JP2012078189A - Detection sensor system, detection sensor, discrimination device and abnormality detection method of detection sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a detection sensor system, a detection sensor, a discrimination device capable of clarifying a cause of undetectability when a detection object cannot be correctly detected, and an abnormality detection method of the detection sensor.SOLUTION: A detection sensor includes: a light receiving part 25 which acquires a detection signal to change according to a detection state of an object to be detected; a CPU 20 which determines what determination signal is output among a plurality of determination signals based on a comparison result between a signal level of the detection signal acquired by the light receiving part 25 and a detection threshold stored in a memory 23; a light receiving element 26, a floodlight element 27, an output circuit 28 which output determination signals determined to be output by the CPU 20, respectively; and a CPU 51 which discriminates presence/absence of abnormality based on comparison results of the respective determination signals output by the light receiving element 26, the floodlight element 27, and the output circuit 28, respectively, in which the CPU 51 discriminates that there is the abnormality in one of the light receiving element 26, the floodlight element 27, and the output circuit 28 when the respective determination signals to be compared are different from one another.

Description

  The present invention relates to a detection sensor system, a detection sensor, a discrimination device, and an abnormality detection method for the detection sensor.

  For example, a detection sensor such as a photoelectric sensor detects light to be detected by receiving light projected from a light projecting element with a light receiving element (acquisition means). In other words, the amount of light received (detection signal) received by the light receiving element varies depending on the state of the detection target. Therefore, the detection sensor detects the detection target by comparing the set threshold level (detection threshold) with the amount of received light. (For example, refer to Patent Document 1).

  In such a photoelectric sensor, the amount of received light changes due to deterioration of the light projecting element and the light receiving element, changes in ambient temperature, dirt, etc., so that the amount of received light falls below the threshold level and the detection target can be detected correctly. There are things that cannot be done. Therefore, the detection sensor of Patent Document 1 corrects the threshold level according to the change in the amount of received light.

JP 2008-252463 A

  By the way, when the detection target cannot be detected correctly, there may be an abnormality in the output circuit that outputs the detection result. However, the conventional detection sensor cannot determine whether the output circuit is faulty or the threshold level is not correctly set when the detection target cannot be detected correctly.

  The present invention has been made in view of the above problems, and its purpose is to detect a detection sensor system, a detection sensor, a discrimination device, and a detection capable of elucidating the cause of the detection failure when the detection target cannot be detected correctly. An object of the present invention is to provide a sensor abnormality detection method.

  In order to solve the above-mentioned problem, the invention according to claim 1 relating to a detection sensor system includes an acquisition unit that acquires a detection signal that changes in accordance with a detection state of a detection target, and the detection acquired by the acquisition unit. Based on the comparison result between the signal level of the signal and the detection threshold value stored in the threshold value storage unit, either one of the first determination signal and the second determination signal different from the first determination signal is output. Determination means for determining whether or not, an output circuit for outputting the determination signal determined to be output by the determination means, an optical communication means for outputting the determination signal determined to be output by the determination means by optical communication, Determination means for determining presence or absence of abnormality based on a comparison result of each determination signal output by each of the output circuit and the optical communication means, and the determination means is the comparison target If the determination signal to each other are different, and summarized in that determining that there is an abnormality in one of said output circuit and said optical communication means.

  Usually, when the determination signal determined to be output by the determination means is output by the output circuit and the optical communication means, if the output circuit and the optical communication means are not abnormal, the determination signals to be compared match. Therefore, if the determination signals to be compared are different from each other in this respect, it can be determined that there is an abnormality in the output circuit or the optical communication means. Therefore, when the detection target cannot be detected correctly, the cause of the detection failure can be clarified.

  According to a second aspect of the present invention, in the detection sensor system according to the first aspect, the output circuit and the optical communication unit are configured such that the determination unit is based on a comparison result between the signal level of the detection signal and the detection threshold. When it is determined that the first determination signal is output, the first determination signal is output, and when it is determined that the first determination signal is not output, the second determination signal is output. The determination means determines that the output circuit and the optical communication means that output the second determination signal have an abnormality when the determination signals to be compared are different from each other. And

  According to a third aspect of the present invention, in the detection sensor system according to the first or second aspect, the determination unit outputs the first determination signal when the signal level of the detection signal is equal to or higher than the detection threshold. It is determined that the second determination signal is output when the signal level of the detection signal is lower than the detection signal, and the determination unit determines that the determination signals to be compared are all the second determination signal. In the case of the determination signal, it is determined that the detection threshold value is abnormal.

