Serial transmission communication system

Abstract

To provide a serial transmission communication system capable of suppressing the deviation of time in signals transmitted from a plurality of slave stations connected to a master station.SOLUTION: A serial transmission communication system 1 includes a master station 2 and a plurality of slave stations 3 connected to the master station 2 in a bus-like multi-drop manner. The master station 2 includes a calculation unit 8 and a notification unit 9. The calculation unit 8 calculates a correction time for each slave station 3 based on time difference between a time required for receiving a reply to transmission from the master station 2 and a preset reference time. The notification unit 9 notifies each slave station 3 of the correction time calculated by the calculation unit 8. Each slave station 3 includes a storage unit 13 and an adjustment unit 14. The storage unit 13 stores the correction time notified from the notification unit 9. The adjustment unit 14 adjusts reply timing based on the correction time stored in the storage unit 13 so that replies from the respective slave stations 3 to the master station 2 are received at the same time.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a serial transmission communication system. [Background technology]

[0002] Patent Document 1 discloses an example of a communication system. In the communication system, a plurality of remote stations are connected to a main station in a bus-like multi-drop manner. Each remote station simultaneously outputs a signal to the main station. A signal in which the signals from each remote station are superimposed is input to the main station. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 4-261243 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the communication system of Patent Document 1, when a time lag occurs in the signals transmitted from the slave stations such as the remote stations, the signals may not be correctly superimposed in the master station such as the main station, which may cause a communication error.

[0005] The present disclosure is directed to solving such problems, and provides a serial transmission communication system capable of suppressing time lag in signals transmitted from a plurality of slave stations connected to a master station. [Means for solving the problem]

[0006] A serial transmission communication system according to the present disclosure is a serial transmission communication system including a parent station and a plurality of child stations connected to the parent station in a bus-like multi-drop manner and replying to a transmission from the parent station, the parent station including a calculation unit that calculates a correction time for each of the plurality of child stations to adjust a time difference based on a time difference between a time until a reply to a transmission from the parent station is received and a preset reference time, and a notification unit that notifies each of the plurality of child stations of the correction time calculated by the calculation unit, and at least one of the plurality of child stations includes a storage unit that stores the correction time notified from the parent station, and an adjustment unit that adjusts a timing of a reply based on the correction time stored in the storage unit so that replies from each of the plurality of child stations to a transmission from the parent station are simultaneously received at the parent station. At least one of the plurality of slave stations is a slave station that does not include the adjustment unit, and the reference time is set to a time required for a slave station that does not include the adjustment unit to receive a reply to a transmission from the master station. . Effect of the Invention

[0007] With the serial transmission communication system according to the present disclosure, time lag in signals transmitted from multiple child stations connected to a parent station is reduced. [Brief description of the drawings]

[0008] [Figure 1] 1 is a configuration diagram of a serial transmission communication system according to a first embodiment. [Diagram 2] FIG. 1 is a diagram illustrating an example of normal communication in a serial transmission communication system. [Diagram 3] 1A and 1B are diagrams illustrating an example of abnormal communication in a serial transmission communication system. [Figure 4] 4 is a timing diagram showing an example of a signal delay in the serial transmission communication system according to the first embodiment. FIG. [Diagram 5] 5 is a flowchart showing an example of the operation of the serial transmission communication system according to the first embodiment. [Figure 6] 5 is a flowchart showing an example of the operation of the serial transmission communication system according to the first embodiment. [Figure 7] 1 is a hardware configuration diagram of a main part of a serial transmission communication system according to a first embodiment. [Figure 8] 10 is a flowchart showing an example of the operation of the serial transmission communication system according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The embodiments for carrying out the present disclosure will be described with reference to the accompanying drawings. In each drawing, the same or corresponding parts are given the same reference numerals, and duplicated descriptions are appropriately simplified or omitted. Note that the subject of the present disclosure is not limited to the following embodiments, and any component of the embodiment may be modified, added, or omitted within the scope of the gist of the present disclosure.

