WO1995010789A1 - Capteur de faisceau lumineux a axes optiques multiples et surete integree - Google Patents
Capteur de faisceau lumineux a axes optiques multiples et surete integree Download PDFInfo
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- WO1995010789A1 WO1995010789A1 PCT/JP1993/001463 JP9301463W WO9510789A1 WO 1995010789 A1 WO1995010789 A1 WO 1995010789A1 JP 9301463 W JP9301463 W JP 9301463W WO 9510789 A1 WO9510789 A1 WO 9510789A1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V8/00—Prospecting or detecting by optical means
- G01V8/10—Detecting, e.g. by using light barriers
- G01V8/20—Detecting, e.g. by using light barriers using multiple transmitters or receivers
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V8/00—Prospecting or detecting by optical means
- G01V8/10—Detecting, e.g. by using light barriers
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K2217/00—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00
- H03K2217/94—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00 characterised by the way in which the control signal is generated
- H03K2217/941—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00 characterised by the way in which the control signal is generated using an optical detector
- H03K2217/94114—Optical multi axis
Definitions
- a plurality of light-emitting elements and light-receiving elements arranged face-to-face with a risk area to be monitored are sequentially scanned and driven in synchronization with each other, and when a light beam from the light-emitting element is received by the light-receiving element, the risk area is detected.
- a dangerous area hazard area
- a safe area even if one exists (safe area)
- the element and the light receiving element are arranged facing each other, and a light beam is emitted from the light emitting element toward the light receiving element.
- a light beam is emitted from the light emitting element toward the light receiving element.
- the input signal of the receiver R is an AC signal. B, — B in Fig. 1.
- the output signal (light beam B) of the projector T is transmitted to the receiver R as an alternating signal in which the state with light (B,) and the state without light (B.) are output alternately. Is done.
- This method when viewed from the receiver R side, means that the level of B, (with light) means that the light beam is not blocked by an obstacle (ie, safe).
- a level of (no light) means that the light beam was blocked by an obstacle (ie, not safe).
- the light receiving element and the amplifier constituting the light receiver R receive and amplify this alternating signal, so that when an obstacle actually enters the area X (the area where safety is to be confirmed), the alternating signal is not received. This alternating signal will be received when no obstacle is present. In other words, in this method, even when the obstacle is absent (safe), the signal indicating danger (B.) is included in the received signal indicating this.
- capacitor C A has input signal level B. (Indicating danger) is received, the first charge of the polarity shown in FIG occurs via a diode D A. Then, the input signal level 8 (indicating safety) is superimposed on this charging voltage and is stored as the output voltage V DC of the DC to the capacitor C B via the diode D B. This stored voltage V DC is the input signal level B. No long as the capacitor C A is not charged by. That is, the DC output signal V DC indicating safety is the input signal level B indicating danger. This will only occur when we can receive
- the alternating light beam B transmitted from the transmitter T checks whether there is an obstacle in the dangerous area X and at the same time checks whether the light receiving element and the amplifier of the receiver R are operating normally. This is an inspection signal for inspecting the data.
- the output signal is output at a level higher than the power supply potential.
- the voltage doubler rectifier circuit is clamped at the power source potential V cc using the diode D A, the signal y is rectified output voltage V DC is output by being superimposed on the power source potential V cc.
- Output signal referred to as a power source outside the frame potential
- the reason for this output signal superimposed on the power source potential Vcc is generated, as indicated by the dotted line in FIG, event, occurs a short circuit fault in the capacitor C A This is so that even if the power supply potential Vcc is directly output to the output side, it can be distinguished from the output potential VDC on the output side. That is, in the figure, assuming that the output potential of the voltage doubler rectifier circuit is V, the binary output signal y is determined as follows.
- the signal y 1 indicating safety is generated by mistake. There is no such thing.
- a fail-safe multi-optical axis beam sensor that employs the above-described fail-safe signal processing principle and periodically drives and scans each light-emitting element and light-receiving element facing each other.
- Japanese patent application Japanese Patent Application No. 5-30068
- c This is a scan output signal that is continuous on the time axis from the light-emitting side and light-receiving side scanning circuits. Are generated in synchronization with each other, the light emitting element and the light receiving element are sequentially scanned and driven, and a light beam is sequentially emitted from the light emitting element side to the light receiving element side to detect an object in a dangerous area.
- the normal state is set, and two or more scanning output signals are simultaneously overlapped on the time axis, or during one scanning cycle.
- the sensor output is stopped as an abnormal state.
- An error detection method based on a fail-safe multi-valued logical operation by addition is employed for detecting an abnormal state of the scanning output signal.
- the voltage levels of the scanning output signals generated for scanning the light emitting element and the light receiving element are sequentially added by using a voltage doubler rectifier circuit, and the added voltage level is subjected to a threshold operation by a safe window comparator. . And that there is always one scan output signal on the time axis, By setting the respective added value levels to detect that all the scanning output signals are generated in one scanning cycle, when each added value is within a predetermined range, the window comparator generates the scanning output signal. An output voltage (logical value 1) indicating that the state is normal is generated. When the output voltage is out of the predetermined range, the output voltage is set to zero (logical value 0) to indicate that the generation state of the scan output signal is not normal.
