COMMUNICATION SYSTEM, COMMUNICATION METHOD, PROGRAM, AND COMMUNICATION DEVICE

Abstract

The communication system (1) includes a PC (10) and an HMI (20). The PC (10) includes a first communication unit that communicates with the HMI (20) and a first communication control unit that transmits a highlighting signal to the HMI (20) via the first communication unit. The HMI (20) includes a touch screen (200), a second communication unit that communicates with the PC (10), and a display control unit that, when the second communication unit receives the highlighting signal, causes the touch screen (200) to display a highlighting screen that emphasizes that communication with the PC (10) is possible.

Description

Technical Field

[0001] The present disclosure relates to a communication system, a communication method, a program, and a communication device.

Background Art

[0002] There is a need for a technology that can easily set FA (Factory Automation) devices such as programmable logic controllers (PLCs) and human machine interfaces (HMIs) from connected devices such as personal computers (PCs) and tablet terminals.

[0003] For example, Patent Document 1 discloses a technology that enables communication between a PC and a PLC without setting up registration of an IP address through broadcast communication on an Ethernet (registered trademark) network, making it possible to easily set the PLC from the PC.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the technology of Patent Document 1, the PLC and the PC need to be connected to the same Ethernet network. Also, since broadcast communication is performed during setting, it is necessary that no devices other than the PC and the PLC are connected.

[0006] Numerous FA (Factory Automation) devices may be deployed in a production environment. Furthermore, not all deployed FA devices are necessarily connected to the same network. Therefore, in order to configure a PLC using the technology described in Patent Document 1, it is necessary to confirm that the PLC to be configured and the PC are connected to the same network, and further, to confirm that no other FA devices are connected to that network. Performing this verification in an environment with many FA devices requires checking physical wiring, network settings, etc., which is a burdensome task.

[0007] The purpose of this disclosure is, in light of the circumstances described above, to provide a communication system, etc., that allows for easy confirmation of the network connection status. [Means for solving the problem]

[0008] To achieve the above objectives, the communication system relating to this disclosure is First communication device and multiple It is equipped with a second communication device, The first communication device and each of the second communication devices are connected to a network capable of communication via broadcast communication. The first communication device is The aforementioned broadcast communication via the aforementioned network The aforementioned each A first communication means that communicates with a second communication device, The first communication means each A first communication control means that transmits a highlighting signal to a second communication device, Equipped with, The aforementioned each The second communication device is Display means and The aforementioned broadcast communication via the aforementioned network The first communication device and other second communication devices A second communication means for communicating with, When the second communication means receives the highlighting signal, a display control means causes the display means to display a highlighting screen on the display means that highlights that it is possible to communicate with the first communication device, An input means that accepts selection operations by the user, When the input means accepts the selection operation, the second communication means transmits a blockage request signal to the network, and when the second communication means receives the blockage request signal transmitted by another second communication device, the second communication control means blocks communication with the network by the second communication means. It is equipped with. [Effects of the Invention]

[0009] According to the present disclosure, the connection status to the network can be easily confirmed.

Brief Description of the Drawings

[0010] [Figure 1] Figure showing the overall configuration of the communication system according to an embodiment of the present disclosure [Figure 2] Figure showing an example of the screen displayed on each HMI according to an embodiment of the present disclosure [Figure 3] Figure showing an example of the screen displayed on each HMI according to an embodiment of the present disclosure [Figure 4] Figure showing the functional configuration of the PC according to an embodiment of the present disclosure [Figure 5] Figure showing the functional configuration of the HMI according to an embodiment of the present disclosure [Figure 6] Figure showing an example of the hardware configuration of the PC and HMI according to an embodiment of the present disclosure [Figure 7] Sequence diagram showing an example of the flow of HMI setting by the communication system according to an embodiment of the present disclosure

Embodiments for Carrying Out the Invention

[0011] Hereinafter, a communication system according to an embodiment of the present disclosure will be described while referring to the drawings. In each drawing, the same or equivalent parts are denoted by the same reference numerals.