[0010] Embodiment 1 FIG. 1 is a configuration diagram of a serial transmission communication system 1 according to the first embodiment.

[0011] The serial transmission communication system 1 is applied to, for example, an elevator.

[0012] The elevator is applied to a building having a plurality of floors. In the building, a hoistway (not shown) is provided. The hoistway is a vertically long space that spans the plurality of floors. On each floor of the building, a landing (not shown) is provided. The landing of each floor is a location adjacent to the hoistway. On each landing, landing equipment (not shown) is disposed. The landing equipment is elevator equipment disposed on the landing. The landing equipment includes, for example, a landing operation panel. The landing operation panel is equipment that accepts operations such as registering landing calls by elevator users. The elevator includes a car (not shown). The car is equipment that transports users between a plurality of floors by traveling up and down the hoistway. The elevator includes a control device (not shown). The control device is equipment that controls each device of the elevator. For example, the control device collects information on landing calls received by each landing operation panel, and controls the running of the car based on the information such as the landing calls. In this example, the controller is located, for example, in the hoistway or elevator machine room.

[0013] The serial transmission communication system 1 is a system that communicates signals by a serial transmission method. In the serial transmission communication system 1, serial transmission communication is performed, for example, by a UART (Universal Asynchronous Receiver / Transmitter) method. The serial transmission communication system 1 includes a master station 2 and a plurality of slave stations 3. In the serial transmission communication system 1, the plurality of slave stations 3 are connected to the master station 2 in a bus-like multi-drop manner. The master station 2 and each of the slave stations 3 are connected via a communication cable 4. In this example, the master station 2 is mounted on an elevator control device. Each of the slave stations 3 corresponds to one of the elevator hall equipment. Each of the slave stations 3 is mounted on the corresponding hall equipment. The master station 2 and each of the slave stations 3 are responsible for communication between the elevator control device and the hall equipment.

[0014] The master station 2 includes a master station communication board 5. The master station communication board 5 includes a master station communication circuit 6 and a master station processing circuit 7. The master station communication circuit 6 is a circuit that handles communication of signals with external devices of the master station 2. The external devices of the master station 2 include each of the slave stations 3. The master station communication circuit 6 is sometimes called a master station communication I / F (Interface). The master station communication circuit 6 includes, for example, a transmitting circuit that transmits a signal through a communication cable 4, and a receiving circuit that receives a signal through the communication cable 4. The master station processing circuit 7 is a circuit that handles information processing in the master station 2 regarding signals communicated in the serial transmission communication system 1. The master station processing circuit 7 includes a calculation unit 8 and a notification unit 9. The calculation unit 8 is a part that includes a function of calculating a correction time for adjusting the timing of communication for each of the slave stations 3. Here, the correction time for any one of the slave stations 3 is used to adjust the time difference between the time from when the master station 2 transmits a signal to that slave station 3 until the master station 2 receives a reply from that slave station 3, and the reference time. The reference time is set in advance in the serial transmission communication system 1. The notification unit 9 is a part that has a function of notifying any one of the slave stations 3 of the correction time calculated by the calculation unit 8 for that slave station 3, to that slave station 3. The notification unit 9 notifies the slave station 3 via the master station side communication circuit 6.

[0015] Each of the slave stations 3 includes a slave station side communication board 10. The slave station side communication board 10 includes a slave station side communication circuit 11 and a slave station side processing circuit 12. The slave station side communication circuit 11 is a circuit that handles communication of signals with external devices of the slave station 3. The external devices of the slave station 3 include the master station 2. The slave station side communication circuit 11 is sometimes called a slave station side communication I / F. The slave station side communication circuit 11 includes, for example, a transmitting circuit that transmits a signal through the communication cable 4 and a receiving circuit that receives a signal through the communication cable 4. The slave station side processing circuit 12 is a circuit that handles information processing in the slave station 3 regarding the signal communicated in the serial transmission communication system 1. The slave station side processing circuit 12 includes a storage unit 13 and an adjustment unit 14. The storage unit 13 is a part that has a function of storing the correction time notified from the notification unit 9 of the master station 2. The adjustment unit 14 is a portion that has a function of adjusting the timing of a response to a signal received from the master station 2 based on the correction time stored in the storage unit 13.

