JP2009118041A - Position relation detection system for node station - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect the position relation of a slave and a repeater, etc., connected to a network in a field network of bus type. <P>SOLUTION: A master unit 11 and a measurement tool apparatus 60 send a command to selected two node stations #1 and #2 and measure the time t1, t2, s1 and s2 taken until the return of a response. Obtained measured values are substituted to y=(t1-t2)-(s1-s2), and it is determined that the node station #1 is positioned on the master unit side when the value of y is negative and that the node station #2 is on the master unit side when it is positive. Even while the respective node stations have the internal processing time intrinsic to a communication IC and it is individually different, since the subtraction processing of the measured values takes place for the same node station like t1-s1 and -t2-(-s2) in the determination equation, the internal processing time is offset, the value of y corresponds to a distance, and the position relation is accurately specified. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a positional relationship detection system for a node station.

  In a network system in FA (Factory Automation), a PLC (programmable controller) that controls production facilities and a device whose operation is controlled by the PLC are connected to a network of a control system. These PLCs and devices communicate with each other cyclically via the network of the control system, thereby transmitting / receiving IO data and controlling production facilities.

  At this time, there is a type in which a master unit constituting a PLC and a slave such as an IO terminal are connected via a field network, and IO data is transmitted and received by master-slave communication. In addition, this type of field network is known as a network used for the purpose of remote control of equipment and operation state management at a production site. The setting and status monitoring of each node of the field network is performed using a tool device connected to a host controller (for example, a PLC having the above master unit).

  This tool device is, for example, a general personal computer from the viewpoint of hardware, and each function is realized by an application program that runs on an operating system such as Windows (registered trademark). As one of the functions of this tool device, there is one that obtains a node address of a slave that actually joins a network, creates a network configuration diagram based on the obtained information, and outputs it to a display device.

Fig.1 (a) has shown an example of the network block diagram displayed on a display apparatus. As shown in the figure, in this network configuration diagram, a master S2, a plurality of slaves S3, and a repeater S4 are connected to the trunk network S1, and a termination resistor S5 is connected to the end of the trunk network S1. Further, a branch line network S6 is connected to the lower side of the repeater S4, a slave S3 is connected to the branch line network S6, and a termination resistor S5 is connected to an end of the branch line network S6. Then, the slave S3 connected in the middle of the networks S1 and S6 is displayed in the order of the node address from the master S1 side. Note that the tool device has acquired information on which network of each of the slave networks S1 and the branch network S6 each slave S3 is connected to, and accordingly recognizes which network each slave has joined, Create a network configuration diagram by connecting to each appropriate network.
JP 2000-115213 A

  Although the conventional tool device can confirm the node address of the slave joining the network, it cannot grasp the positional relationship of the slave. Therefore, it is assumed that the arrangement of the master 2, slave 2, repeater 3 and termination resistor 5 connected to the trunk network cable 1 and branch network cable 6 in the actual network configuration is as shown in FIG. However, the network configuration diagram displayed on the tool device is as shown in FIG. 1A, and there is a high possibility that a phenomenon in which both do not match will occur.

  On the other hand, maintenance of facilities is regarded as important at production sites. In particular, when an equipment abnormality occurs, the user needs to perform a quick recovery response. Therefore, when an equipment failure occurs, the user must quickly grasp the location and cause of the failure and perform recovery work. However, the node address of the slave where the network failure occurs in the tool device (management software) Even if I knew, I couldn't visually know where the place was, and the response could be delayed.

  Further, in production sites, slaves are often added later due to the expansion of facilities. In that case, the added slaves may be assigned different numerical addresses even within the same facility. In that case, it is particularly difficult to grasp the positional relationship.

  By the way, in order to grasp the positional relationship of the slaves, it is only necessary to know the distance from the master to each slave. As a means for that, it is conceivable to measure the time until the response from the slave returns to the command transmitted by the master. However, in practice, there is a large variation in performance unique to the communication IC of each slave, and thus the measured command-response time difference of each slave may be different from the actual distance difference. Therefore, a technique for simply obtaining the positional relationship based on the time until the master receives a response cannot be adopted.

  As a method for solving this problem, a method described in Patent Document 1 has been devised. In this method, a network connection apparatus is connected to both ends of a bus network, and a loop network is constructed by connecting both ends. When a frame transmitted from a certain slave is received, the positional relationship is obtained by comparing the transmission time transmitted clockwise and the transmission time transmitted counterclockwise. The relative positional relationship is obtained by performing sorting for all slaves and applying sorting.

  However, in this method, it is necessary to form a loop network, and the method cannot be applied as it is to the bus field network targeted by the present invention. Furthermore, there is a problem that reception synchronization must be taken in order to accurately obtain the time difference between clockwise and counterclockwise.

  It is an object of the present invention to provide a node station positional relationship detection system capable of detecting the arrangement order (positional relationship) of node devices (slave, repeater, etc.) connected to a network in a bus-type field network. .

