JP2007221292A - Communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication system whereby a time until a master station obtains responses from a plurality of slave stations can be reduced, a communication efficiency at a response request can be improved, and a period of a downlink communication frame can be decreased. <P>SOLUTION: The master station 12 transmits the downlink communication frame signal F1 wherein designation information of optional slave stations 11-1 to 11-N being response request objects are established, and a received data judgement section 22 of each slave station judges distinguishment between down link and uplink of the communication frame signal and the presence/absence of the response request to its own station. Further, each received data judgement section 22 executes response transmission by an uplink communication frame signal F2 of its own station to a transmission section 25 when receiving the response request addressed to its own station after the end of the reception of the downlink communication frame signal F1. Moreover, each received data judgement section 22 executes response transmission by the uplink communication frame signal F2 after the end of the reception of the uplink communication frame signal F2 transmitted from the slave station with a station number younger than that of its own station when receiving the response request addressed to its own station. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a communication system in which a master station and a plurality of slave stations in a power conversion device and servo motor control system applying power electronics technology are connected by a serial transmission line, and data transmission is performed between them. .

  Conventionally, in a system that performs coordinated control by a plurality of control devices in a power conversion device or servo motor control system that applies power electronics technology, a communication system is configured with a plurality of slave stations and a master station that controls these slave stations. There are many cases to do. As this type of communication system, for example, as shown in FIG. 11, first to Nth slave stations 1-1, 1-2, 1-3,..., 1-N and a master station 2 are half-duplex. There is a communication system connected by a communication line 3 which is a serial transmission bus line. Since the master station 2 is communicating, the slave stations 1-1 to 1-N cannot communicate and the master station 2 is in communication with any of the slave stations 1-1 to 1-N. Cannot communicate.

In this communication system, Patent Document 1 discloses a conventional technique for exchanging communication frame signals from a master station to a slave station and conversely from a slave station to a master station. This technique will be described with reference to a time chart shown in FIG.
In this specification, the communication frame signal may be abbreviated as a communication frame, the master station as a master, the slave station as a slave, and the like.

  At time t1, a downlink communication frame signal including a response request (first slave response request) to the first slave station 1-1 to all the slave stations 1-1 to 1-N by broadcast communication from the master station 2. Send. Of all the slave stations 1-1 to 1-N that have received this signal, only the first slave station 1-1 corresponding to the reception destination of the first slave response request is transmitted to the master station 2 at time t2. A communication frame signal is returned.

Similarly, at time t3, the master station 2 that has received this transmits a downlink communication frame signal including the second slave response request to all the slave stations 1-1 to 1-N, and the second slave response Only the second slave station 1-2 corresponding to the reception destination of the request returns an uplink communication frame signal to the master station 2 at time t4.
Thereafter, transmission / reception is sequentially performed in the same manner, and as shown at time t5, the downlink communication frame signal including the Nth slave response request is transmitted from the master station 2, and the Nth slave station 1-N receiving this transmits the time At t6, the upstream communication frame signal is returned to the master station 2, and this is performed until the master station 2 receives it. As a result, the master station 2 can exchange information with all the slave stations 1-1 to 1-N.

In addition, there is a conventional technique described in Patent Document 2, which will be described with reference to a time chart shown in FIG.
After the master station 2 transmits the downlink communication frame signal to all the slave stations 1-1 to 1-N, and all the slave stations 1-1 to 1-N receiving this receive the downlink communication frame signal. The internal timer (not shown) is cleared all at once at a reference point indicated by a predetermined time t2, and then started. After the timer values T _{1 to} T _N set at predetermined time intervals for each of the slave stations 1-1 to 1-N from this reference point, the slave stations 1-1 to ₁ -N master the upstream communication frame signal. Reply to station 2. As a result, the master station 2 can exchange information with all the slave stations 1-1 to 1-N.
JP 2004-28581 A JP 2005-45672 A

However, in the above prior art of Patent Document 1, in order to obtain responses from the plurality of slave stations 1-1 to 1-N, a “response request” is transmitted for each of the slave stations 1-1 to 1-N. Since it must be transmitted to all the slave stations 1-1 to 1-N by broadcast communication each time, there is a problem that it takes too much time to obtain a response.
In addition, the communication frame signal usually includes information for communication procedures such as a flag indicating start and end and check data in addition to the data to be transmitted, and a “response request” is transmitted with the communication frame signal for each slave station. As a result, the ratio of information for communication procedure increases, resulting in a problem that effective communication efficiency decreases.

On the other hand, in Patent Document 2, all slave stations 1-1 to 1-N that have received the downlink communication frame signal from the master station 2 send back responses, but all slave stations 1-1 to 1-N send back responses. Until the process is completed, the next downlink communication frame signal cannot be transmitted from the master station 2. For this reason, there exists a problem that the period of a downlink communication frame signal cannot be shortened.
For example, depending on the application to which the power conversion device is applied, there are many specifications in which the response of a part of the slave stations is sufficient for one downlink communication frame signal, and instead the period of the downlink communication frame signal is desired to be shortened. In such a case, the technique of Patent Document 2 cannot be used.

  The present invention has been made in view of such problems, and can shorten the time until a master station obtains responses from a plurality of slave stations, and can improve communication efficiency when a response is requested. Another object of the present invention is to provide a communication system that can shorten the period of the downlink communication frame.