- N additions are required for all scan output signal (N) detections, and the sum of the voltage levels of the N scan output signals is required.
- the voltage change for one scan output signal with respect to the sum is 1 ZN.
- the number N of scanning output signals the number of optical axes
- the setting of the threshold value becomes delicate, and it becomes difficult to make a determination by threshold value calculation.
- the added voltage value increases.Therefore, it is necessary to increase the withstand voltage of the capacitor used for the addition operation, and the shape of the capacitor used increases. There is a problem such as burning out.
- scanning circuits are separately provided on the light-emitting side and the light-receiving side, and the scanning of the light-emitting side and the scanning of the light-receiving side are synchronized with the final light-emitting element.
- Configuration to transmit to the light-receiving side that the scan output signal is the same, and verify that they are synchronized by checking that they match the scan output signal of the last light-receiving element on the light-receiving side.
- the synchronization of the scanning on the light-emitting side and the light-receiving side is checked by another system. Therefore, the circuit configuration of the sensor is complicated.
- the present invention is an improvement of the above-described multi-optical axis light beam sensor, and aims at facilitating the calculation of the threshold value of the added value irrespective of the increase in the scanning output signal and simplifying the circuit configuration of the sensor. I do. [Disclosure of the Invention]
- the file safe multi-optical axis light beam type sensor includes a scanning signal generating circuit for generating a scanning signal including a clock signal at a fixed interval, and a clock signal input from the scanning signal generating circuit every time a clock signal is input from the scanning signal generating circuit.
- a shift register for sequentially generating an output; a scan output signal for sequentially switching and driving a plurality of light emitting elements based on the output of the shift register for generating a scan output signal;
- a light-emitting side scanning circuit for emitting light, and a shift register for sequentially generating an output each time the same cross-talk signal is input to the light-emitting side scanning circuit, based on the output of the shift register.
- a scanning output signal for sequentially switching and driving the same number of light receiving elements arranged facing the plurality of light emitting elements is generated, and an AC light receiving output signal is generated when the light receiving element receives a light beam from the light emitting element.
- a light-receiving-side scanning circuit that performs amplifying, level-testing, and rectifying the received-light output signal when an alternating-current light-receiving output signal is generated from the light-receiving-side scanning circuit to generate a logical 1 output and output when a circuit failure occurs Is a logical value of 0, and the sum of the scan output signal levels of the light emitting side scanning circuit and the above-mentioned scan output signal is always one when the logical level of the added value is 1.
- a fail-safe scan output signal that outputs a logical value of 0 as at least one of the abnormal conditions in which a scan output signal does not occur and that outputs a logical value of 0 when a circuit fails And ⁇ path, the light-emitting side and the output of each shift register evening of the last stage of the light receiving side and add operations, the logical level of the sum is synchronized output of the last stage when 1 And outputs a logical value of 1, and when the logical level of the added value is 2 or 0, it is determined that the output of the final stage is asynchronous and generates an output of logical value 0 and a circuit failure.
- the output of the fail-safe coincidence detection circuit whose output becomes a logical value 0, and the outputs of the amplification / level test circuit, the scanning output signal inspection circuit, and the coincidence detection circuit are logically operated, and all of these outputs have the logical value 1
- a fail-safe AND operation circuit that generates an output of logical value 1 at the time of output and outputs a logical value 0 in the event of a circuit failure; and outputs the output of logical value 0 when the output of the AND operation circuit is logical value 0.
- At least one scan period of the scan output signal is held, and a fail-safe sample-hold circuit is provided that outputs a logical value of 0 when the circuit fails.
- the circuit configuration of the sensor can be simplified, the threshold value of the added value can be easily calculated even when the number of optical axes increases, and the withstand voltage of the capacitor used in the addition circuit can be reduced. There is no need to worry about the increase in size.
- the light emitting side scanning circuit inputs a shift register composed of a plurality of DK flip-flops corresponding to the number of light emitting elements, and a scanning signal from the scanning signal generating circuit, and receives the scanning signal.
- a monostable multivibrator output to the input terminal of the flip-flop at the first stage of the shift register after extending the pulse width for a predetermined time, and a non-inverting output terminal of each flip-flop.
- a plurality of first NOT circuits connected to each other, a plurality of light emitting elements having a power source connected to the output side of each of the NOT circuits, and a plurality of light emitting elements connected to the anode side of each of the light emitting elements via respective resistors;
- a carrier signal generating circuit for generating a carrier signal having a predetermined frequency, and an input side connected between each of the light-emitting elements and a resistor, and an output side connected to a flip-flop of the next stage.
- a plurality of second negation circuits connected to an input terminal, wherein a clock signal from a scanning signal generation circuit is input to a clock input terminal of each of the DK flip-flops, An output signal to the scanning output signal inspection circuit is extracted from an intermediate point between each second NOT circuit and each flip-flop input terminal.
- the light receiving side scanning circuit is provided with a shift register including a plurality of DK flip-flops corresponding to the number of light receiving elements, and a scanning signal from the scanning signal generating circuit, and receives the scanning signal as a predetermined signal.
