Contact output device and monitoring device

Abstract

To provide a contact output device and a monitoring device capable of detecting the activation state of a connected device, the presence or absence of cable connection, and the failure of a switch.SOLUTION: A logic IC 38 of a contact output device 3 controls an inspection mode in which the current of a signal input from a contact input device 1 is detected to determine normality or abnormality, an operation mode during operation, and an alarm mode in which an alarm is issued and the mode thereof is switched to the inspection mode at startup or restart, and shifts to the operation mode if the inspection is normal or to the alarm mode if the inspection is abnormal by a monitoring unit provided in a monitoring device.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a contact output device that monitors switches used in an electric power system, and more particularly to a contact output device and a monitoring device that can detect the startup state of a connected device, the presence or absence of a cable connection, and a switch failure. [Background technology]

[0002] [Prior Art] Conventional communication equipment includes switches that transmit isolated signals to notify the status of equipment such as rectifiers. In recent years, there has been an increasing need for devices that automatically monitor the operation of switches for these communication facilities from the standpoint of improving the reliability of these switches, improving ease of installation, reducing maintenance work, and preventing accidents.

[0003] One of the devices for automatically monitoring the operation of switches that notify the status of such communication facilities is a switching time sensor that measures the operation time of a switch. However, when the destination device can monitor, or when the destination device can monitor by a server that manages the destination device, an opening / closing time sensor is often not implemented.

[0004] Furthermore, even conventional devices for monitoring switches are not capable of distinguishing and detecting the start-up state of a connected device, the presence or absence of a cable connection, and a switch failure.

[0005] [Conventional surveillance device: Figure 12] Next, a conventional monitoring device (actual contact interface unit) will be described with reference to Fig. 12. Fig. 12 is a circuit diagram of the conventional monitoring device. In the conventional monitoring device, as shown in FIG. 12, a contact input device 1 and a contact output device 3′ are connected by a cable 2.

[0006] [Contact input device 1] The contact input device 1 includes a photocoupler 11, and a power source 14 of an applied voltage (VccI1) to an external terminal is applied to the cathode of a diode of the photocoupler 11 via a limiting resistor (R), and the output of the photocoupler 11 is output to a logic IC (CMOS Logic-IC) 12. The logic IC 12 receives the output from the photocoupler 11 and judges whether the contact output device 3' connected thereto is normal or abnormal.

[0007] Furthermore, a logic level power supply (VccI2) 13 is connected to the output of the photocoupler 11 via a limiting resistor (R). Furthermore, the cathode of the diode of the photocoupler 11 is connected to a terminal 15 via the diode, and the terminal 15 is connected to a contact output device 3' by a cable 2. Furthermore, the contact input device 1 is provided with a terminal 16 connected to ground, which serves as a lead-in terminal from the contact output device 3'. The contact input device 1 is of dry input contact specification.

[0008] [Contact output device 3'] The contact output device 3' includes a real contact relay circuit 31 having a coil, one end of the coil of the real contact relay circuit 31 is connected to a logic level power supply (VccO) 33 via a limiting resistor (R), and the other end of the coil is connected to a logic IC (CMOS Logic-IC) 32. Furthermore, the input terminal of the logic IC 32 is connected to a power supply 33 via a diode. The power supply 33 and a limiting resistor (R) form a logic-level power supply and limiting resistor.

[0009] Here, the real contact relay circuit 31 controls the ON / OFF of the switch by opening and closing the relay circuit. Under normal circumstances, terminal (B) 30b and terminal (C) 30c are connected, and a signal from an external device connected to the switch is input to terminal (A) 30a. If an abnormality occurs in the input signal, the logic IC 32 connects terminal (A) 30a and terminal (C) 30c and outputs an alarm.

[0010] The alarm output is generated when the output of the photocoupler 11 of the contact input device 1 is input to the contact output device 3' and a path is formed that returns to the contact input device 1 via the real contact relay circuit 31, so that the detection result of the photocoupler 11 is obtained by the logic IC 12 and becomes an alarm output.