  To achieve the above object, a communication system according to claim 1 of the present invention has a plurality of slave stations and a master station that controls these slave stations, and the plurality of slave stations and the master station are half-duplex. In a communication system that connects with a communication line, transmits a downlink communication frame signal from a master station to a plurality of slave stations, and transmits an uplink communication frame signal in the opposite direction, the master station transmits the downlink communication frame signal to the downlink communication frame signal. , Comprising a first communication means for superimposing designation information for designating an arbitrary number of slave stations to be response requests among the plurality of slave stations as a specific station and a station other than the specific station, wherein the slave station receives It is determined whether the signal is the downlink communication frame signal or the uplink communication frame signal. When the signal is determined to be the downlink communication frame signal, the local station uses the designation information in the signal to If it is designated as a specific station, an uplink communication frame signal in which the specific information of the local station is written in the designation information is transmitted, and when it is determined to be the uplink communication frame signal, the designation in this signal And a second communication means for transmitting an uplink communication frame signal in which the specific information of the own station is written in the designated information when the own station is designated as a station other than the specific station by the information. And

  According to this configuration, in the half-duplex communication system, the master station can issue an instruction to request an arbitrary number of slave stations as a response request target by transmitting the downlink communication frame signal once. When the slave station receives a downlink communication frame signal from the master station and has a response request to the own station, the slave station can transmit a response of the uplink communication frame signal of the own station to the master station. Further, when there is a response request to the own station when the uplink communication frame signal is received, the response transmission of the own station's uplink communication frame signal can be performed to the master station. As described above, the slave station can transmit the response of the uplink communication frame signal by transmitting the downlink communication frame signal only once from the master station. As a result, there is no need to transmit a response request from the master station to each slave station as in the prior art, and accordingly, the time required to obtain a response can be greatly shortened.

Further, since the downlink communication frame signal is transmitted once, information for communication procedures such as a flag and check data indicating start and end included in the signal is only required once, and the downlink communication frame signal is transmitted a plurality of times. In comparison, the ratio of information for communication procedures is greatly reduced. As a result, effective communication efficiency can be improved. In addition, since only an arbitrary number of slave stations specified by this signal respond to a single downlink communication frame signal, it is possible to prevent all slave stations from replying as in the past. And the cycle of the downlink communication frame can be shortened.
Furthermore, since the number of slave stations for which a response is to be obtained can be changed for each downlink communication frame signal, it is possible to flexibly change the period of the downlink communication frame signal and the number of slave stations for which a response is to be obtained according to the control state. It is possible to provide a communication system for a power conversion device.

  The communication system according to claim 2 of the present invention is the communication system according to claim 1, wherein the first communication unit specifies each slave station in advance when specifying any number of slave stations to be a response request target in the specification information. The station number assigned from the station number assigned in ascending or descending order to the station, and the station number range from the station number next to the start station number to the end station number of the response request are designated, and the second communication means When it is determined as a communication frame signal, if the local station number is specified as the start station number in the designation information in this signal, an upstream communication frame signal in which the local station number is written in the designation information is transmitted, Further, when the local station number is included in the station number range of the designation information in the signal when it is determined as the upstream communication frame signal, the upstream communication frame signal from the slave station of the station number immediately preceding the local station number Response After Shin completion, and transmits the upstream communication frame signal writing the own station code in the designated information.

  According to this configuration, when the downlink communication frame signal is transmitted only once from the master station, and when a plurality of slave stations perform response transmission of the uplink communication frame signal, each slave station has the slave station of the previous station number. Since the uplink communication frame signal of the local station is transmitted after the transmission of the uplink communication frame signal is completed, it is possible to prevent two or more slave stations from overlappingly transmitting the response of the uplink communication frame signal to the master station. A response can be made appropriately.

A communication system according to claim 3 of the present invention includes a plurality of slave stations and a master station that controls the slave stations, and connects the plurality of slave stations and the master station with a full-duplex communication line. In a communication system that transmits a downlink communication frame signal from a master station to a plurality of slave stations and transmits an uplink communication frame signal in the opposite direction, the master station includes the plurality of slave stations in the downlink communication frame signal. And a third communication means for superimposing designation information for designating an arbitrary number of slave stations as response request targets as a specific station and a station other than the specific station, wherein the slave station receives the downlink communication frame signal. When the local station is designated as the specific station by the designation information in this signal, the uplink communication frame signal in which the specific information of the local station is written in the designation information is If the local station is designated as a station other than the specific station when the uplink communication frame signal is received, the specific information of the local station is written in the designation information. And a fourth communication means for transmitting the received upstream communication frame signal.
According to this configuration, the same effect as that of the first aspect can be obtained in a full-duplex communication system.

Further, the communication system according to claim 4 of the present invention is the communication system according to claim 3, wherein the third communication means specifies each slave station in advance when specifying any number of slave stations to be a response request target in the specification information. The station number assigned from the station number assigned to the station in ascending or descending order is designated as the start station number of the response request and the station number range from the station number next to the start station number to the end station number of the response request, and the fourth communication means When receiving the communication frame signal, if the local station number is designated as the start station number in the designation information in this signal, an upstream communication frame signal with the local station number written in the designation information is transmitted, and When the upstream communication frame signal is received, if the local station number is included in the station number range of the designation information in the signal, the response of the upstream communication frame signal from the slave station of the station number immediately before the local station number Send To After the completion, and transmits the upstream communication frame signal writing the own station code in the designated information.
According to this configuration, the same effect as that of the second aspect can be obtained in a full-duplex communication system.