- a monostable multivibrator that extends the time pulse width and outputs it to the input terminal of the flip-flop at the first stage of the shift register, and is connected to the inverting output terminal of each flip-flop.
- the same clock signal as that of the light-emitting side scanning circuit is input to the clock input terminal of each DK flip-flop, and the output side of the third NOT circuit is connected to the AC amplifier circuit. After connecting to the output line, the AC amplifier circuit It is configured to connect to the de Isseki input of the next full re Ppufuro-up via the output line.
- the scanning output signal inspection circuit includes a plurality of coupling capacitors connected in series to a plurality of input terminals to which a plurality of scanning output signals sequentially input from a shift register of the light emitting side scanning circuit are input, A plurality of first diodes for clamping the output side of each of the coupling capacitors to the power supply potential, and an output of the coupling capacitor clamped to the power supply potential by each of the first diodes.
- An adder circuit composed of a second diode for rectifying and transmitting to one output terminal; a threshold value operation of the output level of the adder circuit; Generate output, When the output level is a logical value of 0 or 2 or more, a logical value of 0 is generated outside the threshold range, and a full-safe first window comparator that outputs a logical value of 0 upon a failure. It is a structure provided with.
- the coincidence detection circuit outputs the output of the last-stage flip-flop of the shift register of the light-emitting side scanning circuit and the output of the last-stage flip-flop of the shift register of the light-receiving side scanning circuit.
- a coupling capacitor connected in series to each input terminal to which an output is input, a third diode for clamping the output side of each coupling capacitor to a power supply potential, and a third diode
- An adder circuit composed of a fourth diode for rectifying and transmitting the output of each coupling capacitor clamped to the power supply potential to one output terminal by the diode of the third diode, and performing a threshold operation on the output level of the adder circuit When the output level is a logical value 1, an output of a logical value 1 is generated within the threshold range, and when the output level is a logical value 0 or 2, an output of a logical value 0 is generated outside the threshold range.
- a first window comparator for fail-safe operation wherein the output of the flip-flop at the last stage of the shift register of the light emitting side scanning circuit and the shift register of the light receiving side scanning circuit are provided. In this configuration, the outputs of the flip-flops at the final stage are input to the adder circuit in a complementary manner.
- sample-and-hold circuit is constituted by a fail-safe on-delay circuit whose output becomes a logical value 0 at the time of failure.
- FIG. 1 is a circuit diagram showing the configuration principle of a full-safe light beam type sensor.
- FIG. 2 is an overall configuration diagram showing one embodiment of a full-safe multi-optical axis light beam type sensor according to the present invention.
- FIG. 3 is a time chart for explaining the operation of the embodiment.
- FIG. 4 is a circuit diagram of a scanning output signal inspection circuit.
- FIG. 5 (A) is a time chart for explaining the operation of the scanning output signal inspection circuit when the output of the scanning output signal is normal.
- Fig. 5 (B) is a time chart illustrating the operation of the scanning output signal inspection circuit when an abnormality occurs in which the output of the scanning output signal overlaps.
- FIG. 6 is a circuit diagram of a light emitting side scanning circuit.
- FIG. 7 (A) is a time chart illustrating the operation of the shift register of the light emitting side scanning circuit.
- FIG. 7 (B) is a time chart for explaining the signal transmission process between shift registers.
- FIG. 8 is a circuit diagram of the light-receiving-side scanning circuit.
- Fig. 9 (A) is a time chart explaining the operation of the shift circuit of the light-receiving side running circuit in the same as above.
- FIG. 9 (B) is a time chart for explaining a signal transmission process between shift registers.
- Fig. 9 (C) is a circuit diagram explaining the principle of the wiring structure during the shift register.
- FIG. 10 is a circuit diagram of the coincidence detection circuit.
- Fig. 11 is a time chart explaining the operation of the match detection circuit.
- FIG. 2 shows a schematic configuration diagram of the multi-optical axis light beam type sensor of the present embodiment.
- a scanning signal generation circuit 1 includes a clock generation circuit that generates a clock signal at regular intervals, a start signal generation circuit that generates a start signal for starting scanning, and A scanning signal (start signal and clock signal) for sequentially driving each shift register of a light-emitting side scanning circuit 2 and a light-receiving side scanning circuit 6, which will be described later, comprises a logical sum circuit for generating a logical sum output of a signal generation circuit. (OR output of the lock signal).
- the light emitting side scanning circuit 2 includes a light emitting circuit 3 that sequentially emits an AC light beam in a time-division manner using a plurality of light emitting elements in a dangerous area, and an AC light beam that emits a plurality of light beams emitted from the light emitting circuit 3. And a light emitting circuit 3 based on a clock signal sequentially input at predetermined intervals from the scanning signal generating circuit 1 at a predetermined interval.
- Light receiving circuit 7 and light emitting side shift Light receiving side shift register 8 that generates a scan output signal that enables multiple light receiving elements of the light receiving circuit 7 to sequentially receive light on the time axis based on the same clock signal as the clock signal input to the register 3.
- the c- scan output signal inspection circuit 9 includes an addition circuit and a conventionally known fail-safe window connector (U.S. Patent No. 4, 661.880, etc.). .