  In order to achieve the above object, a node station positional relationship detection system according to the present invention is (1) a positional relationship detection system for detecting the positional relationship of a plurality of node stations joining a bus-type field network, A measuring device that is connected to both ends of a network cable and has a measuring tool function for measuring a time from when a command is transmitted to each node station connected to the network cable until a response is received, and the measuring tool And a positional relationship determination device that identifies the positional relationship of each node station based on the measured value measured by the function. Then, the positional relationship determination device selects any two node stations from among the plurality of node stations as the first determination target station and the second determination target station, and both the selected two node stations with respect to the selected two node stations. By identifying the relative positional relationship connected to the network cable of the two node stations from the measured values respectively obtained by the measuring device, and performing the process for obtaining the relative positional relationship for all combinations selected as determination targets And a function of specifying the positional relationship of a plurality of node stations. The above processing for obtaining the relative positional relationship between the two node stations is such that the difference between the measurement value for the first determination target station and the measurement value for the second determination target station obtained by one measurement apparatus is Δt, and the other measurement apparatus When the difference between the obtained measurement value for the first determination target station and the measurement value for the second determination target station is Δs, Δt and Δs are subtracted from one to the other, and the result of the processing is determined to be positive or negative did.

  Examples of the bus-type field network include CC-Link, CC-Link / LT, and device network. For the measurement device, a case where it is realized by being incorporated in a node station constituting the network system, or a separate measurement device (corresponding to the “measurement tool device” in the embodiment) are prepared, and a termination resistor (termination terminal) (Device). In the embodiment, the termination resistor 40 is replaced with a measurement tool device. However, a measurement tool function may be mounted on the termination resistor so that it is also used as a measurement device. In the embodiment, the positional relationship determination device is realized by the tool device 50. However, the positional relationship determination device may be integrated in the measurement device.

  Assuming that the processing time for returning a response executed inside the node station is the same at each node station, Δt and Δs calculated based on the measured values obtained by the measuring apparatus are greater for the first determination target station. When it is close to the measuring device, it becomes a negative value, and when the second determination target station is closer to the measuring device, it becomes a positive value. Since the two measurement devices are arranged at both ends of the network, if the first determination target station is close to one measurement device, the second determination target station is close to the other measurement device. Therefore, if Δt is positive, Δs becomes negative, and if Δt is negative, Δs becomes positive. Therefore, it is possible to determine whether the first determination target station is nearer or farther from the reference measurement device based on the sign of Δt−Δs (or Δs−Δt).

  Furthermore, according to the present invention, the time required to receive responses to the two determination target stations is measured by the measuring devices provided at both ends of the network cable, and Δt− as described above based on the obtained measurement values. Since Δs (or Δs−Δt) is obtained, the influence of variations in the communication processing time required to generate and transmit a response after receiving a command in each node station is eliminated. In other words, each node station has a variation in performance inherent in the communication ICs installed therein, so that the measurement value measured by the measurement device is the time required to transmit a frame determined according to the distance, and the communication IC. It includes the processing time within the node station that is determined based on the inherent performance. Therefore, when the difference in the distance between the installation positions of the two determination target stations is short and the difference in processing time within the node station based on the performance unique to the communication IC is large, the measurement value for the determination target station closer to the measurement device is better. It can be long.

  Therefore, when Δt−Δs (or Δs−Δt) is calculated, since Δt and Δs include measurement values obtained for the same target station, the calculation processing is performed by each measurement device for the same target station. Since the difference between the obtained measurement values is also executed, the processing time in the node station determined based on the performance unique to the communication IC is canceled out. Therefore, the value finally obtained by the arithmetic processing is not affected by the processing time in the node station and is determined by the time based on the frame transmission, and the relative positional relationship between the two determination target stations is determined. Can be judged accurately.

  Then, when determining the positional relationship for all combinations of node stations that join the network to be determined, when focusing on one node station, the node station located on the one measuring device side with reference to that node station And a node station located on the other measuring device side can be separated. Therefore, by sequentially changing the node stations of interest, it is possible to specify the positional relationships of all the node stations as a result. The identification processing of the positional relationship of all the node stations is based on, for example, one measurement apparatus, and the node station closer to one of the two measurement target node stations is added (for example, +1). By performing this operation for all combinations, it can be said that the node station having the highest value of the added total score is in the position closest to one of the measurement apparatuses. Therefore, the positional relationship of the node stations can be specified by arranging them in descending order of the total score. Of course, the method of specifying the positional relationship of all node stations is not limited to the above.

  As described above, since the positional relationships of all the node stations can be specified, if a network configuration diagram is created based on the positional relationship information, a network configuration diagram that matches the actual network arrangement status can be created. Therefore, the user can visually know the positional relationship between the node stations.

  In addition, since the two measuring devices independently send a command to each node station and measure the time until receiving a response to obtain a measured value, it is necessary to synchronize the two measuring devices. Absent.

