Meta Vision SystemsSmart Laser ProbeOperating Manual © Meta Vision Systems Ltd.March 2011Version 1.0Part number: DOC-S1E-10ForewordThis manual describes the operation of the Smart Laser Probe seam tracking system.Meta Vision Systems Ltd. has made every effort to ensure that the information presented in this user manual is correct. If you have any comments on the manual, please send them to us on the form at the end of this manual.Any questions about information contained in this manual or requests for further information should be forwarded to your equipment provider or Meta Vision Systems at the address below.This manual and its contents is copyright © Meta Vision Systems Ltd. No part of this manual may be copied or distributed without the written consent of Meta Vision Systems.Meta Vision Systems Ltd. Oakfield House Oakfield Industrial Estate EynshamOxfordshireOX29 4THUNITED KINGDOM Tel: +44 (0)1865 887900 Fax: +44 (0)1865 887901Meta Vision Systems Inc. 8084 TransCanada Highway St-LaurentQuébecH4S 1M5CANADATel: +1 514 3330140Fax: +1 514 3338636Web page: Email: support@1.SAFETY INFORMATION AND WARNINGS (5)2.INTRODUCTION (7)3.SYSTEM COMPONENTS (8)4.HOW THE SENSOR WORKS (12)5.OPERATION (17)5.1.Control Unit Switches 17 5.1.1.On/Off Switch 17 ser Enable Keyswitch 18 5.1.3.Mode Switch Keyswitch 185.2.Operator Pendant - Description 195.3.Operator Pendant - in Standby – Operations 19 5.3.1.Jogging the slides 19 5.3.2.Turning the sensor lasers (measurement) on and off 20 5.3.3.Automatically adjusting the picture brightness 20 5.3.4.Teaching the sensor zero position 21 5.3.5.Starting the sensor 21 5.3.6.Error acknowledge 22 5.4.Operator Pendant - Sensor Active 22 5.4.1.Extended move (configurable option) 22 5.4.2.Vertical search (configurable option) 22 5.4.3.Searching 22 5.5.Operator Pendant - RUN mode with Sensor Active - Operations 24 5.5.1.Offset 24 5.5.2.Stopping 24 5.6.Typical operating sequence 255.7.Operating modes in more detail 26 5.7.1.Locate mode (Not yet implemented) 26 5.7.2.Search mode 265.7.2.1.Extended movement mode 275.7.2.2.Vertical search mode 275.7.2.3.Extended search mode 275.7.2.4.Search mode 28 5.7.3.Tracking mode 28 5.8.Adjusting the welding position 26 5.8.1.Offset the tracked position 29 5.8.2.Re-teach the sensor zero position 29 5.8.3.Adjust the sensor or welding torch mounting 306.MAINTENANCE (31)6.1.Mounting and dismounting the sensor head 31 6.2.Protective window 32 6.3.Air and Water Supply Lines 33 6.4.Slides 34 6.5.Cables 34 6.6.Operator Pendant 346.7.Cooling plate (optional item) 347.APPLICATION NOTES (35)7.1.Search and track positioning issues 35 7.2.Abrupt changes of seam or part position 36 7.3.Changes of material 367.4.Cleanliness of parts 368.ERROR MESSAGES (37)9.FEEDBACK ON THIS MANUAL (41)1. Safety information and warningsSafetyThe system control unit contains hazardous voltages (110V AC or 230V AC mains depending on market). Disconnect or isolate from the mains supply before opening the door of the control unit. Power can be disconnected from the IEC plug on the underside of the control unit. The control unit must be earthed.The sensor head contains a visible laser diode of up to 35mW. The side of the sensor head has a warning label indicating the wavelength and intensity of the lasers in the sensor head.The system is a Class 3B device, according to EN60825: 1992. It is dangerous to look directly into the laser beam. Ensure that suitable precautions are taken so that direct viewing of the beam or viewing of reflections from mirror-like surfaces is not possible.The system is provided with fail-safe indicators on the sensor head and on the operator pendant. A keyswitch is also provided on the control unit to allow the laser to be disabled.The laser should be disabled before any maintenance is performed on the sensor head or welding torch when it may be possible to view the laser directly.The sensor head and control unit contain no user serviceable parts. No work should be undertaken on these items except by or under the direct guidance of appropriately trained personnel.To ensure safe and reliable operation of the system, all operators must be made aware of the correct operation and safety procedures for the system. The safety procedures should be based on the above information, installation specific issues concerning the use of the system and anylocal safety requirements.WarningsDo not weld with the sensor unless a spatter shield and a protective window have been fitted correctly.Please ensure that clean, dry, oil free air or gas is supplied to the air connectors on the top of the sensor body. Oil or water in the air supply will obscure the sensor view and stop it working correctly. It may also damage the sensor optics at the