  According to a fourth aspect of the present invention, in the detection sensor system according to the third aspect, the reference value storage unit stores a reference value set based on a difference between the maximum value and the minimum value of the signal level of the detection signal. And at least one of the output circuit and the optical communication unit outputs a signal level of the detection signal in addition to the determination signal, and the determination unit includes all the determination signals to be compared. When it is a second determination signal and the difference between the maximum value and the minimum value of the signal level is larger than the reference value, it is determined that the detection threshold is abnormally set. To do.

  Similarly, in order to solve the above problem, the invention according to claim 5 according to the detection sensor includes the acquisition unit in the detection sensor system according to any one of claims 1 to 4, The gist is provided with a judging means, the output circuit, and the optical communication means, and the judgment signal judged to be outputted by the judging means is outputted by the output circuit and the optical communication means, respectively.

  Similarly, in order to solve the above-described problem, the invention according to claim 6 according to the discriminating device includes the first determination signal and the first determination based on the detection signal that changes according to the detection state of the detection target. A determination device connected to a detection sensor for outputting any one of the second determination signals different from the signals by the output circuit and the optical communication means, wherein the determination signal output by the output circuit And receiving means for receiving the determination signals output by the optical communication means, and determining means for determining the presence or absence of abnormality based on a comparison result of the determination signals received by the receiving means. The gist is to determine that the detection sensor is abnormal when the determination signals to be compared are different from each other.

  Similarly, in order to solve the above problem, the invention according to claim 7 related to the abnormality detection method of the detection sensor is an abnormality detection method of the detection sensor that outputs information according to the detection state of the detection target, An acquisition stage for acquiring a detection signal that changes according to the detection state of the detection target, and a plurality of types based on a comparison result between the signal level of the detection signal acquired in the acquisition stage and the detection threshold value stored in the threshold value storage unit A determination step for determining which one of the determination signals is to be output, an output step for outputting each of the determination signals determined to be output in the determination step by a plurality of output means, and in each of the output steps The gist of the present invention is to provide a determination step of determining that the output means is abnormal when the output determination signals are different from each other.

  According to the present invention, when a detection target cannot be detected correctly, the cause of the detection failure can be clarified.

The front view of the detection sensor system in this embodiment. The block diagram explaining the electrical constitution of a detection sensor system. (A) The graph showing the signal level of the detection signal at the time of Hi signal output, (b) The graph showing the signal level of the detection signal at the time of Lo signal output. The flowchart of the abnormality detection process routine of a detection sensor.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
As shown in FIG. 1, the detection sensor system 100 of the present embodiment includes at least one (four in the present embodiment) detection sensor 10, and a main unit 30 arranged so as to sandwich the detection sensor 10 from both sides. And an end unit 40. Further, the detection sensor system 100 includes a controller 50 as a determination device connected to the main unit 30.

  As shown in FIG. 2, the detection sensor 10 in the present embodiment includes four detection sensors 10 (that is, first to fourth detection sensors 10 a to 10 d), and each detection sensor 10 (10 a to 10 d). Each base end side is connected to the connector 11. Each detection sensor 10 (10a to 10d) includes a first detection sensor 10a adjacent to the main unit 30 and a fourth detection sensor 10d connected to the end unit 40 between the main unit 30 and the end unit 40. It is fixed on a rail (not shown) so as to be adjacent.

  As shown in FIG. 1, the detection sensor 10 is formed in a substantially rectangular parallelepiped, and a digital display unit 12 capable of displaying, for example, 8 digits is disposed on the upper surface thereof. The digital display unit 12 is configured in such a manner that eight 7-segment LEDs (light emitting diodes) are connected in a line.

