JP2014096698A - Communication device - Google Patents

Abstract

[PROBLEMS] To suppress a decrease in communication speed associated with transmitting sensor error information to a PLC.
A communication unit is physically and electrically connected to a PLC and a plurality of sensors, and transmits information received from the plurality of sensors to the PLC. When the communication unit receives error information indicating an error in response to a command from the PLC from the sensor, the communication unit transmits only some types of error information to the PLC among the plurality of types of error information received from the plurality of sensors. Since not all types of error information received from a plurality of sensors but only some types of error information are transmitted from the communication unit to the PLC, the amount of data during transmission of error information can be minimized. . Therefore, it is possible to suppress a decrease in communication speed due to error information transmitted from the sensor.
[Selection] Figure 13

Description

  The present invention relates to a communication device, and more particularly to a technique for transmitting error information received from a plurality of sensors to a control device.

In general, a production line is provided with a plurality of sensors. A PLC (Programmable Logic Controller) as a control device controls a manufacturing machine in response to signals input from various sensors. In such a manufacturing system, there is a need to unify input systems from sensors in order to simplify the system configuration.

  In response to such needs, as described in Japanese Patent Application Laid-Open No. 2011-28525 (Cited document 1), the network unit (communication unit) collectively manages data transmitted from a plurality of sensors and transfers it to the control device. A system can be used.

JP 2011-28525 A

  In a system in which the communication path between the sensor and the control device is unified by a communication unit as described in JP 2011-28525 A, error information from each sensor is also collected in the communication unit. However, the type of error is not one, and different types of errors may be reported for each sensor. In this case, the amount of data to be transmitted from the communication unit to the control device can be increased. As a result, the communication speed can be reduced.

  The present invention has been made in view of the above-described problems, and an object thereof is to suppress a reduction in communication speed due to error information transmitted from a sensor.

  The communication device is physically and electrically connected to the control device and the plurality of sensors, and transmits information received from the plurality of sensors to the control device. This communication device has a means for receiving error information indicating an error in response to a command from a control device from a sensor, and only some types of error information among a plurality of types of error information received from a plurality of sensors. For transmitting to the control device.

  Not all types of error information received from multiple sensors, but only some types of error information are sent from the communication device to the control device, minimizing the amount of data when sending error information it can. Therefore, it is possible to suppress a decrease in communication speed due to error information transmitted from the sensor. In addition, after dealing with errors recognized by the user, etc., if the next command is issued and error information is obtained, all errors can be finally resolved by repeating the same processing. Therefore, there is no problem in transmitting only some types of error information.

  Only the error information of the type having the highest priority set in advance may be transmitted to the control device. As an example, the priority is determined by the user in consideration of the time required for the user to resolve the error. For example, the shorter the time required to resolve an error, the higher the priority of the error information type.

  The command from the control device may be given to the sensor by transmitting predetermined information such as command identification information to the sensor via the communication device. In this case, when a command from the control device is executed, the communication device may receive predetermined information from the sensor. When an error occurs in response to a command from the control device, the communication device may receive error information from the sensor instead of the predetermined information. That is, each sensor may return the information obtained from the control device as it is if execution of the given command is successful, and may return the information obtained from the control device with error information if an error occurs. . As a result, it is possible to clearly indicate the success or failure of the command and to suppress an increase in the amount of data associated with the transmission of error information. Therefore, adverse effects on the communication speed can be reduced.

  Not all types of error information received from multiple sensors, but only some types of error information are sent from the communication device to the control device, minimizing the amount of data when sending error information it can. Therefore, it is possible to suppress a decrease in communication speed due to error information transmitted from the sensor.

It is the schematic which shows a photoelectric sensor system. It is a perspective view which shows the external appearance of a communication unit. It is a functional block diagram of a communication unit. It is a perspective view which shows the external appearance of a dispersion | distribution unit. It is a functional block diagram of a distributed unit. It is a perspective view which shows a sensor. It is a figure which shows the binary data which the sensor of a main | base station transmits. It is a figure which shows the binary data which the sensor of a subunit | mobile_unit transmits. It is a figure which shows the command data which PLC transmits toward each sensor. It is a figure which shows the command data transmitted to the sensor connected to the communication unit. It is FIG. (1) which shows the command data transmitted to the sensor connected to the distribution unit. It is the figure (the 2) which shows the command data transmitted to the sensor connected to the distribution unit. It is a figure which shows the error of each classification. It is a flowchart which shows the process which a communication unit performs.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  A photoelectric sensor system 1 as an example of a sensor system will be described with reference to FIG. A sensor system other than the photoelectric sensor system may be used. The photoelectric sensor system 1 includes a communication unit 10, a plurality of distributed units 20 (20A, 20B), and a plurality of sensors 30 (30A to 30N).