front of the sensor head. The welding shield gas or other bottled gas may be used, or alternatively air from a compressor can be used as long as it is clean, dry and oil free. A flow rate of approximately 5-8 litres per minute is normally required. When you place your hand underneath the sensor, you should feel a gentle breeze on the back of your hand. The flow should not be so high as to disturb the shield gas, while being sufficient to keep most of the smoke and spatter off the protective window.It is important that the sensor is provided with adequate cooling. The air supply above provides some cooling, but where this is not sufficient, additional cooling to the mounting plate for the sensor head can be used. This may be connected to a supply of cool water or to provide additional air cooling.The sensor head can also be cooled by providing chilled air from a Vortex type cooler unit. This cooled air can be supplied to both the air connector (at a flow rate of 5-8 litres per minute) and also to the ‘water cooled’ mounting plate by feeding the chilled air into either one of the ‘water connectors’ and allowing it to escape out of the other connector. The flow rate to the mounting plate should not exceed 12litres/minute.The user of the equipment must ensure that the cooling does not cause condensation to form on the windows or optics at the front of the sensor head, as this can stop the sensor from performing correctly. Although the sensor head is sealed against dust and being splashed by water, condensation must not be allowed to remain on the sensor head or pool around it for extended periods.You must turn the system off when replacing any parts, including the External GIO or the sensor head. If you do not do this, the system may fail to operate correctly.2. IntroductionThis manual describes the operation of Smart Laser Probe seam tracking system. The Smart Laser Probe system has been designed to be simple and reliable in normal operation. To get the best use from the system, please pay attention to the contents of this manual, particularly the sections ‘Safety Information’ and‘Maintenance’.For further details on the installation and configuration of the system, please refer to the Smart Laser Probe Installation and Support manual.For further information on the PC based set-up program, please refer to the Smart Laser Tools manual or alternatively use the help built into the Smart Laser Tools program.This manual refers to Smart Laser Probe software Version 1.0.3. System componentsThe Smart Laser Probe System consists of the following parts.•Smart Laser Probe Control Unit•Smart Operator pendant•SLS Sensor cable•SLS sensor head withMounting plate with spatter protectionDisposable windows•Optional servo amplifiers (different specification models available according to requirements)•Optional cross slides and slide cables (different specification models available according to requirements)You will also have a GIO (Graphical I/O) unit, either built into the Control Unit or as a Remote GIO in its own small box with a cable to the Control Unit.The SLS sensor head is available in a range of field of views and working distances (stand-off), depending on the application.Figure 1 SLS Sensor headFigure 3 - Operator PendantFigure 4 – Control Unit front4. How the sensor worksThe sensor head contains an advanced camera, and a laser. The laser shines a red stripe onto the surface under the sensor. The camera views this stripe and from the shape of the stripe is able to see the shape (profile) of the seam. In front of the camera is a special filter that allows the light from the lasers to pass, but keeps out nearly all other light, such as the light from the welding arc.The sensor must be mounted in front of the welding torch in a position such that it can see the seam clearly. The distance from the sensor body to the workpiece should be correct for the type of sensor being used. When the welding torch is correctly positioned over the seam, the seam should be close to the middle of the laser stripe. This is so that the camera can clearly see the laser stripe and the seam within it. When the sensor is mounted correctly, the sensor picture of the seam will show the picture near the middle of the sensor view when the welding torch is at a good welding position.Sensor Head Laser stripe on the surface Camera viewThe sensor head is available with a range of different views depending on the application. The SLS V sensors are the standard range. The SLS H range are specially designed to be able to fit inside small diameter tubes and pipes (down to 6”/150mm ID).Table 1 Sensor heads field of view and standoff distanceSensor Head Field Of Viewmm Stand OffmmTypical ApplicationSLS 50 V 1 50 65Bigger