JP6969298B2 - Communication equipment, restoration method, restoration program and image forming equipment - Google Patents

Description

The present invention relates to a communication device, a recovery method, a recovery program, and an image forming device.

Conventionally, as a control method in a large-scale commercial printing machine or the like, a method is known in which each module has a CPU (Central Processing Unit) and the control is distributed by executing processing by each CPU. In the communication between the CPUs of each module, a communication configuration (network communication) using a two-wire communication line may be used. In such network communication, it is preferable that a plurality of modules communicate using one bus, and the modules located at both ends are terminated in order to suppress signal reflection. Commercial printing machines are expandable, and the presence or absence of each module and the layout configuration differ depending on the presence or absence of options. Therefore, each module has a resistance for termination, and the CPU controls the termination connection of the connected modules. As a result, in a commercial printing machine or the like, it is possible to terminate even if the arrangement configuration is different, and a communication environment can be realized.

However, if an abnormality such as a disconnection of the bus connecting the modules occurs, the termination will not function and it will be difficult to maintain the communication environment of all the modules. Therefore, in Patent Document 1 (Japanese Unexamined Patent Publication No. 2003-304265), when an abnormality such as a disconnection occurs in the bus of a two-wire communication line, the preliminary resistance of the module arranged near the abnormal portion is used as a terminating resistor. A technology for restoring communication between a newly terminated module and a module located on the opposite side to the abnormal location side by instructing the main module located at the end to connect is disclosed. Has been done.

However, the above-mentioned conventional technique has a problem that there are restrictions on the arrangement and configuration of modules. Specifically, in the prior art, since the module located at the end is the main module, there are restrictions on the arrangement configuration of the modules. That is, the above-mentioned method of the prior art cannot be applied to a commercial printing machine or the like in which the main module does not exist at the end.

The present invention has been made in view of the above, and an object of the present invention is to realize abnormality detection and communication recovery without limiting the arrangement configuration of modules.

In order to solve the above-mentioned problems and achieve the object, the communication device according to the present invention is a communication device capable of communicating with a plurality of communication stations via a two-wire communication line, and is at least one of the plurality of communication stations. The first communication station indicating one has a resistor that can be connected to the two-wire communication line, a detection unit that detects that an abnormality has occurred in the two-wire communication line, and a detection unit that detects the occurrence of the abnormality. In this case, a connection control unit that controls the connection of the resistor to the two-wire communication line, and a communication control unit that controls individual transmission of a response request to another communication station different from the first communication station. The detection unit divides the other communication stations into two or more groups, and includes the location where the abnormality occurs based on the response to the response request from the other communication stations belonging to each group. The group is specified, and the location where the abnormality occurs is specified based on the response to the response request from another communication station belonging to the specified group .

According to the present invention, there is an effect that abnormality detection and communication recovery can be realized without limiting the arrangement configuration of modules.

FIG. 1 is a diagram showing a configuration example of a communication device according to the first embodiment. FIG. 2 is a diagram illustrating an example of communication recovery when a disconnection failure occurs according to the first embodiment. FIG. 3 is a block diagram showing a functional configuration example of the communication station according to the first embodiment. FIG. 4 is a flowchart showing an example of the flow of the communication abnormality detection process according to the first embodiment. FIG. 5 is a block diagram showing a functional configuration example of the communication station according to the second embodiment. FIG. 6 is a flowchart showing an example of the flow of the abnormal portion detection process according to the second embodiment. FIG. 7 is a flowchart showing an example of the flow of the terminal connection instruction processing according to the second embodiment. FIG. 8 is a diagram showing an example of a time chart from the occurrence of a disconnection failure of a two-wire communication line to the restoration of communication. FIG. 9 is a diagram showing a modified example of the terminal circuit. FIG. 10 is a flowchart showing an example of the flow of communication abnormality detection processing at the time of data transmission. FIG. 11 is a flowchart showing an example of the flow of the abnormality location detection process by individual transmission. FIG. 12 is a diagram showing a configuration example of a communication device when the number of communication stations is n. FIG. 13 is a flowchart showing an example of the flow of the abnormality location detection process when the number of communication stations is n. FIG. 14 is a configuration diagram showing an example applied to a printing machine. FIG. 15 is a configuration diagram showing an example applied to the image forming apparatus. FIG. 16 is a block diagram showing an example applied to a refrigerator.

Hereinafter, embodiments of the communication device, the recovery method, the recovery program, and the image forming apparatus according to the present invention will be described with reference to the accompanying drawings. The present invention is not limited to the following embodiments. In addition, the embodiments can be appropriately combined as long as the contents do not contradict each other.

(Embodiment 1)
The configuration of the communication device 10 according to the first embodiment will be described with reference to FIG. FIG. 1 is a diagram showing a configuration example of the communication device 10 according to the first embodiment.

As shown in FIG. 1, the communication device 10 includes a communication station 31, a communication station 32, a communication station 33, a communication station 34, and a communication station 35. Each communication station included in the communication device 10 corresponds to a module. In FIG. 1, a communication device 10 having five communication stations is taken as an example, but the number of communication stations is not limited to five, and may be any number as long as it is three or more. In addition, a number is assigned to each communication station. In the example of FIG. 1, the communication station 31 is the communication station (1), the communication station 32 is the communication station (2), the communication station 33 is the communication station (3), the communication station 34 is the communication station (4), and the communication station 35 is. A number is assigned as the communication station (5). In the following, such a number may be referred to as a "communication station number".