  (2) The field network is a master-slave type field network, in which one of the measuring devices is constituted by a master, and the other one of the measuring devices is attached to the installation position of the terminating device. The one measuring device can be configured to obtain a measured value for a designated node station in accordance with a message transmitted from the master, and return the measurement result to the master. The measuring device attached to the installation position of the termination device (in the embodiment, termination resistor) may be replaced with the termination device and connected to the end of the network cable, or incorporated in the termination device as a function. Also good. The master stores and holds the measurement values obtained by measurement by itself and the measurement values measured by other measurement devices. Therefore, the master passes the measurement value to the positional relationship determination device using the stored two measuring devices, and specifies the positional relationship of the nodes joining the network there. When the master also serves as a positional relationship determination device, the positional relationship is obtained by the master. For example, the tool device that creates the network configuration diagram acquires the positional relationship obtained by the master and obtains an appropriate network configuration diagram. Will be created.

  (3) In the field network, a repeater is joined, and a plurality of node stations are connected to a branch network cable connected to the lower level of the repeater, and a plurality of node stations connected to the branch network cable are connected. The connection relationship can be obtained based on the measured values obtained by the master and the measuring device connected to the end of the branch network.

  (4) A repeater is added to the field network, and a plurality of node stations are connected to a branch network cable connected to the lower side of the repeater, and a plurality of node stations connected to the branch network cable are connected. The connection relationship can also be determined based on the measured values obtained by the repeater and the measuring device connected to the end of the network cable connected to the lower part thereof.

  According to the inventions of (3) and (4), even in a network system having a branch network branched from a trunk network, the positional relationship of node stations that join the network system can be specified. As in the invention of (4), by incorporating the measuring device into the repeater, the node station connected to the lower level of the repeater has a positional relationship based on the measured values obtained by the repeater and the measured values provided at the terminal. Since it can be specified, the influence of the time required for repeater processing in the repeater is eliminated, and the positional relationship can be specified more accurately.

  (5) The measured value may be the total of the times acquired by executing command transmission and response reception processing a predetermined number of times. Since the comparison is made with the total time of a plurality of command-responses, the sampling time can be increased, and the difference can be easily obtained to determine the positional relationship.

  In the present invention, in the bus-type field network, the arrangement order (positional relationship) of node stations (slave, repeater, etc.) connected to the network can be specified.

  FIG. 2 shows an example of a network system to which the present invention is applied. This network system is a type of FA network, and is a network for communicating between a PLC and various field devices in order to perform device control within a line. CC-Link, CC-Link / LT, device network Etc. In this embodiment, a bus type field network is configured.

  The master unit 11 of the PLC 10 is connected to one end of the main line network cable 1. One or more slaves 20 are connected to the main network cable 1, and a termination resistor 40 is connected to the other end of the main network 1. In addition, when the branch network cable 6 is branched from the main network cable 1, the repeater 30 can be arranged at the branch point. One or more slaves 20 are connected to the branch network cable 6 connected to the lower side of the repeater 30, and a termination resistor 40 is connected to the other end of the branch network cable 6. In some cases, a branch network cable may be connected to the main network cable 1 using a T-branch connector or the like without using the repeater 30 and branched.

  Further, the tool device 50 is connected to the PLC 10. In the illustrated example, the tool device 50 is directly connected to the PLC 10 with a cable, but can also be connected via a network.

  When the repeater 30 is not present, the total length of the trunk line network cable 1 can reach a maximum of 500 m depending on the communication speed. Therefore, each slave 20 is installed at an appropriate location in a wide range according to the layout of the production line on the production site, and after being arranged once, addition / deletion of slaves and change of the installation position by changing the production line, etc. Therefore, it is not practical to actually go to the installation position of the slave and confirm the node address of each slave. Therefore, the tool device acquires the positional relationship between the slaves 20 and the repeater 30 and creates a network configuration diagram that matches the actual positional relationship so that it can be displayed.

  FIG. 3 shows a connection relationship between the PLC 10 and the tool device 50 and its internal configuration. The tool device 50 is a general personal computer from the viewpoint of hardware, and each function of this device is realized by an application program that runs on an operating system such as Windows (registered trademark). Therefore, as shown in FIG. 3, the tool device 50 has a hardware configuration of a processor (MPU) 50a that executes various processes and a memory (RAM) that is used as a work area when the processor 11 executes the processes. ) 50b, an input device 50c such as a keyboard and a pointing device, a display device 50d, and an external interface 50e for connecting to an external device. Although not shown, a hard disk is also provided as a database for storing various types of information. The external interface 50e is a communication interface and is connected to the PLC 10 (CPU unit 12), and in relation to the present invention, sends an instruction to collect information on the positional relationship between slaves and repeaters, and collects and acquires information. .

  As is well known, the PLC 10 is a CPU unit that performs operations based on a control program, an input unit that connects an input device such as a sensor or switch, and takes in an on / off signal as an input signal, an actuator or a relay. Output unit that connects output devices such as, and sends output signals to them, communication unit that transmits and receives data with other devices connected to the network, master unit for master-slave communication, power to each unit It is configured by combining a plurality of units such as a power supply unit that supplies power. FIG. 3 shows the CPU unit 12 and the master unit 11 related to the present embodiment among the above-described units.