[0012] (Embodiment) Referring to FIG. 1, a communication system according to an embodiment will be described. The communication system 1 includes a PC 10 and a plurality of HMIs 20. The PC 10 and the HMIs 20 are communicably connected via a network NT. Each HMI 20 includes a touch screen 200. Although details will be described later, the communication system 1 allows a user to easily confirm whether each HMI 20 is connected to the network NT. Also, the user can easily set the HMI 20 to be a setting target among the HMIs 20 by touching the touch screen 200 of the HMI 20 to select it, without changing the wiring of the other HMIs 20. The communication system 1 is an example of the communication system according to the present disclosure.

[0013] The network NT is a network capable of communication by broadcast communication. The network NT is, for example, a network constructed by Ethernet. The PC 10 and each HMI 20 communicate by broadcast communication via the network NT. Therefore, all the signals transmitted by the PC 10 are transmitted to all the HMIs 20, and all the signals transmitted by each HMI 20 are transmitted to the PC 10 and all the other HMIs 20. The network NT is an example of the network according to the present disclosure.

[0014] The PC 10 is a PC used by a user for setting the HMI 20. The PC is, for example, a FA PC installed with a program of an engineering tool. The functional configuration of the PC 10 will be described later. The PC 10 is an example of the first communication device according to the present disclosure.

[0015] The HMI 20 is, for example, a programmable display installed at a production site. As described above, the HMI 20 includes a touch screen 200. The touch screen 200 of the HMI 20 displays a screen and receives an input operation by a touch operation from the user. The functional configuration of the HMI 20 will be described later. The HMI 20 is an example of the second communication device according to the present disclosure.

[0016] Referring to Figures 2 and 3, the confirmation of the network connection status by the communication system 1 and the configuration of the HMI 20 will be briefly explained. First, when the user operates the PC 10 and performs the operation to configure the HMI 20, the screen shown in Figure 2 is displayed on the touchscreen 200 of each HMI 20. This screen is a highlighting screen that highlights that communication with the PC 10 is possible. It is preferable that the highlighting screen is displayed in a manner that is easy for the user to notice, such as by making the background color red and displaying the text in large size.

[0017] By checking the highlighted screen, the user can recognize that each HMI20 displaying the highlighted screen is able to communicate with the PC10. In other words, the user can recognize that each HMI20 is connected to the same network as the PC10. Furthermore, if there is an HMI20 that is not connected to network NT, the highlighted screen will not be displayed on that HMI20. Therefore, the user can recognize that HMI20s that do not display the highlighted screen are not connected to the same network as the PC10.

[0018] In summary, according to communication system 1, users can easily check the network connection status of each HMI 20 by checking the highlighting screen displayed on the touchscreen 200 of each HMI 20.

[0019] The highlighted screen also indicates that the HMI20 to be configured can be selected by touch operation. When the user touches the touchscreen 200 of the HMI20 to be configured according to the highlighted screen, the screen displayed on the touchscreen 200 of each HMI20 changes to what is shown in Figure 3. Hereafter, the HMI20 that was touched, i.e., the HMI20 that was selected for configuration, will be referred to as HMI20a, and the HMI20 that was not touched, i.e., the HMI20 that was not selected for configuration, will be referred to as HMI20b. The same applies to Figure 3 and Figure 7 described later. When there is no need to distinguish between them, they will simply be referred to as HMI20.

[0020] The touchscreen 200 of HMI20a displays a screen indicating that HMI20a has been selected as the target for configuration and that configuration is currently in progress. The touchscreen 200 of each HMI20b displays a screen indicating that communication is currently blocked and will be restored after a certain period of time. As will be explained in detail later, after a user touch operation, HMI20b blocks communication for a certain period of time, and during this time, HMI20a registers PC10 with itself. This registration requires communication between only PC10 and HMI20a via broadcast communication, thus necessitating the blocking of HMI20b's communication. After registration, PC10 sends configuration data to the network NT via broadcast communication, and only HMI20a, which has registered PC10, configures itself based on the configuration data.

[0021] As described above, HMI20b, which is an HMI20 that is not selected, will have its communication automatically blocked for a certain period of time. Therefore, broadcast communication between only PC10 and HMI20a can be achieved without requiring any physical layer work, such as turning off the power to HMI20b itself or disconnecting the communication cable connected to HMI20b, for HMI20b that is not being configured. Thus, according to communication system 1, HMI20a can be easily configured without requiring any physical layer work.

[0022] The functional configuration of PC10 will be explained with reference to Figure 4. PC10 comprises a first communication unit 101, a first communication control unit 102, and a setting unit 103.