seams up to 40mmSLS 25 V 1 25 45 Smaller seams up to 20mm SLS 50 H 1 50 65 Special format for inside pipeBigger seams up to 40mm SLS 25 H 1 25 45 Special format for inside pipeSmaller seams up to 20mm SLS 50 V 1 LR 50 150 Long range (higher standoff)version of 50mm sensorSLS 100 V 1 LR 100 150 Long range, large field of viewsensorThe Stand off distance is measured from the flat front part of the sensor head, where the end of the narrowing section, not from the spatter shield.Figure 5 Standard SLS Vertical sensor headFigure 6 SLS Horizontal sensor headFigure 7 - Principle of operationSensor pictureSensor pictureSensor pictureSensor HeadWorkpiece at normal standoffheightWork piece at smaller standoffrear of sensorWorkpiece at larger standoffThe picture from the camera is then processed by the electronics in the sensor head. It looks in the picture and decides where the stripe is in the picture. The software then uses the settings from the seam type to divide the stripe into lines that form the seam. From the position of the lines that make the seam, the system can then decide where the position of the seam is. This is then converted from a measurement in the picture into a measurement in mm of the seam position under the sensor. This conversion is performed using the ‘calibration data’ that is stored in each sensor head.When the system is tracking, it uses the welding speed and the distance between the sensor and the welding torch to calculate a delay time. It compensates for this delay time when using the measurements of the seam position to drive the slides to keep the welding torch positioned over the seam.5. OperationThis section describes the operation of the Laser Probe. For details of how to install and set-up the Laser Probe system, please refer to the Laser Probe Installation and Support manual.The Laser Probe system is operated from the Operator Pendant, and also by the switches on the Control Unit.5.1. Control Unit SwitchesThe control unit has the following switches.•Power on/off switch•Laser Enable keyswitch•Mode keyswitch5.1.1. On/Off SwitchTurning the power switch on the front of the control unit clockwise turns on the system. When power is on the touch screen display (GIO) will start to turn on. The system performs a range of self tests, and if it doesn't find any problems will turn on the LED in the start button on the operator pendant to show that the system is ready to be started. If the system does detect a problem it will turn on the red status LED. You can then use the display on the GIO or the Smart Laser Tools program to determine the cause of the error. Note that the GIO may take longer than the rest of the system to power on - the rest of the system can be used as soon as the green pendant start button illuminates, even if the GIO is still starting up.Turn the power switch anti-clockwise to turn off the system. Note that all settings that have been entered are stored in the Smart Laser Probe system, so the power can be turned off and on without the need to set-up the system again. When not in use the equipment can be left turned on or turned off as convenient.5.1.2. Laser Enable KeyswitchFor safety reasons, it is possible to disable the lasers in the sensor head. This is done by turning the Laser Enable keyswitch to the anticlockwise (OFF) position. The key can only be removed in the OFF position. To operate the system it is necessary to place the key in the switch and turn it to its clockwise (ON) position. It is necessary for the lasers to be enabled before it is possible to make any measurements with the system. If you try to use the system with the lasers disabled, an error message will be displayed on the GIO and the red status LED on the Operator Pendant will illuminate.When performing maintenance on the sensor head or welding torch, or when untrained personnel are working by the sensor head, the Laser Enable key must be turned to the OFF position. The Laser Enable keyswitch must also be turned to the OFF position if the sensor head is to be moved to a position where it is possible to look directly into the end of the sensor.Please refer to the safety regulations in force in your area for appropriate safety information.5.1.3. Mode Switch KeyswitchThe mode switch controls the operating mode for the equipment. It is a two-position keyswitch, and in normal use it should be in its anticlockwise position, RUN. The key can be removed when it is in the RUN position to ensure that the system set-up cannot be modified.Certain aspects of the set-up that has been made for your system can be adjusted from the menus that are displayed when this keyswitch is turned to the SETUP position. Please only attempt this if you are familiar with the set-up of the Smart Laser Probe system and are authorised to do so. To control access to these modes, it is possible to remove the key when in the RUN position.5.2. Operator Pendant - DescriptionThe Operator Pendant is used to operate the Smart Laser Probe system.The Operator Pendant has the following LED lamps and controls.