  The CPU unit 12 connects an MPU 12a that cyclically executes a user program, IO refresh, and peripheral processing, a memory 12b such as an IO memory that stores work data and IO data when the MPU 12a is executed, and an external device. An external interface 12c for connecting to the PLC bus, a PLC bus interface 12d connected to the PLC bus, and an input / output unit 12e such as an LED display unit for indicating an operation state or abnormality / normality and a setting switch for setting an address, etc. I have. The basic hardware configuration and the like are the same as those of the conventional CPU unit, and thus detailed description thereof is omitted.

  The master unit 11 is connected to the main line network cable 1 which is a field bus, and performs communication between the master and slave via a network communication unit (communication interface) 11c that actually transmits and receives data, and the network communication unit 11c. MPU 11a for performing various controls such as transmission / reception of I / O data between the slave 20 and the repeater 30, transmission of a predetermined command and reception of a response based on it, and a master ASIC is mounted if necessary. A memory (RAM) 11b used as a work area at the time of execution of various controls, an EEPROM (not shown) storing a program for performing the above control, various setting data, and the like, P for communicating with a unit (for example, a CPU unit) via a PLC bus It includes a C bus interface 11d, and the output unit 11e of the setting switch for performing such operation state (communication state) and abnormal / normal etc. LED display unit as well as the setting of the address indicating the a. The basic hardware configuration and the like are the same as those of the conventional master unit, and thus detailed description thereof is omitted.

  As shown in FIG. 4A, the slave 20 is connected to a fieldbus communication cable (main network cable 1, branch network cable 6), and actually receives I / O data and various data with the master unit 10. A network communication unit 20c that transmits and receives messages and the like, and transmits / receives acquired I / O data through the network communication unit 20c, receives predetermined commands, and transmits responses based on them, and performs various controls. MPU 20a (slave ASIC is mounted if necessary), a memory 20b used as a work area or storing IO data when executing various controls, a program for performing the above control, EEPROM (not shown) that stores setting data, etc., and external devices such as input devices and output devices I / O interface 20e that connects to O equipment and transmits / receives I / O data, LED display unit indicating operation state (communication state), abnormality / normality, and setting switch for setting node address, etc. And an input / output unit 20d. Note that the configuration and operational effects of the slave 20 are the same as those of the conventional one, and a detailed description thereof will be omitted.

  As shown in FIG. 4B, the repeater 30 includes a first network communication unit 30c connected to a higher-level fieldbus communication cable (such as the trunk network cable 1) and a lower-level fieldbus communication. The second network communication unit 30d connected to the cable (branch network cable 6 etc.) and the two network communication units 30c, 30d are mounted between the network communication units 30c and 30d, and shaping processing and other predetermined processing MPU 30a for performing various controls (installing a repeater ASIC if necessary), an EEPROM (not shown) storing a program for performing the above control, various setting data, and the like, and an operating state (communication state) And an input / output unit 30e such as a setting switch for setting an LED display unit indicating abnormality or normality and a node address, etc. It is equipped with a. The configuration and operational effects of the repeater 30 are the same as those of the conventional one, and a detailed description thereof will be omitted.

  In this embodiment, instead of the termination resistor 40, the measurement tool device 60 shown in FIG. 5 is connected, and the master unit 11 and the measurement tool device 60 transmit commands to the slave 20 and the repeater 30, respectively, and the command. The positional relationship between each slave 20 and the response 30 is detected from the information obtained from the response. The measurement tool device 60 is connected to a fieldbus communication cable (trunk network cable 1, branch network cable 6), and a network communication unit 60c that transmits and receives various messages to and from other devices that join the network. The MPU 60a that receives a predetermined command and transmits a response based on the command and performs various controls, the memory 60b that is used as a work area when executing various processes, and the information for detecting the positional relationship are acquired. EEPROM (not shown) that stores programs and various setting data, etc., LED display that indicates operating status (communication status), abnormality / normality, etc., and settings for setting node addresses And an input / output unit 60d such as a switch. That is, the measurement tool device 60 also has a node address and becomes one node station on the network. Therefore, when the measurement tool device 60 is connected to the terminal resistance side, the master unit 11 recognizes that the measurement tool device 60 is connected, as in the case where a new slave is added. In the case of the network system shown in FIG. 2, since there are two termination resistors 50 (the end of the main network cable 1 and the end of the branch network cable 6), the measurement tool device 60 is finally used. Is replaced with each termination resistor 50, but a plurality of measurement tool devices 60 may be prepared and replaced with a plurality of termination resistors, or may be replaced one by one.

  Two node stations (slave 20 and / or repeater 30) are selected as targets for specifying the positional relationship, and master unit 11 and measurement tool device 60 send commands to the selected two node stations, Measure the time until the response is returned. That is, as shown in FIG. 6, when two node stations (first determination target station and second determination target station) to be determined (specific targets) are slaves 20 of node addresses # 1 and # 2, the master unit 11 transmits a command to each slave and measures the times t1 and t2 from when the response is received until the response is received. Similarly, the measurement tool device 60 transmits a command to each slave. , S1 and s2 are measured from when the call is sent until the response is received.