Each communication station having a CPU shares a pair of bus lines with two lines for communication. This is called a two-wire communication line. The bus line 1 (CAN_L: Controller Area Network_Low) and the bus line 2 (CAN_H: Controller Area Network_High) forming the two-wire communication line transmit a differential signal. The CPU 41, CPU 42, CPU 43, CPU 44, and CPU 45 of each communication station control communication and terminal connection. Of these, the CPU 43 is the main CPU that manages the entire communication station included in the communication device 10. The communication station 33 having the main CPU 43 corresponds to the "first communication station". The terminal circuit 51, the terminal circuit 52, the terminal circuit 53, the terminal circuit 54, and the terminal circuit 55 of each communication station have a resistor and a switch, and can switch the terminal connection according to a signal from each CPU. In the normal state, the communication station 31 and the communication station 35 arranged at the ends are terminated, and the termination is turned on in the termination circuit 51 and the termination circuit 55. Further, communication stations other than the main communication station 33 periodically transmit a signal indicating normal operation to the communication station 33, in addition to normal data transmission / reception. In the following, such a signal may be referred to as a heartbeat signal.

Next, with reference to FIG. 2, communication recovery in the event of a disconnection failure according to the first embodiment will be described. FIG. 2 is a diagram illustrating an example of communication recovery when a disconnection failure occurs according to the first embodiment.

In FIG. 2, a case where a disconnection failure occurs in CAN_H between the communication station 31 and the communication station 32 will be taken as an example. At this time, although the terminal circuit 51 of the communication station 31 has the terminal connection turned on, it does not function as a terminating resistor due to a disconnection failure. Therefore, communication between each communication station becomes impossible. Therefore, the communication station 33 detects that an abnormality has occurred between the communication station 31 and the communication station 32, and turns on the switch of its own terminating circuit 53 to function as a terminating resistor. As a result, communication can be performed at the communication stations 32 to 35, excluding the communication station 31 among the two-wire communication lines.

Next, the functional configuration of the communication station 33 according to the first embodiment will be described with reference to FIG. FIG. 3 is a block diagram showing a functional configuration example of the communication station 33 according to the first embodiment. Note that communication stations other than the communication station 33, which is the main communication station, may have the same functional configuration.

As shown in FIG. 3, the communication station 33 has a communication control unit 61, a storage unit 62, a detection unit 63, a connection control unit 64, an output control unit 65, and a state management unit 66.

The communication control unit 61 controls various communications using a two-wire communication line between the communication station 33 and another communication station different from the communication station 33 according to the control of the state management unit 66. For example, the communication control unit 61 controls transmission / reception of various data exchanged between communication stations included in the communication device 10. Here, the communication control unit 61 converts the transmission command acquired from the storage unit 62 according to the communication method at the time of data transmission, and then transmits the data. Further, the communication control unit 61 converts the received data and stores it in the storage unit 62.

Specifically, the communication control unit 61 performs broadband transmission (broad transmission) to all other communication stations and requests a response to the broadband transmission. In addition, the communication control unit 61 controls reception of a heartbeat signal periodically transmitted from another communication station, in addition to normal data transmission / reception. Upon receiving the heartbeat signal, the communication control unit 61 turns on the timer mounted on the communication station 33 and measures the time until the heartbeat signal is received. Here, if the heartbeat signal cannot be received (within a predetermined time) due to a timeout, the above-mentioned broadband transmission is performed. The communication control unit in another communication station controls the periodic transmission of the heartbeat signal.

The detection unit 63 detects that an abnormality has occurred in the two-wire communication line. More specifically, the detection unit 63 acquires the received data stored in the storage unit 62 under the control of the state management unit 66, and detects that an abnormality has occurred in the two-wire communication line. Specifically, the detection unit 63 detects that an abnormality has occurred in the two-wire communication line when the heartbeat signal is not received within a predetermined time due to a timeout or the like. Then, the detection unit 63 detects that there is a disconnection failure in the two-wire communication line when there is no response from any communication station after the broadband transmission is performed by the communication control unit 61. On the other hand, if there is a response from any of the communication stations, the detection unit 63 detects that the abnormality is caused by a cause other than the disconnection failure.

For example, the abnormality caused by a cause other than the disconnection failure is caused by the soft reset being performed at the communication station 31 or the communication station 35 which is the end communication station. It is considered that the soft reset is performed, so that the terminal connection is temporarily turned off, communication cannot be performed between all the communication stations, and the heartbeat signal cannot be transmitted. However, when the soft reset in the communication station 31 and the communication station 35 is completed and the terminal connection is turned on again, communication can be performed between all the communication stations, and the state returns to the state where the heartbeat signal can be transmitted. .. It should be noted that the processing for the occurrence of an abnormality due to a cause other than the disconnection failure is omitted in the present embodiment.

The connection control unit 64 controls the connection of the resistor to the two-wire communication line according to the control of the state management unit 66. More specifically, the connection control unit 64 turns on the terminal connection of the terminal circuit 53 of the communication station 33 when the detection unit 63 detects that a disconnection failure has occurred in the two-wire communication line. Output a signal for. When the terminal connection of the terminal circuit 53 of the communication station 33 is turned ON, the communication stations 32 to 35, excluding the communication station 31 among the two-wire communication lines, are in a state where communication can be performed.

The output control unit 65 controls the output of various information according to the control of the state management unit 66. More specifically, the output control unit 65 displays information such as that an abnormality has occurred in the 2-wire communication line, and more specifically, that a disconnection failure has occurred in the 2-wire communication line (for example,). Output to the operation panel, etc.). The state management unit 66 manages the state of each of the above-mentioned units.

Next, the flow of the communication abnormality detection process according to the first embodiment will be described with reference to FIG. FIG. 4 is a flowchart showing an example of the flow of the communication abnormality detection process according to the first embodiment. In FIG. 4, among the communication stations included in the communication device 10, the case where the communication station 33, which is a communication station arranged at a position other than the end, detects an abnormality in the two-wire communication line is taken as an example.

As shown in FIG. 4, the communication station 33 turns on the timer (step S101). Such a timer is used to confirm whether communication is normally performed depending on whether or not a heartbeat signal sent from another communication station can be received. Then, the communication station 33 determines whether or not the heartbeat signal has been received (step S102). At this time, when the communication station 33 receives the heartbeat signal (step S102: Yes), the communication station 33 resets the timer (step S103). After the timer is reset, the process of step S101 is executed again. On the other hand, when the communication station 33 has not received the heartbeat signal (step S102: No), the communication station 33 determines whether or not a time-out has occurred based on the turned-on timer (step S104).