  A plurality of setting mode indicator lamps 13 a are provided on the right side (front end side) of the digital display unit 12. The setting mode at that time is displayed by these setting mode indicator lamps 13a. The setting modes include “RUN (normal detection mode in which only detection operation is executed)”, “TEACH (detection threshold value setting)”, “L / D (light-on / non-light-on setting)” There is. Further, a plurality of setting mode indicator lamps 13b are provided on the left side (base end side) of the digital display unit 12. The setting modes displayed by these setting mode indicator lamps 13b include “TIMER (timer operation setting)”, “CUST (custom setting content display)”, and “PRO (detailed setting)”.

  Further, a jog switch (trademark registration) 15 is provided on the left side of the setting mode indicator lamp 13b, and a setting mode switching switch 16 for switching the setting mode is provided on the further left side of the jog switch 15. The jog switch 15 can be pressed and rotated. Further, a connection hole (not shown) for connecting the light projecting fiber 17 and the light receiving fiber 18 is provided on the side surface on the distal end side of the detection sensor 10.

  As shown in FIG. 2, the CPU 20 of the detection sensor 10 includes an operation unit 21, a display unit 22, a memory 23 as a threshold storage unit, a light projecting unit 24, a light receiving unit 25 as an acquisition unit, a light receiving element 26, and a light projecting unit. The element 27 and the output circuit 28 are connected. The output circuit 28 is connected to signal lines 29 provided on the connector 11.

  The operation unit 21 includes the jog switch 15 and the setting mode change switch 16 described above, and the display unit 22 includes the digital display unit 12 and the setting mode display lamps 13a and 13b described above.

  The light projecting unit 24 includes, for example, a light emitting diode (LED), and is configured to guide the light of the light emitting diode to the light projecting fiber 17. On the other hand, the light receiving unit 25 includes a photodiode (PD) that receives light emitted from the light projecting fiber 17 and guided by the light receiving fiber 18 and converts the light into an electric signal. That is, the light projecting fiber 17 and the light receiving fiber 18 are mounted such that their base ends face the light emitting diode and the photodiode.

  Then, the CPU 20 reads the detection conditions stored in the memory 23, drives the light projecting unit 24 to emit light according to the detection conditions, and drives the light receiving unit 25 to irradiate and receive light from the light projecting unit 24. Convert light into electrical signals.

  Further, the CPU 20 acquires the electric signal converted by the light receiving unit 25 as a detection signal, and compares the signal level of the detection signal with the detection threshold value stored in the memory 23, thereby determining among the plurality of types of determination signals. It is determined which signal is output. That is, the detection signal is a signal that changes according to the detection signal of the detection object, and the CPU 20 of the detection sensor 10 functions as a determination unit.

  In this embodiment, as shown in FIG. 3A, when the signal level of the detection signal is equal to or higher than the detection threshold, the CPU 20 determines to output the Hi signal as the first determination signal. ing. In addition, when the signal level of the detection signal is less than the detection threshold, the CPU 20 determines to output the Lo signal as the second determination signal. That is, the CPU 20 outputs a Lo signal when it is determined not to output a Hi signal. Specifically, the Lo signal is continuously output from the output circuit 28, and the Hi signal is output when the signal level of the detection signal is equal to or higher than the detection threshold.

  As shown in FIG. 1, the main body 31 of the main unit 30 is formed in a substantially rectangular parallelepiped. A power line 32 and a communication cable 33 connected to the end unit 40 are connected to the side surface 31 a of the main unit 30. A connecting portion 34 connected to the controller 50 is provided on the upper surface 31 b of the main body portion 31.

  As shown in FIG. 2, on the side surface of the main unit 30 on the detection sensor 10 (specifically, the first detection sensor 10a) side, there is a light projecting element 36 that is driven by a CPU 35 and transmits data based on an optical signal. Is provided. Further, a communication unit 37 capable of communicating with the controller 50, an optical communication receiving unit 38, and a line communication receiving unit 39 are connected to the CPU 35 of the main unit 30. A communication cable 33 is connected to the optical communication receiver 38, and a signal line 29 is connected to the line communication receiver 39, respectively.

  That is, the optical communication receiving unit 38 receives data from the end unit 40 via the communication cable 33. On the other hand, the line communication receiving unit 39 individually receives the determination signal output from the output circuit 28 of each detection sensor 10 via each signal line 29 wired for each detection sensor 10.

