IO Units and End Units

Abstract

To provide an IO unit system capable of appropriately detecting an abnormality in the supply state of IO power supply.SOLUTION: An IO unit (20A) includes: first power input terminals (221) that receive first power from other connected IO units; a power port (211) supplying the first power to a device connected to the power port; power lines (4) connecting the first power terminal and the power port; and a monitoring unit (50) for monitoring whether or not the first power is being supplied to the power line by measuring the voltage of the power line.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an IO unit and an end unit. [Background technology]

[0002] Conventionally, there is known an IO unit system having a plurality of IO units that perform predetermined input / output control for externally connected devices. Patent Document 1 discloses a PLC device having a bus interface, a bus function register, and a bus fault diagnosis register on an end cover. Patent Document 2 discloses a remote I / O unit having an overcurrent detection means that detects overcurrent in a power supply line that supplies power to an externally connected device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-070284 A [Patent Document 2] JP 2009-099002 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the PLC device described in Patent Document 1 performs bus fault diagnosis, and does not monitor the state of power supply to externally connected devices. In the remote IO unit described in Patent Document 2, power for the internal circuit and power for the externally connected devices are supplied from the same external power source. Therefore, if a voltage drop occurs in the external power source due to multiple connections of IO units or poor contact between IO units, there is a possibility that sufficient power is not supplied to the internal circuit including the overcurrent detection means, and the detection operation by the overcurrent detection means cannot be performed. In other words, the remote IO unit described in Patent Document 2 cannot detect a voltage drop in the IO power source.

[0005] One aspect of the present invention has been made in consideration of the above problems, and has an object to provide an IO unit system that can appropriately detect an abnormality in the supply state of IO power. [Means for solving the problem]

[0006] In order to solve the above problems, an IO unit according to one embodiment of the present invention includes a first power input terminal that receives a first power from another connected IO unit, a power port that supplies the first power to a device connected to the power port, a power line that connects the first power terminal and the power port, and a monitoring unit that monitors whether the first power is being supplied to the power line by measuring a voltage of the power line.

[0007] According to the above configuration, the IO unit includes a monitoring unit, and is thereby able to monitor the supply state of the first power. This allows the monitoring unit to detect an abnormality in the supply state of the first power to the power line. The monitoring unit also monitors the voltage of the power line as the supply state of the first power. Therefore, compared to the case where the current of the power line is monitored, it is also possible to detect a voltage drop of the first power due to multiple connections or poor contact. Therefore, it is possible to detect multiple connections or poor contact.

[0008] The monitoring unit may also include a determination unit that determines whether the first power is being supplied to the power line, and a display control unit that displays the supply status of the first power to a user based on a determination result of the determination unit.

[0009] According to the above configuration, the display control unit displays the supply state of the first power to the user, so that if there is an abnormality in the supply state of the first power, the user can easily identify the location of the abnormality.

[0010] The monitoring unit may further include a determination unit that determines whether the first power is being supplied to the power line, and a notification unit that notifies a controller that controls the IO unit of a determination result made by the determination unit.

[0011] According to the above configuration, the supply state of the first power can be notified to the controller that controls the IO unit, and the controller can notify the user of the supply state.

[0012] Furthermore, the determination unit may determine that a first state is occurring in which the first power is normally supplied to the power line when a value corresponding to the voltage of the power line is equal to or greater than a predetermined first threshold, determine that a second state is occurring in which the first power is sufficiently supplied to the power line but a voltage drop is occurring when a value corresponding to the voltage of the power line is equal to or greater than a predetermined second threshold that is smaller than the first threshold and is less than the first threshold, and determine that a third state is occurring in which the first power is not properly supplied to the power line when the value corresponding to the voltage of the power line is less than the second threshold.

[0013] According to the above configuration, it is possible to detect the second state in which the first power is sufficiently supplied to the power supply line but a voltage drop occurs, and therefore the user can fix the abnormality before a problem occurs.

[0014] Moreover, the IO unit may further include a power output terminal that outputs the first power to another connected IO unit, and the power line may connect the first power input terminal and the power output terminal.

[0015] Moreover, the IO unit may further include a second power supply input terminal that receives a second power from the other IO unit connected thereto, and a circuit constituting the monitoring unit may operate using the second power.