[0023] The first communication unit 101 is connected to the network NT and communicates with each HMI 20 via broadcast communication. The first communication unit 101 is implemented, for example, by an Ethernet card. The first communication unit 101 is an example of the first communication means according to this disclosure.

[0024] The first communication control unit 102 controls the first communication unit 101. The first communication control unit 102 has the functions described below. In the following, the first communication control unit 102 controlling the first communication unit 101 to perform communication will simply be described as "the first communication control unit 102 communicates." The first communication control unit 102 is an example of the first communication control means according to this disclosure.

[0025] When the user initiates the setup of the HMI20 by operating an input device (not shown), the first communication control unit 102 transmits a highlighting signal to each HMI20 via broadcast communication over the network NT, instructing the display of the highlighting screen.

[0026] As will be explained in detail later, when the first communication unit 101 receives a blockage request signal transmitted by the HMI 20a, the first communication control unit 102 transmits a confirmation signal to the HMI 20a via broadcast communication over the network NT to confirm that communication with the HMI 20a that transmitted the blockage request signal is possible. Note that this confirmation signal must be transmitted while all HMI 20b are blocking communication. For this reason, it is preferable for the first communication control unit 102 to transmit the confirmation signal after a predetermined time has elapsed since the first communication unit 101 received the blockage request signal. The "predetermined time" is sufficient time for all HMI 20b to block communication after receiving the blockage request signal.

[0027] When the first communication unit 101 receives a response from the HMI 20a to an acknowledgment signal, the first communication control unit 102 broadcasts a registration request signal to the HMI 20a requesting registration of the PC 10. This communication must also take place while all HMI 20b are blocking communication. The registration request signal includes at least information identifying the PC 10. This information identifying the PC 10 may include, for example, the MAC (Media Access Control) address and IP (Internet Protocol) address of the PC 10.

[0028] The first communication control unit 102 transmits a registration request signal, and then transmits configuration data for setting up HMI20a to each HMI20 via broadcast communication. This communication may occur when HMI20b has resumed communication, because only the HMI20a that has registered PC10 will configure itself based on the configuration data. The configuration data is created by the configuration unit 103, which will be described later.

[0029] After transmitting the configuration data, the first communication control unit 102 sends a deactivation request signal to each HMI 20 via broadcast communication to deactivate the registration of PC 10 by HMI 20a. This communication may also occur when HMI 20b has resumed communication, because each HMI 20b has not registered PC 10 and therefore ignores the deactivation request signal.

[0030] The setting unit 103 creates setting data based on the user's operation of an input device (not shown) to configure the HMI 20a.

[0031] The functional configuration of the HMI20 will be explained with reference to Figure 5. The HMI20 comprises a touchscreen 200, a second communication unit 201, a second communication control unit 202, a display control unit 203, and a setting unit 204.

[0032] The touchscreen 200 has the function of displaying a screen and the function of receiving touch operations from the user. The touchscreen 200 displays a screen based on the control of the display control unit 203. In particular, when the highlight screen is displayed, the touchscreen 200 outputs a signal to the second communication control unit 202 and the display control unit 203 indicating a selection operation in which the user touches the touchscreen 200 to select the HMI 20. In other words, the touchscreen 200 receives a selection operation from the user and outputs a signal indicating the received selection operation to the second communication control unit 202 and the display control unit 203. The touchscreen 200 is an example of a display means and input means according to this disclosure.

[0033] The second communication unit 201 is connected to the network NT and communicates with the PC 10 and other HMI 20s via broadcast communication. The second communication unit 201 is implemented, for example, by an Ethernet card. The second communication unit 201 is an example of the second communication means according to this disclosure.

[0034] The second communication control unit 202 controls the second communication unit 201. The second communication control unit 202 has the functions described below. In the following, the act of the second communication control unit 202 controlling the second communication unit 201 to perform communication will simply be described as "the second communication control unit 202 communicates." The second communication control unit 202 is an example of the second communication control means according to this disclosure.

[0035] When the second communication control unit 202 receives a highlighting signal from the PC 10, it outputs a signal to the display control unit 203 instructing it to display the highlighting screen.

[0036] When the second communication control unit 202 receives a signal indicating a selection operation from the touchscreen 200, it broadcasts a block request signal to the PC 10 and other HMI 20s. The "other HMI 20s" are those that were not the target of the selection operation, and are therefore designated as HMI20b. The HMI 20 that sent the block request signal is the one that was the target of the selection operation, and is therefore designated as HMI20a.