  The communication unit 10 is physically and electrically connected to the PLC 2 and the plurality of sensors 30 in a mode described below, and transmits information received from the plurality of sensors 30 to the PLC 2.

  The communication unit 10 is connected to the PLC 2 via a network such as a LAN (Local Area Network). In the present embodiment, the communication unit 10 is configured to communicate with the PLC 2 using EtherCAT (registered trademark). CC-LINK (registered trademark), DeviceNET, CompoNET, etc. may be used instead of EtherCAT (registered trademark).

  The distribution units 20A and 20B are connected to the communication unit 10 in a bus format. In the present embodiment, two distribution units 20A and 20B are used, but the number of distribution units is not limited to two, and may be any number.

  In the present embodiment, each of the distribution units 20A and 20B is physically connected to the communication unit 10 through a serial transmission path. Each of the distribution units 20A and 20B may be physically connected to the communication unit 10 through a parallel transmission path.

  Different sensors 30 are connected to the communication unit 10 and the distribution units 20A and 20B, respectively. That is, the sensors 30 </ b> A to 30 </ b> N are installed in a distributed manner in the photoelectric sensor system 1. As an example, in the present embodiment, the sensors 30 </ b> A to 30 </ b> F are connected to the communication unit 10. The sensors 30G to 30I are connected to the distribution unit 20A. The sensors 30J to 30N are connected to the distribution unit 20B. Each sensor 30 may be arranged in a row adjacent to each other.

  The total number of sensors 30 and the number of sensors 30 connected to each of the communication unit 10 and the distribution unit 20 are not limited to the numbers shown in FIG. As an example, a sensor may not be connected to the communication unit 10.

  In the present embodiment, the communication unit 10 transmits signals from the sensors 30A to 30F to the PLC 2. The distribution unit 20A transmits signals from the sensors 30G to 30I to the communication unit 10, and the communication unit 10 transmits signals from the distribution unit 20A to the PLC 2. The distribution unit 20B transmits signals from the sensors 30J to 30N to the communication unit 10, and the communication unit 10 transmits signals from the distribution unit 20B to the PLC2. Therefore, signals from the sensors 30A to 30N are unified by the communication unit 10 and transmitted to the PLC 2.

  As an example, a discrimination signal (on / off value) obtained as a result of comparing the detection value of each sensor 30 with a threshold value, error information, detection value bottom value, detection value peak value, bottom value, or peak value are threshold values. Setting values such as warning (warning) information obtained by comparing values, sensor detection values, threshold values set in the sensors, etc. are directly sent from each sensor 30 to the communication unit 10 or indirectly via the distribution unit 20. Are transmitted in a predetermined cycle. In the present embodiment, the detection value of the sensor 30 is an amount of received light as an example. The set value is, for example, a threshold value that is compared with the amount of received light, a peak value, a bottom value, or the like. The information transmitted from each sensor 30 to the communication unit 10 is not limited to these. In addition, the communication unit 10 may notify the PLC 2 of the number of sensors 30 in the photoelectric sensor system 1 and the state of the communication unit 10 (initialization state, pre-operational state, safe operational state, and operational state).

  The communication unit 10 will be further described with reference to FIGS. As shown in FIG. 2, the communication unit 10 includes an input connector 101 and an output connector 102 used for connection to the PLC 2, a connection connector 104 used for connection to the distribution unit 20, and a connection connector used for connection to the sensor 30. 106 and a power input connector 108.

  Furthermore, as shown in FIG. 3, the communication unit 10 includes an MPU (Micro Processing Unit) 110, a communication ASIC (Application Specific Integrated Circuit) 112, a serial communication circuit 114, a parallel communication circuit 116, a serial communication circuit 118, and a power supply circuit 120. Is provided.

