JP4376998B2 - Scale fault diagnosis device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a scale fault diagnosis apparatus, and more particularly to a scale fault diagnosis apparatus incorporated in a numerical control device (NC device).
[0002]
[Prior art]
Conventionally, a linear scale or the like has been incorporated for position control of the NC device, and the detected position signal is supplied to the controller of the NC device or the like for feedback control.
[0003]
FIG. 9 shows a system configuration diagram of a scale incorporated in the NC apparatus. The scale 20 is incorporated in, for example, the table 18 of the NC device, detects the position of the table 18, and supplies it to the controller 10 (more precisely, a servo amplifier). Based on this position signal, the controller 10 supplies a drive signal to the motor 14 via the cable 12 to rotationally drive the ball screw 16. The table 18 is moved by the rotational drive of the ball screw 16 and adjusted to a desired position. Usually, the scale 20 is incorporated in the NC apparatus and is not exposed to the outside.
[0004]
High-speed serial communication is used as the interface of the NC device. Compared to two-phase sine wave (analog) and two-phase square wave (digital), this high-speed serial communication has a constant transmission line communication speed, so data can be transferred stably even for high-speed feed. Since an error detection code can be added, there are advantages such as high data reliability. On the other hand, there are drawbacks, such as the need for a serial transmission circuit, which makes it difficult to reduce the cost and size of the apparatus, and there is no means for observing high-speed serial data after the scale 20 is incorporated.
[0005]
The high-speed serial interface outputs a synchronization signal from the NC (more specifically, from the NC controller) according to the control cycle of the NC. The output period is about 50 to 300 μs, but is expected to become shorter in the future.
[0006]
On the other hand, the data output from the incorporated scale 20 detects position data at the timing of the synchronization signal, converts it into serial data, and transmits it to the NC controller.
[0007]
For example, if the position resolution is 0.1 μm and the effective length of the scale 20 is 10 m, 27 bits of data are required, and if status information such as an alarm or an error detection code is added thereto, a data capacity of at least about 32 bits is required. If the NC control period is 64 μs, data cannot be transmitted within the control period unless data is transmitted at a transmission rate of 500 kbps or higher.
[0008]
[Problems to be solved by the invention]
Thus, when performing failure diagnosis of the scale 20 incorporated in the NC device, it is desirable to use a general-purpose device such as a personal computer in which dedicated software is installed. This is because an apparatus can be obtained easily and inexpensively as a failure diagnosis apparatus. However, the serial data transmission speed of the RS232C port mounted on the personal computer is at most 9.6 kbps to 115.2 kbps, and the above transmission speed (500 kbps or higher) cannot be satisfied. Further, USB and IR-DA, which are higher-speed serial ports, have complicated (redundant) protocols and are difficult to reduce the cost. In addition, the protocol specification itself does not match the high-speed interface between the NC and the scale, and there is a problem that protocol conversion is necessary. Therefore, a dedicated device configuration is required for the failure diagnosis device for the scale 20 incorporated in the NC device. Alternatively, a signal conversion circuit that can be processed by a personal computer is required.
[0009]
Moreover, it is necessary to perform failure diagnosis of the scale 20 in a state where the NC device and the scale 20 are connected. That is, when an abnormality occurs in the scale 20, it is desirable to monitor the position data from the scale 20 while performing servo operation with the NC device and identify the abnormal part. Since the scale 20 has not failed and failure of the NC device or the signal cable itself is conceivable, it is an effective analysis method to monitor the position data of the serial signal in order to reliably identify the failure location.
[0010]
Of course, since position data and other detection signals are supplied from the scale 20 to the NC controller 10, it is possible in principle to monitor the position data with the NC device, but it cannot be separated from the failure of the NC device itself. Alternatively, there is a problem that it is difficult if the user is not familiar with the NC device failure diagnosis method. Furthermore, if the manufacturer of the NC device is different from the manufacturer of the scale 20 incorporated, failure diagnosis via the NC device will be difficult.
[0011]
The present invention has been made in view of the above-described problems of the prior art, and its purpose is to enable easy monitoring of serial data from a scale in real time in a state where it is connected to an NC device, and to quickly An object of the present invention is to provide an apparatus capable of performing failure diagnosis.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is a failure diagnosis device for a scale incorporated in a numerical control device, wherein the detection signal supplied from the scale to the controller of the numerical control device is branched and output. and means, the branch means comprises units and the receiving unit, before Kiyu knit, a branch circuit for branching the detected signal, connected to the branch circuit, converting the detection signal into an optical signal and a light emitting element, the receiving-side unit includes a light receiving element for receiving a light signal from the light emitting element is connected to the light receiving element, a serial / parallel converting a signal from the light receiving element into parallel data And the serial / parallel converter transmits the parallel data to a computer.