  As described above, according to the present invention, it is possible to shorten the time required for the master station to obtain responses from a plurality of slave stations, to improve the communication efficiency at the time of response request, and to further reduce the downlink communication. There is an effect that the cycle of the frame can be shortened.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, parts corresponding to each other in all the drawings in this specification are denoted by the same reference numerals, and description of the overlapping parts will be omitted as appropriate.
(First embodiment)
FIG. 1 is a block diagram showing the configuration of a half-duplex communication system according to the first embodiment of the present invention.
1, the first to Nth slave stations 11-1, 11-2, 11-3,..., 11-N and the master station 12 are half-duplex serial transmission buses. It is configured to be connected by a communication line 13 that is a line.

The master station 12 includes a communication controller (first communication means) 12a that performs communication with each of the slave stations 11-1 to 11-N, and a CPU 12b that controls the communication controller 12a and the own station. It is configured.
Each of the slave stations 11-1 to 11-N includes a communication controller (second communication means) 11a that performs communication with the master station 12, and a CPU 11b that controls the communication controller 11a and the own station. Has been.

  As shown in FIG. 2, the communication controller 11a includes a reception unit 24 including a reception serial / parallel conversion unit 21, a reception data determination unit 22, a reception buffer memory 23, a transmission unit 25, a station number setting unit 26, It is configured with. The reception data determination unit 22 includes a frame type storage unit 27, a first response request storage unit 28, a second response request storage unit 29, and a transmission activation request storage unit 30. .

  3A to 3D, the formats of the downlink communication frame signal F1 transmitted from the master station 12 to the slave stations 11-1 to 11-N and the uplink communication frame signal F2 in the opposite direction are shown. An example is shown. However, the downlink communication frame signal F1 is generated by the communication controller 12a of the master station 12, and the uplink communication frame signal F2 is generated by the communication controller 11a of the slave stations 11-1 to 11-N.

  (A) shows the format structure of the downlink communication frame signal F1 transmitted from the master station 12 toward the slave stations 11-1 to 11-N. The downlink communication frame signal F1 includes a start flag F1a indicating the start of a communication procedure, a frame determination header F1b described later, a plurality of data F1c used for cooperative control as a power conversion device, and these data It consists of check data F1d that checks for errors in F1c and the like, and an end flag F1e that indicates the end of the communication procedure.

(B) shows the format configuration of the uplink communication frame signal F2 transmitted from the slave stations 11-1 to 11-N toward the master station 12. Similarly, the upstream communication frame signal F2 includes a start flag F2a, a frame determination header F2b, a plurality of data F2c including response information to the master station 12 in addition to the above, check data F2d, and an end flag F2e. It is composed of
The order in which the downlink communication frame signal F1 and the uplink communication frame signal F2 are received from the head of the frame determination headers F1b and F2b is the same.
(C) shows a configuration of frame determination headers F1b and F2b including a TY portion, an ST portion, and an LN portion.

  (D) shows the instruction contents of the TY part, ST part and LN part of the frame determination headers F1b and F2b. The TY unit sets a value that enables discrimination between the downlink communication frame signal F1 and the uplink communication frame signal F2. The ST unit sets a value expressing the start station number of the slave station number requesting a response in the downlink communication frame signal F1, and sets a value expressing the responding slave station number in the uplink communication frame signal F2. The LN unit sets a value representing the range of slave station numbers for which a response is requested in the downlink communication frame signal F1, and sets a dummy value because it is not used in the uplink communication frame signal F2. In these TY part, ST part, and LN part, the values representing the communication frame distinction and the slave station number and range may be directly the station number number, for example, a code that enables error correction, etc. Also good.

  Returning to FIG. 1, when the reception serial / parallel conversion unit 21 detects the start flag F1a from the serially received downlink communication frame signal F1, the reception data number DN is cleared to 0, and the serial downlink communication frame signal F1 is set to 1. Conversion to parallel data in units of bytes or 1 word is performed, and this is output as received data D1, and at the same time, the number of received data DN is incremented. Further, when the end flag F1e is detected from the serial downstream communication frame signal F1, a reception status DS that is a reception end status is output.

Further, the reception serial / parallel converter 21 may receive an upstream communication frame signal F2 from another slave station.
The received data determination unit 22 executes the process from the start to the end of the flowchart shown in FIG. 4 every time the received data number DN changes.
That is, in step S1, it is determined whether the number of received data DN is equal to the number of received data in the frame determination header F1b or F2b (=) and exceeds the number of received data in the frame determination header F1b or F2b (>). To do. If it is determined that they are equal (=), that is, if it is determined that the received data number DN has reached the count value corresponding to the frame determination header F1b or F2b, in step S2, the received serial signal is a downlink communication frame signal. It is determined whether the frame is F1 or uplink communication frame signal F2, and in steps S3 and S4, it is stored whether it is a downlink communication frame signal F1 or an uplink communication frame signal F2. Thereafter, the processing differs depending on the downlink communication frame signal F1 and the uplink communication frame signal F2 until the end of the flowchart.

  Accordingly, when it is determined in step S2 that the frame is the downlink communication frame signal F1, in step S3, the TY portion of the frame determination header F1b indicating that the frame is the downlink communication frame signal F1 is stored in the frame type storage unit 27. . At the same time, the start station number of the slave station that is the response request target is decoded from the ST unit, this is stored in the first response request storage unit 28, and the range of the station number of the slave station that is the response request is decoded from the LN unit. Is stored in the second response request storage unit 29.