[0016] According to the above configuration, the first power supplied to the device via the power port and the second power for operating the circuit constituting the monitoring unit are supplied from different terminals of the IO unit. Therefore, even if a voltage drop of the first power occurs due to multiple connections or poor contact, the circuit constituting the monitoring unit can be operated by the second power supplied from the different terminal. Therefore, even if the first power is not supplied appropriately, an abnormality in the supply state of the first power can be detected.

[0017] In order to solve the above problems, an end unit according to one embodiment of the present invention is an end unit connected to the termination side of a plurality of IO units connected to each other, and includes a first power input terminal connected to a first power line of the IO unit that supplies a first power to a device connected to the IO unit, a second power line connected to the first power input terminal, and a monitoring unit that monitors whether power is being supplied to the second power line by measuring the voltage of the second power line.

[0018] According to the above configuration, the end unit is provided with a monitoring unit, and is thereby able to monitor the supply state of the first power. This allows the monitoring unit to detect an abnormality in the supply state of the first power to the power line. The monitoring unit also monitors the voltage of the power line as the supply state of the first power. Therefore, compared to the case of monitoring the current of the power line, it is also possible to detect a voltage drop of the first power due to multiple connections or poor contact. Also, the end unit, which is originally connected for the purpose of protecting the termination side of the IO unit, is provided with a monitoring unit. In other words, the structure can be simplified compared to a configuration in which a new member having a monitoring unit is provided.

[0019] The monitoring unit may include a determination unit that determines whether the first power is being supplied to the second power line, and a display control unit that displays the supply status of the first power to a user based on a determination result of the determination unit.

[0020] The monitoring unit may include a determination unit that determines whether the first power is supplied to the second power line, and a notification unit that notifies a controller that controls the IO unit of a determination result of the determination unit.

[0021] The determination unit may determine, when a value corresponding to the voltage of the second power line is equal to or greater than a predetermined first threshold, that the second power line is in a first state in which the first power is normally supplied to the second power line; determine, when a value corresponding to the voltage of the second power line is equal to or greater than a predetermined second threshold that is smaller than the first threshold and is less than the first threshold, that the second power line is in a second state in which the first power is supplied to the second power line but a voltage drop is occurring; and determine, when a value corresponding to the voltage of the second power line is less than the second threshold, that the second power line is in a third state in which the first power is not normally supplied to the second power line.

[0022] The end unit may further include a second power supply input terminal that receives a second power from a termination side of the plurality of IO units, and a circuit constituting the monitoring unit may be operated by the second power. Effect of the Invention

[0023] According to one aspect of the present invention, there is provided an IO unit system capable of appropriately detecting an abnormality in the supply state of IO power. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a schematic diagram showing a schematic configuration of an IO unit system. [Diagram 2] 1A to 1C are a front perspective view, a front view, and a rear perspective view of an IO unit. [Diagram 3] 11 is a diagram illustrating an abnormality in the supply state of IO power due to poor contact in an IO unit system. [Figure 4] 11 is a diagram illustrating an abnormality in the supply state of IO power due to multiple connections in an IO unit system. [Diagram 5]2 is a block diagram showing an example of a configuration of a main part of an IO unit according to an embodiment of the present invention; FIG. [Figure 6] 13 is a diagram showing how the IO unit detects an abnormality in the supply state of IO power. FIG. [Figure 7] FIG. 11 is a block diagram showing an example of a configuration of a main part of an end unit according to another embodiment of the present invention. [Figure 8] 13 is a diagram showing how the end unit detects an abnormality in the supply state of IO power. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, an embodiment according to one aspect of the present invention (hereinafter also referred to as "the present embodiment") will be described with reference to the drawings. However, the present embodiment described below is merely an example of the present invention in every respect. It goes without saying that various improvements and modifications can be made without departing from the scope of the present invention. In other words, in implementing the present invention, a specific configuration according to the embodiment may be appropriately adopted.

[0026] §1 Examples of application (Outline of IO unit system 1) An example of a situation in which the present invention is applied will be described with reference to Figs. 1 to 4. Fig. 1 is a schematic diagram showing a schematic configuration of an IO unit system 1. As shown in Fig. 1, the IO unit system 1 includes a communication coupler unit 10, a plurality of IO units 20, and an end unit 30. The communication coupler unit 10 is connected to a higher-level master device via a network. The IO unit system 1 performs predetermined input / output control on externally connected devices.

