (3.82) 52.0 (2.05) 19.0 (0.75) 11.20 (0.44) 10.40 (0.41) Fig. 3.5 Heatsink Dimensions 3.1.6 Servo Driver Board Baseplate Dimensions 45.0 (1.77) 44.2 (1.74) 1.6 (0.06) 24.2 (0.95) 33.0 (1.3) 7.2 (0.28) 15.0 (0.59) 3.0 (0.12) 74.0 (2.9) 45.88 (1.81) 25.5 (1.0) 3.0 (0.12) 3.5 (0.14) DIA and CSK to Suit M3 Screw on Underside (4 Positions) 54.0 (2.13) Slot 66.0 (2.6) 6.0 Typ (2.36) 9.07 (0.36) 5.0 (0.2) 4.8 (0.19) M3 (3 Positions) 52.5 (2.07) 3.5 (0.14) DIA 6.5 (0.26) 3.3 (0.13) 74.8 (2.95) 3.0 (0.12) 24.0 (0.94) All dimensions in mm (inches) 25.0 (0.98) 85.1 Fig. 3.6 Servo Driver Board Baseplate Dimensions 11 Chapter 3 3.2 Mechanical Installation 3.2.1 Introduction Caution The galvo motor assembly and associated driver board are tuned at the factory before they are shipped and further adjustment is not normally necessary. If the accuracy of the system is in doubt, e.g due to accidental adjustment of trim pots, contact Thorlabs for information on the tuning procedure. During Installation, ensure that the motors are connected to the driver card to which they were tuned. Both the motor and the driver card should carry the same serial number. The location of the serial number labels is shown below . Fig. 3.7 Serial Number Label Location It is essential that the user mounts heatsinks to the driver board and motor mounts which are suitable for their intended application. If this is not done the devices will overheat and permanent damage may occur. The choice of heatsink will primarily be determined by the power which the devices dissipate, a value which is dependant on the average speed at which the user moves the scanners. The larger the power the heatsink must dissipate the larger the heatsink will need to be. 12 HA0193T Rev 21 Jan 2018 Single- and Dual-Axis Scanning Galvo Systems for Small Beam Diameters 3.2.2 Fitting The Heatsinks Servo Driver Board Heatsink The servo driver board is supplied complete with a large heatsink, suitable for all applications, even those involving more vigorous usage and rapidly changing drive waveforms. 1) Secure the heatsink bracket to the heat sink using two M3 x 8 scre ws and two plain M3 washers (arrowed in the photo below). Fig. 3.8 Driver Board Heatsink Screws Motor/Mirror Mount Heat Sink Caution Due to the large torque to weight ratio, thermal managment is crucial to the successful operation of galvo motors. Consequently the galvo motors must be kept cool (<50 °C). For most app lications, the mo unting bracket will provide adequate heat sinking, however for more vigorous applications, it may be necessary to fit some heatsinking in addition to the galvo motor mount. Thorlabs supply a combined post adapter and heatsink (GHS003) suitable for both single and dual axis applications. If using a third party heatsink, please see Appendix B the power dissipation in the motor. for details on how to calculate 1) Secure the heatsink to the motor/mirror mount using the two M3 x 5 screws supplied. Fig. 3.9 XY Mount Heatsink Screws 13 Chapter 3 3.2.3 Typical System Set Up 1) Fit a GHS003 post adapter to the XY mounting block 2) Fit a lens post into the bottom of the post adapter and clamp it to the breadboard. 3) Arrange a beam steering system such that a laser beam shines on to the X axis mirror, at right angles to the mount and is then reflected onto a screen, also at right angles to the mount.. Typical example: If the optical scan angle Ø = ±25° l = 2d x Tan 25° (Note. In this case, the mechanical scan angle is ±12.5°) Fig. 3.10 Typical Beam Steering System 3.3 Electrical Installation 3.3.1 Choosing A Power Supply Thorlabs recommends usin g the GPS011 linear power supply to power the galvo controller board(s) as this power supply has been specifically designed for this purpose. The GPS011 can power up to two driver cards under any drive conditions and is supplied with all the cables required to connect to the driver cards. However, customers also have the option of using a third-party power supply or incorporate the boards into their existing system. In this case care must be taken to ensure that the power supply voltage and