- the added value becomes the logic level corresponding to the logic value 2 or 0, and the sum is outside the threshold range of the window comparator and the output of the window comparator becomes It is zero (logical value 0).
- the coincidence detection circuit 10 inputs the shift register output of the last stage of the light-emitting side shift register 5 and the light-receiving side shift register 8 in a complementary relationship to each other, and outputs both outputs to the scan output signal inspection circuit 9. Similarly, a circuit that checks whether the light-emitting side and the light-receiving side are synchronized by adding the values and calculating the threshold value using the window comparator. When both outputs are synchronized, the logical level of the added value is calculated. Becomes 1 and falls within the threshold range of the wind comparator, an output (logical value 1) is generated from the wind comparator, and when both outputs are not synchronized, the added value is the logical value corresponding to the logical value 0 or 2. A level occurs and the output falls outside the window comparator threshold range, and the output of the window comparator becomes zero (logical value 0).
- the amplification / level test circuit 11 amplifies the received signal generated from the light receiving circuit 7, performs level test, rectifies it, and generates it as a DC output in the same manner as the configuration shown in FIG. If the danger area is safe (no objects), an output level of logical value 1 is generated. If even one of the light receiving elements does not receive light from the light emitting side or a circuit failure occurs, it is considered dangerous. Output becomes zero level (logical value 0).
- An AND gate 12 as an AND operation circuit has been conventionally known (U.S. Pat. nt No. 4, 757, 417), which is a fail-safe AND gate 35.
- the outputs of the amplification / level test circuit 11, the match detection circuit 10 and the scan signal test circuit 9 are all logical 1 Occasionally, a logical 1 output is generated, and if any one of them outputs a logical 0, a logical 0 output is generated.
- the sample / hold circuit 13 is configured to hold the output of the logical value 0 for at least one scan period when the output of the AND gate 12 has the logical value 0. Then, it is a file-safe configuration in which the output becomes a logical value 0 in the event of a circuit failure.
- Such a sample-and-hold circuit 13 can be constituted by a fail-safe on-delay circuit (see PCTZJP93 / 004111).
- the output amplifier circuit 14 amplifies the AC output signal of the sample-and-hold circuit 13 and then rectifies it to generate a DC detection output.
- the light beam is blocked by an object while the sensor is operating normally. Otherwise, it will output a logical 1 indicating safety, and if the sensor is abnormal or at least one of the light beams is shut off, it will output a logical 0 indicating danger.
- the operation of the light beam type sensor shown in FIG. 2 will be described with reference to the time chart of FIG. 3 by taking as an example the case where the number of optical axes is eight (the number of light emitting elements and light receiving elements is eight).
- the clock signal generation circuit of the scanning signal generation circuit 1 generates serial clock signals on the time axis at fixed intervals as shown in the figure, and the start signal generation circuit generates one clock signal for every eight clock signals.
- the start signal is generated at the rate of the number.
- a scan signal in which the clock signal and the start signal are mixed is sent from the scan signal generation circuit 1 via the OR circuit, and the light receiving side shift register 5 of the light emitting side scanning circuit 2 and the light receiving side of the light receiving side scanning circuit 6 receive light. Side shift Input to register 8.
- the light-emission-side shift register 5 uses the signal obtained by extending the falling component of the start signal in the scanning signal as a pulse width as a data input signal of the shift register, and when this data input signal is generated.
- the operation starts with this clock signal, and then the scan output signal is sequentially generated in synchronization with the input of the clock signal, and eight light emitting elements are sequentially emitted in one scanning cycle, and this operation is repeated.
- the light emitting element is driven by an AC carrier signal from the carrier signal generating circuit 4 in synchronization with the generation of the scanning output signal, as shown by CH1, CH2,..., CH8 in FIG. A light beam is emitted toward the danger area.
- the light-receiving-side shift register 8 starts operating in synchronism with the light-emitting-side shift register 5 in response to the input of the scanning signal from the scanning signal generating circuit 1 to correspond to each light-emitting element.
- AC reception output from the light-receiving circuit 7 is generated in series on the time axis and amplified. Then, the output is amplified and level-tested by the level test circuit 11 1, and a serial logical 1 output is generated as shown in the figure and input to the AND gate 12.
- the scanning output signal from the light emitting side scanning circuit 2 is normal, and one signal is always generated on the time axis as shown in the figure. Also, the light emitting side shift register 5 and the light receiving side shift If the output of the last stage of the register 8 is synchronized, both the outputs of the scanning output signal inspection circuit 9 and the coincidence detection circuit 10 have a logical value of 1, and the output of the AND gate 12 has a logical value of 1.
- a detection output indicating the safety of logic value 1 is generated from the output amplification circuit 14 via the hold circuit 13 to indicate that there is no object in the dangerous area and that the safety is maintained.
- the output of the sample-and-hold circuit 13 is held at the logical value 0, and the output of the output amplifier circuit 14 is also as shown by the dotted line in FIG.
- a logical value of 0 indicates that an object exists in the danger area and is dangerous.