[0037] When the second communication unit 201 receives an acknowledgment signal from the PC 10, the second communication control unit 202 transmits a response to the acknowledgment signal to the PC 10 via broadcast communication. This response must be made while all HMI 20b communications are interrupted.

[0038] When the second communication unit 201 receives a registration request signal from the PC 10, the second communication control unit 202 forwards the registration request signal to the setting unit 204.

[0039] When the second communication unit 201 receives setting data from the PC 10, the second communication control unit 202 transfers the setting data to the setting unit 204.

[0040] When the second communication unit 201 receives a release request signal from the PC 10, the second communication control unit 202 forwards the release request signal to the setting unit 204.

[0041] When the second communication unit 201 receives a disconnection request signal transmitted by the HMI 20a, the second communication control unit 202 disconnects communication with the network NT by the second communication unit 201. The second communication control unit 202 disconnects communication with the network NT, for example, by not transmitting any signals from the second communication unit 201 and ignoring all signals received by the second communication unit 201. Alternatively, the second communication control unit 202 may disconnect communication with the network NT by cutting off the power supply to the second communication unit 201. After a certain period of time has elapsed since the disconnection, the second communication control unit 202 resumes communication with the network NT by the second communication unit 201. "A certain period of time" is sufficient time from when HMI20a sends a disconnection request signal until PC10 registers. The second communication control unit 202 outputs signals to the display control unit 203 when communication is disconnected and when communication is restored.

[0042] The display control unit 203 controls the touchscreen 200 to display a screen on the touchscreen 200. The display control unit 203 has the following functions in particular. The display control unit 203 is an example of a display control means according to this disclosure. When the display control unit 203 receives a signal from the second communication control unit 202 instructing it to display the highlighting screen, it displays the highlighting screen as shown in Figure 2.

[0043] When the display control unit 203 receives a signal indicating a selection operation from the touchscreen 200, it displays a screen, as shown in Figure 3, indicating that the HMI 20a has been selected and is being configured.

[0044] When the display control unit 203 receives a signal from the second communication control unit 202 indicating that communication has been interrupted, it displays a screen, as shown in Figure 3, indicating that communication is currently interrupted on the HMI 20b and that communication will be restored after a certain period of time.

[0045] When the display control unit 203 receives a signal from the second communication control unit 202 indicating that communication has been restored, it displays a screen indicating that communication has been restored.

[0046] When the setting unit 204 receives a registration request signal from the PC 10 via the second communication control unit 202, it temporarily registers the PC 10 based on the information identifying the PC 10 contained in the registration request signal.

[0047] When the setting unit 204 receives setting data from the PC 10 via the second communication control unit 202, it sets the HMI 20 itself based on the setting data.

[0048] When the setting unit 204 receives a release request signal from the PC 10 via the second communication control unit 202, it temporarily cancels the registration of the PC 10.

[0049] Next, an example of the hardware configuration of PC10 and HMI20 will be explained with reference to Figure 6.

[0050] PC10 and HMI20 each comprise a processor 1001, memory 1002, interface 1003, and secondary storage device 1004, which are connected to each other via a bus 1000.

[0051] The processor 1001 is, for example, a CPU (Central Processing Unit). The processor 1001 loads the operation program stored in the secondary storage device 1004 into the memory 1002 and executes it, thereby realizing the functions of the PC 10 and HMI 20.

[0052] Memory 1002 is a main memory device, for example, composed of RAM (Random Access Memory). Memory 1002 stores the operational program read by the processor 1001 from the secondary memory device 1004. Memory 1002 also functions as working memory when the processor 1001 executes the operational program.

[0053] Interface 1003 is an I / O (Input / Output) interface such as a serial port, USB (Universal Serial Bus) port, or network interface.

[0054] The secondary storage device 1004 is, for example, flash memory, an HDD (Hard Disk Drive), or an SSD (Solid State Drive). The secondary storage device 1004 stores the operational programs that the processor 1001 executes.

[0055] Next, an example of the HMI20 setup process using the communication system 1 will be explained with reference to Figure 7. The process shown in Figure 7 takes place after the user initiates the HMI20 setup by operating an input device (not shown) on the PC 10. Also, in Figure 7 and the following explanation, explanations of screen displays other than the highlighted screen are omitted.