Next, in step S <b> 5, it is determined whether or not the starting station number stored in the first response request storage unit 28 is a set station number in the station number setting unit 26. If it is the set station number, it means that the master station 12 has requested a response to the own station, so that in step S6, the transmission activation request storage unit 30 stores that there is a response request from the master station 12 (set) )
In step S7, the count value of the reception data number DN is decoded to generate a memory address MA, and the frame determination header F1b shown in FIG. 3 is stored in the storage area of the reception buffer memory 23 designated by the memory address MA. The subsequent data F1c is stored.

If it is determined in step S5 that the station number is not set, only the storage process in step S7 is executed.
On the other hand, if it is determined in step S2 that the frame is the uplink communication frame signal F2, in step S4, the TY portion of the frame determination header F2b indicating the uplink communication frame signal F2 is stored in the frame type storage unit 27. To do. In this case, after the end of the upstream communication frame signal F2 returned by another slave station, the local station monitors whether it is necessary to return the upstream communication frame signal F2.

  In step S8, when the received data number DN is a count value corresponding to the frame determination header F2b, it is determined whether the set station number of the own station by the station number setting unit 26 is included in the range in which the master station 12 requests a response. To do. That is, it is determined whether or not the start station number stored in the first response request storage unit 28 <the set station number ≦ the range value of the response request station numbers stored in the second response request storage unit 29.

If this result is Yes, in step S9, referring to the ST part of the frame determination header F2b, it is determined whether or not the current upstream communication frame signal F2 is transmitted by the slave station with the station number immediately before the own station. to decide. If this determination result is Yes, it is set in step S10 that there is a request in the transmission activation request storage unit 30.
In the case of the uplink communication frame signal F2, since only monitoring is performed, the data F2c after the frame determination header F2b is not stored in the reception buffer memory 23 unlike the case of the downlink communication frame signal F1 described in step S7. .

Furthermore, when it is determined in step S1 that the received data number DN exceeds the received data number of the frame determination header F1b or F2b (>), in step S11, the received serial signal is the downlink communication frame signal F1. It is determined whether it is an upstream communication frame signal F2.
In the case of the downlink communication frame signal F1, in step S12, the count value of the received data number DN is decoded to generate the memory address MA, and the frame determination is made in the storage area of the reception buffer memory 23 designated by the memory address MA. Data F1c after the header F1b is stored. This process is not performed for the uplink communication frame signal F2.

  Next, in step S13, it is determined whether the reception of the downlink communication frame signal F1 or the uplink communication frame signal F2 is completed. In the case of termination, in step S14, it is determined whether or not a transmission activation request is set in the transmission activation request storage unit 30. If it is set, in step S15, a transmission activation trigger signal T1 for activating the return transmission of the uplink communication frame signal F2 is output from the own station to the transmission unit 25, and then the request of the transmission activation request storage unit 30 is transmitted. clear.

The transmission unit 25 returns the uplink communication frame signal F2 when the transmission activation trigger signal T1 is input.
With such a half-duplex communication system, each of the slave stations 11-1 to 11-N can determine whether the communication frame signal is downlinked or uplinked and whether there is a response request to the own station. In other words, as described in steps S3 to S7, each of the slave stations 11-1 to 11-N receives a response request to the own station after the reception of the downlink communication frame signal F1. The response transmission of the uplink communication frame signal F2 of the own station can be performed.

Further, as described in steps S4 to S10 above, each slave station 11-1 to 11-N transmits an uplink transmitted by the slave station with the station number immediately preceding itself when there is a response request to the own station. After receiving the communication frame signal F2, the response transmission of the uplink communication frame signal F2 of the own station can be performed.
In this way, in the half-duplex communication system, any one of the slave stations can perform response transmission of the uplink communication frame signal F2 with one downlink communication frame signal F1 from the master station 12. . A specific operation in this case will be described with reference to the time chart of FIG.

It is assumed that unique station numbers 1a to Na corresponding to the slave stations 11-1 to 11-N are set in the station number setting unit 26 of the communication controller 11a of each slave station 11-1 to 11-N. That is, the station number 1a is set in the first slave station 11-1, the station number 2a is set in the second slave station 11-2, and the station number Na is set in the Nth slave station 11-N.
The formats of the downlink communication frame signal F1 and the uplink communication frame signal F2 are as described above with reference to FIG. 3, and the roles of the TY part, ST part, and LN part of the frame determination headers F1b and F2b are also described above. Street. In the figure, the TY part, ST part, and LN part may be expressed only as TY, ST, and LN.

  In this example, the TY unit represents the downlink communication frame signal F1 as “0” and the uplink communication frame signal F2 as “1”. In the downlink communication frame signal F1, the start and range of the slave station that is the response request target are specified in the ST part and the LN part. For example, when station number 1a to station number 4a are targeted for response request (ST part: 1a, LN part: 3a), when station number 10 to station number 11 are targeted for response request (ST part: 10a, LN part: 1a) ) When only the station number 10 is a response request target, the setting is made as (ST part: 10a, LN part: 0).

  As another method for designating the start and range of slave stations for which a response is requested by the ST and LN units in the downlink communication frame signal F1, when station numbers 1 to 4 are to be requested for response (ST Part: 1a, LN part: 4a), when station number 10 to station number 11 are subject to response request (ST part: 10a, LN part: 11a), when only station number 10 is subject to response request (ST part 10a) , LN part: 10a) and other setting methods are also available.