•Four bicolour illuminated JOG buttons (left, right, up and down)•Illuminated START button•Illuminated STOP button•LASER button and laser warning lamp•Illuminated bicolour STATUS button•Illuminated SEAM button•Illuminated OFFSET buttonSome operator functions described below can be turned off when the system is installed if they are not required. This is done during the installation of the system, and it is noted in the description below. Some operations such as starting the sensor searching and tracking, and seam number selection can be performed by a connection to a PLC. These are also described below, but for details of how this is set-up, please refer to the Smart Laser Probe installation manual.The boxes in the following description show what you will see on the display on the Operator Pendant.5.3. Operator Pendant - in Standby – OperationsThis section describes the operations that you can perform on the Operator Pendant, when the sensor is not searching or tracking a seam. This mode is called Standby.5.3.1. Jogging the slidesThe 4 JOG buttons can be used to jog the slides. When jogging the slides, the slide will move slowly at first, gradually getting faster over a few seconds until the maximum jog speed is reached. This allows fine control of the jog position to be achieved while still being able to jog larger distances at a higher speed. The green LEDs in the joy switches are lit when it is possible to jog the slides. Note that if the system is under automatic control, e.g. searching for or tracking along the seam, the greed LEDs in the jog switches will turn off, to show that you are not able to jog the slides.The slides will stop when they reach the limit switch, and will not move any more in the direction of that limit switch. Note that when in Standby and jogging, reaching a limit switch does not cause an error to be reported. However, when a limit switch is active the red LED in the jog switches is illuminated, and the end of the slide icon on the GIO turns red to indicate which limit is active.Selecting the seam numberIf necessary, the Smart Laser Probe system can be set up to search for and track several different seams. The different settings that the system needs for the different seams are stored as separate seam numbers.Different seam numbers can be selected by holding down the SEAM button, and using the JOG up to increase the seam number or JOG down to decrease the seam number. The green led in the jog up or down button will flash briefly if the seam number changed. Seam numbers always start from 1. Only seam numbers where the seam have been created will be selected - any seam number that has not been created will be skipped. It is also possible to select the seam number from the GIO, from the 'seam' tab.It is possible to disable changing seam number from the pendant. It is also possible to select the seam number from a PLC via digital signals. Whichever way it is selected, the active seam number is shown on the GIO display.5.3.2. Turning the sensor lasers (measurement) on and offPressing the LASER button will turn the lasers on. When the lasers are on, the Smart Laser Probe system will continuously attempt to measure the position of the seam, relative to the middle of the field of view of the sensor. Pressing the LASER button again will turn the lasers off. You can also turn the lasers and measurements on and off from the GIO. When the laser is on, the STATUS LED will turn green when the sensor is able to measure the position of the seam, and turns off if the seam is not visible.5.3.3. Automatically adjusting the picture brightnessThe SLS sensor head will normally automatically adjust the picture brightness depending on the current surface below the sensor. Adjustment of the picture brightness is not normally required.5.3.4. Teaching the sensor zero positionPressing the SEAM then LASER buttons together will ‘teach’ the correct tracking position for the seam. This will normally be done when the system is installed, and will need to be redone if the sensor or welding torch position changes. Section 5.7 has more details if this happens.Teaching the seam tells the sensor that the current position of the seam under the sensor is the correct position for the seam. When the seam is taught, the sensor will measure the position of the seam underneath it and store this position as the correct (zero) position for the seam. When the