[0056] The first communication control unit 102 of the PC 10 transmits a highlighting signal to each HMI 20 via broadcast communication in response to user operation (step T1).

[0057] Upon receiving the highlighting signal, the display control unit 203 of each HMI 20 displays the highlighting screen on the touchscreen 200 (step T2).

[0058] The user performs a touch operation by touching the highlighted screen displayed on the touchscreen 200 of the HMI20a, which is the HMI20 to be configured (step T3).

[0059] The second communication control unit 202 of HMI20a transmits a blockage request signal to PC10 and each HMI20b via broadcast communication (step T4).

[0060] Upon receiving a blockage request signal, the second communication control unit 202 of each HMI 20b blocks communication with the network NT (step T5).

[0061] Upon receiving the blockage request signal, the first communication control unit 102 of PC10 transmits an acknowledgment signal to HMI20a via broadcast communication (step T6). At this point, all HMI20b communications are blocked, so even though it is broadcast communication, the acknowledgment signal is transmitted only to HMI20a. The same applies to other communications while HMI20b communications are blocked.

[0062] Upon receiving the confirmation signal, the second communication control unit 202 of the HMI20a sends a response to the PC10 via broadcast communication (step T7).

[0063] Upon receiving the response, the first communication control unit 102 of the PC 10 transmits a registration request signal to the HMI 20a via broadcast communication (step T8).

[0064] Upon receiving the registration request signal, the setting unit 204 of the HMI20a temporarily registers the PC10 (step T9).

[0065] The second communication control unit 202 of HMI20b restores the communication that was interrupted in step T5 (step T10). This step can be performed at any time after HMI20a receives the registration request signal in step T8.

[0066] Following step T8, PC10 transmits configuration data to each HMI20 via broadcast communication (step T11). If this step is performed after step T10, the configuration data will be sent to HMI20b as well as HMI20a, but this is not a problem because only HMI20a, which registered with PC10 in step T9, will perform the configuration based on the configuration data. The same applies to step T13, which will be described later.

[0067] Upon receiving the configuration data, the configuration unit 204 of the HMI20a configures the HMI20a itself based on the configuration data (step T12).

[0068] Following step T11, PC10 sends a release request signal to each HMI20 via broadcast communication (step T13).

[0069] Upon receiving the release request signal, the setting unit 204 of the HMI20a releases the registration of PC10, which was temporarily registered in step T9 (step T14).

[0070] The communication system 1 according to the embodiment has been described above. With the communication system 1, the user can easily check the network connection status of each HMI 20 by checking the highlighting screen displayed on the touchscreen 200 of each HMI 20. Furthermore, with the communication system 1, communication is blocked for HMI 20b that was not selected as a target for configuration, so even though only PC 10 and HMI 20a need to perform broadcast communication, the user can easily configure HMI 20a without having to perform any work related to the physical layer.

[0071] (modified version) In this embodiment, the HMI20 is used as an example of the FA equipment to be configured. However, the communication system 1 can be applied to any FA equipment capable of displaying a highlighting screen, not just the HMI20. For example, a PLC equipped with a display unit may be applied to the communication system 1.

[0072] In this embodiment, the PC10 is used to configure the HMI20, but the configuration is not limited to the PC10; a tablet device, smartphone, or other device may also be used to configure the HMI20.

[0073] In this embodiment, there are multiple HMI20s, but there may be only one HMI20. In this case as well, the network connection status of the HMI20 can be checked by looking at the presence or absence of the highlighting screen.

[0074] In the hardware configuration shown in Figure 6, the PC 10 and HMI 20 are equipped with a secondary storage device 1004. However, the configuration is not limited to this; the secondary storage device 1004 may be located outside the PC 10 and HMI 20, and the PC 10 and HMI 20 may be connected to the secondary storage device 1004 via an interface 1003. In this configuration, removable media such as USB flash drives and memory cards can also be used as the secondary storage device 1004.

[0075] Alternatively, instead of the hardware configuration shown in Figure 6, the PC10 and HMI20 may be configured using dedicated circuits such as ASICs (Application Specific Integrated Circuits) or FPGAs (Field Programmable Gate Arrays). Furthermore, in the hardware configuration shown in Figure 6, some of the functions of the PC10 and HMI20 may be implemented by dedicated circuits connected to interface 1003, for example.