current rating s are within the l imits specified. The drive electronics require a split rail DC supply in the range ±15V to ±18V. The cards do not require an accurately regulated supply as the boards themselves have their own regulators. The maximum current drawn by the driver cards will not exceed 1.2 A rms on each rail. In addition to this, for optimum performance the supply should be able to provide peak currents of up to 5A on either rail. 14 HA0193T Rev 21 Jan 2018 Single- and Dual-Axis Scanning Galvo Systems for Small Beam Diameters Caution Both switching and linear power supplies can be used with the Thorlabs galvo systems, however it is important to limit the inrush current when the power supply is turned on, in order to ensure that the power supply reservoir capacitors on the board are not damaged by the large surge currents that can occur on power-up. Most power supplies naturally “soft start” when they are switched on at the mains side and provide inrush current limiting. If, however, the power supply is turned on at the output (DC) side, it can output its peak current instantaneously. In this case it is important to limit this peak current to less than 2 Amps. 3.3.2 Using the GPS011 Linear Power Supply The unit is supplied with a variety of mains power cords. 1) Select the power cord appropriate for your territory. 2) Connect the power cord to the socket on the rear panel of the unit - see Fig. 3.11. 3) Select the correct voltage range for your region. Caution Selecting the incorrect voltage range will damage the unit. 4) Plug the power cord into the wall socket. Fig. 3.11 Power Supply Unit Rear Panel 15 Chapter 3 3.3.3 Electrical Connections Caution During the electrical installation, cables should be routed such that power and signal cables are separated so that electrical noise pick up is minimized J10 J9 J6 JP7 1 2 3 JP4 J7 Fig. 3.12 Connector Identification 1) Identify connector J10 on each driver board, and make power connections as shown below. Thorlabs supply a suitable PSU (GPS011) for powering a single or dual axis system (see Section 3.3.1.). A bare cable, crimp connectors (Molex Pt No 2478) and housings for use with general lab PSUs is supplied with each driver board. 3 -15V 2 Ground 1 +15V Fig. 3.13 J10 Power Connector Pin Identification 16 HA0193T Rev 21 Jan 2018 Single- and Dual-Axis Scanning Galvo Systems for Small Beam Diameters 2) Connect a motor cable to the connector J9 on each driver board as shown below. Pin 1 Position Sensor A Current 5 1 Pin 2 Position Sensor Ground 6 2 Pin 3 Position Sensor Cable Shield 3 Pin 4 Drive Cable Shield 7 8 4 Pin 6 Position Sensor Power Pin 5 Position Sensor B Current Pin 7 Motor + Coil Pin 8 Motor -Coil Fig. 3.14 J9 Motor Connector Pin Identification. 3) Note the serial numbers of the galvo motors and driver boards, then connect the galvo motors to their associated driver boards. If using a custom cab le, the pin outs for the connectorson the Driver PCB and the Motor connector are detailed in Fig. 3.14 and Fig. 3.15 respectively. 5 6 4 7 3 8 2 9 1 10 Pin 1 Motor + Coil (power shield floating) Pin 2 Motor -Coil (power shield floating) Pin 3 Not Used Pin 4 Not Used Pin 5 Position Sensor B Current Pin 6 Position Sensor Ground Pin 7 Position Sensor A Current Pin 8 Position Sensor Power (Automated Gain Control) Pin 9 Position Sensor Cable Shield Pin 10 Not Used Fig. 3.15 Galvo Assembly Motor Connector Pin Identification 4) Connect a command input (e.g. function generator) to J7 of each driver board as shown in Fig. 3.16. J7 accepts Molex pins Pt No 56134-9100. Note The scanner accepts a differential analog command input. If the scaling is 0.8 Volt per degree mechanical movement (see Section 3.3.5.), -10 V to +10 V gives -12.5 to +12.5 degrees mechanical movement. The driver will attempt to set the mirror position to the command input value. Pin 3 (DRV_OK) is an open collector output that is low when the board is operating normally and floating if a fault occurs. To use Pin 3 as a fault indicator, connect a pull-up resistor to give a high signal when the fault occurs. DRV_OK limits are 30 mA 30 V. Do not connect a relay to this output. 