[0016] Next, an example of a communication abnormality that may occur due to a timing discrepancy between signals transmitted from a plurality of slave stations will be described with reference to FIGS.

[0017] FIG. 2 is a diagram illustrating an example of normal communication in the serial transmission communication system.

[0018] The serial transmission communication system of this example includes a plurality of child stations, eight or more. In the serial transmission system of this example, the parent station and the plurality of child stations are connected in the same manner as the parent station 2 and the plurality of child stations 3 of the serial transmission communication system 1 according to the first embodiment. In this example, one of the child stations transmits reply data R1 to the parent station. Similarly to the child station, the other child stations transmit reply data R2 to R8 to the parent station, respectively. Here, when there is no particular distinction as to which child station the data transmitted to the parent station is from, it may be simply written as reply data R. The plurality of child stations transmit reply data R so that the reply data R is received at the parent station simultaneously. The reply data R from the plurality of child stations is received as composite data S1 at the parent station.

[0019] In this example, each reply data R is 11 bits of data consisting of a start bit, 8 data bits, a parity bit, and a stop bit. Generally, on the signal receiving side, the edge of the start bit is detected, and the H / L (High / Low) level of each bit is detected by the potential at the center position of the bit. When H level and L level are superimposed in the composite data S1, it is treated as negative logic or L active, so the composite result is L level.

[0020] Each data bit, for example, corresponds to one of the floors on a one-to-one basis. Each data bit indicates, for example, the presence or absence of a hall call at the corresponding floor.

[0021] The D2 bit of the reply data R3 and the D4 bit of the reply data R5 are at L level, and all other data bits are at H level. In the combined data S1, the D2 bit and the D4 bit are at L level, and the other data bits are at H level. In this way, the combined data S1 is normally combined by the negative logic. The combined data S1 is normally received by the master station.

[0022] FIG. 3 is a diagram illustrating an example of abnormal communication in the serial transmission communication system.

[0023] In this example, the reply data R0 from one of the slave stations is returned earlier than the other reply data R by more than 1 / 2 bit. At this time, the parent station detects the edge of the start bit of the reply data R0, and the potential of the center position of each bit is detected as the H / L level of the bit based on the timing of the detection. Since the timing of the start bits of the reply data R0 and the other reply data R is shifted, the composite data S2 is not normally combined. That is, the L level of the start bits from the reply data R1 to the reply data R7 is detected as the L level of the D0 bit of the composite data S2. Also, the L level of the D2 bit of the reply data R3 is detected as the L level of the D3 bit of the composite data S2. Also, the L level of the D4 bit of the reply data R5 is detected as the L level of the D5 bit of the composite data S2. In this way, the composite data S2 is not normally combined, and a communication abnormality may occur in the parent station.

[0024] Such a timing shift of the reply data R may occur due to differences in generation or model between the respective slave stations. Such differences between the respective slave stations may occur, for example, when some of the multiple slave stations are replaced for maintenance inspection or the like. When the generations or models are different, a timing shift in the reply may occur due to, for example, differences in electrical characteristics due to new and old electronic components on the circuit mounted on the slave station, or differences in processing time due to differences in software languages ​​used to write programs that run on the slave stations. In addition, in a high-rise building where the communication distance between the master station and the slave station may be long, a timing shift in the reply may occur due to signal delays and the like caused by the influence of signal distortion during the long communication distance.

[0025] FIG. 4 is a timing diagram showing an example of a signal delay in the serial transmission communication system 1 according to the first embodiment.

