1 Operating Manual Wedge Angle Scanner

Transcription

1 1 Operating Manual Wedge Angle Scanner Operating Manual Wedge Angle- Scanner (Wedge Angle Scanner Flatscan HUD) OEG GmbH Wildbahn 8i Frankfurt (Oder) Tel.: Fax: Internet: Contents 1. Proper use of the device 2. Safety warnings 3. Connection requirements, space requirements 4. Measurement principle 5. Construction of the device, maintenance instructions 6. Operating the device 7. Completing the measurement in USER Mode (automatically measuring) 8. Service mode 8.1 Measurement template 8.2 Settings 8.3 Single measurements 8.4 Calibrating 8.5 Motor settings 8.6 Camera settings 9. Installation warnings 10. Service contact data OEG GmbH

2 2 Operating Manual Wedge Angle Scanner 1. Proper Use of the Device The device wedge angle scanner serves only to measure the course of a wedge error on glass plates, especially automobile front windshields with the maximum dimensions: - Length 1600mm - Height 1000mm - Thickness 10mm. - The mass of the sample may not exceed 25kg. 2. Safety Warnings Emergency stop: The emergency stop switch must always remain accessible and may not be removed. The emergency stop switch cuts off the electricity supply for the stepper motor control. This function may not be altered. Motor power/travel speeds: The permissible phase current for the step motors is 2.5 A. The permissible travel speed of the portal is 30mm/s. Linear guides/portal: Heed instructional decals. When the device is engaged, do not reach between the rubber lips. (crushing danger) Laser: A semi-conductor laser with a maximum output of 1mW is used (class 2). Avoid looking directly into the laser beam when the device is operationally ready. During maintenance work, disconnect the laser from the power supply (pull power cable on the sensor head out). Program start: Remove all objects from the sample table before starting the measurement program. 3. Connection Requirements / Space Requirement Power supply: 220V..240V, 10A Space requirement: 2.5mx2.5m (device and space for operator) Weight: ca. 300kg Working temperature: 18 C to 25 C, Temperature constancy: During a measurement +/-1K Attention! Avoid draughts during measurement.

3 3 Operating Manual Wedge Angle Scanner 4. Measurement Principle electronic autocollimator Reference mirror Laser half mirror rack Figure 1: Functional Principle The measurement principle is based on highly precise measurements of the beam deflection. It is based on the fact that a collimated light bundle is deflected when it passes through a glass plate whose surfaces are not parallel. The deflection (δ) is proportional to the so-called wedge error (ε). In the case of double light transmission: δ 2k ε (1) with k as calibration factor. Equation (1) applies only to small wedge angles (<1 ) and not to larger angles for the test sample with respect to the measurement system. In the concrete case, the laser beam passes through the test sample more or less deflected to a reference mirrors, will be reflected back by it, passes through the test sample a second time and a then finally comes into a collimating tube through a 90 with a CCD camera. In the video image, an image of the laser spot will appear, whose position is directly associated with the wedge angle of the test sample. Before any measurement, a reference measure of the position of the laser spot will be taken without the test sample (front windshield). This defines the zero point (ε=0).

4 4 Operating Manual Wedge Angle Scanner Attention! The calibration value, that is the proportionality k from the equation (1) for the wedge angle measurement depends on the refractive index of the glass and/or layer system of an automobile windshield. If precise absolute values of the wedge are demanded, theoretically it needs to be re-calibrated for every type of glass. If you are only interested in small fluctuations in wedge angles, you can calibrate using a standard glass since in that case small differences in the refractive index of the various types of glass hardly play any role. Important! The decisive factor is the fixed (unchangeable) angle position of the reference mirror to the AKF. For that reason a reference measurement is taken automatically prior to every wedge angle measurement. One can assume that no change in the relative position between the reference mirror and sensor will occur during the brief time of the measurements. Over long time periods however this cannot be excluded due to expansion caused by temperature fluctuations. For this reason the reference measurement is highly important for measurement precision. Sensor measurement range (laser auto-collimation system) /ε/ <+- 20mRad The measurement range derives from the focal length of the collimator used. Measurement range portal system: X axis: Y axis: Position uncertainty: 1650mm 700 mm 0.1mm

5 5 Operating Manual Wedge Angle Scanner 5. Structure of the Device Figure 2: Structure of the front windshield scanner with the linear advancers, sample holder and automobile windshield Profile frame construction One can see the linear guides in Figure 2. This has the advantage that the device can be completely disassembled for transport and reassembled with relative ease and remains very stable mechanically.