[0013]
The present invention further includes means for converting the detection signal branched by the branching means into an optical signal and outputting the optical signal. By converting the branched detection signal (serial data) into an optical signal, wireless signal reception is possible, and failure diagnosis can be performed without impairing the noise resistance of the system.
[0014]
In addition, the present invention is characterized by further comprising transmission means for transmitting the detection signal branched by the branching means. As a result, the detection signal (serial data) can be monitored remotely. As the transmission means, a computer network, a telephone line, the Internet, or the like can be used, and wireless transmission is also possible. When a computer network is used, failure diagnosis can be performed by transmitting a detection signal to a remote computer.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0016]
FIG. 1 shows a system conceptual diagram of the present embodiment. A linear scale 20 is incorporated in the table 18 of the NC device, and a position signal detected by the linear scale 20 is supplied as serial data to the controller 10 via a servo amplifier of the NC device. The controller 10 adjusts the position of the table 18 by supplying a drive signal to the motor 14 via the cable 12 based on this position signal and rotationally driving the ball screw 16.
[0017]
In order to perform serial communication, the cable 12 has, for example, REQ, REQ (−), DATA, and DATA (−) signal lines as shown in FIG. Transmit the signal. REQ is a timing signal for requesting position data from the NC device to the scale 20, and coincides with the servo cycle T1 inside the NC device. In accordance with the timing of REQ, DATA adds information such as an alarm status indicating a self-diagnosis result of scale 20 and a data transmission error detection code in addition to position data, and transmits the data as serial data to the NC unit.
[0018]
In the conventional apparatus shown in FIG. 9, the serial data from the scale 20 is directly supplied to the NC controller 10, but in this embodiment, as shown in FIG. A unit 22 is provided between the servo amplifier (NC servo amplifier), and serial data from the scale 20 is branched and output to the personal computer 24 and the controller 10.
[0019]
FIG. 3 shows a configuration block diagram of the unit 22 in FIG. The unit 22 includes a branch circuit 22a connected in parallel to the data lines (DATA, DATA (-)) of the cable 12, a serial / parallel converter 22b connected to the branch circuit 22a and converting serial data into parallel data, and various processing devices. It is comprised including.
[0020]
As shown in the figure, specific examples of various processing apparatuses in the present embodiment include an LED array 22c that directly visually displays data converted in parallel by the serial / parallel converter 22b, and externally converts parallel data into analog data. DAC (digital / analog converter) 22d to be supplied to the oscilloscope 26, etc., storing parallel data, further converting the protocol and converting the serial data into a signal that can be processed by the personal computer 24, the protocol converter 22f, and the parallel data A microcontroller 22g or the like that processes and displays on the liquid crystal display 22h.
[0021]
Of course, it is also possible to omit the various processing devices described above and output the parallel data from the serial / parallel converter 22b to the outside as it is.
[0022]
In such a configuration, when any abnormality occurs in the scale 20, the scale 20 is connected to the NC device, and is positioned in the NC device, but the position from the scale 20 by the LED 22c or the liquid crystal display 22h. Data values can be monitored.
[0023]
Further, in the NC operation state, the correspondence between the detection position and time can be monitored in real time by the oscilloscope 26 by analog output from the DAC 22d.
[0024]
Further, when it is necessary to perform a more detailed analysis, the data can be transferred to the personal computer 24, and the data can be stored in the storage device of the personal computer 24 as appropriate, and monitored offline.
[0025]
As described above, according to the present embodiment, serial data from the scale can be easily monitored in a state where the scale 20 is connected to the NC device, and the maintainability is greatly improved, and the cause when a failure occurs. Specific work is facilitated and speeded up.
[0026]
FIG. 4 is a conceptual diagram of a system according to another embodiment. In the above-described embodiment, serial data from the scale 20 is branched and connected to the external personal computer 24 or the like by cable, but in this embodiment, high-speed serial communication of 500 kbps or more is performed using light. In the present embodiment, when the failure diagnosis of the scale 20 is performed, the receiving unit 30 is disposed close to the unit 22 via the hook 32. The receiving side unit 30 is connected to the portable personal computer 24 via a cable.