  Here, the data format of the command to be transmitted adopts the structure shown in FIG. 7A, for example, and the data format of the response to be returned takes the structure shown in FIG. 7B, for example. By storing code data for predetermined measurement in the service code, command-response communication for determining the positional relationship is performed. When a slave or repeater joins a network, it transmits its own address to the master unit, and the repeater acquires the address of the slave (repeater) connected to its lower branch network cable. Therefore, since it is transmitted to the master unit, the master unit 11 knows the addresses of slaves and repeaters that have joined the network. Therefore, when transmitting the above-mentioned command, the master unit 11 stores the target address in the transmission destination address based on the information acquired by the master unit during the subscription process. Further, the measurement tool device 60 can perform command-response communication by acquiring the target address from the master unit 11. Further, the host tool device 50 can know the address and the positional relationship by receiving data from the master and the repeater.

If each time is measured as described above, next, the second determination target station (FIG. 6) is calculated from the measured values (t1, s1) for the first determination target station (node address # 1: # 1 in FIG. 6). 6, the difference between the measured values is obtained by subtracting the measured values (t2, s2) from the node address # 2: # 2). The calculation result of the difference is, in principle, a negative value when the first determination target station is closer, and a positive value when the second determination target station is closer. Therefore, substituting the obtained measured value into the following formula,
y = (t1-t2)-(s1-s2)
If the value of y is negative, # 1 that is the first determination target station is located on the master unit 11 side, and # 2 that is the second determination target station is located on the measurement tool device 60 side (when viewed from the master unit). It can be determined that the positional relationship is in the order of # 1 and # 2 in the trunk network cable 1 (the same state as that illustrated in FIG. 6), and if the value of y is positive, it is the second determination target station. # 2 is located on the master unit 11 side, and # 1, which is the second determination target station, is located on the measurement tool device 60 side (when viewed from the master unit, the positions are arranged in the order of # 2 and # 1 on the trunk network cable. It can be determined that

  Furthermore, by using the above-described determination formula, it is possible to eliminate the influence of variations in communication processing time required for generating and transmitting a response after receiving a command at each slave and repeater. That is, since each slave repeater has a variation in performance unique to the built-in communication IC, the measured command-response time (t1, t2, s1, s2) is a frame determined according to any distance. And the processing time within the station determined based on the performance unique to the communication IC. Therefore, as shown in FIG. 6, even when the # 1 slave 20 is located on the master unit 11 side, the processing time in the station based on the performance unique to the communication IC of the # 1 slave 20 is very long. If the processing time in the station of the slave # 2 is long and conversely very short, the measured values t1 and t2 obtained by adding the time required for frame transmission to the processing time in each station may be t1> t2. possible.

  However, in this embodiment, the measurement tool device 60 is provided in addition to the master unit 11, and the measurement value in the master unit 11 and the measurement value in the measurement tool device 60 are obtained for one determination target station. As is clear from the determination formula, the difference between the two measured values (t1 and s1, t2 and s2) obtained for the same target station is taken, so that the processing within the station determined based on the performance unique to the communication IC The time is offset, and as a result, the value of y obtained from the determination formula is not affected by the processing time in the station, and is determined by the time based on the frame transmission. That is, when attention is paid to the measurement values t1 and s1 for the first determination target station, “t1−s1” is calculated in the determination equation y, and the measurement values t2 and s2 for the second determination target station are calculated. When attention is paid, in the determination formula y, “−t2 − (− s2)” is calculated, and the processing time in the station included in each measurement value is reduced to 0.

In the present embodiment, there is practically no difference in only one time. Therefore, for example, a total time of 100 times is measured and set as the above-described measured values t1, t2, s1, and s2. Furthermore, the following measured value is obtained by repeating the measurement a plurality of times (N times).

Then, an average process is performed on the N measurement values obtained as described above, and the positional relationship between the respective determination target stations is specified in a state where the measurement error component is eliminated according to the following determination condition formula.

The above positional relationship determination processing is performed for all combinations in any two node stations among slaves and repeaters that join the network. That is, the node stations having the node address i and the node address j are selected as the determination target stations, and the above-described measurement values t1, t2, s1, and s2 are measured for the determination target stations of the selected combination. Then, the obtained measurement values (actually, a total time of a plurality of times is measured and the measurement is repeated N times) according to the following sort algorithm determination formula, “1 / 0 ”is determined. This determination formula means that the node station of the node address i is closer to the master unit than the node station of the j.

  In this way, if 1/0 is obtained for all combinations of elements, a matrix is created as shown in FIG. 8, and the sum of each row is calculated. Note that this matrix shows a concept, and the evaluation value of each node address may be calculated using an evaluation formula for obtaining the evaluation value S described in the right column without actually creating the matrix. . Then, by sorting in descending order of the evaluation value Si, the node stations can be arranged in the order from the master unit 11, thereby identifying the positional relationship between the node stations (slave and repeater).