- the scanning output signal inspection circuit 9 detects this abnormal state and the output of the scanning inspection circuit 9 becomes logical.
- the output of the match detection circuit 10 becomes the logical value 0, and both are AND gated.
- the output of 12 becomes a logical value 0, and a detection output indicating danger is generated from the output amplifier circuit 14.
- FIG. 4 shows a circuit configuration of the scanning output signal inspection circuit 9.
- the scanning output signal inspection circuit 9 includes a resistor R 1 connected to a plurality of input terminals to which a plurality of scanning output signals F sl to F s8 described later sequentially input from the light emitting side shift register 5 of the light emitting side scanning circuit 2 are input. Through R8, a plurality of coupling capacitors C1 to C8, which are connected in series.
- the scan output signals Fsl, Fs2, ⁇ , Fs8 of the light-emitting side shift register 5 are output to the diodes D21 to D28 via the capacitors C1 to C8 and the resistors R1 to R8. Are clamped to the power supply potential Vcc by using, and are output from the diodes D11 to D18 to the window comparator WC1.
- the time chart in FIG. 7A shows a case where the scan output signal of the light-emitting side shift register 5 is normal.
- the time chart in FIG. 3B shows an abnormal case in which the scan output signal Fs8 of the light-emitting side shift register 5 does not occur at the time when the scan output signal Fs8 should be output, and the scan output signal Fsi occurs erroneously. I will show you.
- the addition signal ⁇ Fsi of the addition circuit 21 is always a logical value.
- the logic level is 1 (output in which the scanning output signal Fsi is superimposed on the power supply potential Vcc of the wind comparator).
- the addition signal ⁇ Fsi is at the time t 8 when the scan output signal Fs8 is to be generated, the scan output signal Fs8 does not exist, and the logic level 0 is the logical level b (the power supply potential Vcc). And generate the scanning output signal F si. At time t, the scan output signal Fs8 overlaps to produce a logic level a of logic value 2.
- the upper and lower threshold values of the wind comparator WC1 are set lower than the logical value 2 and higher than the logical value 0 with the logical level of the logical value 1 interposed therebetween, as indicated by HT and LT in FIG. Therefore, in the case of Fig. (A), a test output indicating that the logical value of 1 is normal is generated from the window comparator WC1, and as shown in Fig. (B), the addition signal ⁇ F si is the logical value of the logical value of 0 and 2 At the level, a test output indicating an abnormality of logical value 0 is generated from the wind comparator WC1.
- the circuit configuration of the scanning output signal inspection circuit 9 has the following features.
- Capacitor C 1 -C 8 and Daio de D 11 ⁇ D 18 and adder circuit 21 consists of D21 ⁇ D28 is a capacitor coupling, moreover, the power source potential V cc using Daio one de D21 ⁇ D28 Since it is clamped (coupling due to the potential outside the power supply frame), the signal is transmitted only when a positive signal change occurs in the scanning output signals Fsl to Fs8. For this reason, when a fixed failure occurs in which the scan output signal F si is fixed to 1 or 0 at the light-emitting side shift register 5, the output of the logical value 1 does not occur in the adder circuit 21 (light-emitting side shift).
- the running output signal inspection circuit 9 has another important failure inspection function. Since the shift register is composed of C-M ⁇ SIC, for example, the data input line of the light-emitting side shift register 5 is disconnected; if a failure occurs, the flip-flop that constitutes the shift register 5 For circuit noise Error output occurs.
- the time chart in FIG. 5 (A) is for the case where the output signals F si to F s8 of the shift register are normally output, and the addition signal ⁇ Fsi always has a logic level of 1.
- FIG. 9B when the scanning output signal Fs8 occurs at (t) instead of (or instead of) time t8, at time t, when the scanning output signal Fsi occurs.
- the added signal ⁇ Fsi becomes a logical level obtained by adding the two scan output signals at the time t ,.
- the scan output signal Fsi overlaps due to the failure of the light-emitting side shift register 5, and a failure occurs in the adder circuit 21 that should transmit this overlapped signal, that is, the light-emitting side shift register 5 and the adder circuit 21 If two faults occur simultaneously, a logical 1 output signal may occur.
- the circuit that transmits the signal Fsi or the circuit that transmits the signal Fs8 at the time t, in the time chart of FIG. 5 (B) fails (for example, a disconnection failure occurs in the capacitor C1 or the capacitor C8). Occurs, the logic level of the addition signal ⁇ Fsi becomes 1. This is a drawback of the circuit of FIG. 5, but this drawback can be compensated for by the circuit configuration of the light emitting side scanning circuit 2 described later. If the adder circuit 21 fails while the light emitting side shift register 5 is operating normally, the addition signal ⁇ F si The logic level is 0.
- FIG. 6 shows a circuit configuration of the light emitting side scanning circuit 2.
- DK flip-flops FF1 to FF8 constitute shift registers.
- the single multivibrator MM 1 receives the scanning signal from the scanning signal generation circuit 1, extends the pulse width for a predetermined time, and outputs it to the data input terminal of the flip-flop FF 1 of the first stage of the shift register. .