  A light receiving element 41 is provided near the side surface of the end unit 40 on the detection sensor 10 (specifically, the fourth detection sensor 10d) side so as to face the light projecting element 27 of the detection sensor 10. Yes. When the CPU 42 of the end unit 40 receives data at the light receiving element 41, the CPU 42 transmits the data from the transmission unit 43. Data transmitted from the end unit 40 is received by the optical communication receiver 38 of the main unit 30 via the communication cable 33.

  In the present embodiment, the CPU 35 of the main unit 30 controls the light projecting element 36 and outputs an optical communication start command, whereby the light receiving element 26, the light projecting element 27, and the end unit 40 of each detection sensor 10. Optical communication using the light receiving element 41 is started.

  Specifically, the CPU 20 of each detection sensor 10 converts a transmission signal received as an optical signal by the light receiving element 26 into an electrical signal, creates a transmission signal reflecting its detection result and the like, and communicates downstream. To the detection sensor 10 on the side. That is, the CPU 20 of each detection sensor 10 creates a transmission signal by associating the Hi signal or Lo signal determined to be output with the identifier of each detection sensor 10. Each detection sensor 10 transmits a signal output from the upstream side, that is, the main unit 30 side, to the downstream side by a relay method. Then, the CPU 42 of the end unit 40 converts the optical signal received by the light receiving element 41 into a digital signal and transmits the digital signal to the main unit 30 via the communication cable 33.

  Therefore, the main unit 30 collectively receives the Hi signal or the Lo signal output from each detection sensor 10 by one optical communication start command. Therefore, the light receiving element 26 and the light projecting element 27 function as optical communication means.

  The controller 50 is a personal computer having a CPU, RAM, ROM and the like. Note that a PLC (Programmable Logic Controller) may be used as the controller 50.

  A communication unit 52, a display screen 53, a memory 54, and a timer 55 are connected to the CPU 51 as a determination unit of the controller 50. The communication unit 52 is connected to the communication unit 37 via the connection unit 34 (see FIG. 1) of the main unit 30 and can transmit and receive data to and from the main unit 30. The memory 54 of the controller 50 stores a control program and a reference value for controlling each detection sensor 10, the main unit 30, and the end unit 40. That is, the memory 54 functions as a reference value storage unit.

  The reference value is set based on the difference between the maximum value and the minimum value of the signal level of the detection signal acquired by the CPU 20 of the detection sensor 10 in the initial state where the detection sensor 10 is mounted on the detection sensor system 100. Value.

  Specifically, as shown in FIG. 3, when the detection sensor 10 is attached to the detection sensor system 100, the CPU 51 of the controller 50 causes the main unit 30 to output a signal level acquisition command. That is, when the CPU 35 of the main unit 30 controls the light projecting element 36 to output a signal level acquisition command, the signal level of the detection signal detected by each detection sensor 10 is associated with the identifier of each detection sensor 10. Transmitted in state. Therefore, the controller 50 receives the signal level of the detection signal of each detection sensor 10 via the main unit 30 and the end unit 40, and the signal level corresponding to the newly mounted detection sensor 10 is provided in the CPU 51. Temporarily stored in a RAM (not shown).

  Then, when the detection sensor 10 detects the detection object as the detection target in a state where the signal level acquisition command is repeatedly output, the signal level changed depending on whether or not the detection object is detected is stored in the RAM. become. Accordingly, by calculating the difference D1 between the maximum value max and the minimum value min among the signal levels stored in the RAM, it is possible to acquire a change in the signal level depending on whether or not the detection object is detected. Then, the reference value is set to a minimum change amount (for example, half of the difference D1) necessary to determine whether or not the detection object is detected based on the difference D1.

  Further, the controller 50 causes the main unit 30 to output a detection threshold setting command, and stores the detection threshold in the memory 23 of the newly mounted detection sensor 10. The detection threshold is a rewritable value and is set between the maximum value max and the minimum value min of the signal level of the detection signal (for example, the average value of the maximum value max and the minimum value min).