[0027] The communication coupler unit 10 receives a start instruction to start power supply from a master device (not shown). The IO unit system 1 may include a PLC (Programmable Logic Controller) unit that is a master device instead of the communication coupler unit 10.

[0028] The communication coupler unit 10 includes a communication section (not shown) that exchanges data with the master device, a power supply terminal block 11, and a connector 12. The power supply terminal block 11 is provided with an IO power supply terminal 111 that is connected to an external IO power supply 2, and a unit power supply terminal 112 that is connected to an external unit power supply 3. The connector 12 is provided with an IO power supply output terminal 121, a unit power supply output terminal 122, and a communication terminal (not shown).

[0029] Inside the communication coupler unit 10, the IO power supply terminal 111 is connected to the IO power output terminal 121 by an IO power line 4 (first power line). Also, inside the communication coupler unit 10, the unit power supply terminal 112 is connected to the internal power supply circuit 13 and the unit power output terminal 122 via a bus power supply circuit 15. The internal power supply circuit 13 is connected to the internal circuit 14 of the communication coupler unit 10. Furthermore, inside the communication coupler unit 10, the communication section is connected to the communication terminal of the connector 12 by a communication line (not shown).

[0030] Each of the multiple IO units 20 includes a terminal block 21, an upper connector 22, and a lower connector 23. The upper connector 22 and the lower connector 23 are provided on both side surfaces of the IO unit 20, respectively (see FIG. 2). The terminal block 21 is provided with multiple power supply ports 211 that are connected to external devices. The upper connector 22 is provided with an IO power supply input terminal 221 (first power supply input terminal), a unit power supply input terminal 222 (second power supply input terminal), and a communication terminal (not shown). The lower connector 23 is provided with an IO power supply output terminal 231 (power supply output terminal), a unit power supply output terminal 232, and a communication terminal (not shown).

[0031] The multiple IO units 20 are connected in series to the communication coupler unit 10. Specifically, the connector 12 of the communication coupler unit 10 and the upper connector 22 of the IO unit 20a are connected so that corresponding terminals (the IO power output terminal 121 and the IO power input terminal 221, and the unit power output terminal 122 and the unit power input terminal 222) are connected to each other. Similarly, the upper connectors 22 of the IO units 20b to 20e are connected to the lower connectors 23 of the IO units 20a to 20d, respectively. Note that, although FIG. 1 shows an example in which five IO units 20a to 20e are connected in series to the communication coupler unit 10, the number of IO units is not limited to this.

[0032] The IO power input terminal 221 receives IO power (first power) from the IO power output terminal 121 of the communication coupler unit 10 or the IO power output terminal 231 of the IO unit 20 connected on the upstream side. The unit power input terminal 222 receives unit power (second power) from the unit power output terminal 122 of the communication coupler unit 10 or the unit power output terminal 232 of the IO unit 20 connected on the upstream side.

[0033] Inside the multiple IO units 20, the IO power input terminal 221 is connected to the power port 211 and the IO power output terminal 231 by the IO power line 4. Furthermore, inside the multiple IO units 20, the unit power input terminal 222 is connected to the internal power circuit 27 and the unit power output terminal 232 by the unit power line 5. The internal power circuit 27 is connected to the internal circuit 24 of each IO unit 20 by the unit power line 5. Furthermore, inside the multiple IO units 20, the communication terminal of the upper connector 22 is connected to the communication terminal of the lower connector 23 by a communication line.

[0034] The IO power supply 2 and the unit power supply 3 are typically DC 24V power supplies. The bus power supply circuit 15 steps down the power voltage supplied from the unit power supply 3 (for example, from DC 24V to DC 5.8V). The bus power supply circuit 15 supplies the stepped-down power to the internal power supply circuits 13, 27. The internal power supply circuits 13, 27 step down the power voltage supplied from the bus power supply circuit 15 (for example, from DC 5.8V to DC 3.3V or DC 1.2V). The internal power supply circuits 13, 27 supply the stepped-down power to the internal circuits 14, 24, respectively.

[0035] In addition, of the multiple terminals of each connector (connector 12, upper connector 22, lower connector 23), two are used for IO power supply + and IO power supply -, two are used for unit power supply + and unit power supply -, and the remainder are used for communication lines.

[0036] The end unit 30 is connected to the terminal end (IO unit 20e) of the multiple interconnected IO units 20. The end unit 30 is a cover member that protects the lower connector 23 of the IO unit 20e.

