DE2545470A1 - Automatic centring of electric conductor in insulation sleeve - uses signal pulse gating unit automatically calibrated during preset time intervals by means of CRT display - Google Patents

Abstract

A signal pulse is used for automatically centring an electric conductor in an insulating sleeve. The pulse gating unit is automatically calibrated during predetermined time intervals by comparing the received measurement pulse with predetermined nominal values. The measurement pulse is picked up with a calibration-cable balancing network and brought into the beam path of a CRT. Spatially limited interference from points on the insulation shell is tuned out in the video signals from which (signal) is formed a threshold signal converted into a positive output. This reverts to zero only when one complete line of the picture on the target is dark.

Description

Centering an electrical conductor in an insulating sleeve

The invention relates to a method and an arrangement for automatic Centering an electrical. Conductor in an insulating sheath, especially in the case of cables.

The main patent deals with the task of an electrical conductor to center automatically in an insulating sleeve, so that the conductor over its entire Length is evenly surrounded by the insulating sleeve and this, as with plastic high-voltage cables all over has the same electrical resistance to applied voltages. After this The main patent is achieved in that the position of the conductor within the insulating sleeve constantly by means of the insulating sheath penetrating rays on a target one Image pick-up tube (e.g. Vidikon) imaged and here by an electron beam is scanned and that a deviation from the central position of the conductor to the insulating sleeve an asymmetry of the video signal caused, from which with the help of a pulse evaluation device Control pulses are derived that bring about a central position of the conductor can be used inside the insulating sleeve.

To carry out this procedure, an arrangement is provided, in the case of the two perpendicular to each other in a short distance behind an extruder Radiation sources set up on levels with their receivers depicting the cable cores are provided in which the extruder through two located in these levels Servomotors can be centered and the servomotors obtained by the receivers Control values are controllable.

The present invention is based on the object of a further To achieve improvement of the process and the arrangement according to the main patent.

In a method according to the main patent, this object is achieved according to the invention solved in that the pulse evaluation device at predetermined time intervals by comparing the calibration cable simulation brought into the beam path received measuring pulses is automatically calibrated with predetermined setpoints and that Disturbances caused by spatially limited defects on the insulating sleeve in the Video signal can be faded out by converting the video signal into a threshold signal is formed, which in turn is converted to a positive output signal, that only goes back to zero when at least one complete, from the electron beam scanned line of the image on the target is dark.

According to the invention, the video signal is converted with the aid of the pulse evaluation device the outer diameter of the insulating sleeve is also determined.

The arrangement for carrying out this procedure in which in a short time Distance behind an extruder are two mutually perpendicular planes Radiation sources are provided with their receivers depicting the cable cores, in which the extruder is driven by two servomotors located in these levels can be centered and the servomotors by the control values obtained in the receivers are controllable and in the case of the image blanking signals obtained in the radiation receivers Pulse evaluator are provided, the comparators for the setpoint and actual values with the servomotors are in connection, is characterized according to the invention in that each pulse evaluator a self-adjusting device and an eliminating device for eliminating due spatially limited flaws on the cable circumference contains incorrect measurements, that the self-calibration device is composed of one in the beam path of the camera fade-in calibration standard, a video signal evaluator, facilities for determination the actual values of the eccentricity and the position of the conductor, a comparator for comparison of calibration actual and target values, a calibration board for preparation and storage the deviations determined by the calibration value comparator up to the start of the calibration process following measuring process and one in the measuring circuit between the video signal evaluator and the devices for determining the actual values of the eccentricity and the position and the error subtraction stage connected to the measured value comparator and connected downstream of the calibration board and that the eliminating device consists essentially of a retriggerable monostable There is a multivibrator in the video signal evaluator.

The calibration value comparator is expediently provided with a display device connected, which with a minimum deviation of the Calibration actual value from Setpoint responds. In a corresponding manner, the measured value comparator has a Connected display device that shows any deviation of the actual value from the target value.

The error subtraction stage are devices according to the invention for measuring and displaying the conductor eccentricity and devices for measuring and display of the position of the conductor in the insulating sleeve connected downstream. With the calibration board an error display device is connected. According to the invention are to the video signal evaluator additional devices for measuring and displaying the cable diameter are connected. Accordingly, the measured value and calibration comparators are also used to compare actual and target values of the cable diameter. To print out all measured values the arrangement according to the invention with a connection for a digital printer rusted out.

The advantages of the invention are particularly to be seen in the fact that besides the eccentricity of the conductor, the outer diameter of the cable and the position of the conductor contactless in its insulating sleeve in the immediate vicinity of the extruder can be measured. Pendulum movements of the cable and water droplets on the According to the invention, cables cannot influence the measurement result. A significant one Another advantage is that the arrangement is automatically calibrated.

An embodiment of the invention is shown in the drawings.

FIG. 1 shows the measuring arrangement in a schematic representation. Figure 2 contains a block diagram of the pulse evaluators 10 and 11. Figure 3 is the Figure of a cable core can be seen in the parallel line grid. Figure 4 shows a cable section with a water drop and the line grid.

Figure 5 illustrates the evaluation of a video signal with interferences, caused e.g. by water droplets on the edge of the cable core.