[0011] The logic IC 32 uses, for example, LVCMOS (Low Voltage CMOS) or LVTTL (Low Voltage Transistor / Transistor Logic), and if the current draw of the coil is insufficient, additional transistors are implemented. Here, the terminal 30a is an output terminal, and the terminal 30c is a common (COM) terminal.

[0012] [Conventional lightning protection monitoring system: Figure 13] A conventional lightning-resistant monitoring system, as shown in Fig. 13, is basically similar to that in Fig. 12, but includes a lightning-resistant circuit shown in the dashed block. Fig. 12 is a circuit diagram of a conventional lightning-resistant monitoring system. Arrester, varistor, etc. are used as lightning protection circuits.

[0013] [Related Technology] As related prior art, there are JP-A-2003-308751 "Operational Characteristics Monitoring Device for Switch" (Patent Document 1) and JP-A-02-106118 "Switch" (Patent Document 2).

[0014] Patent Document 1 discloses a monitoring device that monitors pulse switching intervals to determine whether or not there is an abnormality. Patent Document 2 discloses a switch that monitors the rising edge of a pulse count to diagnose an abnormality. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] JP 2003-308751 A [Patent Document 2] Japanese Patent Application Publication No. 02-106118 Summary of the Invention [Problem to be solved by the invention]

[0016] However, conventional switch monitoring devices have the problem that they cannot individually detect the startup state of the connected device, the presence or absence of a cable connection, or a switch failure, and therefore cannot identify the cause of the abnormality.

[0017] Incidentally, Patent Documents 1 and 2 describe monitoring by time counting and pulse counting, but do not disclose a configuration capable of identifying a specific cause of an abnormality.

[0018] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a contact output device and a monitoring device that are capable of detecting the startup state of a connected device, the presence or absence of a cable connection, and a switch failure. [Means for solving the problem]

[0019] In order to solve the problems of the above-mentioned conventional example, the present invention is a contact output device having a real contact, The electrical equipment includes a terminal for a destination device connected to the switch, a first switch for controlling the on / off of the switch and switching whether or not to output a signal input from the terminal, a detection circuit for detecting the current of a signal input from the contact input device using the terminal, a monitoring unit for performing contact monitoring of the signal input from the contact input device by detecting the current in the detection circuit and controlling an operating mode, and a second switch provided between the first switch and the detection circuit for switching whether or not to output a signal from the first switch to the detection circuit, wherein the monitoring unit: Signals input from contact input devices The first switch is switched to output the signal from the terminal, and the second switch is switched to output the signal to the detection circuit, and the detection circuit detects the signal. A test mode in which the current is detected to determine whether the current is normal or abnormal; The first switch is used to switch the terminal so that it does not output a signal, and the second switch is used to switch the terminal so that it does not output a signal to the detection circuit. The operation mode, The first switch is used to switch the terminal so that it outputs a signal, and the second switch is used to switch the terminal so that it does not output a signal to the detection circuit. It controls the alarm mode, which issues an alarm, and switches to the inspection mode at startup. If the inspection is normal, it switches to the operation mode, and if the inspection is abnormal, it switches to the alarm mode. The monitoring unit is capable of detecting the start-up state of the connected device, the presence or absence of a cable connection, and a switch failure based on the state of the contact monitoring in the inspection mode, operation mode, and alarm mode. This is characterized by the fact that

[0020] The present invention is characterized in that in the above-mentioned contact output device, the monitoring unit operates in operation mode and when an abnormality occurs, it transitions to inspection mode, and when an abnormality is determined in the inspection mode, it transitions to alarm mode.

[0021] The present invention is characterized in that in the above-mentioned contact output device, the monitoring unit is operating in an alarm mode and when it recovers from an abnormality, it transitions to an inspection mode, and when it is determined to be normal in the inspection mode, it transitions to an operation mode.

[0023] The present invention is characterized in that a monitoring device comprises a contact input device and the above-mentioned contact output device.