17 Chapter 3 . Pin 1 Command Input +ve Standard O/P Function Generator + Differential O/P Function Generator + Pin 2 Command Input -ve 1 2 3 4 Pin 3 DRV OK - Pin 4 External Enable Pin 5 -12V Output (low impedence O/P) Pin 6 +12V Output (low impedence O/P) 8 7 6 5 Pin 7 Ground Pin 8 Ground Earth J7 1 2 7/8 J7 1 2 7/8 Fig. 3.16 J7 Command Input Connector Pin Identification 5) Using a suitable cable, connect the Diagnostic Terminal J6 to the diagnostic device (e.g. oscilloscope) in your appl ication. Pin ide ntification is givem belo w, signal descriptions are detailed in the next section. Pin 1 Scanner Position Pin 2 Internal Command Signal 8 7 6 5 1 2 3 4 Pin 3 Positioning Error x 5 Pin 4 Motor Drive Current Pin 5 Not Connected Pin 6 Test Input (NC) Pin 7 Motor + Coil Voltage / 2 Pin 8 Ground Fig. 3.17 J6 Diagnostics Connector Pin Identification Note All diagnostic signals from J6 have 1 KΩ output impedance except Pin 7 (Motor Coil Voltage/2) which has 5 KΩ J6 Diagnostics and J7 Command Input Mating Connector Details Mating Connector body: Manufacturer: Molex, Mfr. P/N: 513530800 Example Vendor: Farnell, Vendor P/N: 1120387 Crimps (22-26AWG): Manufacturer: Molex, Mfr. P/N: 56134-8100 Example Vendor: Farnell, Vendor P/N: 1120545 Crimps (22-28AWG): Manufacturer: Molex, Mfr. P/N: 56134-9100 Example Vendor: Farnell, Vendor P/N: 1120546 18 HA0193T Rev 21 Jan 2018 Single- and Dual-Axis Scanning Galvo Systems for Small Beam Diameters 3.3.4 Diagnostic Signal Descriptions Scanner Position - This signal is proprotional to the position of the scanner mirror, with a scaling of 0.5 Volts per degree of mechanical movement. Internal Command Signal - The command signal following amplification by the input stage. The scaling is 0.5 Volt per degree of mechanical movement. Note The Scanner Position and Internal Command signals are scaled internally by the driver circuit and are essentially equivalent to the input signal /2. Positioning Error x 5 - This signal is pro portional to the d ifference between the demanded and the actual positions - (Position - Command) x 5 (i.e. (Pin 1 - pin 2) x 5). Motor Drive Current - The drive current of the motor (2V per A), i.e. if drive signal is 2V, the drive current is 1 A. Motor + Coil Voltage /2 - This pin outputs the drive voltage to the “+” side of the motor coil. It is scaled down by a factor of 2. The drive voltage determines the current, which then determines the acceleration. It is not required if the user only wants to monitor position. 3.3.5 Setting the Volts/Degree Scaling Factor Servo driver cards manufactured after October 2015 have a jumper which is used to set the Volts per Degree scaling factor. The cards are shipped with the scaling set to 0.8 V/°, wh ere the max sca n angle is ±12.5°, an d is compa tible with driver ca rds manufactured before October 2009. To set the scaling factor to 1 V/° an d the maximum scan angle to ±10°, proceed as follows: 1) Identify JP7 as shown in Fig. 3.18. 2) Set the jumper position for the corresponding scaling factor as shown below. Note The 0.5V/° scaling factor is provided to allow the full scan angle to be achieved using small input signals. In this case, the input voltage should be limited to ±6.25 V max 1V/° 0.8V/° 0.5V/° JP7 Fig. 3.18 Setting the Volts/Degree Scaling Factor 19 Chapter 4 Operation 4.1 General Operation 1) Connect the system as described in Section 3.3. 2) Apply power to the driver boards. 3) Input a command signal to each driver board to obtain the desired behviour. Note After powering the boards, there may be a delay of up to 10 seconds before the motors start to follow the command signal. 4.2 External Enabling of the driver board 1) The drive ele ctronics can be c onfigured for external enabling by placing a jumper across pins 2 and 3 of JP4. 1 2 3 2) Once this has been done the user can enable or disable the drive electronics by applying a 5V CMOS signal to J7 pin 4. Pin 1 Command Input +ve 1 2 3 4 Pin 2 Command Input -ve Pin 3 No Connect Pin 4 External Enable Pin 5 -12V Output 8 7 6 5 Pin 6 +12V Output Pin 7 Ground Pin 8 Ground Fig. 4.1 J7 Command Input Connector Pin Identification If a logic high or no signal is applied, the drive electronics will be enabled. If a logic low signal is applied then the driver will be disabled. 