At this time, if it is determined that the time-out has not occurred (step S104: No), the communication station 33 re-executes the process of step S102. On the other hand, when the communication station 33 determines that the time-out has occurred (step S104: Yes), the communication station 33 performs broadband transmission and requests a response from all the other communication stations (step S105). Then, the communication station 33 determines whether or not one or more response signals have been received (step S106). At this time, the communication station 33 detects that a disconnection failure has occurred when no response signal from another communication station can be received (step S106: No), and is its own (main) termination circuit. Turn on the terminal connection of the terminal circuit 53 (step S107). On the other hand, when the communication station 33 can receive one or more response signals (step S106: Yes), since an abnormality due to a cause other than the disconnection failure has occurred, the communication station 33 executes an abnormality process according to this (step S106: Yes). Step S108).

As described above, the communication station 33 detects an abnormality in the 2-wire communication line depending on whether or not the heartbeat signal can be received, and the disconnection failure of the 2-wire communication line occurs in response to the response to the broadband transmission. Is detected and its own terminal connection is turned on, so that it is possible to detect an abnormality and restore communication without setting restrictions on the module arrangement configuration.

(Embodiment 2)
The functional configuration of the communication station 33 according to the second embodiment will be described with reference to FIG. FIG. 5 is a block diagram showing a functional configuration example of the communication station 33 according to the second embodiment. In FIG. 5, the same reference numerals are given to the same configurations as the functional configurations of the communication station 33 according to the first embodiment, and detailed description thereof may be omitted.

As shown in FIG. 5, the communication station 33 includes a communication control unit 61, a storage unit 62, a detection unit 63a, a connection control unit 64, an output control unit 65a, a state management unit 66, and an instruction unit 67a. Have.

The detection unit 63a identifies a location where an abnormality occurs in the two-wire communication line. More specifically, the detection unit 63a confirms from which communication station the response is received in response to the broadband transmission, and identifies the location where the abnormality occurs in the two-wire communication line. For example, when the detection unit 63a does not receive a response from the communication station 32 having the communication station number "2" after the broadband transmission by the communication control unit 61, the detection unit 63a and the communication station 32 having the communication station number "2". It is specified that a disconnection failure has occurred with the communication station 33 having the communication station number "3". Here, the detection unit 63a receives the response from the communication station 32 having the communication station number "2" and not receiving the response from the communication station 31 having the communication station number "1". It is specified that a disconnection failure has occurred between the communication station 31 which is "1" and the communication station 32 which is the communication station number "2".

Further, the detection unit 63a receives the response from the communication station 31 having the communication station number “1” and does not receive the response from the communication station 34 having the communication station number “4”, the communication station number “3”. It is specified that a disconnection failure has occurred between the communication station 33, which is the communication station 33, and the communication station 34, which is the communication station number “4”. Further, the detection unit 63a receives the response from the communication station 34 having the communication station number “4” and does not receive the response from the communication station 35 having the communication station number “5”, the communication station number “4”. It is specified that a disconnection failure has occurred between the communication station 34, which is the communication station 34, and the communication station 35, which is the communication station number “5”. When the response signal is received from all of the other communication stations, the detection unit 63a detects that the abnormality is not caused by a disconnection failure but is caused by a soft reset or terminal instability.

For example, the abnormality due to the soft reset is due to the fact that the termination is temporarily turned off because the reset is performed by the communication station arranged at the end included in the communication device 10. In addition, for example, an abnormality due to terminating instability is caused by an unstable situation such as software runaway or hardware termination not being connected, or a communication line near the terminating resistor is broken. Is.

In the above-mentioned identification of the abnormal location of the disconnection failure, it is first determined whether or not the response from the communication station 32 having the communication station number "2" smaller than the communication station number "3" of the main communication station 33 is received. The case is taken as an example, but it is not limited to this. For example, in identifying an abnormal location of a disconnection failure, it is first determined whether or not a response from a communication station 34 having a communication station number "4" larger than the communication station number "3" of the main communication station 33 is received. Is also good.

The instruction unit 67a instructs a terminal connection to another communication station. More specifically, after the detection unit 63a identifies the abnormal location, the indicating unit 67a makes a terminal connection to another communication station located next to the communication station 33 from the location where the abnormality occurs. Instruct. The instruction of the terminal connection by the instruction unit 67a is transmitted and controlled by the communication control unit 61. For example, when the detection unit 63a detects that a disconnection failure has occurred between the communication station 31 and the communication station 32, the instruction unit 67a instructs the communication station 32 to make a terminal connection. Further, when the detection unit 63a detects that a disconnection failure has occurred between the communication station 34 and the communication station 35, the instruction unit 67a instructs the communication station 34 to make a terminal connection. When the referent of the terminal connection is the communication station 33 (self), the communication station 33 is in a state of being already terminated (terminal connection ON), so that the terminal connection is maintained. Communication between communication stations is restored in response to the instruction from the instruction unit 67a. After instructing another communication station to make a terminal connection, the connection control unit 64 outputs a signal for switching the terminal connection of the terminal circuit 53 of the communication station 33 from ON to OFF.

The output control unit 65a controls the output of various information according to the control of the state management unit 66. More specifically, the output control unit 65a outputs information on the location of the disconnection failure to the display device in order to notify the user of the location of the disconnection failure specified by the detection unit 63a.

Next, the flow of the abnormality location detection process according to the second embodiment will be described with reference to FIG. FIG. 6 is a flowchart showing an example of the flow of the abnormal portion detection process according to the second embodiment.