  The MPU 110 operates so as to execute all processes in the communication unit 10 in an integrated manner. The communication ASIC 112 manages communication with the PLC 2. As described above, the communication unit 10 communicates with the PLC 2 using EtherCAT. The communication unit 10 transmits data requested from the PLC 2 to the PLC 2 using message communication, and transmits data to the PLC 2 periodically using cyclic communication. As an example, data received from the sensor 30 and data generated by the communication unit 10 are temporarily stored in the memory 111a in the MPU 110, and the data stored in the memory 111a is transmitted by cyclic communication. That is, the transmission cycle of cyclic communication is determined as the cycle for reading data from the memory 111a. The transmission period of cyclic communication is determined according to the priority determined for each data type according to the table stored in the memory 111b. The data transmission cycle will be described in detail later.

  The serial communication circuit 114 is used for serial communication between the communication unit 10 and the distribution unit 20. Note that parallel communication may be used. As an example, two communication lines are used for connection between the communication unit 10 and the distribution unit 20 for transmission and reception.

  The parallel communication circuit 116 is used for parallel communication between the communication unit 10 and the sensor 30, and the serial communication circuit 118 is used for serial communication between the communication unit 10 and the sensor 30. That is, the communication unit 10 and the sensor 30 are physically connected by a serial transmission path and a parallel transmission path. Note that the communication unit 10 and the sensor 30 may be connected to either the serial transmission path or the parallel transmission path.

  The distribution unit 20 will be further described with reference to FIGS. As shown in FIG. 4, the distribution unit 20 includes a connection connector 202 used for connection to the communication unit 10, a connection connector 204 used for connection to the sensor 30, a power input connector 206, and a rotary switch 208.

  Further, as shown in FIG. 5, the distribution unit 20 includes an MPU 210, a serial communication circuit 212 for communication with the communication unit 10, a serial communication circuit 214 for communication with the sensor 30, and a power supply circuit 216.

  The MPU 210 operates so as to execute all processes in the distributed unit 20 in an integrated manner. As described above, the communication unit 10 and the distribution unit 20 are connected in a bus format, and serial communication is used.

  The sensor 30 is attached to the side surface of the dispersion unit 20, for example. Serial communication is used for communication between the distribution unit 20 and the sensor 30, but parallel communication may also be used. On the other hand, the dispersion unit 20 and the sensor 30 are physically connected to at least one of a serial transmission path and a parallel transmission path. The dispersion unit 20 and the sensor 30 may be connected by a serial transmission path and a parallel transmission path.

  In the present embodiment, since a plurality of distributed units 20 are provided in the photoelectric sensor system 1, in order to distinguish each distributed unit 20 and communicate with the communication unit 10, the identification number of each distributed unit 20 is specified. There is a need to. For this purpose, the user can set the identification number of each distribution unit 20 using the rotary switch 208. The communication unit 10 can identify the distribution unit 20 that is the data transmission source from the identification number included in the received data. Further, by including an identification number in the data transmitted from the communication unit 10, a command can be given to a desired distributed unit 20.

  In the present embodiment, the identification number of each distribution unit 20 is also transmitted to the PLC 2.

  The sensor 30 will be further described with reference to FIG. The sensor 30 includes an amplifier unit 301 and a fiber unit 302. The amplifier unit 301 includes an opening / closing cover that is rotatably attached to the casing, and a frame that is accommodated in the main body casing. A display unit and an operation unit are provided on the upper surface of the frame exposed when the open / close cover is open. When the user operates the operation unit, a set value such as a threshold value can be set. The sensor 30 can also automatically set a set value based on a command from the PLC 2 or the like.

  Connection connectors 304 and 306 to the communication unit 10, the distribution unit 20, or other amplifier units 301 are provided on both side wall portions of the amplifier unit 301. Therefore, a plurality of amplifier units 301 can be connected to the communication unit 10 or the distribution unit 20 in series. Therefore, a signal from the amplifier unit 301 connected to the other amplifier unit 301 is transmitted to the communication unit 10 or the distribution unit 20 via the other amplifier unit 301.

  A fiber unit 302 is connected to the front wall portion of the amplifier unit 301. The fiber unit 302 includes a head portion, a light projecting side optical fiber, and a light receiving side optical fiber.

  In this embodiment, each amplifier is configured to recognize its own channel number. As an example, in a period in which all the sensors 30 are controlled to transmit a predetermined signal to the adjacent sensor 30, the sensor 30 that does not receive the signal recognizes itself as a parent device, and the channel number is “1”. ”. Then, the sensor 30 that is the parent device transmits binary data illustrated in FIG. 7 to the adjacent sensor 30. Since the sensor 30 that has received this binary data, that is, the sensor 30 that is a slave unit, has entered the data “0x01” in the “own CH number” of the received binary data, the sensor 30 that has received this binary data It recognizes that the channel number is channel “2”. That is, a number that is one greater than the channel number represented by the “own CH number” of the received binary data data is recognized as the channel number.