[0026] Timing T1 is the timing when data transmission processing is started in the parent station processing circuit 7. Timing diagram C1 is a timing diagram showing the output of a start bit in the parent station processing circuit 7. Timing diagram C2 is a timing diagram showing the output of a start bit in the parent station communication circuit 6. Timing diagram C3 is a timing diagram showing the rounding of a signal waveform in the communication cable 4. Timing diagram C4 is a timing diagram showing the input of a start bit in the child station communication circuit 11. Timing diagram C5 is a timing diagram showing the input of a start bit in the child station processing circuit 12. Timing T2 is the timing when data reception processing is started in the child station processing circuit 12.

[0027] The time Δt1 represents the bit discrimination time from the edge of the start bit to the center position of the bit. The time Δt2 is the total signal delay time including the bit discrimination time Δt1 from when the data transmission process of the master station processing circuit 7 starts at timing T1 to when the data reception process of the slave station processing circuit 12 starts at timing T2. In ideal serial transmission communication, the total signal delay time Δt2 is equal to the bit discrimination time Δt1. In real serial transmission communication, the total signal delay time Δt2 is longer than the bit discrimination time Δt1 due to factors such as the processing time in each of the master station processing circuit 7, the master station communication circuit 6, the slave station communication circuit 11, and the slave station processing circuit 12, and the rounding of the signal waveform in the communication cable 4. In addition, the rounding of the signal waveform increases in proportion to the length of the communication cable 4, so the effect on the total signal delay time Δt2 also increases accordingly. In addition, in the return path from the slave station 3 to the master station 2, a delay similar to that in the outward path from the master station 2 to the slave station 3 occurs. The total signal delay time Δt2 is a time that is taken into consideration in the design of the serial transmission communication system 1, and this time itself is not a problem. However, if the total signal delay time Δt2 varies among the slave stations 3, there is a possibility that a communication abnormality such as that shown in Fig. 3 will occur in the master station 2 due to a shift in the timing of data communication. Variation in the total signal delay time Δt2 among the slave stations 3 can occur, for example, in the following situations.

[0028] Variations in the total signal delay time Δt2 can occur, for example, when one of the slave stations 3 is replaced with one of a different generation or model from the other slave stations 3. In general, when electronic components are replaced with new ones, the signal delay time tends to become shorter due to improved performance. For this reason, the total signal delay time Δt2 between the replaced slave station 3 and the master station 2 tends to become shorter. On the other hand, the total signal delay time Δt2 between the other slave stations 3 and the master station 2 does not change, which can cause a deviation in the timing of data communication.

[0029] Also, the variation in the total signal delay time Δt2 may occur, for example, when the communication speed is increased only in one of the slave stations 3. The communication speed is increased, for example, by replacing parts or the entire slave station 3, or by updating the software. When the communication speed of one of the slave stations 3 is doubled, for example, the bit width of the slave station 3 is halved. At this time, the bit identification time Δt1 of the slave station 3 is also halved, and the total signal delay time Δt2 is also shortened. On the other hand, the total signal delay time Δt2 between the other slave stations 3 and the master station 2 does not change, and this may cause a shift in the timing of data communication.

[0030] The serial transmission communication system 1 is equipped with a function for suppressing such a time lag in signals transmitted from a plurality of slave stations 3 connected to a master station 2.

[0031] Next, an example of the operation of the serial transmission communication system 1 will be described with reference to FIGS. 5 and 6 are flowcharts showing an example of the operation of the serial transmission communication system 1 according to the first embodiment.

[0032] FIG. 5 shows an example of the operation of the master station 2 in relation to calculation of the correction time.