For example, as shown in FIG. 9, for example, when the slaves 20 of node addresses # 4, # 1, # 2, and # 3 are connected to the trunk network cable in order from the master unit 11, all combinations are performed. The measured value is obtained for 1 and 1/0 is determined for each element according to the judgment formula. Then, a matrix as shown in FIG. 10 is obtained, and when the sum of each row is calculated, as shown in FIG.
S1 = 2
S2 = 1
S3 = 0
S4 = 3
It becomes. Therefore, the slaves 20 can recognize that they are arranged in the order shown in FIG.

  FIG. 9 shows a simple network configuration in which each slave is connected to a trunk network cable. However, the positional relationship is similarly applied to a network configuration having a branch network cable as shown in FIG. Can be identified. That is, for example, in the case shown in FIG. 2, the master unit 11 recognizes that the two slaves 20 connected to the branch network cable 6 are under the repeater 30, so that the master unit 11 is connected to the end of the branch network cable 6. The connected measurement tool device 60 and the master unit 11 can specify the positional relationship by performing the same processing as described above with the two slaves as the determination target stations. In addition, the position of the repeater connected to the main line network cable can specify the positional relationship including other slaves connected to the main line network cable.

  Furthermore, it is preferable to install a measurement tool function on the repeater because errors due to the repeater process are eliminated and the positional relationship between branch destinations can be grasped more accurately.

  In the above description, two determination target stations are selected, the command-response time for each determination target station is measured, and any of the two determination target stations is closer to the master station based on the obtained measurement value. Although the positional relationship of (distant) is determined, a specific command-response time measurement may be performed for each combination of two determination target stations, or each slave or Measurement values (100 measurements + N measurements) are obtained for the repeater, and the obtained measurement values can be used when obtaining the positional relationship between the two determination target stations. .

  Next, specific functions (algorithms) of each device for performing the above positional relationship determination process will be described. The tool device 50 composed of a host PC has a function of executing the flowchart shown in FIG. In other words, the tool device 50 transmits a positional relationship measurement instruction message to the master unit (S1). Then, the tool device 50 receives the positional relationship data from the master unit (repeater as necessary) as a response to the message (S2). This positional relationship data is data relating to measurement values acquired by the above-described master units and measurement tool devices.

  Based on the acquired data, the tool device 50 obtains the positional relationship of node stations such as slaves and repeaters that join the network, creates a network configuration diagram that matches the actual arrangement based on the obtained positional relationship, and displays it. It is displayed on the device (S3). If the positional relationship data sent from the master is not a measurement value but a result of determining the positional relationship of each node station on the master side, the tool device 50 determines the actual location based on the positional relationship data. A network configuration diagram that matches the situation is created and displayed on the display device.

  The master unit 11 has a function of executing the flowchart shown in FIG. That is, when the master unit 11 receives a measurement instruction from the tool device 50, which is a host PC (S11), it sends a command for sequentially obtaining a positional relationship to each slave or repeater, and sends a response from the transmission. Time ti until reception is obtained and stored in the memory 11b (S12). Since the data for a plurality of times is actually acquired at this time t1 by transmitting a predetermined number of times to the same network address, the data for the plurality of times is stored.

  Next, the master unit 11 sends a measurement instruction message to the measurement tool device connected to the end of the network cable (S13). This measurement instruction message includes information such as a node address for specifying a node station to be measured. Upon receiving the measurement instruction message, the measurement tool device performs processing to be described later, obtains measurement values for each slave and repeater, and returns the measurement results as a response. Therefore, the master unit 11 receives the measurement result sent from the measurement tool device 60 (S14). The received measurement result is stored in the memory 11b.

  Next, the master unit 11 determines the presence or absence of a repeater (S15). This is because when the repeater joins the network, the information is transmitted to the master unit together with the node address, so that the master unit 11 can know the presence or absence of the repeater from the information. When the repeater is present (Yes in S15), the master unit 11 transmits a measurement instruction message to the repeater (S16). Then, the master unit 11 receives the measurement result sent from the repeater and stores it in the memory 11b (S17).

  Here, the measurement tool device / function is also implemented in the repeater, and the positional relationship of the slaves and the like subordinate to the repeater is the same as that of the repeater and the measurement tool device connected to the end of the branch network cable 6. This processing step is applied to those for specifying the positional relationship based on the measurement values measured in step (b), and this processing step can be omitted when the function of the measurement tool device is not implemented in the repeater.

  The master unit 11 obtains the positional relationship based on the measurement result obtained by itself and the measurement result obtained from the measurement tool device (including the repeater) (S18), and the tool device which is the host PC using the obtained result as a response. 50 (S19). In the calculation of the positional relationship in the processing step S18, the evaluation value Si for determining the final positional relationship of each slave or repeater is calculated based on each acquired measurement value, and information until the positional relationship can be specified is determined. Alternatively, the total sum of the measured values for a predetermined number of times may be obtained. Furthermore, the master unit 11 may simply store the measurement values measured or received by the measurement tool device and send the measurement values to the tool device 50 at a predetermined timing. . In that case, the processing step S18 may be omitted. That is, the processing steps of S15 to S17 and the processing step of S17 may not be provided in the flowchart in FIG.