In the ST part of the uplink communication frame signal F2, the station number of the slave station that has transmitted the response is set. For example, the ST part of the upstream communication frame signal F2 of the slave station number 2a is “2a”.
Next, it is assumed that each of the slave stations 11-1 to 11-N receives the first downlink communication frame signal F1 transmitted from the master station 12 at time t1 in FIG. However, (ST portion: 1a, LN portion: 3a) is set in the frame determination header F1b in the signal F1.

In this case, each of the slave stations 11-1 to 11-N has “1a” in the first response request storage unit 28 and 1a + 3a in the second response request storage unit 29 as described in step S3 of FIG. = "4a" is set.
In the other setting method described above, “1a” is directly set in the first response request storage unit 28 and “4a” is directly set in the second response request storage unit 29.
Among the slave stations 11-1 to 11-N, for the first slave station 11-1, the determination result in step S5 of FIG. 4 is Yes, and a request is set in the transmission activation request storage unit 30 in step S6. Is done.

When the end flag F1e of the first downlink communication frame signal F1 is received and the reception status is the reception end, the first slave station 11-1 receives from the reception data determination unit 22 as shown in step S15 of FIG. A transmission activation trigger signal T1 is output to the transmission unit 25. Accordingly, at time t2 in FIG. 5, the uplink communication frame signal F2 (ST unit: 1a) is transmitted as a response from the first slave station 11-1.
The upstream communication frame signal F2 is monitored by the slave stations 11-1 to 11-N through the processes of steps S4, S8 to S10, and S13 to S15 in FIG. In the slave station 11-2, the determinations in steps S8 and S9 in FIG. 4 are both Yes, and a request is set in the transmission activation request storage unit 30 in step S10.

  In the slave station 11-2, when the reception status is ended by receiving the end flag F2e of the upstream communication frame signal F2 of (ST unit: 1a), the reception data determining unit 22 performs the process of step S15 in FIG. A transmission activation trigger signal T1 is output to the transmission unit 25. Thus, at time t3 in FIG. 5, the uplink communication frame signal F2 of (ST unit: 2a) is transmitted as a response from the slave station 11-2.

Thereafter, similarly, the uplink communication frame signal F2 from (ST unit: 3a) is transmitted in response from the slave station 11-3 at time t4, and the uplink communication frame signal from (ST unit: 4a) from the slave station 11-4 at time t5. F2 is transmitted as a response.
Among these, the upstream communication frame signal F2 of (ST unit: 4a) is monitored by the slave stations 11-1 to 11-N by the processes of steps S4, S8 to S10, and S13 to S15 of FIG. In this case, since there is no slave station in which the determination in steps S8 and S9 in FIG. 4 is both Yes, when the upstream communication frame signal F2 of (ST unit: 4a) is transmitted, the first downlink All the response transmissions of the slave stations requested to respond by the communication frame signal F1 are completed.

As described above, the slave station 11-1 to 11-4 can transmit the response of the uplink communication frame signal F2 only by transmitting the downlink communication frame signal F1 from the master station 12 only once. As a result, there is no need to transmit a response request from the master station to each slave station as in the prior art, and accordingly, the time required to obtain a response can be greatly shortened.
Further, since the downlink communication frame signal F1 is transmitted once, information for communication procedures such as a flag and check data indicating the start and end included in the signal F1 is sufficient, and a plurality of downlink communication frame signals F1 are transmitted. Compared to transmitting twice, the ratio of information for communication procedures is greatly reduced. As a result, effective communication efficiency can be improved.

In addition, since only an arbitrary number of slave stations (for example, 11-1 to 11-4) designated by the signal F1 respond to one downlink communication frame signal F1, It is possible to prevent all slave stations from replying, and to shorten the cycle of the downlink communication frame.
Furthermore, in this embodiment, since the number of slave stations for which a response is obtained can be changed for each downlink communication frame signal F1, the number of slave stations for which the period of the downlink communication frame signal F1 and the response are obtained according to the control state. It is possible to provide a flexible communication system for a power conversion device that changes the above.

(Second Embodiment)
FIG. 6 is a block diagram showing a configuration of a full-duplex communication system according to the second embodiment of the present invention.
In the communication system shown in FIG. 6, the first to Nth slave stations 51-1, 51-2, 51-3,..., 51-N and the master station 52 are serial duplex buses. It is configured to be connected by a downlink communication line 53D and an uplink communication line 53U which are lines.
The master station 52 includes a communication controller (third communication means) 52a that performs communication with each of the slave stations 51-1 to 51-N, and a CPU 52b that controls the communication controller 52a and the own station. It is configured.

Each of the slave stations 51-1 to 51-N includes a communication controller (fourth communication means) 51a that communicates with the master station 52, and a CPU 51b that controls the communication controller 51a and the own station. Has been.
As illustrated in FIG. 7, the communication controller 51 a includes a downlink reception unit 54 </ b> D, an uplink reception unit 54 </ b> U, a transmission unit 55, and a station number setting unit 56.

The downlink reception unit 54D includes a reception serial / parallel conversion unit 21D, a reception data determination unit 22D, and a reception buffer memory 23D. The reception data determination unit 22D includes a first response request storage unit 28D, a second response request storage unit 28D, and a second response request storage unit 28D. And a response request storage unit 29D.
The upstream reception unit 54U includes a reception serial / parallel conversion unit 21U and a reception data determination unit 22U, and the reception data determination unit 22U includes a transmission activation request storage unit 30U.