[0033] In step S1, the master station processing circuit 7 judges whether the operation mode of the master station 2 is the adjustment mode. Here, the adjustment mode is a mode for performing dedicated data communication different from normal data communication, which adjusts the timing of a reply from the slave station 3. The operation mode is switched from the normal mode to the adjustment mode through an information terminal such as a PC (Personal Computer) that can access the master station 2. Alternatively, the operation mode of the master station 2 may be automatically switched to the adjustment mode when the master station 2 is started. Alternatively, the operation mode of the master station 2 may be automatically switched to the adjustment mode at a preset timing. If the operation mode is the adjustment mode, the serial transmission communication system 1 proceeds to the process of step S2. On the other hand, if the operation mode is not the adjustment mode, the serial transmission communication system 1 proceeds to the END process and performs normal data communication.

[0034] In step S2, the parent station processing circuit 7 sets an index N, which indicates a child station 3 for which a correction time is to be calculated, to 1. In the serial transmission communication system 1 of this example, natural number indexes are assigned to each child station 3 in order starting from 1. Thereafter, the serial transmission communication system 1 proceeds to the process of step S3.

[0035] In step S3, the parent station processing circuit 7 transmits a control signal for calculating the correction time to the target child station 3 through the parent station communication circuit 6. Here, the control signal for calculating the correction time is a control signal for requesting a reply from the child station 3. Thereafter, the serial transmission communication system 1 proceeds to the process of step S4.

[0036] In step S4, the master station processing circuit 7 determines whether there is a reply from the target slave station 3 through the master station communication circuit 6. If there is a reply, the serial transmission communication system 1 proceeds to processing in step S5. On the other hand, if there is no reply within a preset time, the serial transmission communication system 1 proceeds to END processing and performs normal data communication. Note that if there is no reply within the preset time and there is a slave station 3 that has not yet been subject to calculation of the correction time, the serial transmission communication system 1 may add 1 to the index N and proceed to processing in step S3.

[0037] In step S5, the calculation unit 8 measures the response time from when the control signal for calculating the correction time is transmitted to the target slave station 3 until when the response is received from the slave station 3. Thereafter, the serial transmission communication system 1 proceeds to the process of step S6.

[0038] In step S6, the calculation unit 8 compares the measured response time with a reference time. The reference time is set in advance in the master station 2. The calculation unit 8 calculates, for example, a time difference between the measured response time and the reference time. After that, the serial transmission communication system 1 proceeds to the process of step S7.

[0039] In step S7, the calculation unit 8 calculates a correction time based on the result of comparing the measured response time with the reference time, for example, as follows. If the measured response time is shorter than the reference time, the calculation unit 8 calculates a positive correction time according to the time difference between the response time and the reference time so as to delay the timing of the response from the slave station 3. On the other hand, if the measured response time is longer than the reference time, the calculation unit 8 calculates a negative correction time according to the time difference between the response time and the reference time so as to advance the timing of the response from the slave station 3. After the calculation unit 8 calculates the correction time, the serial transmission communication system 1 proceeds to the process of step S8.

[0040] In step S8, the notification unit 9 notifies the slave station 3 of the correction time calculated by the calculation unit 8 for the target slave station 3 together with a correction command through the parent station side communication circuit 6. The correction command is a control signal that requests the slave station 3 to adjust the communication timing. Thereafter, the serial transmission communication system 1 proceeds to the process of step S9.

[0041] In step S9, the parent station processing circuit 7 adds 1 to the index N representing the child station 3 for which the correction time is to be calculated. After that, the serial transmission communication system 1 proceeds to the process of step S3. If there are no more child stations 3 for which the correction time is not to be calculated, the serial transmission communication system 1 may proceed to the END process and perform normal data communication.

[0042] FIG. 6 shows an example of the operation of the slave station 3 in relation to the adjustment of communication timing.

[0043] In step S10, the slave station processing circuit 12 determines whether or not a correction command has been received from the master station 2 through the slave station communication circuit 11. If a correction command has been received, the serial transmission communication system 1 proceeds to processing in step S11. On the other hand, if a correction command has not been received, the serial transmission communication system 1 proceeds to END processing and performs normal data communication.