  When the measurement tool device / function is mounted on the repeater 30, the repeater 30 has a function of executing the flowchart shown in FIG. That is, when the repeater 30 receives the measurement instruction from the master unit 11 (S41), the repeater 30 transmits a command for sequentially obtaining the positional relationship to each slave or repeater, and the time from the transmission to the reception of the response ti is obtained and stored in the memory 11b (S42). Since the data for a plurality of times is actually acquired at this time t1 by transmitting a predetermined number of times to the same network address, the data for the plurality of times is stored.

  Next, the repeater 30 sends a measurement instruction message to the measurement tool device connected to the end of the network cable (S13). This measurement instruction message includes information such as a node address for specifying a node station to be measured. Upon receiving the measurement instruction message, the measurement tool device executes processing described later to obtain measurement values for each slave or repeater that joins the network cable to be measured, and returns the measurement result as a response. Therefore, the repeater 30 receives the measurement result sent from the measurement tool device 60 (S44). The received measurement result is stored in the memory 30b.

  Next, the repeater 30 determines the presence or absence of another repeater (S45). This is because when the repeater joins the network, the information is transmitted to the master unit (upper repeater) together with the node address, so that the repeater 30 determines whether the repeater joins the lower network from the information. to decide. When there is a repeater (Yes in S45), the repeater 30 transmits a measurement instruction message to the repeater (S46). Then, the repeater 30 receives the measurement result sent from the repeater existing in the lower order that transmitted the message, and stores it in the memory 30b (S47).

  The repeater 30 obtains the positional relationship based on the measurement result obtained by itself and the measurement result obtained from the measurement tool device (including from other repeaters) (S48), and transmits the obtained result to the master unit 11 as a response. (S49). In the calculation of the positional relationship in this processing step S48, an evaluation value Si for determining the final positional relationship of each slave or repeater is calculated based on each acquired measurement value, and information until the positional relationship can be specified is determined. Alternatively, the total sum of measured values for a predetermined number of times may be obtained. Further, the repeater 30 may simply store the measurement values measured or received by the measurement tool device and send the measurement values to the master unit 11 at a predetermined timing. As in the case of the master unit 11, the processing steps S45 to S46 and the processing step S48 may not be provided in the flowchart in FIG.

  The measurement tool device 60 has a function of executing the flowchart shown in FIG. When the measurement tool device 60 receives a measurement instruction message from the master unit or repeater connected to the other end of the network cable to which the measurement tool device 60 is connected (S21), the node address of the measurement target included in the received message Based on the above, a command for sequentially obtaining the positional relationship is transmitted to each slave (including the repeater), and a time si from the transmission to the reception of the response is obtained and stored in the memory 60b (S22). And the measurement tool apparatus 60 transmits a measurement result as a response with respect to the master unit or repeater of the transmission origin of the message received by process step S21 (S23).

  The slave 20 (including the repeater 30) has a function of executing the flowchart shown in FIG. That is, when the slave receives a positional relationship measurement command from the master unit, repeater, or measurement tool device (S31), the slave executes a process of returning a response to the command transmission source (S32).

  When each device that joins the network has a function of executing the above-described flowcharts (implementing a measurement tool function in a repeater), for example, in a system having a network configuration as shown in FIG. Each positional relationship can be specified. First, the node addresses of the four slaves 20 joined to the trunk network cable 1 are assigned # 1 to # 4 as shown in the figure, and the node address of the repeater 30 joined to the trunk network cable 1 is # 5 is assigned. The repeater 30 has a measurement tool function M3. The master unit 11 also has a measurement tool function M1, and a measurement tool device 60 (M2, M4) is connected to the end of each network cable 1, 6 in place of the termination resistor. Further, three slaves 20 are joined to the branch network cable 6 below the repeater 30, and node addresses # 6 to # 8 are assigned as shown in the figure.

  In this case, the master unit 11 receiving the instruction from the tool device 50 transmits a command to the slaves (# 1 to # 4) and the repeater 30 (# 5) that join the trunk network cable 1 and receives a response. Measure the time to complete. The master unit 11 transmits a message to the measurement tool device (M2) and receives each measurement value # 1 to # 5 measured by the measurement tool device as a measurement result. Based on the measured values obtained by these M1 and M2, the positional relationship between the slaves # 1 to # 5 and the repeater can be specified. The positional relationship may be specified by the master unit or the tool device 50.