[0037] With the above configuration, IO power supplied from the IO power supply 2 is supplied to an external device connected to the power supply port 211 via the IO power supply line 4. Moreover, unit power supplied from the unit power supply 3 is supplied to the internal circuits 14, 24 via the unit power supply line 5. Moreover, the communication section of the communication coupler unit 10 exchanges data with each IO unit 20 via the communication line.

[0038] (Schematic configuration of IO unit 20) 2 is a front perspective view (reference number 2A in FIG. 2), a front view (reference number 2B in FIG. 2), and a rear perspective view (reference number 2C in FIG. 2) of the IO unit 20. As shown in FIG. 2, the IO unit 20 includes a terminal block 21, an upper connector 22, a lower connector 23, an engaging portion 25, and an engaged portion 26. In the following description, the side of the IO unit 20 where the terminal block 21 is located is referred to as the front, the opposite side is referred to as the rear, the left side facing the rear is referred to as the left side, and the right side is referred to as the right side.

[0039] The terminal block 21 is provided on the front surface of the IO unit 20. The terminal block 21 includes a plurality of power supply ports 211 for connecting external devices. In the example of FIG. 2, the power supply port 211 has 16 terminals.

[0040] The upper connector 22 is provided on the right side surface of the IO unit 20. The lower connector 23 is provided on the left side surface of the IO unit 20. The IO units 20 are electrically connected by the upper connector 22 and the lower connector 23.

[0041] An engaging portion 25 is provided on the right side of the upper and lower ends on the front surface of the IO unit 20. An engaged portion 26 is provided on the left side of the upper and lower ends on the front surface of the IO unit 20. The engaging portion 25 and the engaged portion 26 are guides for connecting the IO units 20 to each other.

[0042] Fig. 3 is a diagram showing an abnormality in the supply state of IO power due to poor contact in the IO unit system 1. Fig. 3 shows an example in which four IO units 20a to 20d are connected in series to the communication coupler unit 10. For simplicity, the following description will be given with reference to the example in Fig. 3.

[0043] 3, if there is poor contact in the terminal corresponding to IO power between IO unit 20c and IO unit 20d, IO power is not normally supplied to IO unit 20d. Therefore, an external device connected to IO unit 20d does not operate normally. On the other hand, since there is no poor contact in the terminal corresponding to unit power, unit power is supplied to IO unit 20d. Therefore, internal circuit 24 of IO unit 20d is normally driven.

[0044] In the conventional IO unit system 1, when unit power is not supplied to the IO unit 20, the internal circuit 24 does not operate, so it is easy to detect an abnormality in the supply state of unit power. On the other hand, the conventional IO unit system 1 does not have a function to detect whether IO power is being supplied to the IO unit 20. Therefore, when there is no poor contact in the terminal corresponding to the unit power but there is a poor contact in the terminal corresponding to the IO power as shown in Fig. 3, it is difficult to identify the cause of the externally connected device not working.

[0045] FIG. 4 is a diagram showing an abnormality in the supply state of IO power due to multiple connections in an IO unit system. As shown in FIG. 4, a contact resistance R exists at each connector connection part of each IO unit 20. Here, the voltage of the IO power supply 2 is 24V, and the load current flowing to the external connection device via the IO power supply line 4 is I. At this time, the voltage of the IO power supplied from the communication coupler unit 10 to the Nth IO unit 20 is expressed as 24-I×R×N. For example, when I=2A and R=0.1Ω, the voltage of the IO power supplied from the communication coupler unit 10 to the sixth IO unit 20 (i.e., N=6) is 22.8V. Moreover, the voltage of the IO power supplied from the communication coupler unit 10 to the twentieth IO unit 20 (i.e., N=20) is 20.0V. Here, the power supply voltage specification range of the external connection device is 20.4V to 26.4V. At this time, since a sufficient IO power supply voltage is not supplied to the 20th IO unit 20, the external device connected to the 20th IO unit 20 does not operate normally. In the conventional IO unit system 1, even when there is a voltage drop in the IO power due to the multiple connections of the IO units 20 as described above, it is difficult to identify the cause of the external device not operating.