[0076] The programs used in PC10 and HMI20 can be distributed by storing them on computer-readable storage media such as CD-ROMs (Compact Disc Read Only Memory), DVDs (Digital Versatile Discs), USB flash drives, memory cards, and HDDs. By installing these programs on a specific or general-purpose computer, that computer can function as PC10 and HMI20.

[0077] Alternatively, the aforementioned program may be stored in a storage device owned by another server on the Internet, and the program may be downloaded from that server.

[0078] This disclosure allows for various embodiments and modifications without departing from the broad spirit and scope of this disclosure. Furthermore, the embodiments described above are for illustrative purposes only and do not limit the scope of this disclosure. In other words, the scope of this disclosure is indicated by the claims, not by the embodiments. Various modifications made within the scope of the claims and the equivalent significance of the disclosure are considered to be within the scope of this disclosure. [Explanation of symbols]

[0079] 1 Communication system, 10 PC, 20, 20a, 20b HMI, 101 First communication unit, 102 First communication control unit, 103 Setting unit, 200 Touchscreen, 201 Second communication unit, 202 Second communication control unit, 203 Display control unit, 204 Setting unit, 1000 Bus, 1001 Processor, 1002 Memory, 1003 Interface, 1004 Secondary storage device, NT network.

Claims

1. A first communication device and a plurality of second communication devices, the first communication device and each of the second communication devices are connected to a network capable of communicating by broadcast communication; The first communication device is a first communication means for communicating with each of the second communication devices via the network by the broadcast communication; a first communication control means for transmitting a highlighting signal to each of the second communication devices by the first communication means; Equipped with Each of the second communication devices is A display means; a second communication means for communicating with the first communication device and the other second communication device via the network by the broadcast communication; a display control means for controlling, when the second communication means receives the highlighting signal, the display means to display a highlighting screen emphasizing that the second communication means is capable of communicating with the first communication device; An input means for accepting a selection operation by a user; a second communication control means for transmitting a cutoff request signal to the network by the second communication means when the input means accepts the selection operation, and cutting off communication with the network by the second communication means when the second communication means receives the cutoff request signal transmitted by another second communication device; Equipped with Communication systems.

2. the first communication control means further transmits, when the first communication means receives the cutoff request signal, a confirmation signal to the network by the first communication means, the confirmation signal confirming that communication with the second communication device that transmitted the cutoff request signal is possible. The communication system according to claim 1 .

3. The second communication control means further resumes communication with the network when a certain time has elapsed since communication with the network was cut off.

3. A communication system according to claim 1 or 2.

4. A communication method in a communication system in which a first communication device and a plurality of second communication devices are connected to a network capable of communicating by broadcast communication, comprising: the first communication device transmits a highlighting signal to each of the second communication devices via the network by the broadcast communication; Each of the second communication devices, receiving the highlighting signal; In response to receiving the highlighting signal, displaying an highlighting screen on a display means that highlights that communication with the first communication device is possible; Accepting a selection operation by the user, When the selection operation is accepted, a cutoff request signal is transmitted to the network by the broadcast communication; When the cutoff request signal transmitted by the other second communication device is received, the second communication device cuts off communication with the network. Communication methods.

5. A second communication device that communicates with the first communication device via a network capable of communicating by broadcast communication and has a display means, a receiving process for receiving a highlighting signal from the first communication device; a display process for displaying, on the display means, an emphasis display screen emphasizing that communication with the first communication device is possible in response to reception of the emphasis display signal; A reception process for receiving a selection operation by a user; a cutoff request process for transmitting a cutoff request signal to the network when the selection operation is accepted by the acceptance process; a communication control process for cutting off communication with the network when the cutoff request signal transmitted by another of the second communication devices is received; A program that executes the following.

6. A communication device, A display means; A communication means for communicating with an external device via a network capable of communicating by broadcast communication; a display control means for controlling, when the communication means receives an emphasis display signal from the external device, the display means to display an emphasis display screen emphasizing that communication with the external device is possible; An input means for accepting a selection operation by a user; a communication control means for transmitting a cutoff request signal to the network by the communication means when the input means accepts the selection operation, and cutting off communication with the network by the communication means when the communication means receives the cutoff request signal transmitted by another communication device; A communication device comprising:

Images