[0044] In step S11, the child station processing circuit 12 receives data accompanying the correction command through the child station communication circuit 11. The data accompanying the correction command includes information on the correction time calculated by the calculation unit 8. The storage unit 13 stores the data accompanying the correction command. Thereafter, the serial transmission communication system 1 proceeds to the process of step S12.

[0045] In step S12, the adjustment unit 14 reads information on the correction time from the data stored in the storage unit 13. After that, the serial transmission communication system 1 proceeds to the process of step S13.

[0046] In step S13, the adjustment unit 14 adjusts the delay time of the reply based on the read correction time. The delay time is the time by which the reply to the signal transmitted from the master station 2 in normal communication is delayed in the slave station 3. When the correction time is a positive time, the adjustment unit 14 adds the correction time to the delay time to adjust the timing of the reply to the master station 2 to be delayed. When the correction time is a negative time, the adjustment unit 14 subtracts the absolute value of the correction time from the delay time to adjust the timing of the reply to the master station 2 to be advanced. In this way, the adjustment unit 14 adjusts the reply timing so that the replies from each slave station 3 to the transmission from the master station 2 are simultaneously received by the master station 2 in normal communication. Thereafter, the serial transmission communication system 1 proceeds to END processing and performs normal data communication.

[0047] As described above, the serial transmission communication system 1 according to the first embodiment includes the parent station 2 and a plurality of child stations 3. The child stations 3 are connected to the parent station 2 in a bus-like multi-drop manner. Each child station 3 replies to a transmission from the parent station 2. The parent station 2 includes a calculation unit 8 and a notification unit 9. The calculation unit 8 calculates a correction time for each child station 3 based on a time difference between a preset reference time and a time until a reply to a transmission from the parent station 2 is received. The correction time is used to adjust the time difference. The notification unit 9 notifies each child station 3 of the correction time calculated by the calculation unit 8. Each child station 3 includes a storage unit 13 and an adjustment unit 14. The storage unit 13 stores the correction time notified by the notification unit 9. The adjustment unit 14 adjusts the timing of the reply based on the correction time stored in the storage unit 13 so that the replies from each child station 3 to the transmission from the parent station 2 are simultaneously received by the parent station 2.

[0048] With this configuration, the timing of the reply is adjusted by the correction time calculated based on the time difference between the measured reply time and the reference time, so that the replies from each of the slave stations 3 to the transmission from the master station 2 are received simultaneously by the master station 2. That is, the time lag in the signals transmitted from the multiple slave stations 3 connected to the master station 2 is suppressed. Since the reply timing is individually adjusted for each slave station 3 based on the reply time, the lag in the signals received by the master station 2 is suppressed even when slave stations 3 of different generations or models are mixed, or when the communication speed of any of the slave stations 3 is increased to improve communication efficiency. This suppresses the occurrence of communication abnormalities.

[0049] The master station 2 is provided in a control device for the elevator. Each slave station 3 is provided in any one of a plurality of hall devices in the elevator.

[0050] Generally, the product life of an elevator is longer than the life of electronic components, so multiple hall equipment, each equipped with a slave station 3, may be replaced individually. For this reason, multiple hall equipment of an elevator may be of different generations or models. Even in such cases, the occurrence of communication abnormalities between multiple hall equipment and control devices is suppressed, thereby further improving the operating rate of the elevator.

[0051] Next, an example of a hardware configuration of the serial transmission communication system 1 will be described with reference to FIG. FIG. 7 is a hardware configuration diagram of a main part of the serial transmission communication system 1 according to the first embodiment.

[0052] Each function of the serial transmission communication system 1 may be realized by a processing circuit. The processing circuit includes at least one processor 100a and at least one memory 100b. The processing circuit may include at least one dedicated hardware 200 together with or in place of the processor 100a and the memory 100b.