  Then, the sensor 30 of the channel 2 transmits binary data illustrated in FIG. 8 to the adjacent sensor 30. In the binary data shown in FIG. 8, data “0x02” is input as “own CH number” to indicate that the channel number is channel 2 by incrementing the channel number by one. Therefore, when data “0x05” is input in the “own CH number” of the received binary data, data “0x06” is input in the “own CH number” of the binary data to be transmitted.

  In this way, binary data is sequentially sent by each sensor 30. Each sensor 30 recognizes, as a channel number, a number that is one greater than the channel number represented by the “own CH number” of the received binary data data.

  The channel number is identified in each of the communication unit 10 and each distribution unit 20. Thus, for example, there may be a plurality of sensors 30 for channel 1. In the example shown in FIG. 1, the channel number of the sensor 30A, the channel number of the sensor 30G, and the channel number of the sensor 30J are all “1”. The identified channel number is transmitted to the communication unit 10 as well as the PLC 2. The PLC 2 can give a command to a desired sensor 30 by using a destination constituted by the channel number of the sensor 30 and the identification number of the distribution unit 20.

  FIG. 9 shows an example of command data 40 transmitted from the PLC 2 to the communication unit 10 in order to give a command to the sensor 30. In the first data area 401 of the command data 40, the destination of the command data 40 is input. In the second data area 402, a command ID is input as identification information indicating the type of command. In the third data area 403, data representing various numerical values is input. For example, when a command for changing the threshold value set in each sensor 30 to a specific value is issued, a specific value of the threshold value is input in the third data area 403. In addition, various information such as a transmission source address is input to the third data area 403.

  In the first data area 401, the destination is input depending on whether “1” or “0” is input to the location (digit) corresponding to each of the sensors 30. The photoelectric system 1 illustrated in FIG. 1 will be described. A portion 411 of the first data region 401 is a region assigned to the sensors 30 </ b> A to 30 </ b> F connected to the communication unit 10. More specifically, the first digit of the portion 411 is assigned to the sensor 30A. Similarly, the second to sixth digits of the portion 411 are assigned to the sensors 30B to 30F, respectively.

  Of the first data area 401, the portion 412 is an area allocated to the sensors 30G to 30I connected to the distribution unit 20A. The first to third digits of the portion 412 (the seventh to ninth digits of the entire first data area 401) are assigned to the sensors 30G to 30I, respectively.

  In the first data area 401, a portion 413 is an area allocated to the sensors 30J to 30N connected to the distribution unit 20B. The first to fifth digits of the portion 413 (10th to 14th digits of the entire first data area 401) are assigned to the sensors 30J to 30N, respectively.

  In short, the first digit of each of the portions 411 to 413 is assigned to the sensor 30 of the channel 1, and the second digit and thereafter are assigned to the sensor 30 of the channel 2 and later in order.

  In the present embodiment, the command data 40 is transmitted to all the sensors 30. When each sensor 30 receives the command data 40, it is determined whether “1” is input to the location assigned to the sensor 30 or “0”. It is determined whether or not the command data 40 has been transmitted to itself depending on whether or not is input.

  For example, since the channel number is “1”, the sensor 30A transmits the command data 40 to itself depending on whether the numerical value input in the first digit of the portion 411 is “1” or “0”. It is determined whether or not it has been done. When “1” is input in the first digit of the portion 411, the sensor 30A recognizes that the command data 40 is transmitted to itself, and the command ID input to the second data area 402 is received. Executes the command specified by

  However, in the present embodiment, although the channel numbers may be duplicated in the plurality of sensors 30, each sensor 30 cannot know that the channel numbers are duplicated. Therefore, for example, the sensor 30G connected to the distribution unit 20A misidentifies the destination because its own channel number is “1” and the first digit of the portion 412 is the seventh digit of the entire first data area 401. obtain. In this case, even if “0” is input in the first digit of the portion 412, “1” is input in the first digit of the portion 411, and thus the sensor 30G can execute the command by mistake.

  In order to prevent such misidentification of the destination, the communication unit 10 knows the identification number of each distributed unit 20 and the number of sensors 30 connected to each distributed unit 20, and therefore uses those data. Then, only a part of the destination is extracted from the first data area 401, and the processed command data is transmitted to each sensor 30.