  The formats of the downlink communication frame signal F1 transmitted to the downlink communication line 53D and the uplink communication frame signal F2 transmitted to the uplink communication line 53U have been described with reference to FIG. 3 in the first embodiment. It is the same. However, the downlink communication frame signal F1 is generated by the communication controller 52a of the master station 52, and the uplink communication frame signal F2 is generated by the communication controller 51a of the slave stations 51-1 to 51-N.

  The downlink and uplink reception serial / parallel converters 21D and 21U are functionally identical, and receive data when detecting the start flag F1a or F2a from the serially received downlink communication frame signal F1 or uplink communication frame signal F2. The number DN is cleared to 0, the serial communication frame signal F1 or F2 is converted into parallel data in units of 1 byte or 1 word, this is output as received data D1, and at the same time, the received data number DN is incremented. Do. Further, when an end flag F1e or F2e is detected from the serial communication frame signal F1 or F2, a reception status DS that is a reception end status is output.

The downstream received data determination unit 22D executes every time from the start to the end of the flowchart shown in FIG. 8 every time the received data number DN changes.
That is, in step S21, it is determined whether or not the number of received data DN is equal to the number of received data in the frame determination header F1b (=) and exceeds the number of received data in the frame determination header F1b (>). When it is determined that they are equal (=), that is, when it is determined that the received data number DN has reached the count value corresponding to the frame determination header F1b, a response is received from the ST portion of the frame determination header F1b in step S22. The start station number of the slave station to be requested is decoded, stored in the first response request storage unit 28D, the range of the station number of the slave station to be requested for response is decoded from the LN unit, and this is used as the second response request. Store in the storage unit 29D.

  Next, in step S23, it is determined whether or not the start station number stored in the first response request storage unit 28D is a set station number in the station number setting unit 56. If it is the set station number, it means that the master station 52 has requested a response to the own station, so in step S24, the transmission start trigger signal TD for starting the return transmission of the upstream communication frame signal F2 from the own station. Is output to the transmission unit 55.

In step S25, the count value of the reception data number DN is decoded to generate a memory address MA, and the frame determination header F1b shown in FIG. 3 is stored in the storage area of the reception buffer memory 23 designated by the memory address MA. The subsequent data F1c is stored.
If it is determined in step S23 that the station number is not set, only the storage process in step S25 is executed.

  On the other hand, if it is determined in step S21 that the received data number DN exceeds the received data number of the frame determination header F1b or F2b (>), the count value of the received data number DN is decoded in step S26. The memory address MA is generated, and the data F1c after the frame determination header F1b is stored in the storage area of the reception buffer memory 23 designated by the memory address MA.

Next, every time the received data number DN changes, the upstream received data determination unit 22U executes from the start to the end of the flowchart shown in FIG.
The upstream communication frame signal F2 is an operation for monitoring whether or not the local station needs to return the upstream communication frame signal F2 after the upstream communication frame signal F2 returned by another slave station is completed. Unlike 54D, the reception buffer memory 23 does not exist.

  First, in step S31, it is determined whether or not the received data number DN is equal to the received data number of the frame determination header F1b (=) and exceeds the received data number of the frame determination header F1b (>). If it is determined that they are equal (=), that is, if it is determined that the number of received data DN has reached the count value corresponding to the frame determination header F1b, in step S32, the number of received data DN is determined to be the frame determination header F2b. When the count value corresponds to, it is determined whether or not the station number set by the station number setting unit 56 is included in the range in which the master station 12 requests a response. That is, it is determined whether the start station number stored in the first response request storage unit 28D <the set station number ≦ the range value of the response request station number stored in the second response request storage unit 29D.

If this result is Yes, in step S33, referring to the ST part of the frame determination header F2b, it is determined whether or not the current upstream communication frame signal F2 is transmitted by the slave station with the station number immediately before the own station. to decide. If this determination result is Yes, it is set in step S34 that there is a request in the transmission activation request storage unit 30.
On the other hand, if it is determined in step S31 that the received data number DN exceeds the number of received data in the frame determination header F1b or F2b (>), whether the reception of the upstream communication frame signal F2 is completed in step S35. Judge whether or not. In the case of termination, in step S36, it is determined whether or not a transmission activation request is set in the transmission activation request storage unit 30. If it is set, in step S37, a transmission activation trigger signal TU for activating the return transmission of the upstream communication frame signal F2 is output from the own station to the transmission unit 55, and then the request of the transmission activation request storage unit 30 is transmitted. clear.

When the transmission activation trigger signal TD or TU is input, the transmission unit 25 returns the uplink communication frame signal F2 in the format of FIG.
By such a full-duplex communication system, each of the slave stations 51-1 to 51-N can determine whether or not there is a response request to the own station. That is, as described in steps S21 to S26, each of the slave stations 51-1 to 51-N makes a response request to the own station after the reception of the downlink communication frame signal F1 is completed by the downlink reception data determination unit 22D. In this case, a response transmission of the uplink communication frame signal F2 of the own station can be performed.

Further, as described in steps S31 to S37 above, each of the slave stations 51-1 to 51-N causes the upstream received data determination unit 22U to receive a response request to the own station. After the reception of the uplink communication frame signal F2 transmitted by the slave station with the station number of ## EQU2 ## the response transmission of the uplink communication frame signal F2 of the own station can be performed.
In this way, in a full-duplex communication system, any one of the slave stations can perform response transmission of the uplink communication frame signal F2 with one downlink communication frame signal F1 from the master station 12. . A specific operation in this case will be described with reference to the time chart of FIG.