As shown in FIG. 6, the communication station 33 performs broadband transmission and requests a response from all other communication stations (step S201). After the broadband transmission, the communication station 33 is in a state of waiting for receiving a response from another communication station (step S202). Then, the communication station 33 determines whether or not a response has been received from the communication station 32 whose communication station number is "2" (step S203). At this time, when the response is not received from the communication station 32 (step S203: No), the communication station 33 has the communication station number "2" and the communication station number "3" where the disconnection failure occurs. It is specified that it is between the communication station 33 and the communication station 33 (step S204). Here, the communication station 33 stores "3" in the variable T_Node in order to record the communication station to be terminated and connected (the communication station to be instructed to be terminated), and ends the abnormality location detection process.

On the other hand, when the response is received from the communication station 32 (step S203: Yes), the communication station 33 determines whether or not the response is received from the communication station 31 whose communication station number is "1" (step S203: Yes). S205). At this time, when the response is not received from the communication station 31 (step S205: No), the communication station 33 has the communication station number "1" and the communication station number "2" where the disconnection failure occurs. It is specified that it is between the communication station 32 and the communication station 32 (step S206). Here, the communication station 33 stores "2" in the variable T_Node in order to record the communication station to be terminally connected, and ends the abnormality location detection process.

On the other hand, when the response is received from the communication station 31 (step S205: Yes), the communication station 33 determines whether or not the response is received from the communication station 34 whose communication station number is "4" (step S205: Yes). S207). At this time, when the response is not received from the communication station 34 (step S207: No), the communication station 33 has the communication station number "3" and the communication station number "4" where the disconnection failure occurs. It is specified that it is between the communication station 34 and the communication station 34 (step S208). Here, the communication station 33 stores "3" in the variable T_Node in order to record the communication station to be terminally connected, and ends the abnormality location detection process.

On the other hand, when the response is received from the communication station 34 (step S207: Yes), the communication station 33 determines whether or not the response is received from the communication station 35 whose communication station number is "5" (step S207: Yes). S209). At this time, when the response is not received from the communication station 35 (step S209: No), the communication station 33 has the communication station number "4" and the communication station number "5" where the disconnection failure occurs. It is specified that it is between the communication station 35 and the communication station 35 (step S210). Here, the communication station 33 stores "4" in the variable T_Node in order to record the communication station to be terminally connected, and ends the abnormality location detection process.

On the other hand, when the response is received from the communication station 35 (step S209: Yes), the communication station 33 has received the response from all the other communication stations so far, so that the abnormality is not caused by the disconnection failure. , It is identified as an abnormality due to soft reset, unstable termination, or the like (step S211). Here, since the communication station 33 does not have a communication station to be terminally connected, the communication station 33 stores "0" in the variable T_Node and ends the abnormality location detection process.

Next, the flow of the terminal connection instruction processing according to the second embodiment will be described with reference to FIG. 7. FIG. 7 is a flowchart showing an example of the flow of the terminal connection instruction processing according to the second embodiment.

As shown in FIG. 7, the communication station 33 switches the process according to the value stored in the variable T_Node (step S301). When the value "2" is stored in the variable T_Node, the communication station 33 instructs the communication station 32 whose communication station number is "2" to turn on the terminal connection (step S302). Then, the communication station 33 turns off its terminal connection after waiting for a certain period of time (step S303). The fixed time is the time required for the communication station 32 to execute the terminal connection ON in response to the instruction from the communication station 33.

Further, when the value "3" is stored in the variable T_Node, the communication station 33 keeps its terminal connection ON (step S304).

Further, when the value "4" is stored in the variable T_Node, the communication station 33 instructs the communication station 34 whose communication station number is "4" to turn on the terminal connection (step S305). Then, the communication station 33 turns off its terminal connection after waiting for a certain period of time (step S306). Similarly, the fixed time is the time required for the communication station 34 to execute the terminal connection ON in response to the instruction from the communication station 33.

Further, when the value "0" is stored in the variable T_Node, the communication station 33 executes a process (abnormal process) at the time of soft reset or at the time of terminal instability (step S307).

Next, with reference to FIG. 8, a time chart from the occurrence of a disconnection failure of the two-wire communication line to the restoration of communication will be described. FIG. 8 is a diagram showing an example of a time chart from the occurrence of a disconnection failure of a two-wire communication line to the restoration of communication. In FIG. 8, a case where a disconnection failure occurs between the communication station 31 having the communication station number “1” and the communication station 32 having the communication station number “2” will be described as an example.

As shown in FIG. 8, until an abnormality occurs in the two-wire communication line, the communication station numbers "1", "2", "4" and "5" are changed to the main communication station number " A heartbeat signal (“HBM” shown in FIG. 8) is transmitted to the communication station of “3”. The communication station whose communication station number is "3" receives a heartbeat signal from another communication station by the time-out using the timer (within the response waiting time), so that the communication station becomes a two-wire communication line. It is recognized that there is no abnormality and communication between communication stations is performed normally.

Here, it is assumed that a disconnection failure occurs between the communication station whose communication station number is "1" and the communication station whose communication station number is "2". As a result, the communication station whose communication station number is "3" cannot receive the heartbeat signal from another communication station by the time-out using the timer (within the response waiting time). After the time-out occurs, the communication station whose communication station number is "3" detects that an abnormality has occurred in the two-wire communication line and turns on its own terminal connection. As a result, the communication stations other than the communication station whose communication station number is "1" among the two-wire communication lines are in a state where communication can be performed although it is unstable.

A communication station whose communication station number is "3" turns on its terminal connection, then transmits broadband to identify the location of the abnormality, and transmits a heartbeat signal to all other communication stations. Make a request. That is, the heartbeat signal after the broadband transmission is different from the heartbeat signal that is periodically transmitted before the abnormality occurs, and is transmitted according to the request. The communicable communication station responds to this request. Here, other communication stations other than the communication station whose communication station number is "1" will respond.