- the non-inverting output terminals of the D—K flip-flops FF 1 to FF 8 are connected to the negation circuits IVll to IV81, which are the first negation circuits, and the output sides of these negation circuits IVll to IV81.
- the power source side of the light emitting elements LD1 to LD8 is connected to this.
- the anode sides of the light emitting elements LD1 to LD8 are connected to a carrier signal generating circuit 4 for generating a carrier signal CRY of a predetermined frequency via current reducing resistors R1 to R8.
- a negative circuit IV12 to IV82 which is a second negative circuit, is connected to an intermediate point between each of the light emitting elements LD1 to LD8 and the current reducing resistors R1 to R8, and a negative circuit IV12 to The output side of the IV72 is connected to the data input terminal of the flip-flop of the next stage.
- a negation circuit IV is for inverting the output of the flip-flop FF8 of the last stage and outputting the inverted flip-flop FF8 to the coincidence detection circuit 10.
- the shift register consisting of flip-flops FF1 to FF8 is used to demultiplex the scan signal IN with the pulse width extended by the monostable multivibrator MM1 for the first flip-flop FF1. It is the evening input signal.
- the start signal PN included in the scan signal IN is detected and the first clock is detected.
- FIG. 7 (B) is a time chart showing the operation of the coupling circuit between flip-flops. In the figure, the description is made between the flip-flops FF1 and FF2.
- the output of the NOT circuit IVII goes low and the carrier signal CRY flows into the light emitting element LD1 to emit an AC light beam, and the light emission results.
- the input side of the NOT circuit IV12 becomes L level
- the output of the NOT circuit IV12 becomes H level
- the flip-flop of the next stage FF2 H level signal is input.
- the configuration is such that the scanning output signal F si input to the addition circuit 21 is generated as an input signal of the flip-flop FF 2.
- the basic concept of failure detection of the light-emitting side scanning circuit in Fig. 6 using the shift register is as follows. First, a logical value of 0 (L level) is fixed to the flip-flop input signal. If a failure occurs, no logical value 1 (H level) is generated in the output signal of the flip-flop FF8 of the last stage. Second, if a fixed failure with a logical value of 1 occurs in the input signal of the flip-flop (including the case where the light-emitting element emits light continuously), all of the flip-flops at the subsequent stage It is based on the fact that it is fixed at logical value 1.
- the output i of the last flip-flop FF 8 Does not occur, and at the same time, the input signal of the adding circuit 21 is not generated.
- the output signal of the last flip-flop FF8 is usually fixed. However, if the flip-flop is reset for any reason, multiple flip-flops operate simultaneously, and this simultaneous operation is propagated to the subsequent flip-flop. For this reason, the signal overlap shown on the time chart in FIG. 5 (B) usually occurs at a plurality of points, and the scan output signal inspection circuit 9 in FIG. This can compensate for the drawback of the occurrence of blemishes.
- the output of the addition circuit 21 has a logical value of 0, and the output of the scanning output signal inspection circuit 9 has a logical value of 0, thereby notifying the abnormality. Also, if a short-circuit or a disconnection fault occurs in the capacitor C1, a test output indicating an abnormality is also generated.
- the carrier signal CRY never occurs as the output of the logical value 1 (H level) of the NOT circuit IV12.
- the carrier signal CRY becomes the input of the negation circuit IV12, and is based on this input.
- the output signal of the NOT circuit IV12 becomes the input signal of the flip-flop FF2 and the capacitor C1.
- the light emitting element L D1 does not emit light, so that the output of the sensor indicates danger.
- FIG. 8 shows a circuit configuration of the light receiving side scanning circuit 6. .
- the monostable multivibrator MM 2 and the shift register The D—K flip-flops FF1 to FF8 constituting the light-emitting side scanning circuit 2 shown in FIG. Negation circuits IV1 to IV8, which are third negation circuits, are connected to the inverting output terminals of the flip-flops FF1 to FF8.
- the light-receiving elements PD1 to PD8 are arranged to face the light-emitting elements LD1 to LD8 with a dangerous area therebetween, and the light beam reception signals output from the light-receiving elements PD1 to PD8 are fail-safe AC amplification.
- the shift register using the flip-flops FF1 to FF8 is a monostable multivibrator based on the scanning signal IN based on the scanning signal IN, as in the case of the light emitting side scanning circuit 2.
- the output signal of 2 is the data-side input signal of the first flip-flop FF1.
- the first flip-flop FF 1 is synchronized with the input of the first clock signal by the start signal included in the run signal IN. Operates, and thereafter, output signals are generated in the flip-flops FF2 to FF8 in synchronization with the generation of the clock signal.
- Fig. 9 (B) shows the signal transmission process of flip-flops FF1 and FF2.
- the negation circuit is shown.
- the output of IV 1 becomes H level (logical value 1)
- An AC output based on the light beam reception of the light receiving element PD 1 is output as an output signal F rl.
- the connections a, b, and c are connected as shown so that the control of the output signal Frl by the NOT circuit IV1 is always transmitted to the output line of the amplifier circuit A1. .
- the connection c precedes the connection b, and the shift register does not advance even if either connection a or b is disconnected.
