JP5576913B2 - Communication system having automatic setting function of identification number - Google Patents

Description

  The present invention relates to a communication system having a function of automatically setting an identification field number in each of a plurality of communication units constituting a network.

  In a communication system in which a plurality of communication units are connected on the same communication line, it may be required to set an individual identification number (ID) for each communication unit. In such a communication system, a plurality of types of communication units may be connected, or a plurality of the same type of communication units may be connected.

  For example, in Patent Document 1, in a LAN system that manages the entire system by exchanging management information between LAN devices, a management data line is provided separately from the network data line, and this management data line is used. It is described that a signal for assigning an ID is transmitted from the master LAN device to the slave LAN device. Here, a data for ID assignment is transmitted from the master LAN device to the slave LAN device using a management-dedicated data line. When the slave LAN device is in an ID unassigned state, the management data connected to the lower slave LAN device Since signals are not allowed to flow through the line, IDs are assigned to slave LAN devices in the order closest to the master LAN device.

Japanese Patent Laid-Open No. 08-037538

  In the conventional communication system, the user often sets the ID manually for each communication unit using a switch or the like, but it is complicated to set all the IDs so that the IDs do not overlap. Furthermore, providing such a switch in a device that is waterproof or dustproof requires a mechanism for keeping the switch portion waterproof and dustproof, which increases costs.

  In addition, in a system using the RS-485 communication method, which is one of serial communication standards, an automatic ID assignment method can be applied. In this method, when a slave device requests an ID, the master device issues the ID. Then, the ID is automatically assigned to the slave device. When there is an ID request from a plurality of slave devices, the master device can adjust the retransmission signal using a random number or the like and automatically assign an individual ID to each slave device. In Ethernet (registered trademark), a unique ID called a MAC address is written in a ROM of a communication unit at the time of factory shipment, and communication is performed based on the ID. However, these methods have a drawback that the position of the communication unit connected on the same communication line cannot be associated with the ID.

  In the method described in Patent Document 1, IDs are sequentially determined for communication units arranged in series from upstream (in order of proximity to the master). In this method, it is possible to associate an ID with the position of a communication unit connected in series, but each communication unit requires a software process for setting the ID and a circuit for realizing the process. . Further, since the communication unit relays the communication signal, it is necessary to interrupt communication between the upstream and the downstream when the communication unit is exchanged while the system is operating.

  Therefore, the present invention provides an automatic setting function that can solve the above-described problems and can automatically set an identification number (ID) in a communication unit when a plurality of communication units are connected on the same communication line. An object of the present invention is to provide a communication system.

  In order to achieve the above object, a first invention of the present application is a communication system having an identification number automatic setting function for automatically setting an individual identification number for each of a plurality of communication units connected on the same communication line. The communication system includes a short-circuit connector, a plurality of branch units connected in series to the short-circuit connector, and a plurality of communication units respectively connected to the branch unit. A bit string output function for outputting an initial value of a bit string serving as a basis for setting an individual identification number in a communication unit, and each of the branch units includes a first connector for connecting to a corresponding communication unit; A second connector for connecting to the short-circuit connector or the upstream branch unit; a third connector for connecting to the downstream branch unit; A wiring structure in which a part of a bit string input from a second connector is output from the first connector as an identification number setting signal, and the bit string is replaced and output from the third connector, and the communication The unit provides a communication system having a setting function for setting the identification number setting signal output from the first connector of the corresponding branch unit as its own identification number.

  A second invention provides a communication system according to the first invention, wherein the wiring structures in each of the plurality of branch units are the same.

  According to a third invention, in the first or second invention, the number of bit strings is the same as the maximum number of communication units connectable to the communication system, and the wiring structure is the highest in a certain branch unit. A bit structure becomes the least significant bit in one downstream branch unit and each of the other bits moves up to one higher bit, or the lowest bit in one branch unit is one downstream bit Provided is a communication system having a wiring structure in which the branch unit becomes the most significant bit and each of the other bits descends to the next lower bit.

  A fourth invention provides a communication system according to any one of the first to third inventions, wherein the short-circuit connector is a master unit and the communication unit is a slave unit.