sensor sees the seam in this position, it does not need to make any corrections. The system will briefly flash the blue SEAM LED if the teach was successful. If the seam position can't be determined by the sensor, it will turn the STATUS LED red.The ability to ‘teach’ the sensor from the Operator Pendant can be turned off during installation, if it is not required.5.3.5. Starting the sensorWhen the system is ready to be started, the green START LED will be illuminated. If the green start LED is not glowing, then either the system in already started (in which case the green STOP LED will be illuminated), the system may be in error (in which case the STATUS LED will be red), the Smart Tools program may be active or the system is not running (for example, the sensor head is not connected (which will be displayed on the GIO unit). Pressing the START button will start the sensor searching for the seam. See section 5.6, Typical operating sequence, for further details. Pressing the STOP button will stop the sensor, returning it to Standby mode. When the system is started, the green START LED will turn off and the green STOP LED will illuminate to show that you can now press the stop button to stop the system.The START and STOP functions can be controlled from a PLC. The function of these buttons can also be turned off during the installation if start and stop is only to be possible from the PLC.5.3.6. Error acknowledgeIf an error occurs and the red STATUS LED turns on, the cause of the error will be displayed on the GIO. Press the STATUS button to acknowledge the error before continuing to operate the system. Note that the error acknowledgement can also be performed from a PLC if one is connected to the system.When the error is acknowledged, any movements that may have been configured with the extended movement function will be executed. Typically, this function would be used to retract the slides from the workpiece, or to move the slides to a known position.5.4. Operator Pendant - Sensor ActiveThis section describes the use of the Operator Pendant with the sensor searching for or tracking along a seam. The sequence of events listed below starts when the START button is pressed, or, if the Laser Probe system is controlled from a PLC, when the PLC sends the start signal to the sensor.5.4.1. Extended move (configurable option)The extended move function allows a pre-programmed sequence of slide movements to be made before the sensor is activated. This could be used to pre-position the slides. The GIO display will show that an extended move is active, and which move in its sequences it is currently making.5.4.2. Vertical search (configurable option)The vertical search function allows the sensor to search downwards until the sensor can see the part beneath it. It would be used when the part can initially be too far away to be within the view of the sensor. As it drives the slides down, the GIO will display ‘vertical search’. When the part appears in the sensor view near the taught height, it will switch to the normal or (if enabled) the extended search mode.If the sensor still cannot see the laser stripe when it has moved a certain distance, which is called ‘max vertical search distance’ and is specified in the Smart Tools program, vertical search will stop and an error message will be displayed.5.4.3. SearchingWhen searching, the GIO display shows the mode and also the side (Y) and height (Z) correction that it has made in moving to the correct starting position (excluding extended move and vertical search movements).In tracking mode, the GIO display shows the error in the seam position under the sensor head. The green JOG LEDs also flash to indicate the direction that the sensor is correcting in.The GIO display also shows the percentage of pictures over the last second that the sensor was able to make a measurement on. This number should be around 80-100% except when the sensor goes over tacks or other damaged parts of seam when it can drop to zero.In tracking mode, if you press the SEAM button and use the jog up or down buttons you can increase or decrease the active seam number. Changing the seam number while tracking can be useful if the shape of the seam changes as you go along it or if you need to adjust the welding position or measurement settings.During tracking, it is possible for the tracking to be paused for a short time, for example if the welding stops with on a welding fault. If the sensor is given the‘pause’ signal when this happens, the GIO display will change to indicate this.If the system is being controlled by external signals, for example from a PLC, then a further mode is possible. This is called ‘locate’ and is used if the position of the seam under the