[0046] 3 and 4, the conventional IO unit system 1 cannot easily detect a voltage drop of IO power caused by a poor connection or multiple connections. On the other hand, the IO unit system 1 according to the present embodiment is provided with a monitoring unit 50 (described later) in the IO unit or end unit, so that it can easily detect a voltage drop of IO power.

[0047] §2 Configuration Example [Embodiment 1] (IO unit 20A configuration) An IO unit system 1 according to an embodiment of the present invention includes a plurality of IO units 20 including at least one IO unit 20A having a monitoring unit 50 (see FIG. 6).

[0048] Fig. 5 is a block diagram showing an example of a main configuration of an IO unit 20A according to an embodiment of the present invention. As shown in Fig. 5, the IO unit 20A includes a terminal block 21, an upper connector 22, a lower connector 23, an internal power supply circuit 27, and a monitoring unit 50. The circuit constituting the monitoring unit 50 is a part of the internal circuit 24 in Fig. 1. That is, the circuit constituting the monitoring unit 50 is driven by power supplied from the unit power supply 3 via the unit power supply line 5.

[0049] The terminal block 21 may include a terminal for measurement. A user can directly measure the voltage of the IO power line 4 by applying a tester to the terminal for measurement.

[0050] The monitoring unit 50 includes a step-down circuit 51, an AD converter 52, a determination unit 53, a display control unit 54, and a notification unit 55. The monitoring unit 50 monitors the supply state of IO power in the IO unit 20A. The monitoring unit 50 also displays information indicating the supply state to the user or notifies the controller.

[0051] The step-down circuit 51 is connected to the IO power input terminal 221 by the IO power line 4. The step-down circuit 51 steps down the voltage of the IO power line 4. The step-down circuit 51 outputs the stepped-down voltage of the IO power line 4 to the AD converter 52.

[0052] The AD converter 52 converts the voltage of the IO power line 4 as an analog signal input from the step-down circuit 51 into an IO power supply voltage value V1 as a digital signal. The AD converter 52 outputs the IO power supply voltage value V1 to the determination unit 53.

[0053] The determination unit 53 determines the supply state of the IO power based on the IO power supply voltage value V1 acquired from the AD converter 52. For example, when the IO power supply voltage value V1 is equal to or greater than a predetermined first threshold, the determination unit 53 determines that the IO power supply line 4 is in a first state in which the IO power is normally supplied. When the IO power supply voltage value V1 is equal to or greater than a predetermined second threshold that is smaller than the predetermined first threshold and is less than the predetermined first threshold, the determination unit 53 determines that the IO power supply line 4 is in a second state in which the IO power is supplied but a voltage drop occurs. When the IO power supply voltage value V1 is less than the predetermined second threshold, the determination unit 53 determines that the IO power supply line 4 is in a third state in which the IO power is not normally supplied. The predetermined second threshold is set to, for example, a lower limit value of the power supply voltage specification range of the externally connected device. The predetermined first threshold and the predetermined second threshold may be set arbitrarily according to the power supply voltage specification range of the externally connected device. The determination unit 53 outputs the determination result of the supply state of the IO power to the display control unit 54 and the notification unit 55. The determination unit 53 is, for example, an internal processing circuit (MPU) of the IO unit 20A.

[0054] The display control unit 54 controls the display of the display unit (not shown) based on the determination result acquired from the determination unit 53. For example, the display unit is an LED provided in the IO unit 20A, and the display control unit 54 is an LED display circuit. In this case, when the display control unit 54 acquires a determination result from the determination unit 53 that the state is a first state in which IO power is normally supplied, the display control unit 54 turns on a green LED. When the display control unit 54 acquires a determination result from the determination unit 53 that the state is a second state in which IO power is supplied but a voltage drop occurs, the display control unit 54 blinks a green LED. When the display control unit 54 acquires a determination result from the determination unit 53 that the state is a third state in which IO power is not normally supplied to the IO power line 4, the display control unit 54 turns on a red LED. With this configuration, the display control unit 54 can notify the user of the supply state of IO power. Note that the display method of the display unit based on the supply state of the IO power source 2 is not limited to this.

[0055] The notification unit 55 notifies the communication unit of the communication coupler unit 10 via the communication line 6 based on the judgment result acquired from the judgment unit 53. The communication unit of the communication coupler unit 10 notifies the controller of the judgment result. The notification unit 55 is, for example, an ASIC (Application Specific Integrated Circuit) for bus communication.