  In the example of the photoelectric sensor system 1 shown in FIG. 1, as shown in FIG. 10, command data 40 </ b> A in which only a portion 411 is extracted from the first data area 401 is connected to the communication unit 10. It is transmitted to the sensors 30A to 30F.

  Also, as shown in FIG. 11, command data 40B from which only the portion 412 is extracted from the first data area 401 is transmitted to the distributed unit 20A and the sensors 30G to 30I connected to the distributed unit 20A.

  Further, as shown in FIG. 12, command data 40C in which only the portion 413 is extracted from the first data area 401 is transmitted to the distributed unit 20B and the sensors 30J to 30N connected to the distributed unit 20B.

In addition, when transferring the data output from the sensor 30 from the communication unit 10 to the PLC 2, the first data area 401 is restored by connecting the divided parts, contrary to the above process, The data area 401 is sent to the PLC 2 as the data transmission source. As described above, the sensor 30 corresponding to the place where “1” is input is the command specified by the command ID input to the second data area 402. Execute. If the command is valid and the command can be executed normally, each sensor 30 returns the data including the command ID to the PLC 2 without changing the received second data area 402.

  On the other hand, when an error occurs with respect to a command for any reason, the sensor 30 inputs error information in place of the command ID into the second data area 402 and sends it back to the PLC 2. The error information is collected in the communication unit 10 before being transmitted to the PLC 2, and only some types of error information among the plurality of types of error information are transferred to the PLC 2. More specifically, only the error information of the type having the highest priority among the plurality of types of received error information is transmitted from the communication unit 10 to the PLC 2.

  FIG. 13 shows error information and priorities determined for each type. The priority for each type is stored in a memory or the like in the communication unit 10 as a table. Error codes such as “0x08”, “0x04”, “0x02”, and “0x01” in FIG. 13 are input to the second data area 402 as error information instead of the command ID described above, and transmitted to the communication unit 10. The

  In the present embodiment, the priority of the error “0x08” is the highest, and the priority is lower in the order of “0x04”, “0x02”, and “0x01”. The priority is determined in consideration of, for example, the time required for the user to resolve the error. As an example, an error is determined such that the priority is higher as the error takes less time for the user to resolve the error. The method for determining the priority is not limited to this, and the priority may be set as appropriate according to the needs.

  With reference to FIG. 14, the process which the communication unit 10 performs in this Embodiment is demonstrated.

When command data is received from PLC 2 at step (hereinafter abbreviated as S) 100 (YES at S100), the command data is transferred to each sensor 30 at S102. ,
If error information is received from each sensor 30 in S104 (YES in S104), only the error information of the highest priority type among the plurality of types of error information is transmitted to the PLC2.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1 photoelectric sensor system, 2 PLC, 10 communication unit, 20, 20A, 20B dispersion unit, 30, 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H, 30I, 30J, 30K, 30L, 30M, 30N sensor 40, 40A, 40B, 40C command data, 101 input connector, 102 output connector, 104, 106, 202, 204, 304, 306 connection connector, 108, 206 power input connector, 110, 210 MPU, 111a, 111b memory, 112 Communication ASIC, 114, 118, 212, 214 Serial communication circuit, 116 Parallel communication circuit, 120, 216 Power supply circuit, 208 Rotary switch, 301 Amplifier unit, 302 Fiber unit, 400 Data, 401 First data area, 402 Second data area, 403 Third data area

Claims (4)

A communication device that is physically and electrically connected to a control device and a plurality of sensors, and that transmits information received from the plurality of sensors to the control device,
Means for receiving from the sensor error information indicating an error in response to a command from the control device;
A communication apparatus comprising: a transmission unit configured to transmit only some error information of a plurality of types of error information received from the plurality of sensors to the control device.   2. The communication according to claim 1, wherein the transmission unit transmits only error information of a type having a highest priority among a plurality of types of error information received from the plurality of sensors to the control device. apparatus. A command from the control device is given to the sensor by transmitting predetermined information to the sensor via the communication device,
When a command from the control device is executed, the communication device receives the predetermined information from the sensor,
The communication device according to claim 1 or 2, wherein when an error occurs with respect to a command from the control device, the communication device receives the error information from the sensor instead of the predetermined information.   The communication apparatus according to claim 3, wherein the predetermined information is identification information of the command.

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