4.3 Using a DAQ Card Typically, users will deploy a DAQ card with DAC analogue outputs in order to drive the servo drivers supp lied with th e galvos. The minimum recommended specifications for the DAC outputs are:Dual bipolar -10V to 10V DAC analogue output channels (differential). DAC clocking frequency higher than 20kS/s (Kilo Samples/Second), higher sampling frequencies like 100 kS/s are recommended (inputs have a 7 kHz low pass filter). 16 Bit DAC resolution and low out impedance (<= 50 Ω). 20 Single- and Dual-Axis Scanning Galvo Systems for Small Beam Diameters 4.4 Recommended Scanning Angles The ideal scanning angle is dependent upon a number of conditions. Firstly, the larger the diameter of the input laser beam, the smaller the achievable scanning angle. Secondly, the applied input voltage causes the laser beam to move away from the center of the mirrors. The larger the input voltage then the greater the movement from the center, as shown below. Lastly, on dual-axis systems, there is an offset alignment between the X and Y axis mirrors that also limits the scan angle. The table below gives recommended scanning angles for various beam diameters. GVS001, GVS101, GVS201 and GVS301, Input Beam Diameter 4 mm and less 5 mm Mechanical Scan Angle ± 12.5° + 10°, -12.5° Optical Scan Angle ± 25° + 20°, -25° GVS002, GVS102, GVS202 and GVS302, Input Beam Diameter 1 mm 2 mm 3 mm 4 mm 5 mm Mechanical Scan Angle X + 11.0°, - 12.5° + 10°, - 11.5° + 9.5°, - 10° ± 8.5° ± 8° Optical Scan Angle X + 22.0°, - 25° + 20°, - 23° + 19°, - 20° ± 17° ± 16° Mechanical Scan Angle Y ± 12.5° ± 12.5° ± 12.5° ± 12.5° + 12.5°, -3° Optical Scan Angle Y ± 25° ± 25° ± 25° ± 25° + 25, -6° 21 Chapter 5 Troubleshooting 5.1 Common Problems Some of the more common problems encountered when using galvanometers are details below. Motor fails to respond to the command signal This can occur for a number of reasons. The most likely are: 1) 2) 3) 4) power is not correctly applied to the board one of the cables is faulty or not connected properly a fault has been triggered the device has been disabled either by placing a jumper across JP4 pins 1 and 2 or by placing a jumper across JP4 pins 2 and 3 and pulling J7 pin 4 to ground. Note After powering the boards, there may be a delay of up to 10 seconds before the motors start to follow the command signal. Instability of the scanner If uncontrolled, instability of the scanner will cause a whistiling or schreeching noise and uncontrolled movement of the scanner. It will also cause large current to be drawn by the motor and the motor will move spontaneously and unpredictably. If this occurs the user should turn off power to the driver boards immediately to prevent damage to the scanners. However under normal circumstances the instability should be detected by the fault control circuitry. In this case the behaviour most likely to be observed by the user is the following: The mirror w ill suddenly jump from one position to another (probably with a short burst of whistling) and stop and remain still. After a delay of a few seconds the mirror will jump to another position and so on. Here when the mirror is stopped a fault has been triggered and the driver board is disabled. The only movement is during the brief period when the fault control circuitry tries to resume normal operation. Instability can occur for a number of reasons. The most common is if the driver board is incorrectly tuned to the motor. This can occur if the board is connected to a different motor to the one it was originally sold with or if one of the potentiometers have been tampered with. Another common cause for instability is if the motor is driven at large amplitudes and high frequencies then the electronics may be un able to control the scanner. 