Based on the response from other communication stations, the communication station whose communication station number is "3" has the communication station number "1" and the communication station number at the location where the disconnection failure has occurred. It is specified that it is between the communication station and the communication station which is "2". Then, the communication station whose communication station number is "3" instructs the communication station whose communication station number is "2" to turn on the terminal connection. Further, the communication station whose communication station number is "3" turns off its own terminal connection in which the terminal connection is ON. In this way, by detecting the abnormal location and turning on the terminal connection of the communication station one inside the abnormal location, stable communication can be performed between the communication stations that can communicate. ..

As described above, the communication station 33 identifies the location where the disconnection failure occurs based on the response to the broadband transmission, and instructs the next communication station on its own side to make a terminal connection from the identified location. Abnormality detection, abnormality location identification, and communication recovery can be realized without setting restrictions on the module layout configuration.

(Modification 1)
FIG. 9 is a diagram showing a modified example of the terminal circuit. In FIG. 9, as an EMC (Electro Magnetic Compatibility) countermeasure, a configuration in which a capacitor is added to the terminal circuit is taken as an example. As shown in FIG. 9, the CPU 40 controls the terminal connection of the terminal circuit 50. Further, the terminating circuit 50 includes a switch 71, a switch 72, a terminating resistor 81, a terminating resistor 82, and a capacitor 9.

The switch 71 and the switch 72 are controlled to be ON and OFF according to the signal received from the CPU 40. As a result, the connection or non-connection of the terminating resistor 81 and the terminating resistor 82 can be switched. The resistance values of the terminating resistor 81 and the terminating resistor 82 take about half the resistance value of the terminating resistor described in the above embodiment. The capacitor 9 plays a role of letting the noise generated on the bus escape to the ground. The other configurations are the same as those described in the above-described embodiment.

(Modification 2)
In the above embodiment, the main communication station 33 receives a heartbeat signal periodically transmitted from another communication station, or receives a response from another communication station to a broadband transmission, and is abnormal. The case of detecting the occurrence was explained. The occurrence of an abnormality may also occur when the communication station 33 is performing normal data transmission. Therefore, the communication abnormality detection process at the time of normal data transmission will be described.

FIG. 10 is a flowchart showing an example of the flow of communication abnormality detection processing at the time of data transmission. As shown in FIG. 10, the communication station 33 transmits data (step S401). There are no particular restrictions on the data transmitted by data transmission. Then, the communication station 33 determines whether or not the data transmission has failed (step S402). At this time, when the data transmission is successful (step S402: No), the communication station 33 ends the process assuming that no abnormality has occurred in the two-wire communication line.

On the other hand, when the data transmission fails (step S402: Yes), the communication station 33 determines whether or not the data transmission has failed consecutively a predetermined number of times (step S403). The predetermined number of times is, for example, three times, but can be set arbitrarily. When the data transmission has not failed a predetermined number of times in a row (step S403: No), the communication station 33 re-executes the process in step S401. On the other hand, when the data transmission fails a predetermined number of times in a row (step S403: Yes), the communication station 33 performs broadband transmission and requests a response from all the other communication stations (step S404).

Subsequently, the communication station 33 determines whether or not one or more response signals have been received for the broadband transmission (step S405). At this time, the communication station 33 detects that there is a disconnection failure in the two-wire communication line when there is no response from any communication station (step S405: No), and temporarily enables communication. To do so, turn on its own terminating resistor (step S406). On the other hand, when the communication station 33 receives one or more response signals (step S405: Yes), it detects that the abnormality is caused by a cause other than the disconnection failure, and executes an abnormality process according to this abnormality (step S405: Yes). S407).

As a result, the communication station 33 can detect a communication abnormality even during normal data transmission.

(Modification 3)
In the above embodiment, the case where the main communication station 33 identifies the location where the disconnection failure has occurred is described based on the response received for the broadband transmission. The location where the disconnection failure has occurred may be specified based on the response received for the individual transmission to another communication station. Therefore, the abnormality location detection process for identifying the location where the disconnection failure has occurred will be described based on the response received for the individual transmission.

FIG. 11 is a flowchart showing an example of the flow of the abnormality location detection process by individual transmission. As shown in FIG. 11, the main communication station 33 having the communication station number “3” individually transmits to the communication station 32 having the communication station number “2” and requests a response (step S501). .. Then, the communication station 33 determines whether or not the response from the communication station 32 has been received within the predetermined time (step S502). At this time, when the communication station 33 cannot receive the response from the communication station 32 within the predetermined time (step S502: No), the communication station 32 has the communication station number "2" and the communication station number "3". It is specified that a disconnection failure has occurred with the communication station 33 (step S503). Here, the communication station 33 stores "3" in the variable T_Node in order to record the communication station to be terminally connected, and ends the abnormality location detection process.

On the other hand, when the communication station 33 can receive the response from the communication station 32 within the predetermined time (step S502: Yes), the communication station 33 individually transmits and responds to the communication station 31 whose communication station number is "1". (Step S504). Then, the communication station 33 determines whether or not the response from the communication station 31 has been received within the predetermined time (step S505). At this time, when the communication station 33 cannot receive the response from the communication station 31 within the predetermined time (step S505: No), the communication station 33 has the communication station number "1" and the communication station number "2". It is specified that a disconnection failure has occurred with the communication station 32 (step S506). Here, the communication station 33 stores "2" in the variable T_Node in order to record the communication station to be terminally connected, and ends the abnormality location detection process.

On the other hand, when the communication station 33 can receive the response from the communication station 31 within the predetermined time (step S505: Yes), the communication station 33 individually transmits and responds to the communication station 34 whose communication station number is "4". (Step S507). Then, the communication station 33 determines whether or not the response from the communication station 34 has been received within the predetermined time (step S508). At this time, when the communication station 33 cannot receive the response from the communication station 34 within the predetermined time (step S508: No), the communication station 33 has the communication station number "3" and the communication station number "4". It is specified that a disconnection failure has occurred with the communication station 34 (step S509). Here, the communication station 33 stores "3" in the variable T_Node in order to record the communication station to be terminally connected, and ends the abnormality location detection process.