[0027]
FIG. 5 shows a configuration block diagram of the unit 22 and the receiving unit 30 in the present embodiment. The unit 22 includes a branch circuit 22i connected in parallel to the data lines DATA, DATA (−), and a light emitting element 22j connected in series to the branch circuit 22i. On the other hand, the receiving side unit 30 that is disposed close to the unit 22 using the hook 32 has a light receiving element 30a that receives an optical signal from the light emitting element 22j, an amplifier 30b that amplifies the received signal, and the amplified received signal as parallel data. It includes a serial / parallel converter 30c for converting into
[0028]
According to such a configuration, serial data from the scale 20 via the data line is converted into an optical signal by the light emitting element 22j and is spatially transmitted to the receiving side unit 30, and is further held by the operator from the receiving side unit 30. It is supplied to the personal computer 24 as parallel data. The operator can easily monitor the data from the scale 20 only by arranging the receiving side unit 30 using the hook 32.
[0029]
According to the present embodiment, since the branch circuit 22i and the light emitting element 22j can be realized with a small size and a low price, it is possible to always install the unit 22 in the power distribution board as shown in FIG. .
[0030]
In addition, since it is possible to monitor without contact when performing failure diagnosis of the scale 20, it is possible to easily and quickly set up failure diagnosis, which is particularly effective for frequent periodic inspections.
[0031]
Furthermore, since it can be isolated from noise sources such as a serial / parallel converter and a personal computer, there is an advantage that measures against electric accidents can be taken at the same time because it is electrically insulated without impairing the noise resistance of the entire system.
[0032]
As described above, the embodiment of the present invention has been described. In the present embodiment, the data signal from the scale 20 is branched and then transmitted by the transmission means, so that the data signal is not monitored in the vicinity of the NC device at a remote place. It is also possible to monitor.
[0033]
For example, as shown in FIG. 6, after the data signal from the scale 20 is branched by the unit 22, the branch signal is supplied to the sequencer 34, and further supplied from the sequencer to the central monitoring device 36 at a remote location via the LAN. It is also possible to do. According to this, it is not necessary for the operator to go to the vicinity of the NC device, and failure diagnosis of the scale 20 can be performed from a remote location. As shown in the figure, the configuration 100 in which the unit 22 is attached to the cable 12 of the NC device incorporating the scale 20 is regarded as one set, and a plurality of such configurations 100 are connected to the same LAN, It is also possible to perform fault diagnosis intensively with one central monitoring device 36.
[0034]
Further, as shown in FIG. 7, a data signal from the scale 20 branched by the unit 22 is transmitted to the Internet 42 via the network terminal 40, and the state of the scale 20 is monitored by a personal computer 44 connected to the Internet. Is also possible.
[0035]
Further, as shown in FIG. 8, the data signal from the scale 20 branched by the unit 22 may be transmitted to the public telephone line 48 via the modem 46 and taken into the personal computer 52 via the modem 50 from the public telephone line. Is possible.
[0036]
In either case, the operator can monitor the scale 20 in real time at a remote location separated from the NC device.
[0037]
【The invention's effect】
As described above, according to the present invention, the scale can be monitored in real time while being connected to the NC device, and the failure diagnosis of the scale can be performed easily and quickly.
[Brief description of the drawings]
FIG. 1 is a system conceptual diagram of an embodiment of the present invention.
FIG. 2 is an explanatory diagram of data transmission of the cable 12 in FIG. 1;
3 is a configuration block diagram of a unit 22 in FIG. 1. FIG.
FIG. 4 is a system conceptual diagram of another embodiment of the present invention.
5 is a configuration block of a unit and a receiving unit in FIG. 4. FIG.
FIG. 6 is a system configuration diagram of still another embodiment of the present invention.
FIG. 7 is a system conceptual diagram of still another embodiment of the present invention.
FIG. 8 is a system conceptual diagram of still another embodiment of the present invention.
FIG. 9 is a connection explanatory diagram of a conventional NC device and a scale.
[Explanation of symbols]
10 controller, 12 cable, 14 motor, 16 ball screw, 20 scale, 22 unit, 24 personal computer, 30 receiving side unit.

Claims (1)

A fault diagnosis device for a scale incorporated in a numerical control device,
Branching means for branching and outputting a detection signal supplied from the scale to the controller of the numerical controller;
It said branch means comprises units and the receiving unit,
Before Kiyu knit,
A branch circuit for branching the detection signal;
A light emitting element connected to the branch circuit and converting the detection signal into an optical signal;
And the receiving unit includes:
A light receiving element for receiving an optical signal from the light emitting element;
A serial / parallel converter connected to the light receiving element and converting a signal from the light receiving element into parallel data;
The scale / diagnosis device according to claim 1, wherein the serial / parallel converter transmits the parallel data to a computer.

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