It is assumed that unique station numbers 1a to Na corresponding to the slave stations 51-1 to 51-N are set in the station number setting unit 56 of the communication controller 51a of each slave station 51-1 to 51-N. That is, the station number 1a is set to the first slave station 51-1, the station number 2a is set to the second slave station 51-2, and the station number Na is set to the Nth slave station 51-N.
The formats of the downlink communication frame signal F1 and the uplink communication frame signal F2 are as described above with reference to FIG. 3, and the roles of the TY part, ST part, and LN part of the frame determination headers F1b and F2b are also described above. Street. In the figure, the TY part, ST part, and LN part may be expressed only as TY, ST, and LN.

  In this example, the TY unit represents the downlink communication frame signal F1 as “0” and the uplink communication frame signal F2 as “1”. In the downlink communication frame signal F1, the start and range of the slave station that is the response request target are specified in the ST part and the LN part. For example, when station number 1a to station number 4a are targeted for response request (ST part: 1a, LN part: 3a), when station number 10 to station number 11 are targeted for response request (ST part: 10a, LN part: 1a) ) When only the station number 10 is a response request target, the setting is made as (ST part: 10a, LN part: 0).

  As another method for designating the start and range of slave stations for which a response is requested by the ST and LN units in the downlink communication frame signal F1, when station numbers 1 to 4 are to be requested for response (ST Part: 1a, LN part: 4a), when station number 10 to station number 11 are subject to response request (ST part: 10a, LN part: 11a), when only station number 10 is subject to response request (ST part 10a) , LN part: 10a) and other setting methods are also available.

In the ST part of the uplink communication frame signal F2, the station number of the slave station that has transmitted the response is set. For example, the ST part of the upstream communication frame signal F2 of the slave station number 2a is “2a”.
Next, it is assumed that each slave station 51-1 to 51-N receives the first downlink communication frame signal F1 transmitted from the master station 12 at time t1 in FIG. However, (ST portion: 1a, LN portion: 3a) is set in the frame determination header F1b in the signal F1.

In this case, the downlink reception data determination unit 22D of each of the slave stations 51-1 to 51-N receives “1a” in the first response request storage unit 28D, as described in step S22 of FIG. 1a + 3a = “4a” is set in the response request storage unit 29D.
In the other setting method described above, “1a” is directly set in the first response request storage unit 28D, and “4a” is directly set in the second response request storage unit 29D.

Among the slave stations 51-1 to 51 -N, for the first slave station 51-1, the determination result in step S 23 of FIG. 8 is Yes, and in step S 24, the transmission activation trigger signal TD is sent to the transmission unit 55. At time t2 in FIG. 10, the uplink communication frame signal F2 (ST unit: 1a) is transmitted as a response from the slave station 51-1.
The upstream communication frame signal F2 is monitored by the upstream received data determination unit 22U of each of the slave stations 51-1 to 51-N through the processing of steps S31 to S37 in FIG. In the slave station 51-2, the determinations in steps S32 and S33 in FIG. 9 are both Yes, and a request is set in the transmission activation request storage unit 30 in step S34.

  When the reception status is ended by receiving the end flag F2e of the upstream communication frame signal F2 of (ST unit: 1a), a transmission activation trigger signal is transmitted to the transmission unit 55 for the slave station 51-2 by the process of S37 of FIG. TU is output. As a result, as shown at time t3, the upstream communication frame signal F2 of (ST unit: 2a) is transmitted as a response from the slave station 51-2.

Thereafter, similarly, the uplink communication frame signal F2 from (ST unit: 3a) is transmitted in response from the slave station 51-3 at time t4, and the uplink communication frame signal from (ST unit: 4a) from the slave station 51-4 at time t5. F2 is transmitted as a response.
Among these, the upstream communication frame signal F2 of (ST unit: 4a) is monitored by the slave stations 51-1 to 51-N by the processing of steps S31 to S37 in FIG. In this case, since there is no slave station in which the determination in steps S32 and S33 in FIG. 9 is both, the first downlink is performed when the upstream communication frame signal F2 of (ST unit: 4a) is transmitted. All the response transmissions of the slave stations requested to respond by the communication frame signal F1 are completed.

As described above, the slave station 51-1 to 51-4 can perform the response transmission of the upstream communication frame signal F2 by transmitting the downstream communication frame signal F1 from the master station 12 only once. As a result, there is no need to transmit a response request from the master station to each slave station as in the prior art, and accordingly, the time required to obtain a response can be greatly shortened.
Further, since the downlink communication frame signal F1 is transmitted once, information for communication procedures such as a flag and check data indicating the start and end included in the signal F1 is sufficient, and a plurality of downlink communication frame signals F1 are transmitted. Compared to transmitting twice, the ratio of information for communication procedures is greatly reduced. As a result, effective communication efficiency can be improved.

In addition, since only an arbitrary number of slave stations (for example, 51-1 to 51-4) designated by the signal F1 respond to one downlink communication frame signal F1, It is possible to prevent all slave stations from replying, and to shorten the cycle of the downlink communication frame.
Furthermore, in this embodiment, since the number of slave stations for which a response is obtained can be changed for each downlink communication frame signal F1, the number of slave stations for which the period of the downlink communication frame signal F1 and the response are obtained according to the control state. It is possible to provide a flexible communication system for a power conversion device that changes the above.