On the other hand, when the communication station 33 can receive the response from the communication station 34 within the predetermined time (step S508: Yes), the communication station 33 individually transmits and responds to the communication station 35 whose communication station number is "5". (Step S510). Then, the communication station 33 determines whether or not the response from the communication station 35 has been received within the predetermined time (step S511). At this time, when the communication station 33 cannot receive the response from the communication station 35 within the predetermined time (step S511: No), the communication station 34 has the communication station number "4" and the communication station number is "5". It is specified that a disconnection failure has occurred with the communication station 35 (step S512). Here, the communication station 33 stores "4" in the variable T_Node in order to record the communication station to be terminally connected, and ends the abnormality location detection process.

On the other hand, when the communication station 33 can receive the response from the communication station 35 within the predetermined time (step S511: Yes), the response has been received from all the other communication stations so far, which causes the disconnection failure. It is identified as an abnormality due to a soft reset, unstable termination, or the like (step S513). Here, since the communication station 33 does not have a communication station to be terminally connected, the communication station 33 stores "0" in the variable T_Node and ends the abnormality location detection process.

As a result, the communication station 33 can identify the location where the disconnection failure occurs without waiting for the response from all the other communication stations, and when the disconnection failure occurs in a place closer to itself, the speed is higher. It is possible to identify the location of the disconnection.

(Modification example 4)
In the above embodiment, the case where the communication device 10 includes five communication stations has been described. Further, as described above, the number of communication stations is not limited to five. Therefore, a case where the number of communication stations is n will be described.

FIG. 12 is a diagram showing a configuration example of the communication device 10a when the number of communication stations is n. As shown in FIG. 12, the communication device 10a has a communication station whose communication station number is “1” to “n”. Of these, the communication station 31a and the communication station 35a are assumed to be communication stations arranged at the ends. Further, it is assumed that the communication station 32a, the communication station 33a, and the communication station 34a are communication stations arranged other than the ends. Further, the communication station 33a is assumed to be the main communication station.

In the example of FIG. 12, the communication station 31a is the communication station (1), the communication station 32a is the communication station (n / 4), the communication station 33a is the communication station (n / 2), and the communication station 34 is the communication station (3n / 4). ), The communication station 35 is the communication station (n). Since the communication station number (serial number) of each communication station must be an integer, if it is not divisible in the following explanation, the decimal point shall be rounded down or the decimal point shall be rounded up.

FIG. 13 is a flowchart showing an example of the flow of the abnormality location detection process when the number of communication stations is n. As shown in FIG. 13, the communication station 33a individually transmits to the communication station (1) and the communication station (n) and requests a response (step S601). Here, the communication station 33a switches the processing according to the reception pattern of the response (step S602). If the response is received only from the communication station (1), it means that a disconnection failure has occurred between the communication station (1) and the communication station (n / 2). Therefore, when the communication station 33a receives a response only from the communication station (1), the communication station 33a requests the communication station (n / 4) to transmit a heartbeat signal, and confirms whether the communication can be performed normally. (Step S603).

Then, the communication station 33a determines whether or not the heartbeat signal has been received from the communication station (n / 4) (step S604). At this time, when the communication station 33a receives the heartbeat signal from the communication station (n / 4) (step S604: Yes), the communication station 33a stores "n / 4" in the variable l (step S605). That is, since no disconnection failure has occurred between the communication station (n / 4) and the communication station (n / 2), the location where the disconnection failure has occurred between the communication station (1) and the communication station (n / 4). Will be looking for.

On the other hand, when the communication station 33a cannot receive the heartbeat signal from the communication station (n / 4) (step S604: No), the communication station 33a stores "n / 2" in the variable l (step S606). That is, since a disconnection failure has occurred between the communication station (n / 4) and the communication station (n / 2), a further disconnection failure has occurred between the communication station (n / 4) and the communication station (n / 2). You will be looking for the place where the problem occurs. After that, the communication station 33a performs a variable rewriting operation for checking the adjacent communication station from the starting point (step S607).

Subsequently, the communication station 33a requests the communication station (l) to transmit a heartbeat signal, and confirms whether the communication can be performed normally (step S608). Then, the communication station 33a determines whether or not the heartbeat signal has been received from the communication station (l) (step S609). At this time, when the communication station 33a receives the heartbeat signal from the communication station (l) (step S609: Yes), the communication station 33a executes the process of step S607, and further transmits the heartbeat signal to the adjacent communication station. To request. On the other hand, when the communication station 33a cannot receive the heartbeat signal from the communication station (l) (step S609: No), a disconnection failure has occurred between the communication station (l) and the communication station (l + 1). (Step S610). Here, the communication station 33a stores "l + 1" in the variable T_Node in order to record the communication station to be terminally connected, and ends the abnormality location detection process.

Further, in step S602, when the response is received only from the communication station (n), it means that a disconnection failure has occurred between the communication station (n / 2) and the communication station (n). Therefore, when the communication station 33a receives a response only from the communication station (n), the communication station 33a requests the communication station (3n / 4) to transmit a heartbeat signal, and confirms whether the communication can be performed normally. (Step S611).

Then, the communication station 33a determines whether or not the heartbeat signal has been received from the communication station (3n / 4) (step S612). At this time, when the communication station 33a receives the heartbeat signal from the communication station (3n / 4) (step S612: Yes), the communication station 33a stores "3n / 4" in the variable l (step S613). That is, since no disconnection failure has occurred between the communication station (n / 2) and the communication station (3n / 4), the location where the disconnection failure has occurred between the communication station (3n / 4) and the communication station (n). Will be looking for.