6 6 Operating Manual Wedge Angle Scanner Specimen holder Figure 3: Specimen holder consisting of two plastic blocks with a nut, a stop and two outer supports on which it is leaned (only visible in Figure 1) The two plastic blocks and the stop will determine the position of the automobile windshield with respect to the portal system. All components of the specimen holder can be moved and fixed. Suggestion: The resting blocks for all types of automobile windshields should remain in the same position. The adjustment to the size of the windshield is then affected by the position of the stop. In this way the middle of the windshield should remain in the same position, at least in the x- direction. Linear guides The portal consists of two vertical standing guides that each contain a ball screw. The lift equals around 1600mm. The guides are driven with one step motor using the so-called main shaft. The y-axis (lift 700mm) also contains a ball screw. Each of the housings of the linear guides has a stepper motor integrated into it (max. 3.5A). Maintenance The linear guides should be annually lubricated. (See appendix, Isel components ). No other maintenance should be necessary.

7 7 Operating Manual Wedge Angle Scanner Laser Module Strahlteiler POL Filter Lasermodul Figure 4: Laser Assembly Group The intensity of the laser can be regulated (potentiometer on the back). Since the regulator range is not adequate, the beam will be further weakened by a polarisation filter during measurement. The filter can however be moved out of the beam path for purposes of adjustment so that the laser spot can be seen on a screen (paper). With the polarisation filter the laser spot is practically invisible. Beam adjustment The beam splitter plate will be mounted on a platform with an adjustable angle. Without a test specimen ( measurement in the air ), the laser spot should always appear in the middle of the screen image. The laser itself can only be adjusted by trained personnel. Step motor control The step motors are driven by a high-grade step motor control LSTEP. The LSTEP is for its part linked to the PC with a serial interface. The step motor control is configured with special software ( Win Commander ). The measurement program essentially uses the settings that were saved in the file wincom4.ini. You can find more detailed information in the manufacturer s operating manual (CD Win Commander ). Attention: The switch on the front plate of the LSTEP must be set to A.

8 8 Operating Manual Wedge Angle Scanner Camera This is a CCD camera with a USB interface. Connection lines - The LSTEP control device is connected to the PC with the serial interface COM1. - The power supply for the LSTEP goes through the emergency stop switch - One line from each step motor goes to the control device. They are labelled. - The camera is supplied with power through the USB interface. - The laser is supplied with 12V DC (separate plug-in power supply) 6. Putting the Device into Operation Remove all objects from the measurement device that can restrict the portal s range of motion. - Activate the PC. - Activate the step motor controller (LSTEP). The switch is located on the back. Attention: The switch on the front plate must be set to Auto, otherwise the measurement program will not work. - Start the program Flatscan HUD When using a master- slave- table distributor, the LSTEP will be automatically activated when the PC is activated. Directly after the program starts, the reference movements will automatically be carried out. Wait until the guides come to a stop. Switching it off is done by reversing the sequence. 7. Completing a Measurement in USER Mode In User Mode, only the function measure can be called up after the program starts and is initialised (Figure 5). The video image of the laser spot will appear. Attention: The laser spot should not be overshot (no filter). See Figure 6 and Figure 7.

9 9 Operating Manual Wedge Angle Scanner Figure 5: Program start in user mode Figure 6: Incorrect! Laser spot overshot. Diffraction effects are clearly visible.

10 10 Operating Manual Wedge Angle Scanner Figure 7: Correct! Diffraction effects are hardly visible. In spite of this the laser spot is visible as a bright spot. The operator will be asked to select a suitable measurement program for the windshield from a list. After the automobile windshield has been correctly positioned and the HUD and/or PVB number is typed in, the measurement procedure can be initiated with the F4 Start. The measurement begins with a reference measurement. Then the section of the automobile windshield selected in the background will be scanned. The measurement program can include several scanning ranges and/or measurement jobs. After a measurement job is completed, the operator will be asked to save the results and continue the measurement program.

11 11 Operating Manual Wedge Angle Scanner Figure 8: Selecting the measurement program. Once a measurement job is completed, a report window will appear (Figure 9). The report will include the measurement results along with the prescribed value and an evaluation Good (Green) Bad (red).

12 12 Operating Manual Wedge Angle Scanner Figure 9: Protocol window (report).