sensor at the start of the seam can vary by more than the view of the sensor. In this mode, the sensor is scanned over the part until the sensor can see the seam. When this happens, the sensor will turn on the ‘seam’ LED briefly.5.5. Operator Pendant - RUN mode with Sensor Active - Operations5.5.1. OffsetThe JOG switches can be used to offset the position that the sensor is tracking on the seam. This can be used to make small adjustments to the welding position while the system is tracking, without having to stop and re-teach the sensor. You can adjust the side position with the left and right JOG switch, and the welding stick out with the up and down JOG switch. The offset will be in the direction of the Jog switch pressed, relative to the sensor body when looking in the welding direction. Note that if the sensor is not mounted aligned with the slides or if the jog direction has been adjusted, this may not be the same as the jog directions.The offset is added each time you push the jog switch. The switch does not auto repeat when you hold it on. The amount of offset for each push on the switch depends on the view of the sensor being used. The offsets used are shown.Table 2 - Offsets per jog key pressSensor Head Offset per pressSLS 50 V1 0.2 mmSLS 25 V1 0.1 mmSLS 50 H1 0.2 mmSLS 25 H1 0.1 mmThe total amount by which you can offset is limited by the Smart Laser Probe system to an amount depending on the field of view of the sensor. This limit is +/-25% of the sensor view to the side, and +/-50% in height. This is because if you make too much offset, then it would be possible offset the sensor so much that the seam was no longer within the view of the sensor. When you reach this limit, the system will not offset any further in that direction.This ability to offset the seam position can also be turned off during the installation if it is not required.5.5.2. StoppingThe STOP button will stop the tracking. The lasers will be turned off. If the extended move function is enabled, sequence of extended movement will be implemented to move the sensor away from the seam. After that, the slides will be deactivated and the Laser Probe will return to STANDBY mode.The START and STOP functions can be controlled from a PLC. These Operator Pendant buttons can also be turned off during the installation if they are not required. The other buttons on the Operator Pendant have no effect.5.6. Typical operating sequenceThis section describes the typical sequence when the sensor is used in the welding of a seam. It assumes that the sensor can be positioned over the seam before the sensor is activated, and that the sensor starts the welding automatically.The first step is for the sensor to be positioned approximately over the seam. If necessary, this would be done by jogging the slides from the operator pendant.The sensor will then be given a signal to search for the seam. This may come from the operator pendant or from a signal from a PLC.If the lasers are not already turned on, the sensor will turn on the lasers. It will then take a picture and measure the position of the seam. If it can see the seam, it will drive the slides to move the sensor to its ‘teach’ position over the seam. The sensor will then take another picture, measure the position of the seam and move the slides. This will be repeated until the sensor is correctly positioned over the seam.The Laser Probe system then turns on the SEAM LED, and switches to tracking (seam following) mode. The system is now ready to start welding. The sensor also sets an output signal that can be used to start the welding automatically.In tracking mode the sensor measures the position of the seam underneath it, and then smoothly adjusts the slide position to keep the welding torch correctly on the seam. If the part is twisted a little off position, the Laser Probe system will move the slides to correct for this, allowing for the time delay between the welding torch and the sensor head. The system will only correct smoothly, averaging the path over the look-ahead distance to generate a smooth movement. It therefore follows the overall direction of the part rather than every small irregularity in it.The Smart Laser Probe system will continue to work even if it cannot see the seam underneath it, for example when it goes over a tack. This can occur for a distance of up to the ‘tack length’, which will have been set when the system was installed. While the sensor cannot see the position of the seam, it will keep the slides moving as they were before the tack - it keeps going straight in the same direction as the seam before the tack. If the seam is not visible for longer than the tack length, then it will stop with the error ‘seam not visible’.。