[0056] With the above configuration, the IO unit system 1 can monitor the supply state of IO power in the IO unit 20A by including the monitoring unit 50. As a result, the monitoring unit 50 can detect an abnormality in the supply state of IO power to the IO power line 4.

[0057] In addition, the monitoring unit 50 monitors the voltage of the IO power line 4 as the supply state of IO power. Therefore, compared to the case where the current of the IO power line 4 is monitored, it is possible to detect a voltage drop of the IO power due to multiple connections or poor contact.

[0058] (Detected by IO unit 20A) Fig. 6 is a diagram showing how the IO unit 20A detects an abnormality in the supply state of the IO power supply 2. Fig. 6 shows an example in which, of the five IO units 20, the second IO unit 20Aa from the communication coupler unit 10 and the fifth IO unit 20Ab from the communication coupler unit 10 are provided with a monitoring unit 50. For simplicity, the following description will be given with reference to the example in Fig. 6.

[0059] 6, when the monitoring unit 50 of the IO unit 20Aa determines that there is no abnormality in the IO power supply state and the monitoring unit 50 of the IO unit 20Ab determines that there is an abnormality in the IO power supply state, it is found that the cause of the abnormality in the IO power supply state exists between the IO unit 20Aa and the IO unit 20Ab. Also, compared to a configuration in which the monitoring unit 50 is provided in an end unit (to be described later), the IO unit system 1 has a plurality of IO units 20A, so that it is easy to identify the cause of the abnormality in the IO power supply state.

[0060] Also, only some of the IO units 20 may be provided with the monitoring unit 50. With a configuration in which only some of the IO units are provided with the monitoring unit 50, it is possible to detect an abnormality in the supply state of IO power without incurring costs.

[0061] [Embodiment 2] Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0062] (Configuration of end unit 30A) FIG. 7 is a block diagram showing an example of a main configuration of an end unit 30A according to another embodiment of the present invention. As shown in FIG. 7, the end unit 30A includes a connector 32, an internal power supply circuit 33, and a monitoring unit 50. The connector 32 is provided with an IO power supply input terminal 321, a unit power supply input terminal 322, and a communication terminal (not shown). The end unit 30 is connected to the end side of a plurality of IO units connected to each other via the connector 32. Specifically, the lower connector 23 of the IO unit 20 and the connector 32 of the end unit 30 are connected so that corresponding terminals (the IO power supply output terminal 231 and the IO power supply input terminal 321, and the unit power supply output terminal 232 and the unit power supply input terminal 322) are connected.

[0063] The internal power supply circuit 33 is connected to the unit power supply input terminal 322 by a unit power supply line 8. The internal power supply circuit 33 is also connected to the monitoring unit 50 by the unit power supply line 8. With this configuration, the monitoring unit 50 is driven by the unit power supplied to the end unit 30A.

[0064] The configuration of the monitoring unit 50 of the end unit 30A is similar to that of the monitoring unit 50 of the IO unit 20A according to the first embodiment. The step-down circuit 51 is connected to the IO power input terminal 321 by the IO power line 7 (second power line). The step-down circuit 51 acquires the voltage of the IO power line 7 and steps down the voltage.

[0065] (Detection by end unit 30A) Fig. 8 is a diagram showing how an end unit 30A detects an abnormality in the supply state of IO power. Fig. 8 shows an example in which an end unit 30A is connected to the termination side of four IO units 20. For simplicity, the following description will be given with reference to the example in Fig. 8.

[0066] As shown in FIG. 8, when an abnormality occurs in the IO power supply state in any of the multiple IO units 20, the monitoring unit 50 can detect the abnormality in the IO power supply state.

[0067] [Software implementation example] The control blocks of the monitoring unit 50 (particularly the determination unit 53, the display control unit 54, and the notification unit 55) may be realized by a logic circuit (hardware) formed in an integrated circuit (IC chip) or the like, or may be realized by software.

[0068] In the latter case, the monitoring unit 50 includes a computer that executes instructions of a program, which is software that realizes each function. The computer includes, for example, one or more processors, and a computer-readable recording medium that stores the program. The object of the present invention is achieved by the processor reading the program from the recording medium and executing it in the computer. The processor may be, for example, a CPU (Central Processing Unit). The recording medium may be a "non-transient tangible medium," such as a ROM (Read Only Memory), as well as a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like. The computer may further include a RAM (Random Access Memory) that expands the program. The program may be supplied to the computer via any transmission medium (such as a communication network or a broadcast wave) that can transmit the program. Note that one aspect of the present invention may also be realized in the form of a data signal embedded in a carrier wave, in which the program is embodied by electronic transmission.