[0053] When the processing circuit includes the processor 100a and the memory 100b, each function of the serial transmission communication system 1 is realized by software, firmware, or a combination of software and firmware. At least one of the software and firmware is written as a program. The program is stored in the memory 100b. The processor 100a realizes each function of the serial transmission communication system 1 by reading and executing the program stored in the memory 100b.

[0054] The processor 100a is also called a CPU (Central Processing Unit), a processing device, an arithmetic device, a microprocessor, a microcomputer, or a DSP. The memory 100b is composed of a non-volatile or volatile semiconductor memory such as a RAM, a ROM, a flash memory, an EPROM, or an EEPROM.

[0055] Where the processing circuitry comprises dedicated hardware 200, the processing circuitry may be implemented, for example, as a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof.

[0056] Each function of the serial transmission communication system 1 can be realized by a processing circuit. Alternatively, each function of the serial transmission communication system 1 can be realized collectively by a processing circuit. Some of the functions of the serial transmission communication system 1 may be realized by dedicated hardware 200, and the other parts may be realized by software or firmware. In this way, the processing circuit realizes each function of the serial transmission communication system 1 by dedicated hardware 200, software, firmware, or a combination of these.

[0057] Embodiment 2 In the second embodiment, differences from the example disclosed in the first embodiment will be described in particular detail. For features not described in the second embodiment, any of the features of the example disclosed in the first embodiment may be adopted.

[0058] In the serial transmission communication system 1, some of the multiple slave stations 3 may not be equipped with a function for adjusting the timing of a reply. In this example, some of the multiple slave stations 3 are slave stations 3 that do not include an adjustment unit 14. Note that the other part of the multiple slave stations 3 includes the adjustment unit 14.

[0059] FIG. 8 is a flowchart showing an example of the operation of the serial transmission communication system 1 according to the second embodiment.

[0060] 8 shows an example of the operation of the master station 2 in the case where a slave station 3 not equipped with an adjustment unit 14 is present. The serial transmission communication system 1 may operate in the same manner even if there is no reply from some of the slave stations 3 due to a disconnection or a failure. The process of FIG. 8 is performed based on, for example, an operation through an information terminal such as a PC that can access the master station 2. Alternatively, the process of FIG. 8 may be performed automatically when the master station 2 is started up. Alternatively, the process of FIG. 8 may be performed automatically at a preset timing.

[0061] In step S14, the master station processing circuit 7 sets the index N, which indicates the slave station 3 to be the target of the connection confirmation, to 1. After that, the serial transmission communication system 1 proceeds to the process of step S15.

[0062] In step S15, the master station processing circuit 7 transmits a control signal for connection confirmation to the target slave station 3 through the master station communication circuit 6. Here, the control signal for connection confirmation is a control signal requesting a reply from the slave station 3. Here, a slave station 3 equipped with an adjustment unit 14 replies with data incorporating an adjustment possible flag when receiving a control signal for connection confirmation from the master station 2. On the other hand, a slave station 3 not equipped with an adjustment unit 14 replies with data not incorporating an adjustment possible flag when receiving a control signal for connection confirmation from the master station 2. Thereafter, the serial transmission communication system 1 proceeds to the process of step S16.

[0063] In step S16, the master station processing circuit 7 determines whether there is a reply from the target slave station 3 through the master station communication circuit 6. If there is a reply, the serial transmission communication system 1 proceeds to step S17. On the other hand, if there is no reply within a preset time, the serial transmission communication system 1 proceeds to step S19.

[0064] In step S17, the parent station processing circuit 7 checks whether or not an adjustment possible flag is included in the reply from the target child station 3. Thereafter, regardless of the presence or absence of the adjustment possible flag, the serial transmission communication system 1 proceeds to the process of step S18.

[0065] In step S18, the calculation unit 8 measures the response time from when a control signal for confirming connection is transmitted to the target slave station 3 until when a response is received from the slave station 3. Thereafter, the serial transmission communication system 1 proceeds to the process of step S19.