  Next, an abnormality detection method for the detection sensor 10 will be described based on a flowchart of an abnormality detection processing routine shown in FIG. This flowchart is executed by the CPU 51 of the controller 50.

  However, as a premise thereof, each detection sensor 10 causes the CPU 20 to control the light projecting unit 24 to continuously irradiate light, and acquires an electrical signal based on the amount of light received by the light receiving unit 25 as a detection signal at any time. (Acquisition stage). Then, the CPU 20 determines which of the Hi signal and the Lo signal is to be output based on the comparison result between the signal level of the detection signal acquired at any time and the detection threshold value stored in the memory 23. (Judgment stage)

  As shown in FIG. 4, in step S <b> 101, the CPU 51 of the controller 50 controls the CPU 35 of the main unit 30 to acquire the determination signal output from each detection sensor 10. That is, the CPU 35 controls the light projecting element 36 and outputs an optical communication start command to acquire a determination signal, and outputs the acquired determination signal to the controller 50 (optical communication stage). Further, the CPU 35 outputs a determination signal output from each output circuit 28 and acquired individually to the controller 50 (output stage).

  The CPU 51 temporarily stores the determination signal output from the output circuit 28 and received by the line communication receiving unit 39 among the acquired determination signals in the RAM as a line communication signal, and the determination received by the optical communication receiving unit 38. The signal is temporarily stored in the RAM as an optical communication signal.

Next, in step S102, the CPU 51 initializes n to 1. In this flowchart, n is an integer value for identifying the detection sensor 10.
That is, if n = 1, in the next step S103, the CPU 51 determines whether or not the line communication signal of the first detection sensor 10a is a Lo signal. When the line communication signal is a Lo signal (step S103: YES), the CPU 51 determines whether or not the optical communication signal of the first detection sensor 10a is a Lo signal in step S104. If the optical communication signal is also a Lo signal (step S104: YES), the CPU 51 proceeds to step S105.

  In step S105, the CPU 51 of the controller 50 controls the CPU 35 of the main unit 30 to acquire the signal level of the detection signal detected by the first detection sensor 10a. That is, the CPU 35 controls the light projecting element 36 to output a signal level acquisition command, and outputs the acquired signal level to the controller 50. Then, the CPU 51 temporarily stores the signal level of the first detection sensor 10a among the acquired signal levels in the RAM.

  In step S <b> 106, the CPU 51 determines whether the acquisition time (for example, 10 seconds) has elapsed based on the measurement time of the timer 55. When the CPU 51 determines that the acquisition time has not elapsed (step S106: NO), the CPU 51 returns to step S105, acquires the signal level of the first detection sensor 10a, and temporarily stores it in the RAM. The acquisition time is set to be equal to or longer than the time interval from when the previous detection object passes the detection area of the first detection sensor 10a until the next detection object passes through the detection area. It is preferable.

  If the CPU 51 determines that the acquisition time has elapsed (step S106: YES), the difference between the maximum value and the minimum value of the signal level temporarily stored in the RAM is stored in the memory 54 in step S107. It is determined whether or not the reference value is exceeded.

  When the difference between the maximum value and the minimum value of the signal level is equal to or larger than the reference value stored in the memory 54 (step S107: YES), the CPU 51 determines that the threshold setting is abnormal in step S108. Then, the display screen 53 is controlled to notify the abnormality and the process is terminated.

  That is, at this time, the RAM stores a change in the signal level at the acquisition time as shown in FIG. 3B, for example. Therefore, when the difference D2 between the maximum value max and the minimum value min of the signal level is greater than or equal to the reference value, the detection threshold is set to be larger than the maximum value max even though the signal level has changed sufficiently. The detected object cannot be detected correctly. Therefore, since the detection object can be detected by setting the detection threshold value between the maximum value max and the minimum value min again, the CPU 51 determines that the threshold setting is abnormal.

  When the difference between the maximum value and the minimum value of the signal level is less than the reference value stored in the memory 54 (step S107: NO), the CPU 51 detects the first detection sensor 10a. It is determined that the detected object simply does not exist in the area, and an abnormality cannot be detected.