22 Single- and Dual-Axis Scanning Galvo Systems for Small Beam Diameters Mirror periodically shoots off to one side and then stops If the mirror suddenly shoot off to one side and then stops it is likely that either the position sensing circuitry is not functioning correctly or the motor cable is incorrectly wired. When this happens most likely either the drive electronics will output a constant drive voltage or the loop feedback will be positive. Consequently the motor jumps to one extreme and an overposition fault is triggered. Once the drive electronics is disabled the scanner will bounce freely backwards and come to rest. After a delay the electronics will attempt to resume operation and the process will repeat. Galvo mostly behaves normally but periodically becomes unstable If the galvo driver card is incorrectly tuned it is possible that the galvo system can appear to be b ehaving correctly most of th e time, but with a brie f period where the system suddenly becomes unstable repetitively occuring. This can be caused if the maximum error sign al value is excee ded. The fault control circuitry responds by lowering the error gain which may cause the system to behave normally. However, once the system tr ies to res ume normal operation the system is likely to become unstable again and the process will repeat. Oscillation in the galvo motor current If the galvo system is draw ing more current than expected, if th e scanners or the driver cards are overheating, if the scan ners are makin g a hissin g noise or if the position accuracy is less than expected, this may be due to oscillations in the galvo motor current. This can be identified by viewing the coil current signal J6 pin 4 on an oscilloscope. The problem will manifest itself as a high frequency (>1kHz) sinusoidal oscillation in the current, unrelated to the position signal. Normally the scanner will still appear to be correctly following the command signal, but the oscillation may show up in the position signal if the effect is very strong. This effect is normally caused by crosstalk between the position sensing circuitry and the motor drive current. Repositioning the motor drive cable will normally help to avoid this problem. If the user replaces the motor cables with their own cables they should ensure that they keep the wires as short as possible and use separate shielded cables for the position sensing and motor drive signals. Cross talk between axes Cross talk between the two motors will normal show up as a slight movement in one axis when one motor is moved quickly. This typically occurs if both the motors are run off a same po wer supply and the power supply cannot deliver the pe ak currents demanded by the galvos. There will then be a drop in the power supply voltage which will then affect the behaviour of the remaining axis. Choosing a different power supply with sufficient peak drive current capability should solve this problem. 23 Chapter 5 Overshoot in position signal which grows over time It is possible that the position of the motor may show an overshoot when driven with a large square wave or similar, and that this overshoot will grow with time until a fault is triggered. There is usually a certain frequency and amplitude above which thi s starts to occur. This behaviour is caused by choosing a power supply which cannot deliver enough current for the intended application. The oscillation builds up because the power supply voltage is drop ping on the risin g edge of the position signal and effecting the board's behaviour. With every rising edge the e ffect becomes slightly greater as the overshoot grows. 