In Figure 1 is the implementation of the method according to the invention serving arrangement shown schematically. The one in the extruder 2 with an insulating sleeve provided conductor 1 runs through the cross-linking of the insulation of the cable 3, CV tube 45 under vapor pressure. The CV tube 45 is provided with a sight glass unit 19 provided in which the measurements are made. As with the procedure According to the main patent, the cable core 3 is supported by two mutually perpendicular, X-ray bundles emanating from the light sources 6 and 7 are transilluminated. The Rays are received by radiation receivers 8 and 9, where the cable core to be measured on a target, e.g.

of a silicon multidiode vidicon, imaged and by an electron beam is scanned. The electron beam generates 8 and 9 line grids in the cameras parallel to the wire contour.

FIG. 3 shows the cable core 3 to be mapped in a line grid.

The amplitudes of the individual lines reach at the points where the Rays from the radiation source do not yet hit the insulating sleeve, their maximum values (left of A and right of while practically zeroing there where the rays completely shielded by the conductor from the grid (between B and C). By the counting of the lines between A and B and between C and D and by forming the quotient the values determined are used to determine the eccentricity of the conductor. The emerging Image signals are evaluated in the pulse evaluators 10 and 11 and in the: Comparators 12 and 13 compared with the setpoints. In the event of deviations from the image signals Determined values from the setpoints, the extruder drives 4 and 5 are influenced in such a way that that the error in the extruder 2 is corrected.

Based on this process already described in the main patent can, according to the present invention, incorrect measurements due to spatially limited Disturbances on the cable circumference can be avoided.

If there is a fault on the cable shown, such as, for example, an water droplet 44 (FIG. 4), this also causes this in the video signal and in the grid 42 of the lines appearing in the area 43 to be formed a to f Imperfections. In curve 8a, FIG. 5 shows the output j such disturbance points on the pulse train, where these points appear too suddenly Changes in brightness T II and III in the image content of the relevant lines b, c and d lead.

In order to adulterate the measurement results through these fault points prevent, is in the video signal evaluator 24 (Fig. 2) after a SchwellwertU1dung a threshold value signal 3b is generated from the video signal shown in curve 3a. by means of a retriggerable monostable, connected downstream of the threshold switch The trigger stage is the output pulse duration of the voltage curve 3c from the last trigger pulse T determined. Is the time constant of the monostable multivibrator greater than or equal to # + t1 (# = period of the line sync pulse, t1 is the time from the end of the line sync pulse until the end of the image blanking), imperfections are masked out. The one in the curve The signal voltage shown in 3c can only jump back from its positive value to zero if if the image content was black at least one complete line before.

The measuring arrangement according to the invention is constructed in such a way that it is automatic calibrated. It is shown in Figure 2 in a block diagram, which their Provides information about the structure of the pulse evaluators 10 and 11. For the sake of simplicity only the devices connected to the camera 9 are described here. The devices connected to the camera 8 are identical to these.

The image recorded by the camera 9 is sent to the video signal evaluator 24, that of the quartz time base 4D, which are all necessary for the measuring arrangement Presets frequencies is controlled. The signal goes from the video signal evaluator 24 via the error subtraction stage 27 on the one hand for the eccentricity measurement 28 and to the display device 29 for the eccentricity, on the other hand via a device 30 for measuring the position of the conductor in the insulating sleeve and for the position indicator 31. The lamps 31 show the deviations of the conductor from the center to the right or left. From the device 28 for eccentricity measurement and 39 for position measurement the signal goes to the measured value comparator 39, where it is compared with the nominal value. The Me.3wertkom.parator 39 corresponds to the comparator 12 in Figure 1. The setpoint for the eccentricity of the conductor is fixed. It's zero. Is there a If the actual value deviates from the nominal value, it is displayed in the device 38.

The video signal comes from the evaluator to determine the diameter 24 to the diameter evaluator 25, the device with the display 26 for the diameter connected is. The diameter evaluator 25, in turn, is also connected to the measurement value comparator 39 connected, where the actual diameter tn with the entered by means of the digital switch 20 Target diameter is compared.

Deviations are again displayed in the device 38. While At the time of the measurement, the same image will appear almost continuously on the storage layer of the Vidikons pictured. As FIG. 3 shows, the image is very rich in contrast. In the The center of the picture is black because there is no light because of the conductor or the smoothing of the conductor falls on the storage layer. Outside the vein, the light falls from the Light source directly on the target. There is therefore a risk that the picture burns into the storage layer of the vidicon, which can lead to incorrect measurements. In such cases, the measuring instrument can detect sudden changes in the vein pressure not rnenr f-ststellen.

In order to avoid such incorrect measurements, the arrangement according to of the invention monitoring and Jelbsteicheinrichtung provided.

A replica cable 32 is replaced at regular intervals of the cable 3 faded into the beam path of the camera 9 and on the target with With the help of the 3lighting source 6a shown. Again, for the sake of simplicity only the measuring and calibration device according to the invention connected to the camera 9 described. The device 11 connected to the camera 8 is identical to this.