  In step S109, the CPU 51 updates n by n + 1, and in step S110, whether or not the value of n is larger than the number of detection sensors 10 attached to the detection sensor system 100 (4 in the present embodiment). Determine whether. Therefore, when n = 2, the number is smaller than the number of detection sensors 10 (step S110: NO), so the CPU 51 proceeds to step S103, and the second detection sensor is the same as the first detection sensor 10a. The abnormality 10b is detected.

  As described above, when n = 5 is detected by detecting the abnormality of each detection sensor 10, the number of detection sensors 10 becomes larger (step S <b> 110: YES), so the CPU 51 determines all the detection sensors 10. It is determined that the abnormality detection is finished. Then, the CPU 51 proceeds to step S101 to acquire the determination signal again, and repeatedly executes the abnormality detection process of the detection sensor 10.

  When the line communication signal is a Lo signal (step S103: YES) and the optical communication signal is a Hi signal (step S104: NO), the CPU 51 proceeds to step S111. That is, in step S111, the CPU 51 determines that the output circuit 28 has an abnormality, and controls the display screen 53 to notify the abnormality and ends the process (determination stage).

  Furthermore, when the line communication signal is a Hi signal (step S103: NO) and the optical communication signal is a Lo signal (step S112: YES), the CPU 51 proceeds to step S113. That is, in step S113, the CPU 51 determines that the optical communication abnormality has an abnormality in the light receiving element 26 or the light projecting element 27, controls the display screen 53 to notify the abnormality, and ends the process (determination stage). .

  On the other hand, when both the line communication signal and the optical communication signal are Hi signals (step S103: NO, step S112: NO), the CPU 51 determines that the detected object can be normally detected, and the process proceeds to step S109. Then, the next detection sensor 10 is detected for abnormality.

According to the detection sensor system of the above embodiment, the following effects can be obtained.
(1) The CPU 20 of the detection sensor 10 outputs the determination signal determined to be output using the light receiving element 26, the light projecting element 27, and the output circuit 28. That is, when both the light receiving element 26 and the light projecting element 27 and the output circuit 28 are functioning normally, the same determination signal is output to the CPU 51 of the controller 50. Therefore, when the determination signals acquired by the CPU 51 are different, it can be determined that one of the light receiving element 26, the light projecting element 27, and the output circuit 28 is abnormal. Therefore, when an abnormality is found in the detection result of the detection sensor 10 (when the detection sensor 10 cannot correctly detect the detected object to be detected), the cause of the abnormality (the cause that cannot be detected) can be clarified. .

  (2) The output circuit 28 outputs the Hi signal and outputs the Lo signal when not outputting the Hi signal. That is, the output circuit 28 outputs the Lo signal regardless of the determination of the CPU 20 even when communication with the CPU 20 is abnormal. Therefore, when the Lo signal is received regardless of the determination of the CPU 20 as described above and the determination signals are different from each other, the light receiving element 26, the light projecting element 27, and the output circuit 28. It can be determined that there is an abnormality in the output of the Lo signal. Therefore, when the light receiving element 26, the light projecting element 27, and the output circuit 28 are provided, it is possible to easily determine which is abnormal.

  (3) The CPU 20 of the detection sensor 10 determines to output the Hi signal when the signal level of the detection signal is equal to or higher than the detection threshold, and outputs the Lo signal when the signal level of the detection signal is less than the detection threshold. Judge to output. For this reason, when the detection object is located in the detection area of the detection sensor 10 and the determination signals output by the output circuit 28, the light receiving element 26, and the light projecting element 27 are both Lo signals. It is considered that the detection threshold is not set correctly. Therefore, since it is possible to determine whether the light receiving element 26 and the light projecting element 27 or the output circuit 28 is abnormal or the detection threshold setting is abnormal by the combination of the determination signals, the detection result of the detection sensor 10 is abnormal. Can be found, the cause of the abnormality can be clarified.

  (4) By comparing the difference D2 between the maximum value max and the minimum value min of the detection signal with the reference value, the threshold setting is abnormal regardless of the presence or absence of an object to be detected in the detection area of the detection sensor 10. It can be determined whether or not. That is, when the difference D2 between the maximum value max and the minimum value min of the signal level is larger than the reference value, the signal level is less than the detection threshold even though the signal level is sufficiently changed. Therefore, it can be determined that the detection threshold value setting is abnormal. On the other hand, when the difference D2 between the maximum value max and the minimum value min of the signal level is smaller than the reference value, there is no abnormality in the detection sensor 10 simply because no detection object exists in the detection area of the detection sensor 10. It can be determined that there is no.