- the signal Frl on the output line of the amplifier circuit A1 can be similarly controlled using the output signal of the NOT circuit IV1 ( however, If the connection c is broken in Fig. (C), the shift register will operate normally, even though the output signal of the NOT circuit IV1 does not affect the output signal Frl. Cannot be configured for failsafe.
- the circuit of FIG. 8 firstly does not always output the received output signals Frl to Fr8 when the AC amplifier circuits A1 to A8 fail. Secondly, it includes the connection a and the control line. It is based on two logics: if a failure occurs in the elements that make up the shift register, the effect always appears on the last flip-flop.
- the output signal R-SCAN of the shift register 8 on the light-receiving side is compared with the output signal of the shift register on the light-emitting side, and the error-free check (fail-safe check) is performed with the circuit shown in Fig. 8. Then, the following error (2) is allowed.
- connection a is given priority over connection b via the output terminal of the amplifier A1. Therefore, if the connection a or the connection b is broken, the output signal of the NOT circuit IV1 will not be transmitted to the flip-flop FF2).
- the shift register output R—SCAN output is fixed to a logical value of 1 (H level) or 0 (L level)
- the light emitting side shift register output signal ' ⁇ -CAN does not match the light receiving side shift register output signal R-SCAN because the period is significantly extended or cannot be generated in a normal period.
- FIG. 10 shows a circuit configuration of the coincidence detection circuit 10.
- Tsu output of flop FF 8 is the output signal T one S is inverted by the NOT circuit IV 1 AN (serial From the light-receiving-side shift register 8, the inverted output of the final-stage flip-flop FF8 is inverted by the rejection circuit IV8, and the shift on the light-emitting side is performed.
- the output signal of the register T ⁇ S (the output signal R complementary to JAN is generated as R ⁇ SCAN ⁇ these two output signals' ⁇ SCAN and R ⁇ SCAN are the same as in Fig. 4.
- Addition is performed using an adder circuit 22 consisting of diodes D10 to D40 and resistors RIO, R20. (Resistors R10, R20 are connected before capacitors CIO, C20. Then, the addition output is subjected to threshold calculation by a fail-safe window comparator WC2.
- the level of the logical value 0 is below the fail-safe window control, and the level of the logical value 2 is below the lower threshold of WC2. Is greater than the upper threshold, and the output signal has a logical value of 0 (indicating a mismatch between the two signals).
- the failure mode of the coincidence detection circuit 10 is the same as that shown in FIG. 4. In the event of a circuit failure, the output of the addition signal X is stopped or the power supply potential V cc (both correspond to the logical value 0), and the window comparator WC It is outside the threshold range of 2 and outputs a logical value of 0.
- scanning is performed using a shift register.
- the sensor output signal is generated and the scan output signal is inspected only on the light-emitting side, and the output of the last stage of the shift register is monitored for coincidence / mismatch, simplifying the configuration of the sensor system. can do. Further, the addition operation for judging whether the scanning output signal is generated normally or abnormally is easy, and the withstand voltage of the capacitor can be reduced. [Industrial applicability]
- the present invention in a system in which a machine and a human work in a common workspace, can significantly improve the safety of a worker working in the common workspace with the machine and prevent an accident caused by the machine of the worker. Therefore, industrial utility is great.
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- Physics & Mathematics (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- General Physics & Mathematics (AREA)
- Geophysics (AREA)
- Electronic Switches (AREA)
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
- Geophysics And Detection Of Objects (AREA)
Description
Claims
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/JP1993/001463 WO1995010789A1 (fr) | 1993-10-12 | 1993-10-12 | Capteur de faisceau lumineux a axes optiques multiples et surete integree |
US08/454,378 US5640006A (en) | 1993-10-12 | 1993-10-12 | Control circuit for a fail-safe multi-axis light beam type sensor |
JP51157595A JP3306715B2 (ja) | 1993-10-12 | 1993-10-12 | フェールセーフ多光軸光線式センサ |
EP93922066A EP0675376B1 (en) | 1993-10-12 | 1993-10-12 | Fail-safe multiple optical-axis light beam sensor |