  Also, the master unit 11 knows that the # 5 node station is the repeater 30 and that the measurement tool function is installed (information transmitted from the repeater 30 when the repeater 30 joins the network). By). Furthermore, the master 11 also knows that the slave 20 having node addresses # 6 to # 8 has joined the branch network cable 6 below the repeater (when the slave 20 joins, the master 11 sends the slave 20). (Depending on the information) Therefore, the master unit 11 sends a measurement instruction message for checking the positional relationship of the slaves 20 having node addresses # 6 to # 8 connected to the lower level to the repeater. Then, the repeater 30 (M3) transmits a command to the slaves # 6 to # 8, measures the time until the response is received, and measures the slaves to the measurement tool device 60 (M4). Send a measurement instruction message. The measurement tool device 60 (M4) obtains measurement values for the slaves # 6 to # 8 according to the received message, and returns the measurement result to the repeater 30 (M3) as a response. Then, the positional relationship between the slaves # 6 to # 8 can be specified based on the measured values obtained by M3 and M4 of the repeater 30. The positional relationship may be specified by the repeater 30, the master unit 11, or the tool device 50.

  Then, the repeater 30 returns, as a response, the measurement values obtained by M3 and M4 (data of the positional relationship when the positional relationship is specified by the repeater) to the master unit. Therefore, the master unit returns information (measured value / calculated positional relationship) specifying the positional relationship of # 1 to # 8 to the tool device 50. Thus, the tool device 50 can create and display a network configuration diagram that matches the actual arrangement shown in FIG.

  In the above example, the master unit 11 once acquires the information for specifying the positional relationship such as the measurement values collected by the repeater and passes it to the tool device 50. A measurement instruction message may be transmitted, and the measurement result may be returned from the repeater 30 to the tool device as a response. That is, as described above, the master unit 11 knows that the repeater 30 has the measurement tool function and that three slaves (# 6 to # 8) are joined to the lower part of the repeater 30. Therefore, the master unit 11 notifies the information to the tool device 50. Based on the information acquired from the master unit 11, the tool device 50 transmits the measurement instruction messages of the slaves # 6 to # 8 to the repeater # 5. Based on this, the repeater can perform a predetermined measurement and return the measurement result to the tool device 50.

It is a figure which shows a prior art example. It is a figure which shows an example of a network system. It is a figure which shows the connection relation of PLC10 and the tool apparatus 50, and its internal structure. It is a figure which shows the internal structure of a slave and a repeater. It is a figure which shows the internal structure of a measurement tool apparatus. It is a figure explaining an action and an operation principle. It is a figure which shows an example of the data format of a command response. It is a figure explaining an action and an operation principle. It is a figure explaining an effect | action. It is a figure explaining an effect | action. It is a flowchart explaining the function of a tool apparatus. It is a flowchart explaining the function of a master unit. It is a flowchart explaining the function of a repeater (mounting a measurement tool apparatus). It is a flowchart explaining the function of a measurement tool apparatus. It is a flowchart explaining the function of a slave. It is a figure explaining an effect | action.

Explanation of symbols

10 Master 20 Slave 30 Network

Claims (5)

A positional relationship detection system for detecting a positional relationship of a plurality of node stations joining a bus-type field network,
A measuring device that is connected to both ends of the network cable and has a measurement tool function that measures a time from when a command is transmitted to each node station connected to the network cable until a response is received;
A positional relationship determination device that identifies the positional relationship of each node station based on the measurement value measured by the measurement tool function,
The positional relationship determination apparatus selects any two node stations from among the plurality of node stations as a first determination target station and a second determination target station, and selects both of the selected two node stations with respect to the selected two node stations. By identifying the relative positional relationship connected to the network cable of the two node stations from the measured values respectively obtained by the measuring device, and performing the process for obtaining the relative positional relationship for all combinations selected as determination targets , With the ability to identify the positional relationship of multiple node stations,
The processing for obtaining the relative positional relationship between the two node stations is obtained by using Δt as the difference between the measured value for the first determination target station obtained by one measurement device and the measurement value for the second determination target station, and by the other measurement device. When the difference between the measured value for the first determination target station and the measured value for the second determination target station is Δs, Δt and Δs are subtracted from one to the other, and the result of the processing is determined by the positive / negative A node station positional relationship detection system that is characterized. The field network is a master-slave field network,
One of the measuring devices is constituted by a master, and the other one of the measuring devices is attached to the installation position of the terminal device,
2. The node according to claim 1, wherein the other one measurement device obtains a measurement value for a designated node station in accordance with a message transmitted from the master, and returns a measurement result to the master. Station position detection system. The field network employs a configuration in which a repeater is joined, and a plurality of node stations are connected to a branch network cable connected to the lower side of the repeater.
The connection relationship between a plurality of node stations connected to the branch network cable is obtained based on measured values obtained by the master and a measuring device connected to an end of the branch network. The node station positional relationship detection system according to 1 or 2. The field network employs a configuration in which a repeater is joined, and a plurality of node stations are connected to a branch network cable connected to the lower side of the repeater.
The connection relationship of a plurality of node stations connected to the branch network cable should be determined based on the measured values obtained by the repeater and the measuring device connected to the end of the network cable connected to the lower level. The node station positional relationship detection system according to claim 1 or 2, characterized in that:   5. The node according to claim 1, wherein the measured value is a total of times acquired by executing command transmission and response reception processing a predetermined number of times and obtaining each time. 6. Station position detection system.

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