[0069] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0070] 1 IO Unit System 2 IO power supply 3 Unit Power Supply 4 IO power line (first power line) 7 IO power line (second power line) 10 Communication coupler unit 20A IO unit 30A End Unit 50 Monitoring Department 53 Judgment section 54 Display control section 55 Notification Department 211 Power Port 221, 321 IO power input terminal (first power input terminal) 222, 322 Unit power input terminal (second power input terminal) 231 IO power output terminal (power output terminal)

Claims

1. An IO unit, a first power supply input terminal for receiving a first power from another connected IO unit; a power port for supplying the first power to a device connected to the power port; a power supply line connecting the first power supply input terminal and the power supply port; a monitoring unit that monitors whether the first power is being supplied to the power supply line by measuring a voltage of the power supply line, the monitoring unit includes a determination unit that determines whether the first power is being supplied to the power supply line, The determination unit is When a value corresponding to the voltage of the power supply line is equal to or greater than a predetermined first threshold, it is determined that the power supply line is in a first state in which the first power is normally supplied; when a value corresponding to the voltage of the power supply line is equal to or greater than a predetermined second threshold value that is smaller than the first threshold value and is less than the first threshold value, it is determined that the power supply line is in a second state in which the first power is being supplied to the power supply line but a voltage drop is occurring; When the value corresponding to the voltage of the power supply line is less than the second threshold value, it is determined that a third state is occurring in which the first power is not normally supplied to the power supply line; The second threshold value is a value that falls below the second threshold value when the voltage of the power supply line falls below a lower limit value of a power supply voltage specification range of the device.

2. The IO unit according to claim 1 , wherein the monitoring unit includes a display control unit that displays a supply state of the first power to a user based on a determination result of the determination unit.

3. The IO unit according to claim 1 , wherein the monitoring unit includes a notification unit that notifies a controller that controls the IO unit of a determination result of the determination unit.

4. a power output terminal for outputting the first power to another connected IO unit; The IO unit according to claim 1 , wherein the power supply line connects the first power supply input terminal and the power supply output terminal.

5. a second power supply input terminal for receiving a second power from the other IO unit connected thereto; The IO unit according to claim 1 , wherein a circuit constituting the monitoring unit operates using the second power.

6. An end unit connected to a termination side of a plurality of IO units connected to each other, a first power input terminal connected to a first power line of the IO unit, the first power input terminal supplying a first power to a device connected to the IO unit; a second power supply line connected to the first power supply input terminal; a monitoring unit that monitors whether or not power is being supplied to the second power supply line by measuring a voltage of the second power supply line, the monitoring unit includes a determination unit that determines whether the first power is supplied to the second power supply line, The determination unit is When a value corresponding to the voltage of the second power supply line is equal to or greater than a predetermined first threshold, it is determined that the second power supply line is in a first state in which the first power is normally supplied; when a value corresponding to the voltage of the second power supply line is equal to or greater than a predetermined second threshold value that is smaller than the first threshold value and is less than the first threshold value, it is determined that the second power supply line is in a second state in which the first power is supplied to the second power supply line but a voltage drop is occurring; When the value corresponding to the voltage of the second power supply line is less than the second threshold value, it is determined that the second power supply line is in a third state in which the first power is not normally supplied; The second threshold value is a value that corresponds to the voltage of the second power supply line and falls below the second threshold value when the voltage of the second power supply line falls below a lower limit value of a power supply voltage specification range of the device.

7. 7. The end unit according to claim 6, wherein the monitoring unit comprises: a determination unit that determines whether the first power is being supplied to the second power line; and a display control unit that displays a supply status of the first power to a user based on a determination result of the determination unit.

8. 7. The end unit according to claim 6, wherein the monitoring unit comprises: a determination unit that determines whether the first power is being supplied to the second power line; and a notification unit that notifies a controller that controls the IO unit of a determination result of the determination unit.

9. a second power supply input terminal for receiving a second power from a termination side of the plurality of IO units; The end unit according to claim 6 , wherein a circuit constituting the monitoring unit operates using the second power.

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