In addition, you may change the said embodiment as follows.
In the above embodiment, the signal level of the detection signal may be output together with the determination signal output based on the optical communication start command. Further, the signal level of the detection signal may be output from the output circuit 28.

  In the above embodiment, communication using the communication cable 33 may be performed only when an optical communication start command is output. That is, when feedback is not returned even though the optical communication start command is output, it may be determined that the light receiving element 26 and the light projecting element 27 are abnormal.

In the above embodiment, the output circuit 28 may be a transmitter that transmits radio waves. That is, the determination signal may be output by wireless communication.
In the above embodiment, the number of detection sensors 10 provided in the detection sensor system 100 may be one. Further, the light receiving element 26 may be omitted, and for example, the light projecting element 27 may output the determination signal determined by the CPU 20 at the same timing as the output circuit 28 outputs the determination signal.

  In the above embodiment, without providing the main unit 30 and the end unit 40, the detection sensor 10 and the controller 50 are connected via the light receiving element 26, the light projecting element 27 (optical communication means), and the output circuit 28 (output means). You may connect so that communication is possible.

  -In above-mentioned embodiment, you may make it discriminate | determine abnormality of the detection sensor 10 by CPU35 of the main unit 30. FIG. At this time, the main unit 30 (discriminating device) preferably further includes a memory (reference value storage unit) that stores a reference value, and the CPU 35 functions as a discriminating unit, and the optical communication receiving unit 38 and the line communication receiving unit. The unit 39 functions as a receiving unit.

  In the above embodiment, the CPU 20 may determine that the Hi signal is output when the signal level of the detection signal exceeds the detection threshold, and may determine that the Lo signal is output when the signal level is equal to or lower than the detection threshold.

  In the above embodiment, the Lo signal (first determination signal) is output when the detection threshold is equal to or greater than (or exceeds) the detection threshold, and the Hi signal (the first determination signal) is output when the signal level of the detection signal is less than (or less than) the detection threshold. 2 determination signal) may be output. That is, in the case of a reflective type that receives light bounced off by the detection object, the detection object is detected when the amount of received light (the signal level of the detection signal) increases. On the other hand, in the case of a transmission type in which the detected object blocks the light emitted from the light receiving unit 25 and received by the light projecting unit 24, the detected object is reduced when the amount of received light (the signal level of the detection signal) decreases. To detect. Therefore, the determination signal that the CPU 20 determines to output can be arbitrarily set.

  In the above embodiment, the detection threshold may be set by the user operating the operation unit 21 or the controller 50 of the detection sensor 10. If the CPU 51 of the controller 50 determines that the detection threshold value setting is abnormal, the CPU 51 may be caused to change the detection threshold value setting. That is, for example, the detection threshold value may be corrected so as to be an average value of the maximum value max and the minimum value min of the acquired detection signal. Thereby, the correct detection threshold value can be corrected without bothering the user.

  In the above embodiment, the memory 54 of the controller 50 may store the maximum value max and the minimum value min of the signal level of the detection signal in the initial state where the detection sensor 10 is mounted on the detection sensor system 100. . That is, when determining whether or not the detection threshold value is abnormal, it may be determined based on the maximum value max and the minimum value min stored in the memory 54. Further, the reference value may not be stored.

  In the above-described embodiment, the detection sensor 10 may include a timer and temporarily store the signal level of the detection signal until the acquisition time elapses using the timer. Then, the difference D2 between the maximum value max and the minimum value min among the temporarily stored signal levels may be output to the controller 50.

  In the above embodiment, the detection target is not limited to the presence or absence of an object, and may be temperature, humidity, flow rate, flow velocity, atmospheric pressure, or the like. That is, for example, when the temperature is to be detected, a thermometer is provided instead of the light projecting unit 24 and the light receiving unit 25, and the CPU 20 compares the result output from the thermometer with a detection threshold value. Good.