  According to the present invention, each communication unit is provided with a branch unit for branching a communication signal, an ID setting signal is output in the branch unit, and the downstream branch unit is a bit string of the ID setting signal. It is possible to automatically set a unique identification number for each communication unit by providing a wiring structure that replaces and connecting them. Since the identification numbers to be set are determined in the order of connection of the branch units, the relationship between the identification number and the position is easy to grasp.

  By using the same wiring structure for each branch unit, the same type of equipment can be used for the cables and communication units between the branch units, and replacement is easy when the unit fails or the cable is disconnected. It becomes. Further, even if a certain communication unit is removed or replaced while the communication system is operating, communication between other communication units is not affected.

  By using the short-circuit connector as the master unit and the communication unit as the slave unit, each slave unit can be simply configured to return a response to the request signal from the master unit. In comparison, a communication system can be constructed at low cost.

It is a figure which shows the basic composition of the communication system which concerns on the 1st Embodiment of this invention. It is a figure which shows the basic composition of the communication system which concerns on the 2nd Embodiment of this invention. It is a figure explaining the setting procedure of the identification number in case the number of communication units is four. It is a figure explaining the setting procedure of the identification number in case the number of communication units is eight.

  FIG. 1 is a diagram showing a basic configuration of a communication system 10 according to the first embodiment of the present invention. The communication system 10 includes a short-circuit connector 12, a plurality (four in this case) of branch units 16a to 16d connected in series to the short-circuit connector 12 by the same communication line 14 (shown as a double line), and a branch unit 16a. To a plurality of communication units 18a to 18d (the same number as the branch units) respectively connected to. The branch units 16a to 16d have first connectors 20a to 20d, respectively, and the branch units 16a to 16d and the communication units 18a to 18d are connected via the first connectors 20a to 20d, respectively.

  The branch unit 16a located immediately downstream of the short-circuit connector 12 includes a second connector 22a and a third connector 24a, and the branch unit 16a and the short-circuit connector 12 are connected via the second connector 22a. The branch unit 16a and the branch unit 16b located immediately downstream of the branch unit 16a are connected via the third connector 24a. Further, the branch unit 16b located immediately downstream of the branch unit 16a has a second connector 22b and a third connector 24b, and the branch unit 16b and the branch unit 16a are connected via the second connector 22b. The branch unit 16b and the branch unit 16c located immediately downstream of the branch unit 16b are connected via the third connector 24b. As described above, each branch unit includes the second connector for connecting to the upstream branch unit or the short-circuit connector, and the third connector for connecting to the downstream branch unit. The most downstream branch unit (here, the branch unit 16d) may not include the third connector 24d.

  The maximum connection number of communication units in the communication system is determined in advance, and the bit string that is the basis for setting a unique identification number (hereinafter also referred to as ID) for each communication unit is equal to the maximum connection number of the communication units. It is comprised so that it may become. For the number N of signal lines connected to each communication unit for transmitting an identification number setting signal (ID setting signal), the identification number can represent a number of 2 N at the maximum. It is set to be equal to or greater than the maximum number of units connected. For example, in the first embodiment, the maximum number of communication units is 4, and the bit string that is the basis for setting a unique identification number for each communication unit is 4 bits, and is connected to the branch unit of each communication unit. The number of signal lines for the ID setting signal to be set is two.

  As a method of exchanging the bit string that is the basis for setting individual IDs in the communication unit, for example, the most significant bit in a certain branch unit becomes the least significant bit in the next (one downstream side) branch unit. In addition, a wiring structure in which each of the other bits is advanced to the next higher bit, or the lowest bit in one branch unit becomes the highest bit in the next (one downstream) branch unit and the other bits. There is a method using a wiring structure in which each of these is carried down to the next lower bit. However, the selection method for selecting the ID setting signal to the branch unit from the bit string that is the basis for setting individual IDs is not particularly limited as long as bits at fixed positions are always selected.

  A bit string for generating an individual ID setting signal is output from the short-circuit connector 12. Specifically, in the short-circuit connector 12 shown in FIG. 1, 4-bit bit strings ID0 to ID3 are set, and 0V is input to ID0 and ID3. On the other hand, ID1 and ID2 have no voltage or an external voltage other than 0V is applied. Signal lines 26, 28, 30 and 32 are associated with ID0 to ID3, respectively, and these signal lines are wired to the first branch unit 16a through the second connector 22a. In the branch unit 16a, signal lines 26 and 32 (shown by bold lines) corresponding to two predetermined bits (ID0 and ID3 here) of the input bit strings ID0 to ID3 are connected to the first connector 20a. To the communication unit 18a.

  Each communication unit has an ID setting function that outputs “0” when a voltage of 0V is input, and outputs “1” when there is no voltage input or when there is an input other than 0V. A circuit or the like is provided, and an identification number of each communication unit is determined. Therefore, in the case of FIG. 1, the identification number “00” is set in the first communication unit 18a.

  The external input signal in each communication unit may be set by applying an external voltage instead of 0 V, or may be set using a power supply voltage included in the communication signal. In either case, wiring is performed so that a predetermined voltage corresponding to the initial value of the bit string that is the basis for setting individual IDs is input to the short-circuit connector 12 connected to the uppermost stream of the branch cable.

  Next, the signal lines 26, 28, 30 and 32 are connected to the second connector 22b of the second branch unit 16b. Before that, the signal lines are replaced. In the example of FIG. Before the third connector 24a is reached or in the third connector 24a, the rearmost signal line 32 is moved to the frontmost part, and the other signal line is lowered by one. By performing such replacement, the branch unit 16b has the same configuration as that of the branch unit 16a, but the communication unit 18b has signal lines 32 and 30 corresponding to bits ID3 and ID2 among ID0 to ID3. Are connected via the first connector 20b. Accordingly, in the case of FIG. 1, the identification number “10” is set in the second communication unit 18b.

  Thereafter, by repeating the same processing, the identification number “11” is set for the third communication unit 18c, and the identification number “01” is set for the fourth communication unit 18d. In this way, each communication unit can obtain a unique identification number while having the same configuration with respect to the wiring structure of the signal lines. Also, by using the same wiring structure for each branch unit, the same type of signal line, cable between the branch units, and communication unit can be used, reducing costs and facilitating parts management. Can be planned. Furthermore, even if a communication unit is removed or replaced while the communication system is operating in the event of a unit failure or cable disconnection, communication between other communication units is not affected.

  The communication method between the units is not particularly limited, but the RS-485 communication method capable of bidirectional communication corresponding to multipoint connection is preferable. Depending on the standard of the communication signal, a termination resistor may be required. In this case, termination is performed by connecting a short-circuit connector having a termination resistor to a branch cable corresponding to the end point.

  Here, in the first embodiment, the first communication unit 16a counted from the upstream side is a programmable controller, the second communication unit 16b is a digital I / O input / output device, and the third unit. The operation of the communication system will be described assuming that the communication unit 16c is a robot control device and the fourth communication unit 16d is a display.

  As described above, the programmable controller 16a has ID “00”, the digital I / O input / output device 16b has ID “10”, the robot controller 16c has ID “11”, and the display 16d has ID “01”. Is assigned. The programmable controller 16a, the robot controller 16c, and the display 16d operate as a master device, and the digital I / O input / output device 16b operates as a slave device.

  The master device uses the CSMA / CD used in Ethernet (registered trademark) and other arbitration functions to obtain the bus right for the communication path, and then transmits the “transmission destination identification number, transmission source identification number, command, A packet composed of “data size, data, CRC” and the like is transmitted to another device. The communication unit corresponding to the identification number of the transmission destination sends a reply corresponding to the command of the packet. On the other hand, the slave device does not obtain the bus right by itself and only sends a reply to the packet from the master device.

  For example, by sequentially acquiring and releasing the bus right, the programmable controller 16a controls the digital I / O input / output device 16b, and the robot control device 16c receives data from the programmable controller 16a and performs a desired operation. In addition, the display 16d can obtain information on each communication unit and display information desired by the operator on the display 16d.

  FIG. 2 is a diagram showing a basic configuration of a communication system 110 according to the second embodiment of the present invention. The communication system 110 is different from the communication system 10 according to the first embodiment in that it has one master unit 112 as a device having a function of a short-circuit connector, and any of the units 118a to 118d corresponding to the communication units 18a to 18d. Is also a slave unit. Since other components may be the same as those in the first embodiment, the components having the same functions as those in the first embodiment in FIG.

  As described above, the communication system 110 according to the second embodiment includes one master unit 112 and a plurality of branch units 116a to 116d. As an example, the master unit 112 is a robot control device, and the slave units 118a to 118d connected to each branch unit are a plurality of digital I / O input / output devices. Here, ID “00” is input to the first digital I / O input / output device 118a from the upstream side, and ID “10” is input to the second digital I / O input / output device 118b. ID “11” is assigned to the digital I / O input / output device 118c, and ID “01” is assigned to the fourth digital I / O input / output device 118d.

  In the communication system 110, the robot controller 112 transmits a packet to the first digital I / O input / output device 118a, and the first digital I / O input / output device 118a responds to the packet. Similarly, communication with each digital I / O input / output device is performed, and communication with all the digital I / O input / output devices ends. The robot controller 112 can perform an operation of repeating this periodically.

  In the communication system 110, since only the master unit receives data from the slave unit, the information of “transmission source identification number” is not necessary in the packet. Therefore, in the second embodiment, it is not necessary to set an identification number for the master unit. Further, each slave unit can be configured simply by returning a response to the request signal from the master unit, so that a communication system can be constructed at a lower cost than when a plurality of master units exist.

  Although two embodiments have been described above, it is necessary to set an appropriate value as an initial value for an initial value of a bit string that is a base when setting an individual ID in each embodiment. Hereinafter, a method for constructing a bit string for generating an ID setting signal in the present invention will be described. In short, each time the ID setting signal passes through the communication unit, the value changes like a so-called shift register.

(1) All initial values of the ID setting signal are set to zero (ALL0).
For example, when the maximum number of communication units is 4, since the minimum N satisfying 2 ^N ≧ 4 is 2, a 2-bit string “00” is generated as an initial value. The initial value corresponds to the identification number of the first communication unit. Similarly, when the maximum number of communication units is 8, 16, or 32, a 3-bit string “000”, “0000”, or “00000” is generated as an initial value.

(2) If the least significant bit of the next stage is set to 1 with respect to the initial value obtained in (1), if the bit string is a bit string not yet set as an upstream ID setting signal, Is determined as the ID setting signal of the next stage.
When the maximum number of communication units is 4, when the third bit string following “00” is “1”, the next two bit strings are “01”. Since this is different from the above-mentioned “00”, the third bit string is determined to be “1”. Subsequently, when the fourth bit string following “001” is “1”, the next 2-bit string is “11”. Since this is also different from the previously described “00” and “01”, the fourth bit string is determined to be “1”. The second and third bit strings “01” and “11” obtained in this way are the identification numbers of the second and third communication units, respectively.

(3) On the other hand, if the bit string is a bit string that has already been set as an upstream ID setting signal, the value of the least significant bit is set to 0 and it is determined as the ID setting signal of the next stage.
For example, in (2) above, if the fifth bit string following “0011” is “1”, the next (fourth) 2 bit string is “11”. Since this overlaps with the third “11”, the fifth bit string is determined to be “0” instead of “1”. As a result, the fourth bit string is “10”, which is the identification number of the fourth communication unit.

(4) By repeating the processes (2) to (3), an ID setting signal generation bit string corresponding to the maximum number of communication units is obtained.
According to the above processing, the ID setting signal generation bit string when the maximum number of communication units is 4 is “00110”, but as described with reference to FIG. 1, the most significant bit is the least significant bit in the next stage. Since the wiring for forming the bit is possible, the generated bit string can be “0011”.

  In addition, the above processes (1) to (4) have been described in the case where the first code is set to “0” and the second code is set to “1”. However, both codes can be replaced. is there. That is, when the initial values of the ID setting signal are all 1 (ALL1) in (1) and the least significant bit of the next stage is 0 in (2), the bit string is still set as the upstream ID setting signal. If it is not a bit string, it is determined as the ID setting signal of the next stage. On the other hand, if the bit string is a bit string already set as the upstream ID setting signal in (3), the least significant bit of It is also possible to set the value to 1, determine it as the next stage ID setting signal, and repeat (2) and (3).

  Table 1 shows the results of obtaining the generated bit strings when the maximum number of communication units is 4, 8, 16, or 32 using the above processing. The underlined part (ALL0) attached to the generated bit string represents the initial value of the ID setting signal. In either case, the number of bit strings is equal to the maximum number of communication units.

  Table 1 also shows a case where the maximum number of communication units does not correspond to 2 to the Nth power (where N is a natural number) (for example, six or seven). In such a case, the generated bit string may be obtained by applying the above (1) to (4), or the operator can obtain the bit string by trial and error.

  3 and 4 are diagrams for explaining processing for determining the ID of each communication unit using the generated bit string shown in Table 1. FIG. First, when the maximum number of communication units is 4 (FIG. 3), a 2-bit initial value “00” (inside the frame) is set as the ID of the first communication unit. Next, as the ID of the second communication unit, the first two bits of the bit string obtained by moving the first bit in the generated bit string “0011” to the end of the bit string and moving the other bit up by one, that is, “01” is set. Thereafter, by repeating the same processing, “11” and “10” are set as the IDs of the third and fourth communication units, respectively. There is no overlap in these IDs.

  When the maximum number of communication units is 8 (FIG. 4), a 3-bit initial value “000” (inside the frame) is set as the ID of the first communication unit. Next, as the ID of the second communication unit, in the generated bit string “00011101”, the first bit is moved to the tail of the bit string and the other three bits are moved up one bit, that is, the first three bits of the bit string obtained by “001” is set. Thereafter, by repeating the same processing, “011”, “111”, “110”, “101”, “010”, and “100” are set as the IDs of the third to eighth communication units, respectively. Is done. There is no overlap in these IDs.

10, 110 Communication system 12, 112 Short-circuit connector 14, 114 Communication line 16a-16d, 116a-116d Branch unit 18a-18d, 118a-118d Communication unit 20a-20d, 120a-120d First connector 22a-22d, 122a-122d Second connector 24a to 24d, 124a to 124d Third connector 26, 28, 30, 32, 126, 128, 130, 132 Signal line

Claims (3)

A communication system having an identification number automatic setting function for automatically setting an individual identification number for each of a plurality of communication units connected on the same communication line,
The communication system includes a short-circuit connector, a plurality of branch units connected in series to the short-circuit connector, and a plurality of communication units respectively connected to the branch unit;
The short connector, said to set the unique identification number to the plurality of communication units, it has a bit sequence output function for outputting the initial value of the predetermined bit sequence based on the wiring structure of the branch unit, the column of the bit string The number is the same as the maximum number of communication units connectable to the communication system,
Each of the branch units is connected to a first connector for connecting to a corresponding communication unit, a second connector for connecting to the short-circuit connector or the upstream branch unit, and a downstream branch unit. Of the third connector and the bit string input from the second connector and having the maximum number of communication units connectable to the communication system as the column number, 2 to the Nth power is equal to or greater than the maximum number A wiring structure in which a bit string having the smallest natural number N as the number of columns is output from the first connector as an identification number setting signal, and a bit string having the maximum number as the number of columns is replaced and output from the third connector. Have
The wiring structures in each of the plurality of branch units are the same as each other,
The communication unit has a setting function of setting the identification number setting signal output from the first connector of the corresponding branch unit as its own identification number.
Communications system. Before SL wiring structure, the most significant bit in the branch unit that is repeated up wiring structure to another, each bit of the one upper bits with becomes the least significant bit in the branch unit of one downstream, or it 2. The communication system according to claim 1 , wherein the communication system has a wiring structure in which the least significant bit in the branch unit is one most significant bit in the downstream branch unit and each of the other bits is carried down to the next lower bit. The communication system according to claim 1 or 2 , wherein the short-circuit connector is a master unit, and the communication unit is a slave unit.

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