On the other hand, when the communication station 33a cannot receive the heartbeat signal from the communication station (3n / 4) (step S612: No), the communication station 33a stores "n / 2" in the variable l (step S614). That is, since a disconnection failure has occurred between the communication station (n / 2) and the communication station (3n / 4), a further disconnection failure has occurred between the communication station (n / 2) and the communication station (3n / 4). You will be looking for the place where the problem occurs. After that, the communication station 33a performs a variable rewriting operation for checking the adjacent communication station from the starting point (step S615).

Subsequently, the communication station 33a requests the communication station (l) to transmit a heartbeat signal, and confirms whether the communication can be performed normally (step S616). Then, the communication station 33a determines whether or not the heartbeat signal has been received from the communication station (l) (step S617). At this time, when the communication station 33a receives the heartbeat signal from the communication station (l) (step S617: Yes), the communication station 33a executes the process of step S615, and further transmits the heartbeat signal to the adjacent communication station. To request. On the other hand, when the communication station 33a cannot receive the heartbeat signal from the communication station (l) (step S617: No), a disconnection failure has occurred between the communication station (l) and the communication station (l + 1). (Step S618). Here, the communication station 33a stores "l-1" in the variable T_Node in order to record the communication station to be terminally connected, and ends the abnormality location detection process.

Further, in step S602, when a response is received from both the communication station (1) and the communication station (n), the communication stations at both ends can communicate with each other even though an abnormality has occurred. There will be. Therefore, the communication station 33a identifies that it is not an abnormality caused by a disconnection failure but an abnormality caused by a soft reset, terminal instability, or the like (step S619). Here, since the communication station 33a does not have a communication station to be terminated and connected, "0" is stored in the variable T_Node, and the abnormality location detection process is terminated.

Further, in step S602, if the response cannot be received from both the communication station (1) and the communication station (n), there is a possibility that a plurality of disconnection failures occur at the same time. When the communication station 33a has a disconnection failure at both ends at the same time, it is difficult to recover by itself, so the communication station 33a ends the abnormality location detection process (step S620).

That is, the communication station 33 divides the other communication stations into two or more groups, and identifies and identifies the group including the location where the disconnection failure occurs based on the response from the other communication stations belonging to each group. Based on the responses from other communication stations belonging to the group, the location of the disconnection failure is identified. As a result, the communication station 33 can suitably detect an abnormality, identify an abnormal portion, and restore communication regardless of the number of communication stations.

(Application example 1)
The function of the communication device 10 (10a) described in the above embodiment can be applied to various devices. Therefore, an application example of the communication device 10 (10a) described in the above embodiment will be described below.

FIG. 14 is a configuration diagram showing an example applied to a printing machine. For example, as shown in FIG. 14, a printing machine is composed of a plurality of units. Specifically, the printing machine is composed of a unit 101, a unit 102, a unit 103, a unit 104, a unit 105, a unit 106, a unit 107, a unit 108, a unit 109, a unit 1010, and a unit 1011. Further, a communication station is arranged in each unit, and each communication station is connected so as to be able to communicate.

The unit 101 and the unit 102 are connected paper ejection units. By adopting a plurality of paper ejection units, the paper ejection volume can be increased. If any of the connected paper ejection units operates, the printing operation can be performed. The unit 101 has a communication station 111. The unit 102 has a communication station 112. The unit 103 is a cooling unit and cools the paper heated by the drying unit. The unit 103 has a communication station 113. The unit 104 is a drying unit and plays a role of drying and blending the ink adhering to the paper. The unit 104 has a communication station 114. The unit 105 is an image-making unit, and ink is driven into paper to perform printing. The unit 105 has a communication station 115. The unit 106 is an operation panel, and has a function of an operation screen of a printing machine and a function of notifying a user when a communication abnormality occurs. The unit 106 has a communication station 116.

The unit 107 is a resist unit, and adjusts the paper transport timing and position. The unit 107 has a communication station 117. The unit 108 is a pre-coating unit and coats the pre-coating liquid. As a result, the ink can be blended even on different papers. The unit 108 has a communication station 118. The unit 109, the unit 1010, and the unit 1011 are connected paper feed units. By adopting multiple paper feed units, the paper feed volume can be increased. If any of the linked paper feed units operates, printing can be performed. The unit 109 has a communication station 119. Unit 1010 has a communication station 1110. Unit 1011 has a communication station 1111.

In such a printing machine, even if some functions cannot operate without communication due to a disconnection failure, the printing operation may be performed as a whole. At that time, by making a part of the communication possible by the process as described in the above embodiment, it is possible to make the printing operation possible.

(Application example 2)
FIG. 15 is a configuration diagram showing an example applied to the image forming apparatus. The image forming apparatus includes a printing function, a copying function, a scanner function, a fax function, an operation panel, and the like in one housing. For example, as shown in FIG. 15, the image forming apparatus includes an ADF (Auto Document Feeder) 121, an operation panel 122, a scanner 123, a FAX 124, and an image forming unit 125. In addition, communication stations are arranged in each part, and each communication station is connected so as to be able to communicate.

The ADF 121 is an automatic paper feeding device, and double-sided copying can be performed by the paper reversing function. The ADF 121 has a communication station 131. The operation panel 122 has a function of an operation screen of the image forming apparatus and a function of notifying the user when a communication abnormality occurs. The operation panel 122 has a communication station 132. The scanner 123 captures an image of paper. The scanner 123 has a communication station 133. The FAX 124 performs a FAX communication operation. FAX 124 has a communication station 134. The image-creating unit 125 has a function of printing on paper. The image forming unit 125 has a communication station 135.

In such an image forming apparatus, for example, when a disconnection failure occurs between the communication station 131 of the ADF 121 and the communication station 132 of the operation panel 122, all the functions including the ADF 121 cannot communicate. In addition, it becomes inoperable. At that time, by the process as described in the above-described embodiment, it is possible to restore the communication so that each function other than the ADF 121 can perform communication, and to make the function other than the ADF 121 operable.