  In the above embodiment, the detection sensor 10 mounted on the detection sensor system 100 is embodied, but the present invention may be applied to a detection sensor that is used in other devices and outputs a determination signal as a detection result. it can.

  DESCRIPTION OF SYMBOLS 100 ... Detection sensor system, 10 ... Detection sensor, 20 ... CPU (determination means), 23 ... Memory (threshold value storage part), 25 ... Light receiving part (acquisition means), 26 ... Light receiving element (optical communication means), 27 ... Throw Optical element (optical communication means), 28 ... output circuit, 50 ... controller (discriminating device), 51 ... CPU (discriminating means), 52 ... communication section (receiving means), 54 ... memory (reference value storage section), D1, D2 ... difference, max ... maximum value, min ... minimum value.

Claims (7)

An acquisition means for acquiring a detection signal that changes according to a detection state of a detection target;
A first determination signal and a second determination signal different from the first determination signal based on a comparison result between the signal level of the detection signal acquired by the acquisition means and the detection threshold value stored in the threshold value storage unit Judgment means for judging which judgment signal to output,
An output circuit for outputting the determination signal determined to be output by the determination means;
Optical communication means for outputting the determination signal determined to be output by the determination means by optical communication;
Determination means for determining presence or absence of abnormality based on a comparison result of each determination signal output by each of the output circuit and the optical communication means,
The detection unit is characterized in that, when the determination signals to be compared are different from each other, the determination unit determines that one of the output circuit and the optical communication unit is abnormal. The output circuit and the optical communication unit may perform the first determination when the determination unit determines to output the first determination signal based on a comparison result between the signal level of the detection signal and the detection threshold. Outputs a signal and outputs the second determination signal when it is determined not to output the first determination signal;
The determining means determines that the output circuit and the optical communication means that output the second determination signal are abnormal when the determination signals to be compared are different from each other. The detection sensor system according to claim 1. The determination means determines that the first determination signal is output when the signal level of the detection signal is equal to or higher than the detection threshold, and second when the signal level of the detection signal is lower than the detection signal. Decides to output a decision signal,
3. The determination unit according to claim 1, wherein the determination unit determines that the detection threshold is abnormal when all the determination signals to be compared are the second determination signals. The described detection sensor system. A reference value storage unit that stores a reference value set based on a difference between a maximum value and a minimum value of the signal level of the detection signal;
At least one of the output circuit and the optical communication means outputs a signal level of the detection signal in addition to the determination signal,
In the case where the determination signals to be compared are all the second determination signals, and the difference between the maximum value and the minimum value of the signal level is larger than the reference value, the determination means The detection sensor system according to claim 3, wherein the detection threshold value is determined to be abnormal. The acquisition unit in the detection sensor system according to any one of claims 1 to 4, the determination unit, the output circuit, and the optical communication unit,
The detection sensor, wherein the determination signal determined to be output by the determination means is output by the output circuit and the optical communication means, respectively. Based on the detection signal that changes in accordance with the detection state of the detection target, one of the first determination signal and the second determination signal different from the first determination signal is output to the output circuit and the optical communication means. A discriminator connected to the detection sensor that outputs each of
Receiving means for receiving the determination signal output by the output circuit and the determination signal output by the optical communication means;
Determining means for determining presence or absence of abnormality based on a comparison result of the respective determination signals received by the receiving means;
The discriminating device discriminates that the detection sensor is abnormal when the judgment signals to be compared are different from each other. An abnormality detection method of a detection sensor that outputs information according to a detection state of a detection target,
An acquisition stage for acquiring a detection signal that changes according to the detection state of the detection target;
Based on the comparison result between the signal level of the detection signal acquired in the acquisition step and the detection threshold value stored in the threshold value storage unit, the first determination signal is different from the first determination signal. A determination stage for determining which of the determination signals to output;
An output step of outputting the determination signal determined to be output in the determination step by an output circuit;
An optical communication step of outputting, by an optical communication means, the determination signal determined to be output in the determination step;
A determination step of determining that one of the output circuit and the optical communication means is abnormal when the determination signal output in the output step is different from the determination signal output in the optical communication step. An abnormality detection method for a detection sensor.

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