13 13 Operating Manual Wedge Angle Scanner 8. Service Mode The necessary program settings are made in the so-called Sevice Mode, and the so-called measurement templates (measurement programs) are generated. While the program settings may need to changed rarely or not at all, the generation or change of measurement programs may occur more frequently. Service Mode is password protected. 8.1 Measurement Template Figure 10: Selecting the function Edit Measurement Templates

14 14 Operating Manual Wedge Angle Scanner Figure 11: Generating measurement templates (measurement programs) A measurement program is divided into two parts: a) Gravity Center: Here the geometric data for the scanned field, the measurement point spacing and the measurement direction are set (measurement template). The position of the measurement field is determined by its mid-point ( Gravity Center ). The mid-point can be approached using a joystick and the position learned then. If a new name is assigned, the measurement template just created can be added to the list. All others can be edited or deleted. b) Programs: Multiple measuremetn templates can be combined into a measurement program. The name of the program is saved in a list. Existing measurement programs can be edited or deleted. Note: Assign as short and concise a name as possible that the operator can quickly comprehend in USER Mode and cannot confuse with another. 8.2 Settings The window settings contains essentially the parameters that influence the measurement process. These should not be changed or only in consultation with the OEG. Only the directory structure can be changed from time to time.

15 15 Operating Manual Wedge Angle Scanner Figure 12: First tab in the settings. The terms are actually self-explanatory. Of particular importance is the input field Measurement stroke for on-the-fly measurements. The time entered is the measurement rate during continuous movement of the measurement system. If the values are too large and the movements of the measurement sled are too fast, too few measurement values would be recorded. Cycle times that are too small unnecessarily burden the computer. The cycle time should be the same or somewhat greater than the time that the camera system needs to transmit a video image (transmission rate). Figure 13: Second tab for settings These parameters should only be changed by specially trained personnel. The values are responsible for recognising the position of the laser spot. They are determined experimentally or are based on experience. The optimisation of the parameters for signal recognition makes the right system robust against disruptions in the video image (light reflections, noise, etc.). Figure 14: Third tab for settings Here you select the directories for the measurement data.

16 16 Operating Manual Wedge Angle Scanner 8.3 Single Measurements For repairs, maintenance and trouble-shooting, it is necessary to examine the AKF system without measurement. Use the window single measurements. Figure 15: Single Measurements Using Set, set the AKF display to zero. Using Start measure initiates a continuous display of measured values. This is the best way to test whether the system has any noise, drifts or if there are relevant environmental problems. Depending on the AKF system, the measurements will fluctuate between and +-1. In order to get any <measurements, the <laser spot must be within the socalled measurement window (Figure 16). They are not automatically generated here.

17 17 Operating Manual Wedge Angle Scanner Figure 16: The laser spot must lie inside the so-called Meas. window position. The measurement window can be generated with the scroll bars. 8.4 Calibration The calibration data establish the relationship between the measurement value in the video image in pixels and the actual wedge angle in mrad or arc seconds (proportionality factor). Calibration data can be uploaded, stored, edited or generated from scratch. A second calibration is done in two steps. A first measurement without the wedge (that is, in the air) and then a second measurement with a known wedge. The pixel difference calculated will then be assigned to the known wedge angle. Figure 17: Calibration window. The window is under Video control in the main menu, Attention: Change or initial generation of calibration data may only be carried out by trained service personnel exercising due care. One needs a reference glass wedge, whose refractive index corresponds to the glass of the test specimens. 8.5 Motor Settings The option Measurement table control is in the main menu. Using the first tab, one can complete any of the movements of the portal and determining standard position angles.

18 18 Operating Manual Wedge Angle Scanner Figure 18: First tab for motor settings. Set and then Go means: Travel to the saved standard position. Using Teach in the positions involved will be overwritten with the current positions. Please note that in Flatscan HUD version of the program Load position and Zero position are identical. Figure 19: Motor settings Set speeds and acceleration here. Changes of the parameters should only be completed by trained personnel. During the warranty period these must only be carried out by OEG.

19 19 Operating Manual Wedge Angle Scanner 8.6 Camera Settings Flatscan-HUD can work with different camera systems. Currently we are using USB 2.0 cameras from the manufacturer IDS (Imaging Source). The camera settings are broken down into several Tabs with two of them being particularly important. Figure 20: Setting for light sensitivity using the exposure time. Keep in mind that exposure time, pixel frequency and transfer rate are related. Attention: There is no reason to change the settings that are entered when the device is was installed. Changes can only be beneficial and necessary if the laser for the AKF system needs to be changed. Figure 21: Camera settings that affect the linearity of the video signal transfer. Attention: Never change

20 20 Operating Manual Wedge Angle Scanner 9. Installations Tips First install the camera drivers. Then install the program. Attention: Do not install the program under C:\Program files\... Just install it under C:\oeg 10. Service Contact Information If you have problems please contact us at: