TW201739304A - Industrial wireless communications system - Google Patents

Abstract

An industrial wireless communications system (10) includes a PLC (12) that performs at least monitoring within an industrial facility, at least one master wireless device (18) connected to the PLC (12) by a fieldbus (16), a plurality of slave wireless devices (22), which are installed corresponding to respective hardware devices (20), and carry out wireless communications with the master wireless device (18), a connection processing unit (30) that carries out a connection process wirelessly between the master wireless device (18) and the slave wireless devices (22), and a transmission/reception processing unit (36) that transmits and receives data wirelessly between the master wireless device (18) and the slave wireless devices (22).

Description

Industrial wireless communication system

The present invention relates to industrial wireless communication systems, and more particularly to industrial wireless communication systems capable of implementing wireless communication in a stable manner in a Factory Automation (FA) environment.

So far, as in an industrial facility, a network system disclosed in Japanese Laid-Open Patent Publication No. 05-073795 is known. In this system, a plurality of programmers are connected to the network system by bus bars. The actuator and drive source of the robot are electrically connected to each of the individual programmers via a conductive member and a signal line. Furthermore, the drive source is separately connected to the actuator and the robot via an electrical line.

In addition, there has traditionally been a need to reduce the number of lines in industrial facilities. For example, as shown in Japanese Laid-Open Patent Publication No. 05-073795, the upper host controller and the individual control devices are connected by a field bus according to industrial communication standards. In each of the control devices, a connection is required between the power supply line and the communication line. Therefore, in large facilities or distributed installations, you must connect from this The signal line of the host controller, so the degree of freedom in the installation of the control device is limited.

Furthermore, in order to make the industrial facility intelligent, the facility has also become necessary to lay communication lines to connect with robots or movable workpieces such as rotating mechanisms. In this example, an expensive slip ring must be used, otherwise there is a risk that the signal line will be disconnected, and there is no alternative to abandoning the installation of such a communication device and giving up the intelligence of the industrial facility itself.

The present invention has been designed to address the above problems and has the object of providing an industrial wireless communication system in which the risk of disconnection or the like of a signal line associated with a movable workpiece of various hardware devices installed in an industrial facility is employed. It can be reduced, and the industrial wireless communication system can improve the degree of freedom in such industrial facilities.

[1] An industrial wireless communication system according to the present invention is characterized in that a computer configured to perform at least monitoring in an industrial facility, at least one primary wireless device connected to the computer via a field bus, is installed to correspond to an individual hard And a plurality of slave wireless devices configured to perform wireless communication with the primary wireless device, and a connection processing unit configured to wirelessly perform a connection procedure between the primary wireless wireless device and the secondary wireless device, And a transmission/reception processing unit configured to wirelessly transmit and receive data between the primary wireless wireless device and the secondary wireless device.

In the present invention, the connection processing and signal transmission and reception are connected to a computer (for example, a programmable logic controller or the like). The primary wireless device is wirelessly implemented between slave wireless devices installed in various hardware devices, such as robots, welding torches, rotating clamps, motors, and the like. Therefore, the risk of disconnection of the signal line and the like in the movable assembly of the hardware device can be reduced, and the degree of freedom in design in an industrial facility can be improved. This approach has also led to an increase in intelligent systems in such industrial facilities.

[2] In the present invention, the connection processing unit may perform wireless communication from the primary wireless device to the plurality of dependent wireless devices via the broadcast system and at a synchronous frequency in a time interval of 500 milliseconds or less, and the transmission/ The receiving processing unit can perform wireless communication between the primary wireless device and the secondary wireless device by a frequency hopping method.

According to this feature, from the fact that the connection procedure is performed via the broadcast system and in a time interval of less than 500 milliseconds (for example, at the time of assembling the assembly jig), it is possible to shorten the time from the start of the power supply to the start of communication with it. . Moreover, from the fact that wireless communication is performed by the frequency hopping method between the primary wireless device and the secondary wireless device, it is possible to avoid interference with other wireless communication.

[3] In the present invention, the 2.4 GHz band is preferably used as the radio frequency, and the wireless power is preferably less than or equal to 1 mW.

Since the radio frequency is the frequency of noise generated by a noise source (such as a power cord, a robot, a welding gun, a rotating jig, a motor, etc.) higher than that of an industrialized plant of a factory or the like, it is possible to reduce the noise frequency by The impact of wireless communication. Furthermore, since the wireless power is suppressed to be less than or equal to 1 mW, it is possible to reduce the bit position Interference from other communication devices in the same area.

[4] In the present invention, the complex may include a connection maintenance processing unit configured to connect to the primary wireless device by periodically transmitting clock information of the primary wireless device relative to the slave wireless device Maintenance procedures.

According to this feature, since the clock information from the primary wireless device is periodically transmitted to the slave wireless device for which the connection procedure has been completed, the clock information is in the slave wireless device and the primary wireless device. Simultaneously occur. Therefore, the timing of data transmission and reception or the like can be easily synchronized.

[5] In the present invention, the complex may have a connection confirmation processing unit configured to confirm the primary wireless device by repeating periodic transmissions from the secondary wireless device and periodic reception by the primary wireless device And establishing wireless communication between the plurality of slave wireless devices.

Due to this feature, it is possible to easily decide which of the slave wireless devices are in the connected state, and those slave wireless devices are in the disconnected state and are dependent on the slave wireless determined to be in the disconnected state. Connection processing or maintenance of the device, etc., can be performed at an earlier stage.

According to the industrial wireless communication system of the present invention, it is possible to reduce the risk of disconnection of a signal line or the like of a movable workpiece mounted to various hardware devices in an industrial facility, and in such an industrial facility The freedom of design in the design can be increased.

The above and other objects, features and advantages of the present invention are The following description will become more apparent in conjunction with the appended drawings, in which the preferred embodiments of the invention

10‧‧‧Wireless communication system

12‧‧‧Programmable Logic Controller

14‧‧‧Network

16‧‧‧ on-site bus

18‧‧‧Main wireless devices

20‧‧‧ hardware devices

22‧‧‧Subordinate wireless devices

30‧‧‧Connection processing unit

32‧‧‧Connection Maintenance Unit

34‧‧‧Connection confirmation processing unit

36‧‧‧Send/receive processing unit

40‧‧‧Workpiece

42‧‧‧Rotary production facilities

44‧‧‧Rotating platform

46‧‧‧Manipulator

48‧‧‧Assembled fixture

50‧‧‧Supply unit

1 is a configuration diagram showing an industrial wireless communication system according to an embodiment of the present invention; FIG. 2 is a functional block diagram showing the industrial wireless communication system; and FIG. 3 is an operation conceptual diagram showing an example of a connection procedure. Figure 4A is an explanatory diagram showing the multiplex of the radio frequency in the 2.4 GHz band; Fig. 4B is an explanatory diagram showing the difference in the transmission frequency between the networks; and Fig. 4C is a timing showing an example of the frequency hopping; Figure 5 is a diagram showing an example of synchronous frequency allocation for each network; Figure 6 is a diagram showing the relationship between the number of frequency hopping frequencies and the frequency hopping transmission frequency; Figure 7 is a diagram An operational concept diagram of an example of a connection maintenance procedure; FIG. 8 is an operational concept diagram showing an example of a connection confirmation procedure; and FIG. 9 is a conceptual diagram showing an operation of a transmission procedure from a primary wireless device to a slave wireless device; The figure shows an operational concept diagram of a transmission procedure from a slave wireless device to a primary wireless device; Figure 11 is a timing diagram showing changes in transmission frequency with respect to time, in which case the packets are sequentially transmitted from the primary wireless device to the two slave wireless devices; Figure 12 is a display in accordance with an embodiment of the present invention. A configuration diagram of one of the exemplary embodiments of the industrial wireless communication system; and FIG. 13 is an explanatory diagram showing an example of transmitting and receiving data packets by the transmission/reception processing unit.

Hereinafter, an embodiment of an industrial wireless communication system according to the present invention will be described with reference to Figs. In the specification of the present invention, the symbol "-" (to or through) indicating a numerical value diagram is used to mean that the numerical value of the number written before and after the tilde symbol is included in the numerical value as The lower and upper limits of this numerical range.

As shown in FIG. 1, the industrial wireless communication system (hereinafter referred to as the wireless communication system 10) according to an embodiment of the present invention includes a programmable logic controller 12 (PLC, which performs at least monitoring in an industrial facility. A Programmable Logic Controller), and a plurality of networks 14 connected to the programmable logic controller 12.

In each of the networks 14, there is a primary network device 18 comprising a field bus 16 connected to the programmable logic controller 12, and a plurality of slave wireless devices 22, the slave wireless device 22 being installed It corresponds to an individual hardware device 20 and performs wireless communication with the primary wireless device 18. As an example of such a hardware device 20 in which the slave wireless device 22 is mounted, the distal end of the robot arm can be referenced A movable member (for example, a welding torch or the like), an assembly jig, a rotary table, and the like.

Furthermore, as shown in the functional block diagram of FIG. 2, the wireless communication system 10 includes a connection processing unit 30, a connection maintenance processing unit 32, a connection confirmation processing unit 34, and a transmission/reception processing unit. 36. Such a unit, that is, the connection processing unit 30, the connection maintenance processing unit 32, the connection confirmation processing unit 34, and the transmission/reception processing unit 36 are configured in the primary wireless device 18 and the A functional unit that cooperates between a plurality of slave wireless devices 22.

The connection processing unit 30 performs a wireless connection procedure between the primary wireless device 18 and the secondary wireless device 22.

In particular, as shown in FIG. 3, in a time interval of less than 500 milliseconds, and in accordance with the present embodiment, in the time interval of 250 milliseconds, by the primary wireless device 18 relative to the plurality of slave wireless devices 22 Wireless communication is via a broadcast system and at a synchronous frequency.

The purpose of such a connection procedure is for time adjustment between the primary wireless device 18 and the secondary wireless device 22, and for the exchange of the initial value of the primary wireless device 18 and the initial value of the secondary wireless device 22.

The communication steps in the example of normal operation, and the communication steps in the example of abnormal operation will be described below with reference to FIG.

<normal operation>

(a-1) The synchronization packet Pa in which the primary wireless device 18 includes the clock information, for example, is transmitted to all of the slave wireless devices 22 controlled by it via the broadcast system in an interval of 250 milliseconds. With such transmission, synchronous transmission is performed in accordance with the frequency hopping method.

(a-2) The slave wireless device 22 receives the synchronization packet Pa including the clock information and corrects the clock information of the slave wireless device 22.

(a-3) The slave wireless device 22 transmits the data packet Pb including the connection command and the initial value to the active wireless device 18. With such transmission, transmission is performed from the slave wireless device 22 to the primary wireless device 18 in accordance with a frequency hopping method.

(a-4) the primary wireless device 18 receives the data packet Pb from the slave wireless device 22, and then transmits an initial value including the primary wireless device 18 along with the data packet Pc of the connection command to the slave wireless device twenty two. With such transmission, transmission is performed from the primary wireless device 18 to the secondary wireless device 22 in accordance with a frequency hopping method.

(a-5) The slave wireless device 22 receives the data packet Pc from the primary wireless device 18 and completes the connection. In other words, the establishment of a connection with the primary wireless device 18 will end.

<Exception operation>

After receiving the synchronization packet Pa containing the clock information, each of the slave wireless devices 22 initiates a time-out measurement. For example, if the connection to the primary wireless device 18 is not completed within 4 seconds, then another Try to execute again from the receipt of this clock information.

This frequency hopping method (FHSS) will be briefly described with reference to Figures 4A through 6.

As shown in Fig. 4A, in the frequency hopping method, communication is performed when the multiplex frequency is changed one by one between the transmitter and the receiver.

In accordance with an embodiment of the present invention, as shown in Figures 4B and 4C, frequency hopping methods having different modes are employed for each of the networks. The first network 14A is used as a frequency for the frequency hopping method, for example, 2402 MHz, 2455 MHz, 2421 MHz.... The second network 14B is used as a frequency for the frequency hopping method, for example, 2412 MHz, 2465 MHz, 2405 MHz... The third network 14C is used as the frequency for the frequency hopping method, for example, 2432 MHz, 2445 MHz, 2471 MHz, .

Furthermore, as shown in Figure 4C, communication is performed in each network by means of individual transmission times (t ₀ , t ₀ +t, t ₀ +2t, t ₀ +3t, ...). This is done by jumping the transmission frequency. Furthermore, the interval Fa shows the bandwidth used by the wireless local area network.

In the foregoing method, by employing such a frequency hopping method, together with enabling radio wave interference between the network 14 and interference with the wireless local area network, it is possible to reduce power due to multipath fading. attenuation.

An example of a calculation method for calculating the synchronization frequency used by the frequency hopping method will be described below.

First, the frequency range to be used is converted to 1MHz channel. For example, assuming a minimum frequency of 2403 MHz and a maximum frequency of 2481 MHz, 79 channels from 0ch to 78ch can be obtained.

Assuming that the wireless communication (e.g., three times) of the broadcast from the primary wireless device 18 is considered as a loop, the channel spacing of the three radio communications in each of the loops is defined by JAMP, and The channel spacing between each cycle is defined by SPACE. Furthermore, the deviation of the channel range (maximum channel - (minimum channel - 1)) to be used is defined by CHm, the number of networks (continuous numbers from 0) is defined by Nn, and The number of radio communications within a loop is defined by Nc (=0, 1, 2).

Further, the number of channels SYNC_CH for each of the synchronization frequencies of the wireless communication is calculated by the following arithmetic expression. In the formula, the percentage symbol % represents a remainder operator.

SYNC_CH=Nn * SPACE+JAMP * Nc % CHm

The calculation result of the number of channels of the synchronization frequency is displayed in the following first table, and the result of the conversion of the number of channels of the synchronization frequency into the synchronization frequency is displayed in the following second table. Furthermore, the allocation of the synchronization frequency to the number of networks according to the second table is shown in FIG.

Table 1

As can be understood from the first table and the second table and the fifth figure, since the synchronization frequency is not covered between the networks 14, it is possible to synchronously transmit the synchronization frequency by the broadcasting system, the synchronization frequency is Individually assigned to each of the networks 14.

Next, an example of a calculation method for calculating a transmission frequency (referred to as an FH transmission frequency) by the frequency hopping method will be described.

Initially, similar to the calculation method for calculating the synchronization frequency described above, the frequency range to be used is converted to a channel in units of 1 MHz. For example, assuming that the minimum frequency is 2430 MHz and the maximum frequency is 2481 MHz, 79 channels from 0ch to 78ch can be obtained.

The frequency hopping interval is indicated by JAMP, and the deviation of the channel range (maximum channel - (minimum channel - 1)) to be used is indicated by CHm, the number of networks (continuous numbers from 0) It is defined by Nn, and the number of times the frequency hopping is performed is indicated by FHn.

Then, the number of channels FH_CH of each frequency hopping transmission frequency is calculated using the following arithmetic expression. In the formula, the percentage symbol % represents a remainder operator.

FH_CH=Nn+JAMP * FHn % CHm

In Fig. 6, the relationship between the number of times of the frequency hopping and the frequency of the hopping transmission is shown. As can be understood from Fig. 6, each frequency hopping is performed because the frequency of the frequency hopping transmission is changed in the frequency hopping interval Δf (e.g., 22 MHz), so interference with other wireless communication can be avoided.

Furthermore, the slave wireless device 22 preferably utilizes a Collision Preventing Function (CCA) to prevent interference between radio waves. In this example, the collision prevention function requires waiting time due to random numbers. According to an embodiment of the present invention, since the slave wireless device 22 has four transmission timings, the transmission time is based on the The slave address is determined using a random function.

Next, the connection maintenance processing unit 32 will be described. The connection maintenance processing unit 32 performs connection maintenance with the primary wireless device 18 by periodically transmitting clock information relative to the primary wireless device 18 of the slave wireless device 22, wherein the primary wireless device 18 is associated with the primary wireless device 18 The establishment of the connection has been completed.

In particular, in the time interval relative to the plurality of slave wireless devices 22 that have completed the establishment of the connection with the primary wireless device 18, and at a time interval shorter than the time interval of the wire processing unit 30 noted above. And, in accordance with an embodiment of the invention, wireless communication from the primary wireless device 18 relative to the secondary wireless device 22 is via a broadcast system and at a synchronous frequency, for example, in a time interval of 100 milliseconds.

The purpose of this connection maintenance procedure is to update the clock information of the slave wireless device 22 by transmitting clock information from the primary wireless device 18 to the slave wireless device 22.

The communication steps in this example of normal operation and the communication steps in this example of abnormal operation will be described below with reference to FIG.

<normal operation>

(b-1) The synchronization packet contained in the clock information is transmitted, for example, via a broadcast system in an interval of 100 milliseconds. With such transmission, synchronous transmission is performed in accordance with the frequency hopping method.

(b-2) The slave wireless device 22 receives the synchronization packet Pd including the clock information and corrects the clock information of the slave wireless device 22.

<Exception operation>

In the example where the slave wireless device 22 is unable to receive the synchronization packet Pd (burst information) from the primary wireless device 18, the correction of the clock information will be delayed, and the slave wireless device 22 attempts to receive again after 100 milliseconds. The clock information.

Next, the connection confirmation processing unit 34 will be described. The connection confirmation processing unit 34 confirms between the primary wireless device 18 and the secondary wireless device 22 by repeating periodic transmissions from the secondary wireless device 22 and periodic reception by the primary wireless device 18. The establishment of wireless communication.

Next, the communication step of the connection confirmation processing unit 34 will be described with reference to FIG.

First, the primary wireless device 18 recognizes the connection with the slave wireless device 22, for example, every 5 milliseconds. The slave wireless device 22, for example, transmits a signal to the primary wireless device 18 every 2 milliseconds. An example of this connection confirmation procedure is indicated below.

<Connection confirmation>

(c-1) The slave wireless device 22 performs reception from the primary wireless device 18 or transmits the acknowledgement of the data packet Pe with respect to the primary wireless device 18 every two milliseconds by the frequency hopping method.

(c-2) The primary wireless device 18 acknowledges the presence or absence of transmission and reception with the secondary wireless device 22 every 5 milliseconds and does not have In the example of transmission or reception, it is determined that the slave wireless device 22 is in the off state.

(c-3) In the primary wireless device 18, the data packet Pe is transmitted by the slave wireless device 22, the slave wireless device 22 once determined that it is in the off state, and the data packet Pe is by the In the example received by the primary wireless device 18, the primary wireless device 18 determines that the secondary wireless device 22 is in a connected state.

Next, description will be made regarding the connection transmission/reception processing unit 36.

The transmission/reception processing unit 36 performs transmission and reception of data between the primary wireless device 18 and the secondary wireless device 22.

In more detail, the transmission/reception processing unit 36 performs wireless communication between the primary wireless device 18 and the secondary wireless device 22 by a frequency hopping method. In particular, the transmission is performed by the primary wireless device 18 at the frequency hopping transmission frequency relative to the secondary wireless device 22, and the transmission is performed by the secondary wireless device 22 with respect to the primary wireless device 18 at a frequency hopping transmission frequency.

In the following, the communication steps relating to the transmission from the primary wireless device 18 to the secondary wireless device 22 and the transmission from the secondary wireless device 22 to the primary wireless device 18 will be described with reference to Figures 9 and 10.

<Transmission from primary wireless device 18 to dependent wireless device 22>

(d-1) As shown in FIG. 9, the primary wireless device 18 transmits a data packet Pf containing operation command data at the frequency hopping transmission frequency. To the slave wireless device 22 having the address specified by the transmission request.

(d-2) The slave wireless device 22 receives the data packet Pf from the primary wireless device 18.

(d-3) In the event that the slave wireless device 22 normally receives the data packet Pf, the slave wireless device 22 determines the received power at the three-stage level.

(d-4) The slave wireless device 22 instructs the connected hardware device 20 to perform its own operation in accordance with the operation command data contained in the data packet Pf.

(d-5) at the stage in which the hardware device 20 has completed its instruction operation, the data packet Pg including at least information indicating the completion of such operation and the judgment information of the received power, at the frequency hopping transmission frequency It is passed back to the primary wireless device 18.

(d-6) The example in which the data packet Pf is transmitted by the primary wireless device 18 multiple times before the reply of the usage data packet Pg by the slave wireless device 22 to the primary wireless device 18 after the normal reception of the data packet Pf The slave wireless device 22 first ignores the data packet Pf a plurality of times, and then only returns the data packet Pg to the primary wireless device 18 once the hardware device has completed its predetermined operation.

(d-7) In the case of a transmission failure, for example, if the data packet Pg from a given slave wireless device 22 is not replied, the primary wireless device 18, for example, retry the interval at intervals of 5 milliseconds. Sent 250 times. If the number of retry attempts exceeds the upper limit (250 times), the primary wireless device 18 sets the status of the slave wireless device 22 (which is the transmission) The destination is broken.

<Send from slave wireless device 22 to primary wireless device 18>

(e-1) As shown in FIG. 10, the slave wireless device 22 transmits, at the frequency hopping transmission frequency, a data packet Ph having therein data required by the primary wireless device 18 in accordance with the transmission request, for example The measured value of the sensor connected to the slave wireless device 22, the number of retries, and the like.

(e-2) The primary wireless device 18 receives the data packet Ph from the slave wireless device 22.

(e-3) In the event that the primary wireless device 18 normally receives the data packet Ph, the primary wireless device 18 determines the level of the received power level in three stages.

(e-4) The primary wireless device 18 transmits back to the slave wireless device 22 the data packet Pi including at least the information indicating the normal reception and the determination information of the received power at the frequency hopping transmission frequency.

(e-5) An example in which the data packet Ph is transmitted multiple times by the slave wireless device 22 before the data packet Pi is replied from the primary wireless device 18 to the slave wireless device 22 after the normal reception of the data packet Ph The primary wireless device 18 first ignores the data packet Ph several times. Then, the primary wireless device 18 returns the data packet Pi to the slave wireless device 22 only once by the completion of the required receiving procedure of the primary wireless device 18.

(e-6) in the case of transmission failure, for example, if there is no reply from the The data packet Pi of the primary wireless device 18 then the associated slave wireless device 22, for example, re-attempts the transmission 250 times at intervals of 5 milliseconds. If the number of retries exceeds the upper limit (250 times), the primary wireless device 18 sets the state of the slave wireless device 22 (i.e., the destination) to be disconnected, and then transitions to the connection procedure.

An example in which the data packet Pf is sequentially transmitted from the primary wireless device 18 to the two slave wireless devices 22 will be described with reference to FIG.

First, at time t0, the primary wireless device 18 transmits the data packet Pf at the frequency hopping transmission frequency. The slave wireless device 22 as the transmission destination receives the data packet Pf from the primary wireless device 18 in a normal manner and performs its indication operation with respect to the hardware device connected to the slave wireless device 22, or otherwise , perform input/output operations to obtain sensor values or the like.

At time t1, which has elapsed 5 milliseconds from time t0, the slave wireless device 22 transmits a data packet Pg indicating that its operation has been completed at the frequency hopping transmission frequency. In this example, the wireless transmission (sending and receiving) ends in the fastest manner since there is not even a retry of the transmission. In particular, the fastest response time Tmin is defined by the time period from time ta to time tb, in which the transmission of the data packet Pf by the primary wireless device 18 has been completed, at time tb, The transmission of the data packet Pg by the slave wireless device 22 has been completed. In other networks, wireless communication is performed at different frequency hopping transmission frequencies, and therefore, no interference occurs due to the other network.

Next, at time t2, the primary wireless device 18 transmits the data packet Pf at the frequency hopping transmission frequency. At time t3, which has passed 5 milliseconds from time t2, the slave wireless device 22 transmits the data packet Pg at the frequency hopping transmission frequency indicating that its operation has been completed. At this time, the wireless frequency from the slave wireless device 22 is in the frequency band in which the frequency hopping transmission frequency is used, for example, in a frequency band used by the wireless local area network, and the wireless communication is performed by the wireless local area network. The communication collides with the wireless communication of the wireless local area network, so the transmission to the primary wireless device 18 cannot be completed. Therefore, at time t4 when 5 ms has elapsed since time t3, the primary wireless device 18 transmits the data packet Pf at the frequency hopping transmission frequency. In particular, the transmission of the data packet Pf of the same content is a retry. At time t5, which has passed 5 milliseconds from time t4, the slave wireless device 22 transmits a data packet Pg indicating that its operation has been completed at the frequency hopping transmission frequency. At this time, in other networks, wireless communication is performed at different frequency hopping transmission frequencies, and therefore, no interference occurs due to other networks. Furthermore, in this example, since there is a fact of retrying, the time period from time tc to time td is added as the response delay time period Td, and at time tc, the data packet of the primary wireless device 18 The transmission of Pf has been completed, and at time td, the first retry of the transmission of the data packet Pf has been completed.

Furthermore, it should be noted that the communication technology of Near Field Communication (NFC) is incorporated into the primary wireless device 18 and the slave wireless device 22 and the like. Thus, for example, regarding the internal parameters in the primary wireless device 18 and the secondary wireless device 22 Pairing (identification, etc.) between the primary wireless device 18 and the secondary wireless device 22 and pairing between the secondary wireless device 22 and the hardware device 20 (sensor, etc.) Identity confirmation, etc.) does not require mechanical settings or adjustments. Therefore, parameter setting, pairing, and the like can be easily performed, and it is possible to shorten the time required for the adjustment operation and reduce the number of program steps.

Next, one exemplary embodiment of the wireless communication system 10 will be described with reference to Figures 12 and 13.

As shown in Fig. 12, this exemplary embodiment is a wireless communication system suitable for use in a rotary production facility 42 in which the workpiece 40 is loaded and unloaded in four steps. In the rotary type production facility 42, there are provided a rotary table 44 installed at the center, and four robot arms or robots respectively corresponding to the first step to the fourth step (step 1 to step 4) 46 (46a to 46d) and four assembly jigs 48 (48a to 48d). Further, the power supplied from the power source and the supply air are supplied to the individual robot arm 46 and the assembly jig 48 through the supply unit 50, and the supply unit 50 is provided at the center of the rotary table 44.

Prior to assembly of the rotary production facility 42, individual slave wireless devices 22 are mounted to each of the robot hand 46 and the assembly fixture 48, respectively. In the example shown in Fig. 12, the first slave wireless device 22A is installed in the first robot hand 46a corresponding to the loading step (step 1), and the fifth slave wireless device 22E is mounted to the first Assembly fixture 48a. The second slave wireless device 22B is mounted in the second robot hand 46b corresponding to the first assembly step (step 2), and The sixth slave wireless device 22F is mounted in the second assembly jig 48b. The third slave wireless device 22C is mounted in the third robot hand 46c corresponding to the second assembly step (step 3), and the seventh slave wireless device 22G is mounted in the third assembly jig 48c. The fourth slave wireless device 22D is installed in the fourth robot hand 46d corresponding to the unloading step (step 4), and the eighth slave wireless device 22H is mounted in the fourth assembly jig 48d.

Furthermore, prior to assembly of the rotary production facility 42, the tag information corresponding to the product, and the number of mapped input/output points are set in each of the opposing slave wireless devices 22.

The primary wireless device 18 has the number of the first slave wireless device 22A to the eighth slave wireless device 22H pre-registered therein, the number being used in the rotary production facility 42 and enabling the slave wireless device 22 to Reconfiguration or combination in a different manner may be necessary as during maintenance of the slave wireless device 22. The setting content may be stored in the file as necessary, and if the slave wireless device 22 has been reconfigured, the setting content for the slave wireless device 22 may be replied by the stored file.

The storable setting content includes tag information, the number of input/output points, and other setting parameters.

Moreover, the primary wireless device 18 installed at a location external to the rotary production facility 42 receives signals from the programmable logic controller 12, the programmable logic controller 12 being incorporated, for example, into a power distribution panel, and Sending a signal at the frequency of the frequency hopping transmission to the installation The slave wireless device 22 within the production facility 42 is transformed.

Next, the present invention will be described with reference to Fig. 13 regarding steps 1 to 4.

<Step 1: Loading Step>

Based on the input of the insertion start signal from the programmable logic controller 12, the primary wireless device 18 transmits a data packet Pfa indicating the insertion of the workpiece 40 to the first slave wireless device 22A. Based on the data packet Pfa, the first slave wireless device 22A issues an instruction to the first robot hand 46a to capture the workpiece 40. In response to the command from the first slave wireless device 22A, the first robot hand 46a grips the workpiece 40 and internally transfers the workpiece 40 over the rotary platform 44. During the phase in which the transfer of the workpiece 40 by the first robot hand 46a has been completed, the first slave wireless device 22A transmits a data packet Pga indicating that the workpiece 40 has completed delivery to the primary wireless device 18.

Upon receipt of the data packet Pga from the first slave wireless device 22A, the primary wireless device 18 transmits a data packet Pfe indicating a positioning command to the fifth slave wireless device 22E. Upon receipt of the data packet Pfe, the fifth slave wireless device 22E issues an insertion time positioning command to the first assembly fixture 48a. The first assembly jig 48a performs the positioning of the workpiece 40 in accordance with the command from the fifth slave wireless device 22E. In a stage in which the workpiece 40 has been completed by the positioning of the first assembly jig 48a, the fifth slave wireless device 22E transmits a data packet Pge indicating that the positioning of the workpiece 40 has been completed to the primary wireless device 18. The main The wireless device 18 outputs an insertion completion signal to the programmable logic controller 12 in accordance with receipt of the data packet Pge from the fifth slave wireless device 22E.

<Step 2: First assembly step>

Based on the input of the first assembly signal from the programmable logic controller 12, the primary wireless device 18 transmits the data packet Pfb indicating the supply of the first component to the second slave wireless device 22B. Upon receipt of the data packet Pfb, the second slave wireless device 22B issues an instruction to the second robot hand 46b to supply the component. In response to the command from the second slave wireless device 22B, the second robot hand 46b supplies the member to the second assembly fixture 48b. In the stage in which the component is completed by the supply of the second robot hand 46b, the second slave wireless device 22B transmits a data packet Pgb indicating that the supply of the first component has been completed to the primary wireless device 18.

Upon receipt of the data packet Pgb by the second slave wireless device 22B, the primary wireless device 18 transmits a data packet Pff indicating the assembly command to the sixth slave wireless device 22F. Upon receipt of the data packet Pff, the sixth slave wireless device 22F issues an assembly command to the second assembly fixture 48b. The second assembly jig 48b performs a first assembly operation with respect to the workpiece 40 in accordance with the command from the sixth slave wireless device 22F. In the stage that the first assembly operation is completed for the workpiece 40 by the second assembly jig 48b, the sixth slave wireless device 22F sends a data packet Pgf indicating that the first assembly operation has been completed to the primary Line device 18. The primary wireless device 18 outputs a first assembly completion signal to the programmable logic controller 12 in response to receipt of the data packet Pgf from the sixth slave wireless device 22F.

<Step 3: Second assembly step>

Based on the input of the second assembly signal from the programmable logic controller 12, the primary wireless device 18 transmits the data packet Pfc indicating the supply of the second component to the third slave wireless device 22C. Upon receipt of the data packet Pfc, the third slave wireless device 22C issues an instruction to the third robot hand 46c to supply the component. The third robot hand 46c supplies the member to the third assembly jig 48c in accordance with the instruction from the third slave wireless device 22C. In the stage in which the component has been completed by the supply of the third robot 46c, the third slave wireless device 22C transmits a data packet Pgc indicating that the supply of the second component has been completed to the primary wireless device 18.

Upon receipt of the data packet Pgc by the third slave wireless device 22C, the primary wireless device 18 transmits a data packet Pfg indicating the assembly command to the seventh slave wireless device 22G. Upon receipt of the data packet Pfg, the seventh slave wireless device 22G issues an assembly command to the third assembly fixture 48c. The third assembly jig 48c performs a second assembly operation with respect to the workpiece 40 in accordance with the command from the seventh slave wireless device 22G. In the second assembly operation for the stage in which the workpiece 40 has been completed by the third assembly jig 48c, the seventh slave wireless device 22G transmits a data packet Pgg indicating that the second assembly operation has been completed to the main The wireless device 18 is required. The primary wireless device 18 outputs a second assembly completion signal to the programmable logic controller 12 in accordance with receipt of the data packet Pgg from the seventh slave wireless device 22G.

<Step 4: Uninstallation Step>

Based on the input from the transfer output start signal from the programmable logic controller 12, the primary wireless device 18 transmits a data packet Pfh indicating the positioning command to the eighth slave wireless device 22H. Upon receipt of the data packet Pfh, the eighth slave wireless device 22H issues a transfer output time positioning command to the fourth assembly fixture 48d. The fourth assembly jig 48d performs positioning of the workpiece 40 in accordance with an instruction from the eighth slave wireless device 22H. In a stage in which the workpiece 40 has been positioned by the fourth assembly jig 48d, the eighth slave wireless device 22H transmits a data packet Pgh indicating that the positioning of the workpiece 40 has been completed to the primary wireless device 18. Upon receipt of the data packet Pgh from the eighth slave wireless device 22H, the primary wireless device 18 transmits a data packet Pfd to instruct the fourth slave wireless device 22D to communicate the workpiece 40 output. Upon receipt of the data packet Pfd, the fourth slave wireless device 22D issues an instruction to the fourth robot hand 46d to capture the workpiece 40. In response to the command from the fourth slave wireless device 22D, the fourth robot hand 46d grasps the workpiece 40 and the workpiece 40 is transferred outwardly by the rotary platform 44. During the phase in which the workpiece 40 is externally transferred by the fourth robot hand 46d, the fourth slave wireless device 22D transmits a data packet Pgd indicating that the workpiece 40 has been externally transferred (unloaded) to the primary Wireless device 18. The primary wireless device 18 The delivery completion signal is output to the programmable logic controller 12 in accordance with receipt of the data packet Pgd from the fourth slave wireless device 22D.

The outward transfer of the workpiece 40 is completed by the output of the transfer output from the primary wireless device 18, and the sequence of assembly steps will end.

Since the data packet is exchanged between the primary wireless device 18 and the slave wireless device 22 in accordance with the sequence in which the programmable logic controller 12 generates the various command signals, the necessary operations may be performed from the data packet. The slave wireless device 22 is implemented in response to the slave wireless device 22. In particular, there is no need to perform communication with the non-essential slave wireless device 22, and therefore, the response speed can be achieved.

In the embodiment of the present invention, although the number of channels is 79, the data capacity of the data packet to be sent is small in the same manner as the Bluetooth (registered trademark) frequency hopping method, that is, Less than or equal to 50 bytes. Therefore, the transmission power can be suppressed to less than or equal to 1 milliwatt.

In the foregoing method, the industrial wireless communication system 10 according to an embodiment of the present invention has a programmable logic controller 12 including performing monitoring at least in an industrial facility, and is connected to the field sink 16 by the field. At least one primary wireless device 18 of the programmable logic controller 12, and a plurality of slave wireless devices 22 mounted to correspond to the individual hardware device 20 and in wireless communication with the primary wireless device 18. Furthermore, the wireless communication system 10 includes the connection processing unit 30 and the transmission/reception processing unit 36, and the connection processing unit 30 is at the main To wirelessly connect the wireless device 18 and the slave wireless device 22, the transmit/receive processing unit 36 wirelessly transmits and receives data between the primary wireless device 18 and the secondary wireless device 22.

In particular, the connection processing and signal transmission and reception are performed on the primary wireless device 18 connected to the programmable logic controller 12 and on the various hardware devices 20 (such as robots, welding torches, rotating clamps, motors, etc.) The slave wireless devices 22 are wirelessly implemented between them. Therefore, the risk of disconnection of the signal line and the like can be reduced in the movable assembly of the hardware device 20, and the degree of freedom in design of the industrial facility can be improved. This approach has led to an increase in the smart system at such industrial facilities.

Moreover, during a time interval of less than 500 milliseconds, the connection processing unit 30 performs wireless communication from the primary wireless device 18 with respect to the plurality of slave wireless devices 22 via the broadcast system and at the synchronization frequency. The transmission/reception processing unit 36 performs wireless communication by a frequency hopping method between the primary wireless device 18 and the secondary wireless device 22.

In particular, the connection processing unit 30 performs transmission at a frequency (synchronization frequency) set according to the frequency hopping method with respect to the slave wireless device 22 from the primary wireless device 18, and performs the frequency hopping transmission frequency. The transmission is performed with respect to the primary wireless device 18 from the slave wireless device 22. On the other hand, the transmission/reception processing unit 36 performs transmission at a frequency hopping transmission frequency set according to the frequency hopping method, with respect to the slave wireless device 22 from the primary wireless device 18, and performs transmission at frequency hopping. Frequency transmission, the frequency of the frequency hopping is transmitted by The frequency hopping method is newly set with respect to the primary wireless device 18 from the slave wireless device 22.

In this method, the wireless connection procedure can be shortened by turning on the power supply via the broadcast system and at intervals of 500 milliseconds or less (for example, at the time of connecting or separating the assembly jig). The time of the start of communication with the slave wireless device 22. Moreover, by wireless communication being performed by the frequency hopping method between the primary wireless device 18 and the secondary wireless device 22, interference with other wireless communications can be avoided.

Furthermore, in accordance with an embodiment of the invention, the 2.4 GHz band is used as a radio frequency and the wireless power is set to less than or equal to 1 mW. Since the radio frequency is a frequency higher than that generated by a noise source (such as a power line, a robot, a welding gun, a rotating jig, a motor, etc.) of an industrial device in a factory or the like, the noise can be reduced. The effect of frequency on wireless communications. Furthermore, since the wireless power is suppressed to less than or equal to 1 milliwatt, interference with other communication devices existing in the same area can be reduced.

Moreover, in accordance with an embodiment of the present invention, there is provided with the connection maintenance processing unit 32, by periodically transmitting clock information of the primary wireless device 18 relative to the slave wireless device 22 in which the connection procedure has been performed, The connection maintenance processing unit 32 is configured to perform a connection maintenance procedure with the primary wireless device 18. Since the clock information from the primary wireless device 18 is periodically sent to the slave wireless device 22 for which the connection procedure has been completed, the clock information coincides with the slave wireless device. 22 and between the primary wireless devices 18. Therefore, the timing of data transmission and reception can be easily synchronized.

Furthermore, in an embodiment of the invention, there is a connection confirmation processing unit 34 including an interface for confirming the establishment of wireless communication between the primary wireless device 18 and the plurality of dependent wireless devices 22, by repeating The slave wireless device 22 is periodically transmitted and periodically received by the primary wireless device 18.

While the transmission should be sent periodically by the slave wireless device 22, in the example where such transmission is not received by the primary wireless device 18, the method will determine that the slave wireless device 22 is in a disconnected state. If received from the primary wireless device 18 after transmission from the slave wireless device 22 that has determined to be in the disconnected state, it will be determined that the slave wireless device 22 is in the connected state. Because of this feature, it is easy for the slave wireless device 22 to be in the connected state and the one of the slave wireless devices 22 to be in the disconnected state. Therefore, the connection processing or maintenance or the like can be performed at an earlier stage with respect to the slave wireless device 22 that is determined to be in the disconnected state.

The industrial wireless communication system in accordance with the present invention is not limited to the above-described embodiments, and of course various additional or modified configurations may be employed in the present invention without departing from the invention as set forth in the appended claims. The scope and nature of this.

10‧‧‧Wireless communication system

18‧‧‧Main wireless devices

22‧‧‧Subordinate wireless devices

30‧‧‧Connection processing unit

32‧‧‧Connection Maintenance Unit

34‧‧‧Connection confirmation processing unit

36‧‧‧Send/receive processing unit

Claims (5)

An industrial wireless communication system (10) comprising: a computer (12) configured to perform at least monitoring in an industrial facility; at least one primary wireless device (18) connected to the computer via a field bus (16) ( 12); a plurality of slave wireless devices (22) installed to correspond to individual hardware devices (20) and configured to perform wireless communication with the primary wireless device (18); connection processing unit (30), configuration Wirelessly connecting the main wireless device (18) and the slave wireless device (22); and a transmitting/receiving processing unit (36) configured to be in the primary wireless device (18) and the slave wireless The device (22) wirelessly transmits and receives data. The industrial wireless communication system (10) of claim 1, wherein the connection processing unit (30) is configured to transmit from the primary wireless device (18) to the time interval of less than 500 milliseconds. a plurality of slave wireless devices (22) for wireless communication via a broadcast system and at a synchronous frequency; and the transmit/receive processing unit (36) configured to be in the primary wireless device (18) and the slave wireless device (22) Wireless communication is performed by a frequency hopping method. Industrial wireless communication system as described in claim 1 (10), where the 2.4 GHz band is used as the radio frequency, and the wireless power is less than or equal to 1 mW. The industrial wireless communication system (10) as claimed in claim 1, further comprising a connection maintenance processing unit (32) configured to be connected with respect to the connection The slave wireless device (22) periodically transmits the clock information of the primary wireless device (18) to perform a connection maintenance procedure with the primary wireless device (18). The industrial wireless communication system (10) according to claim 1, further comprising a connection confirmation processing unit (34) configured to repeat from the slave wireless device (22) Periodic transmission and receipt by the primary wireless device (18) to confirm establishment of wireless communication between the primary wireless device (18) and the plurality of dependent wireless devices (22).