[0024] The present invention is characterized in that in a monitoring system, a communication facility device and a higher-level device are connected by the above-mentioned monitoring device. Effect of the Invention

[0025] According to the present invention, there is provided a contact output device having a real contact, The electrical equipment includes a terminal for a destination device connected to the switch, a first switch for controlling the on / off of the switch and switching whether or not to output a signal input from the terminal, a detection circuit for detecting the current of a signal input from the contact input device using the terminal, a monitoring unit for performing contact monitoring of the signal input from the contact input device by detecting the current in the detection circuit and controlling an operating mode, and a second switch provided between the first switch and the detection circuit for switching whether or not to output a signal from the first switch to the detection circuit, wherein the monitoring unit: Signals input from contact input devices The first switch is switched to output the signal from the terminal, and the second switch is switched to output the signal to the detection circuit, and the detection circuit detects the signal. A test mode in which the current is detected to determine whether the current is normal or abnormal; The first switch is used to switch the terminal so that it does not output a signal, and the second switch is used to switch the terminal so that it does not output a signal to the detection circuit. The operation mode, The first switch is used to switch the terminal so that it outputs a signal, and the second switch is used to switch the terminal so that it does not output a signal to the detection circuit. It controls the alarm mode, which issues an alarm, and switches to the inspection mode at startup. If the inspection is normal, it switches to the operation mode, and if the inspection is abnormal, it switches to the alarm mode. The monitoring unit is capable of detecting the start-up state of the connected device, the presence or absence of a cable connection, and a switch failure based on the state of the contact monitoring in the inspection mode, operation mode, and alarm mode. Since the above-mentioned configuration is adopted, various abnormalities can be detected based on the state of each mode. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 is a schematic diagram of the present system. [Diagram 2] FIG. 2 is a circuit diagram of the monitoring device. [Diagram 3] FIG. 2 is a circuit diagram of the lightning protection monitoring device. [Figure 4] FIG. 2 is a schematic diagram showing a mode management state. [Diagram 5] FIG. 13 is a process flow diagram in an inspection mode. [Figure 6] FIG. 11 is a process flow diagram in a relay monitoring mode. [Figure 7] FIG. 11 is a process flow diagram in an operation mode. [Figure 8] FIG. 13 is a process flow diagram in an alarm mode. [Figure 9] FIG. 13 is a diagram showing a state table of the inspection mode. [Figure 10] FIG. 13 is a diagram showing a state table of an operation mode. [Figure 11] FIG. 13 is a diagram showing a state table of an alarm mode. [Figure 12] FIG. 1 is a circuit diagram of a conventional monitoring device. [Figure 13] FIG. 1 is a circuit diagram of a conventional lightning protection monitoring device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. [Outline of the embodiment] The contact output device according to an embodiment of the present invention (this contact output device) is provided with a monitoring unit which controls an inspection mode in which an inspection is performed to detect the current of a signal input from a contact input device to determine whether it is normal or abnormal, an operation mode in which it performs operation, and an alarm mode in which it issues an alarm, and which transitions to the inspection mode at startup, transitions to the operation mode if the inspection is normal, and transitions to the alarm mode if the inspection is abnormal, and is capable of detecting the startup state of the connected device, whether a cable is connected, and any faults in the switch.

[0028] Moreover, the monitoring device according to the embodiment of the present invention (the present monitoring device) has a contact input device and the present contact output device. Moreover, the monitoring system according to the embodiment of the present invention (the present system) connects the communication facility device and the higher-level device via the present monitoring device.

[0029] [This system: Figure 1] This system will be described with reference to Figure 1. Figure 1 is a schematic diagram of the system. As shown in FIG. 1, this system basically includes a monitoring device (digital IO) 100, a higher-level device 200, and devices 310 to 340 that provide various station information in electric power system communication facilities. The monitoring device 100 is connected to a host device 200 and each of the devices 310-340. The monitoring device 100 transmits the monitoring result obtained by the contact output device 3 (to be described later) to the higher-level device 200, and also outputs it to each of the devices 310-340.

[0030] [This monitoring device: Figure 2] The present monitoring device will be described with reference to Fig. 2. Fig. 2 is a circuit diagram of the present monitoring device. Note that the configuration of the contact input device 1 is omitted since it is the same as the conventional configuration shown in Fig. 12, and the contact output device 3 will be specifically described.