(Application example 3)
FIG. 16 is a block diagram showing an example applied to a refrigerator. Refrigerators (electric refrigerators) are equipped with different cooling units, liquid crystal panels, and the like. For example, as shown in FIG. 16, the refrigerator includes a unit 141, a unit 142, a unit 143, a unit 144, a unit 145, and a unit 146. It is assumed that the units 141 to 146 are different cooling units and liquid crystal panels. Further, a communication station is arranged in each unit, and each communication station is connected so as to be able to communicate.

The unit 141 has a communication station 151. The unit 142 has a communication station 152. Unit 143 has a communication station 153. The unit 144 has a communication station 154. The unit 145 has a communication station 155. The unit 146 has a communication station 156.

In such a refrigerator, even if some of the functions cannot communicate due to a disconnection failure and cannot operate, the processing as described in the above embodiment can make a part of the refrigerator communicable. , Some cooling functions, panel display functions, etc. can be put into operation.

In addition, information including processing procedures, control procedures, specific names, various data, parameters, etc. shown in the above documents and drawings can be arbitrarily changed unless otherwise specified. Further, each component of the illustrated device is a functional concept, and does not necessarily have to be physically configured as shown in the figure. That is, the specific form of dispersion or integration of the devices is not limited to the one shown in the figure, and all or part of the devices may be functionally or physically dispersed or physically distributed in arbitrary units according to various burdens and usage conditions. Can be integrated.

Further, the recovery program executed by the communication device 10 is, as one mode, a file in an installable format or an executable format, such as a CD-ROM, a flexible disk (FD), a CD-R, or a DVD (Digital Versatile Disk). It is recorded and provided on a recording medium that can be read by a computer such as. Further, the recovery program executed by the communication device 10 may be stored on a computer connected to a network such as the Internet and provided by downloading via the network. Further, the recovery program executed by the communication device 10 may be provided or distributed via a network such as the Internet. Further, the recovery program may be configured to be provided by incorporating it into a ROM or the like in advance.

The recovery program executed by the communication device 10 has a module configuration including at least each of the above-mentioned parts (detection unit 63, connection control unit 64), and as actual hardware, the CPU (processor) is a recovery program from the storage medium. By reading and executing the above, each of the above units is loaded on the main storage device, and the detection unit 63 and the connection control unit 64 are generated on the main storage device.

10 Communication device 33 Communication station 61 Communication control unit 62 Storage unit 63 Detection unit 64 Connection control unit 65 Output control unit 66 State management unit

Japanese Unexamined Patent Publication No. 2003-304265

Claims (9)

A communication device capable of communicating with multiple communication stations via a two-wire communication line.
A first communication station indicating at least one of the plurality of communication stations
A resistor that can be connected to the two-wire communication line,
A detector that detects the occurrence of an abnormality in the two-wire communication line, and
A connection control unit that controls the connection of the resistor to the two-wire communication line when the occurrence of the abnormality is detected .
It has a communication control unit that controls individual transmission of a response request to another communication station different from the first communication station.
The detection unit divides the other communication stations into two or more groups, and identifies the group including the location where the abnormality occurs based on the response to the response request from the other communication stations belonging to each group. A communication device characterized in that a location where an abnormality occurs is specified based on a response to the response request from another communication station belonging to the specified group. Another communication station different from the first communication station
It has a transmission control unit that controls the transmission of periodic signals to the first communication station.
The communication device according to claim 1, wherein the detection unit detects that the abnormality has occurred when a signal periodically transmitted by the other communication station is not received within a predetermined time. .. The communication device according to claim 1, wherein the detection unit detects that the abnormality has occurred when a transmission error occurs continuously for a predetermined number of times or more during the operation of data transmission. The first communication station
It has a communication control unit that controls simultaneous transmission of response requests to other communication stations different from the first communication station.
The communication device according to claim 1, wherein the detection unit identifies a location where the abnormality occurs based on a response to the response request. The first communication station
It has a communication control unit that controls individual transmission of response requests to other communication stations different from the first communication station.
The communication device according to claim 1, wherein the detection unit identifies a location where the abnormality occurs based on a response to the response request. The first communication station
The claim is characterized in that it has an instruction unit for instructing a terminal connection to the other communication station arranged one adjacent to the first communication station from the identified location where the abnormality occurs. The communication device according to 1, 4 or 5. It is a recovery method executed by a communication device capable of communicating with multiple communication stations via a two-wire communication line.
A first communication station indicating at least one of the plurality of communication stations
It has a resistor that can be connected to the two-wire communication line.
A detection step for detecting that an abnormality has occurred in the two-wire communication line, and
A connection control step that controls the connection of the resistor to the two-wire communication line when the occurrence of the abnormality is detected , and
A communication control step for controlling individual transmission of a response request to another communication station different from the first communication station is included.
In the detection step, the other communication stations are divided into two or more groups, and a group including the location where the abnormality occurs is identified based on the response to the response request from the other communication stations belonging to each group. A recovery method comprising identifying a location where an abnormality has occurred based on a response to the response request from another communication station belonging to the specified group. A first communication station indicating at least one of a plurality of communication stations arranged in a communication device capable of communicating via a two-wire communication line is a first communication station.
It has a resistor that can be connected to the two-wire communication line.
To the first communication station
A detection step for detecting that an abnormality has occurred in the two-wire communication line, and
A connection control step that controls the connection of the resistor to the two-wire communication line when the occurrence of the abnormality is detected , and
A communication control step for controlling individual transmission of a response request to another communication station different from the first communication station is executed.
The detection step divides the other communication stations into two or more groups, and identifies the group including the location where the abnormality occurs based on the response to the response request from the other communication stations belonging to each group. A recovery program that identifies the location of the anomaly based on the response to the response request from another communication station belonging to the specified group. An image forming apparatus provided with the communication device according to any one of claims 1 to 6.
An image forming apparatus having a print control unit that controls execution of printing processing on a recording medium.

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