1 is a block diagram illustrating a configuration of a half-duplex communication system according to a first embodiment of the present invention. It is a block diagram which shows the structure of the communication controller of the slave station in the half-duplex communication system which concerns on 1st Embodiment. It is a format block diagram of the downlink communication frame signal and uplink communication frame signal which are used with the communication system of this Embodiment. It is a flowchart for demonstrating the processing operation of the reception data judgment part of the communication controller in the half-duplex communication system which concerns on 1st Embodiment. It is a time chart for demonstrating the transmission / reception operation | movement of the half-duplex communication system which concerns on 1st Embodiment. It is a block diagram which shows the structure of the full-duplex communication system which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the communication controller of the slave station in the full-duplex communication system which concerns on 2nd Embodiment. It is a flowchart for demonstrating the processing operation of the downlink received data judgment part of the communication controller in the full-duplex communication system which concerns on 2nd Embodiment. It is a flowchart for demonstrating the processing operation | movement of the uplink received data judgment part of the communication controller in the full-duplex communication system which concerns on 2nd Embodiment. It is a time chart for demonstrating the transmission / reception operation | movement of the full-duplex communication system which concerns on 2nd Embodiment. It is a block diagram which shows the structure of the conventional communication system of a half duplex system. It is a time chart for demonstrating the 1st communication operation | movement in the communication system of the conventional half duplex system. It is a time chart for demonstrating the 2nd communication operation | movement in the communication system of the conventional half duplex system.

Explanation of symbols

11-1 to 11-N, 51-1 to 51-N Slave station 12, 52 Master station 11a, 12a, 51a, 51b Communication controller 11b, 12b, 51b, 52b CPU
21 reception serial / parallel conversion unit 22 reception data determination unit 22D downlink reception data determination unit 22U uplink reception data determination unit 23, 23D reception buffer memory 24 reception unit 25, 55 transmission unit 26, 56 station number setting unit 27 frame type storage unit 28, 28D First response request storage unit 29, 29D Second response request storage unit 30, 30U Transmission activation request storage unit 54D Downlink reception unit 54U Uplink reception unit

Claims (4)

It has a plurality of slave stations and a master station that controls these slave stations. A plurality of slave stations and the master station are connected by a half-duplex communication line, and a downlink communication frame is sent from the master station to the plurality of slave stations. In a communication system that transmits a signal and transmits an upstream communication frame signal in the opposite direction,
The master station superimposes on the downlink communication frame signal designation information for designating an arbitrary number of slave stations to be a response request among the plurality of slave stations as a specific station and a station other than the specific station. With communication means,
The slave station determines whether the received signal is the downlink communication frame signal or the uplink communication frame signal. When the slave station determines that the received signal is the downlink communication frame signal, the slave station uses the specified information in this signal to identify the specific station Is specified, the uplink communication frame signal in which the specific information of the own station is written in the specified information is transmitted, and when it is determined to be the uplink communication frame signal, the specified information in this signal is used. And a second communication means for transmitting an uplink communication frame signal in which the specific information of the own station is written in the designation information when the station is designated as a station other than the specific station. system. When the first communication means designates an arbitrary number of slave stations to be a response request in the designation information, a response request start station number is selected from among station numbers assigned in advance to each slave station in ascending or descending order. Specify the station number range from the station number next to the start station number to the end station number of the response request,
When it is determined that the second communication means is the downlink communication frame signal, if the local station number is specified as the start station number in the designation information in the signal, the second communication means writes the local station number in the designation information. When the local station number is included in the station number range of the designation information in this signal when the received upstream communication frame signal is determined to be the upstream communication frame signal, 2. The communication system according to claim 1, wherein an uplink communication frame signal in which the local station number is written in the designation information is transmitted after the transmission of the response of the uplink communication frame signal from the slave station of the station number is completed. It has a plurality of slave stations and a master station that controls these slave stations. A plurality of slave stations and master stations are connected by a full-duplex communication line, and a downlink communication frame is sent from the master station to the plurality of slave stations. In a communication system that transmits a signal and transmits an upstream communication frame signal in the opposite direction,
The master station superimposes on the downlink communication frame signal, designation information that designates an arbitrary number of slave stations to be requested for response among the plurality of slave stations as a specific station and a station other than the specific station. Having communication means,
When the slave station receives the downlink communication frame signal, if the local station is designated as the specific station by the designation information in the signal, the slave station has written the specific information of the local station in the designation information. When a communication frame signal is transmitted and the uplink communication frame signal is received, if the local station is designated as a station other than the specific station by the designation information in the signal, the designation information includes the local station And a fourth communication means for transmitting an upstream communication frame signal in which the unique information is written. When the third communication means designates an arbitrary number of slave stations to be a response request in the designation information, a response request start station number is selected from among station numbers assigned in advance to each slave station in ascending or descending order. Specify the station number range from the station number next to the start station number to the end station number of the response request,
When the fourth communication means receives the downlink communication frame signal and the local station number is designated as the start station number in the designation information in the signal, the fourth communication means writes the local station number in the designation information. When the upstream communication frame signal is transmitted and the upstream communication frame signal is received, if the local station number is included in the station number range of the designation information in this signal, the station number one before the local station number 4. The communication system according to claim 3, wherein after the transmission of the response of the uplink communication frame signal from the slave station is completed, the uplink communication frame signal in which the local station number is written in the designated information is transmitted.

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