[0066] In step S19, the parent station processing circuit 7 stores the reply information from the target child station 3. The reply information includes information such as whether or not there is a reply to the control signal for connection confirmation, whether or not there is an adjustable flag if there is a reply, and the measured reply time if there is a reply. After that, the serial transmission communication system 1 proceeds to the process of step S20.

[0067] In step S20, the parent station processing circuit 7 determines whether there is a child station 3 that has not yet been subject to connection confirmation. If the result of the determination is Yes, the serial transmission communication system 1 proceeds to processing in step S21. If the result of the determination is No, the serial transmission communication system 1 proceeds to END processing and performs normal data communication.

[0068] In step S21, the master station processing circuit 7 adds 1 to the index N representing the slave station 3 to be checked for connection. After that, the serial transmission communication system 1 proceeds to the process of step S15.

[0069] The reply information collected by such connection confirmation is used, for example, to calculate the correction time in the calculation unit 8. The calculation unit 8 determines whether or not the slave station 3 includes the adjustment unit 14 based on the presence or absence of an adjustment possible flag in the reply from the slave station 3. The calculation unit 8 sets, for example, the reply time measured for the slave station 3 that does not include the adjustment unit 14 as the reference time. In addition, when there are multiple slave stations 3 that do not include the adjustment unit 14, the calculation unit 8 may set, for example, the earliest reply time among the reply times calculated for the slave stations 3 that do not include the adjustment unit 14 as the reference time. Thereafter, the calculation unit 8 calculates the correction time by, for example, the process of FIG. 5. Here, the process of FIG. 5 and the process of FIG. 8 may be performed in an integrated manner. In this case, the parent station side processing circuit 7 may omit step S1 in FIG. 5 and proceed to step S2.

[0070] As described above, in the serial transmission communication system 1 according to the second embodiment, some of the multiple child stations 3 are child stations 3 equipped with the storage unit 13 and the adjustment unit 14. Others of the multiple child stations 3 are child stations 3 not equipped with the adjustment unit 14. The reference time is set to the time required for a child station 3 not equipped with the adjustment unit 14 to receive a reply to a transmission from the parent station 2.

[0071] With this configuration, the timing of the response is adjusted based on the response time of the slave station 3 that does not have the adjustment unit 14, so that even when there are slave stations 3 that do not have the adjustment unit 14, the delay in the signal received by the master station 2 can be suppressed. This suppresses the occurrence of communication abnormalities. [Explanation of symbols]

[0072] 1 serial transmission communication system, 2 parent station, 3 child station, 4 communication cable, 5 parent station communication board, 6 parent station communication circuit, 7 parent station processing circuit, 8 calculation unit, 9 notification unit, 10 child station communication board, 11 child station communication circuit, 12 child station processing circuit, 13 storage unit, 14 adjustment unit, 100a processor, 100b memory, 200 dedicated hardware

Claims

1. The parent station, a plurality of slave stations connected to the master station in a bus-like multi-drop manner and replying to transmissions from the master station; A serial transmission communication system comprising: The master station includes: a calculation unit that calculates a correction time for adjusting a time difference based on a time difference between a time taken for a reply to a transmission from the master station and a preset reference time for each of the slave stations; a notification unit that notifies each of the plurality of child stations of the correction time calculated by the calculation unit; Equipped with At least one of the plurality of child stations a storage unit that stores the correction time notified by the notification unit; an adjustment unit that adjusts a timing of a reply based on the correction time stored in the storage unit so that a reply from each of the plurality of slave stations in response to a transmission from the master station is received simultaneously by the master station; Equipped with At least one of the plurality of slave stations is a slave station that does not include the adjustment unit, The reference time is set to a time required for a slave station that does not include the adjustment unit to receive a reply to a transmission from the master station. Serial transmission communication system.

2. The master station is provided in an elevator control device, Each of the plurality of slave stations is provided in any one of a plurality of hall equipment in the elevator.

2. The serial transmission communication system according to claim 1.

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