DE69316241T DE69316241T2 (de) | 1993-10-12 | 1993-10-12 | Ausfallgesicherter optischer vielfachachsen-lichtstrahlsensor |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/JP1993/001463 WO1995010789A1 (fr) | 1993-10-12 | 1993-10-12 | Capteur de faisceau lumineux a axes optiques multiples et surete integree |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1995010789A1 true WO1995010789A1 (fr) | 1995-04-20 |
Family
ID=14070573
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP1993/001463 WO1995010789A1 (fr) | 1993-10-12 | 1993-10-12 | Capteur de faisceau lumineux a axes optiques multiples et surete integree |
Country Status (5)
Country | Link |
---|---|
US (1) | US5640006A (ja) |
EP (1) | EP0675376B1 (ja) |
JP (1) | JP3306715B2 (ja) |
DE (1) | DE69316241T2 (ja) |
WO (1) | WO1995010789A1 (ja) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6046834A (en) * | 1996-03-08 | 2000-04-04 | Nihon Shingo Kabushiki Kaisha | Optical barrier |
US6047634A (en) * | 1996-09-03 | 2000-04-11 | The Nippon Signal Co., Ltd. | Fail-safe automatic sliding operation control apparatus for press |
US6334077B1 (en) | 1997-09-19 | 2001-12-25 | The Nippon Signal Co., Ltd. | Operation apparatus for press |
JP2007228425A (ja) * | 2006-02-24 | 2007-09-06 | Sunx Ltd | 多光軸光電センサ |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3986162B2 (ja) * | 1998-06-03 | 2007-10-03 | 株式会社キーエンス | 多重投光検出可能な多光軸光電スイッチ |
CN106154303B (zh) * | 2016-06-20 | 2019-09-20 | 中国科学院高能物理研究所 | 信号处理装置以及时间探测装置 |
DE202017106755U1 (de) * | 2017-11-08 | 2017-11-20 | Leuze Electronic Gmbh + Co. Kg | Lichtvorhang |
EP4026973A1 (en) * | 2021-01-07 | 2022-07-13 | CAME S.p.A. | Control system for access point devices |
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JPS57142578A (en) * | 1981-02-28 | 1982-09-03 | Riken Lens Kogyo Kk | Automatic check device for light beam type safety device |
JPS61198089A (ja) * | 1985-02-28 | 1986-09-02 | Hokuyo Automatic Co | 光電スイツチの検波回路 |
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US4015122A (en) * | 1974-07-12 | 1977-03-29 | Rubinstein Walter M | Photo-electric object detection system |
US4309693A (en) * | 1974-09-12 | 1982-01-05 | Analog Devices, Incorporated | Solid state digital to analog converter |
JPH0669274B2 (ja) * | 1984-04-19 | 1994-08-31 | 日本信号株式会社 | 負荷駆動用スイッチ回路の監視装置 |
JPS60227326A (ja) * | 1984-04-25 | 1985-11-12 | 日本信号株式会社 | 負荷駆動用スイツチ回路の監視装置 |
JPH0530068A (ja) * | 1991-07-24 | 1993-02-05 | Nec Corp | 調歩式データ多重化方式 |
US5218196A (en) * | 1991-09-05 | 1993-06-08 | Frost Controls, Inc. | Light curtain system with system and watchdog microcontrollers |
EP0646797B1 (en) * | 1993-03-31 | 1998-05-27 | The Nippon Signal Co. Ltd. | Circuit for judging motor rotation and apparatus for confirming motor stop using said circuit |
-
1993
- 1993-10-12 US US08/454,378 patent/US5640006A/en not_active Expired - Fee Related
- 1993-10-12 WO PCT/JP1993/001463 patent/WO1995010789A1/ja active IP Right Grant
- 1993-10-12 JP JP51157595A patent/JP3306715B2/ja not_active Expired - Fee Related
- 1993-10-12 DE DE69316241T patent/DE69316241T2/de not_active Expired - Fee Related
- 1993-10-12 EP EP93922066A patent/EP0675376B1/en not_active Expired - Lifetime
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
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JPS57142578A (en) * | 1981-02-28 | 1982-09-03 | Riken Lens Kogyo Kk | Automatic check device for light beam type safety device |
JPS61198089A (ja) * | 1985-02-28 | 1986-09-02 | Hokuyo Automatic Co | 光電スイツチの検波回路 |
JPS61198094A (ja) * | 1985-02-28 | 1986-09-02 | Fuji Electric Co Ltd | 光電スイツチ |
JPH0330338U (ja) * | 1989-08-01 | 1991-03-26 | ||
JPH0470589A (ja) * | 1990-07-12 | 1992-03-05 | Koufu Nippon Denki Kk | フォトセンサ信号検出回路 |
Non-Patent Citations (1)
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Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6046834A (en) * | 1996-03-08 | 2000-04-04 | Nihon Shingo Kabushiki Kaisha | Optical barrier |
US6178027B1 (en) | 1996-03-08 | 2001-01-23 | Nihon Shingo Kabushiki Kaisha | Optical barrier apparatus |
US6185028B1 (en) | 1996-03-08 | 2001-02-06 | Nihon Shingo Kabushiki Kaisha | Optical barrier apparatus |
US6246503B1 (en) | 1996-03-08 | 2001-06-12 | Nihon Shingo Kabushiki Kaisha | Optical barrier apparatus |
US6047634A (en) * | 1996-09-03 | 2000-04-11 | The Nippon Signal Co., Ltd. | Fail-safe automatic sliding operation control apparatus for press |
US6334077B1 (en) | 1997-09-19 | 2001-12-25 | The Nippon Signal Co., Ltd. | Operation apparatus for press |
JP2007228425A (ja) * | 2006-02-24 | 2007-09-06 | Sunx Ltd | 多光軸光電センサ |
Also Published As
Publication number | Publication date |
---|---|
DE69316241T2 (de) | 1998-06-25 |
US5640006A (en) | 1997-06-17 |
EP0675376A4 (en) | 1996-03-13 |
JP3306715B2 (ja) | 2002-07-24 |
EP0675376A1 (en) | 1995-10-04 |
EP0675376B1 (en) | 1998-01-07 |
DE69316241D1 (de) | 1998-02-12 |
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