24 HA0193T Rev 21 Jan 2018 Single- and Dual-Axis Scanning Galvo Systems for Small Beam Diameters 5.2 Galvanometer Faults The driver ele ctronics monitor numerous signals to ensure the scan ners operate safely and the fault protection circuitry will normally prevent any damage. However, the user should be aware that the galvanometer may become permanently damaged if the system becomes unstable (m anifested by a sc reeching noise, self excitation and unpredicable movement of the scanner). In addition the user should also be aware that the system has no protection against the galvanometer scanners overheating, and it is left to the user to ensure that they are fitted to an adequate heatsink (see Section 3.2.1.). It is worth noting that a fault state may be triggered on applying power to the driver boards and the power amplifier will be disabled. However in this case the bo ard will commence normal operation after a delay of a few seconds. The table below shows the various faults states which can be triggered in the fault control circuitry. Table 5.1 Galvo System Faults and Associated Fault Protection Circuit Action Fault Possible Causes Action Taken by Fault Control Circuit Maximum scanner position exceeded Drive signal too large, instability of scanner Power amplifier turned off Maximum peak current Exceeded Incorrect tuning, instability of the scanner or overly vigorous drive waveforms Power amplifier turned off Maximum postion error exceeded Incorrect tuning, instability of the scanner or overly vigorous drive waveforms Loop gain reduced AGC voltage out of normal range Broken motor position sensor, problem with motor cable connection Power amplifier turned off Power supply voltage drops below minimum value Poor choice of power supply Power amplifier turned off Maximum RMS coil current exceeded Incorrect tuning, instability of the scanner or overly vigorous drive waveforms Power amplifier turned off Maximum junction temperature of power amplifier IC exceeded Inadequate heatsinking of driver board Power amplifier turned off 25 Appendix A Specifications and Associated Parts A.1 Specifications Parameter Mirror Maximum Beam Diameter Finish Damage Threshold* Motor & Position Sensor Linearity Scale Drift Zero Drift Repeatability Resolution With GPS011 Linear PSU With standard switch mode PSU Average Current Peak Current Load Mirror Aperture Coil Resistance: Coil Inductance: Rotor Inertia: Maximum Scan Angle (Mechanical Angle) Motor Weight (inc cables, excl bracket) Operating Temperature Range Optical Position Sensor Output Range Value 5 mm GVS00x: Protected Silver Coated GVS10x: Protected Gold Coated GVS20x: Broadband, E02 GVS30x: Dual Band Hi Power, K13 GVS00x: 3 J/cm2at 1064 nm, 10 ns pulse GVS10x: 2 J/cm2 at 1064 nm, 10 ns pulse GVS20x: 0.25 J/cm2 at 532 nm, 10 ns pulse GVS30x: 5 J/cm2 at 1064 nm, 10 ns pulse 99.9%, range ±20° 40PPM/°C(Max) 10 µRad/°C(Max) 15 µRad 0.0008° (15 µRad) 0.004° (70 µRad) 1A 5A 5 mm 2.2 Ω±10% 150µH ±10% 0.02gm per cm2 ±12.5° (with 0.8V/° scaling factor) 50 g 0 ~ 40° C 40 to 80 µA Note *The way our mirrors a re tested is con tinually updated, please consult www.thorlabs.com for more information. 26 Single- and Dual-Axis Scanning Galvo Systems for Small Beam Diameters Drive Electronics Parameter Full Scale Bandwidth* Small Angle (±0.2°) Bandwidth* Small Angle Step Response Power Supply Analog Signal Input Resistance Position Signal Output Resistance: Analog Position Signal Input Range Mechanical Position Signal Input Scale Factor Mechanical Position Signal Output Scale Factor Operating Temperature Range Servo Board Size (L x W x H) Value 100 Hz Square wave, 250 Hz Sinewave 175 Hz Saw Tooth 175 Hz Triangular Typ. 1kHz with Sinewave 300 µs +/-15V to +/-18V dc (1.25 A rms, 5A peak MAX) 20K±1%Ω (Differential Input) 1K±1%Ω ±10V switchable: 0.5V/°, 0.8V/° or 1.0V/° 0.5V/° 0 ~ 40°C 85 mm × 74 mm × 44 mm (3.35” x 2.9” x 1.73”) * Using heat sink to keep temp <50°C (see Section 3.2.2.). A.2 Associated Products Product Name 2D Galvo System - Protected Silver Mirrors 1D Galvo System - Protected Silver Mirror 2D Galvo System - Protected Gold Mirrors 1D Galvo System - Protected Gold Mirror 2D Galvo System - Broadband E02 Mirrors 1D Galvo System - Broadband E02 Mirror 2D Galvo System - Dual Band High Power K13 Mirrors 1D Galvo System - Dual Band High Power K13 Mirror Motor Assembly Heatsink Galvo Power Supply Servo Driver Card Cover 1D Galvo Cage System Mount 2D Galvo Cage System Mount Tip/Tilt Mount Adapter Part Number GVS002 GVS001 GVS102 GVS101 GVS202 GVS201 GVS302 GVS301 GHS003(/M) GPS011 GCE001 GCM001 GCM002 (/M) GTT001 27 Appendix B Calculating the Power Dissipation 2.1 Motor Heatsink The power