The lighting sources 6 and 6a are controlled by means of the Device 23. How to measure the cable data also the Calibration simulation of the cable shown and electronically scanned. The video signal is used in evaluators with regard to the diameter data and the eccentricity of the conductor evaluated. The measured actual calibration values for diameter and eccentricity are compared in the calibration value comparator 37 with the corresponding setpoint values. The setpoint the eccentricity is fixed in the arrangement. The light diameter is for example entered by means of a digital switch 33. The actual calibration values give way in an a from the setpoint values that goes beyond a predetermined threshold value, so the deviation is displayed by means of the device 36. Regardless, it will every deviation of the actual values from the nominal values is processed in the calibration board 34. The difference is reported with the display 35. Error signals are saved and are used to correct the video signal during the next measurement process. Here will be the correction signals are taken into account in the error subtraction stage 27 in the measured values.

The values measured on the cable are partly due to errors of the measuring arrangement corrected by aging of the components or by instabilities be evoked.

Deviations of the actual value of the conductor eccentricity from the nominal value given via a digital printer control 21 to a digital printer. aside from that can of course also use these values directly to control the Extruder drives 4 and 5 are used, which via the connection 22 with the invention Plant are connected.

In addition, the data of the conductor eccentricity, indicated in 29, the conductor position and the cable diameter with a digital printer can be printed out.

12 pages description 10 claims 2 sheets of drawing with 5 characters

Claims (10)

P a t e n t a n s p r ü c h e Procedure for automatic centering an electrical conductor in an insulating sheath, in which the position of the conductor is inside the insulating shell constantly by means of the insulating shell penetrating radiators on one Target of an image pickup tube (e.g. Vidikon) imaged and here by an electron beam is scanned, with a deviation from the central position of the rider to the insulating sleeve an asymmetry of the video signal caused, from which with the help of a pulse evaluation device Control impulses derived that will help bring about a central Lag conductor can be used within the insulating sleeve, according to patent (patent application P 24 02 480.4-34), characterized in that the pulse evaluation device in predetermined time intervals by comparing the with one in the beam path measurement pulses with predetermined setpoints obtained using calibration cables is automatically calibrated and that of spatially limited spots on the insulating cover Interference caused in the video signal can be hidden by removing it from the video signal a threshold value signal is formed which in turn results in a positive output signal is transformed, which only goes back to I'ull when at least one complete, line of the image scanned by the electron beam on the target is dark. 2. The method according to claim 1, d-characterized in that from the Video signal with the help of the pulse evaluation device also the outside diameter the insulating sleeve is determined. 3. Arrangement for carrying out the method according to Arspruch 1 or 2, when two in a short distance behind an extruder in perpendicular to each other lying levels Radiation sources with their the cable core imaging receivers are provided, in which the extruder is divided by two in Servomotors located in these levels can be centered and the servomotors by the control values obtained in the receivers are controllable urc1. at the r: r die ir: image blanking signals obtained from the radiation receivers, pulse evaluators are provided are, cie via comparators for the setpoint and actual values in connection with the control motors are available according to the main patent (patent application P 24 02 480.4-34), characterized in that that each pulse evaluator (10 or 11) a self-piercing device and an eliminating device for the elimination of defects in the cable circumference due to spatially limited defects Incorrect measurements include that the self-calibration device is made up of an in Elchr.ormal (3.?D, a video signal evaluator (24), devices (28 or 30) for determining the actual values of the eccentricity and the position of the conductor, a comparator (37) for comparing actual and target values of moose, a calibration board (3 At) for the preparation and storage of the calibration value comparator (37) determined deviations up to the beginning of the measuring process following the calibration process and one in the measuring circuit between the video signal evaluator (24) and the devices (28 or 30) to determine the Actual values of the eccentricity and the Position as well as the measured value comparator (3a,) switched, the calibration board (34) switched up Error subtraction stage (27) and that the eliminating device essentially consists of a retrofittable monostable multivibrator in the video signal evaluator (24). t. Arrangement according to Claim 3, characterized in that the calibration value comarapor (3.7) respond with a setpoint in the event of a minimum deviation of the calibration actual value VOffl Display device (36) is connected. 5. Arrangement according to claim 3 or 4, characterized in that the Measured value comparator (39) with an alternation between the actual value and the nominal value Device (38) is connected. 6. Arrangement according to claim 3, 4 or 5, characterized in that the error subtraction stage (27) means for measuring (28) and for display (29) the conductor eccentricity and devices for measurement (30) and display (31) downstream of the position of the conductor. 7. Arrangement according to one of claims 3 to 6, characterized in that with the calibration board (31) is connected to a device (35) for displaying errors. 8. Arrangement according to one of claims 3 to 7, characterized that at the video signal evaluator (24) additional device for measurement (25) ur: d End (26) of the cable diameter are connected. 9. Arrangement according to one of claims 3 to 8, characterized in that that the measured value and calibration value comparators (39, 37) also for comparing actual and Target values of the cable diameter are designed. 10. Arrangement according to one of claims 3 to 9, characterized in that that you can print out all nominal values with a connection (22> for a digital printer is equipped and that he drives connection (22) to control the extruder (4, 5) is used.