dissipated in the motor can be estimated by measuring the RMS current drawn from the PSU and then using the following equation: Pmot = Rmot x [(Irms+ + Irms- - Iq+ - Iq-) / 2]2 Where Pmot is the power dissipated in the motor, R mot is the motor coil resistance (2.2Ω), Irms+ is the rms current drawn from the positive supply rail, Irms- is the rms current drawn from the negative supply rail, Iq+ is the quiescent current drawn on the +ve rail (0.15A under all circumstances) and Iq- is the quiescent current drawn on the -ve rail (0.10A under all circumstances). The power dissipated in the driver boards can be calculated using the following equation: Pdrv = (V+ x Irms+ ) + (V- x Irms- ) - Pmot Where Pdrv is the power dissipated in the driver boards, V+ is positive supply voltage and V- is the negative supply voltage. 2.1.1 Calculating the Required Thermal Conductivity The ability of a heatsink to transfer heat to its surroundings is parameterised either by its thermal conductivity, k or its ther mal resistance, Ø. The lower the thermal resistance the more effectively the heatsink can transfer heat. The required thermal resistance can be calculated from the following equation: Ø = 1/k = (Ths - Ta) / Pmax In the above equation Ths is the maximum permissible heatsink temperature, Ta is the ambient temperature and Pmax is the maxium power the de vice being cooled will dissipate. For the motors it is desireable to keep Ths below 45°C. The following equation can be used to calculate Ths for the driver IC: Ths = Tj - Pmax x Øjhs Here, Øjhs is the thermal resistance between the semiconductor junction of the power amplifier IC and the heatsink. Tj is the maximum temperature allowable at the junction, about 150°C (although the lifetime of the driver IC will be longer if the junction is kept at a lower temperature). The value of Øjhs is 1.3 °C/W. 28 Appendix C Reasons For Image Distortion The deflection of a laser beam with a two-mirror system results in three effects: (1) The arrangement of the mirrors leads to a certain distortion of the image field – see Fig. C.1 below. Ø2 Scanner 2 Ø1 Scanner 1 Beam In Fig. C.1 Field Distortion in a Two-way Mirror Deflection System This distortion arises from the fact that the distance between mirror 1 and the image field depends on the size of the mechanical scan angles of mirror 1 and mirror 2. A larger scan angle leads to a longer distance. (2) The distance in the image field is not proportional to the scan angle itself, but to the tangent of the scan angle. Therefore, the marking speed of the laser focus in the image field is not proportional to the angular velocity of the corresponding scanner. (3) If an ordinary lens is used for focusing the laser beam, the focus lies on a sphere. In a flat image field, a varying spot size results. 29 Appendix C As a result, you will find the scanning field turn out to be a "pillow-shaped" image, see Fig. C.2 below. Fig. C.2 Pillow-shaped Field Distortion Caused by the Arrangement of Mirrors 30 HA0193T Rev 21 Jan 2018 Appendix D Regulatory D.1 Declarations Of Conformity D.1.1 For Customers in Europe This equipment has been tested and found to comply with the EC Directives 2006/42/EC Machinery Directive (MD) 2004/108/EC Electromagnetic Compatibility (EMC) Directive 2011/65/EU Restriction of Use of Certain Hazardous Substances (RoHS. Compliance was demonstrated by conformance to the following specifications which have been listed in the Official Journal of the European Communities: EN ISO 121 00 Safety of Machinery. General Principles for Desig n. Risk Assessment and Risk Reduction 2010 EN61326-1 Electrical Equipment for Measurement, Control and Laboratory Use EMC Requirements 2013 D.1.2 For Customers In The USA This equipment has be en tested an d found to comply with the limits fo r a Class A digital device, persua nt to part 15 of the FCC rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his own expense. Changes or modifications not expressly app roved by th e company could void the user’s authority to operate the equipment. D.2 Waste Electrical and Electronic Equipment (WEEE) Directive D.2.1 Compliance As required by the Waste Electrical and Electronic Equipment (WEEE) Directive of the European Community and the corresponding national laws, we offer all end users in the EC the possibility to return "end of life" units without incurring disposal charges. This offer is valid for electrical and electronic equipment • • • • • sold after August 13th 2005 marked correspondingly with the crossed out "wheelie bin" logo (see Fig. 1) sold to a company or institute within the EC currently owned by a company or institute within the EC still complete, not disassembled and not contaminated 31 Appendix D Fig. 4.1 Crossed out "wheelie bin" symbol As the WEEE directive applies to self contained operational electrical and electronic products, this "end of life" take back service does not refer to other products, such as • • • • pure OEM products, that means assemblies to be built into a unit by the user (e. g. OEM laser driver cards) components mechanics and optics left over parts of units disassembled by the user (PCB's, housings etc.). If you wish to return a unit for waste recovery, please contact Thorlabs or your nearest dealer for further information. D.2.2 Waste treatment on your own responsibility If you do not return an "end of life" unit to the company, you must hand it to a company specialized in waste recovery. Do not dispose of the unit in a litter bin or at a public waste disposal site. D.2.3 Ecological background It is well known that WEEE pollutes the environment by rel easing toxic products during decomposition. The aim of the Europ ean RoHS directive is to re duce the content of toxic substances in electronic products in the future. The intent of the WEEE directive is to enforce the recycling of WE EE. A controlled recycling of end of life prod ucts will thereby avoid negative impacts on the environment. 32 HA0193T Rev 21 Jan 2018 Single- and Dual-Axis Scanning Galvo Systems for Small Beam Diameters D.3 CE Certificates 33 Appendix D 34 HA0193T Rev 21 Jan 2018 Single- and Dual-Axis Scanning Galvo Systems for Small Beam Diameters 35 Appendix D 36 HA0193T Rev 21 Jan 2018 Single- and Dual-Axis Scanning Galvo Systems for Small Beam Diameters 37 Appendix D 38 HA0193T Rev 21 Jan 2018 Single- and Dual-Axis Scanning Galvo Systems for Small Beam Diameters 39 Appendix E Thorlabs Worldwide Contacts USA, Canada, and South America Thorlabs, Inc. 56 Sparta Ave Newton, NJ 07860 USA Tel: 973-579-7227 Fax: 973-300-3600 www.thorlabs.com www.thorlabs.us (West Coast) email: feedback@thorlabs.com Support: techsupport@thorlabs.com Japan Thorlabs Japan Inc. 3-6-3 Kitamachi, Nerima-ku, Tokyo 179-0081 Japan Tel: +81-3-6915-7701 Fax: +81-3-6915-7716 www.thorlabs.co.jp email: sales@thorlabs.jp Europe Thorlabs GmbH Hans-Böckler-Str. 6 85221 Dachau Germany Tel: +49-(0)8131-5956-0 Fax: +49-(0)8131-5956-99 www.thorlabs.de email: Europe@thorlabs.com UK and Ireland Thorlabs Ltd. 1 Saint Thomas Place, Ely Cambridgeshire CB7 4EX Great Britain Tel: +44 (0)1353-654440 Fax: +44 (0)1353-654444 www.thorlabs.de email: sales.uk@thorlabs.com Support: techsupport.uk@thorlabs.com France Thorlabs SAS 109, rue des Côtes 78600 Maisons-Laffitte France Tel: +33 (0) 970 444 844 Fax: +33 (0) 811 381 748 www.thorlabs.de email: sales.fr@thorlabs.com Scandinavia Thorlabs Sweden AB Bergfotsgatan 7 431 35 Mölndal Sweden Tel: +46-31-733-30-00 Fax: +46-31-703-40-45 www.thorlabs.de email: scandinavia@thorlabs.com China Thorlabs China Oasis Middlering Centre 3 Building 712 Room 915 Zhen Bei Road Shanghai China Tel: +86 (0)21-32513486 Fax: +86 (0)21-32513480 www.thorlabs.com email: chinasales@thorlabs.com Brazil Thorlabs Vendas de Fotônicos Ltda. Rua Riachuelo, 171 São Carlos, SP 13560-110 Brazil Tel: +55-16-3413 7062 Fax: +55-16-3413 7064 www.thorlabs.com Email: brasil@thorlabs.com Thorlabs Inc. 56 Sparta Avenue Newton, NJ07860 USA Tel: +1 973 579 7227 Fax: +1 973 300 3600 www.thorlabs.com 40 Thorlabs Ltd. Saint Thomas Place, Ely Cambridgeshire CB7 4EX, UK Tel: +44 (0) 1353 654440 Fax: +44 (0) 1353 654444 www.thorlabs.com
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