[0031] [Contact output device 3] As shown in FIG. 2, the contact output device 3 includes a real contact relay circuit 31 having a coil, one end of the coil of the real contact relay circuit 31 is connected to a logic level power supply (VccO) 33 via a limiting resistor (R), and the other end of the coil is connected to a logic IC (CMOS Logic-IC) 38. Moreover, the input terminal of the logic IC 38 is connected to the power supply 33 via a diode. The power supply 33 and the limiting resistor (R) form a logic-level power supply and limiting resistor.

[0032] As explained in FIG. 12, the real contact relay circuit 31 controls the ON / OFF of the switch by opening and closing the relay circuit. Under normal circumstances, terminal (B) 30b and terminal (C) 30c are connected and in an open state, and a signal from an external device connected to the switch is input to terminal (A) 30a. If an abnormality occurs in the input signal, the logic IC 38 connects terminal (A) 30a and terminal (C) 30c and outputs an alarm.

[0033] When the logic IC 38 is started or restarted, the terminal (A) 30a and the terminal (C) 30c are connected to each other, and the logic IC 38 goes into the inspection mode. The logic IC 38 mainly switches between the inspection mode, operation mode, and alarm mode, the details of which will be described later.

[0034] In addition, the alarm output in this monitoring device is generated when the output of the photocoupler 11 of the contact input device 1 is input to the contact output device 3, and a path is formed that returns to the contact input device 1 via the actual contact relay circuit 31, the monitoring relay circuit 35, etc., and the detection result of the photocoupler 11 is obtained by the logic IC 12 and becomes an alarm output. The logic IC 38 uses, for example, LVCMOS or LVTTL, and if the current draw of the coil is insufficient, additional transistors are implemented.

[0035] In addition, in the monitoring relay circuit 35 of the contact output device 3, the voltage (VccO) of the power supply 34 is applied to one end of the coil via a limiting resistor (R), and the other end of the coil is connected to a logic IC 38.

[0036] Moreover, the monitoring relay circuit 35 has terminals A, B, and C, with the terminal C connected to the terminal C of the real contact relay circuit 31 and the terminal B connected to the cathode of the contact monitoring photocoupler 36 via a limiting resistor (R). The terminal A is directly connected to the terminal 30c.

[0037] The monitoring relay circuit 35 goes into monitoring mode when the contact CB is connected, and goes into operation mode (bypass) when the contact CA is connected. By combining the switching of the contacts of the actual contact relay circuit 31 and the monitoring relay circuit 35, an inspection mode, an operation mode, and an alarm mode are realized.

[0038] The contact monitoring photocoupler 36 has a diode whose cathode is connected to the terminal B of the monitoring relay circuit 35 via a limiting resistor (R), and whose anode is connected to the terminal 30c. An output signal of the detection result of the contact monitoring photocoupler 36 is output to a logic IC 38. A logic level power supply (VccI2) 37 is applied to the input of the logic IC 38.

[0039] The logic IC 38 judges whether the circuit is normal or abnormal based on the detection result of the contact monitoring photocoupler 36. The details of the judgment will be described later. The power supply 34, the monitoring relay circuit 35, the contact terminal photocoupler 36, the logic level power supply 37 and a part of the logic IC 38 correspond to a monitoring section in the claims.

[0040] [This lightning-resistant monitoring device: Figure 3] The lightning protection monitoring device will be described with reference to Fig. 3. Fig. 3 is a circuit diagram of the lightning protection monitoring device. As shown in FIG. 3, this lightning protection monitoring system is basically the same as that shown in FIG. 1, but includes a lightning protection circuit shown in the dashed line block similar to the configuration shown in FIG. Arrester, varistor, etc. are used as lightning protection circuits.

[0041] [Mode Management: Figure 4] The mode states managed by the logic IC 38 will be described with reference to Fig. 4. Fig. 4 is a schematic diagram showing the mode management states. When the logic IC 38 is started or restarted, it transitions to a test mode S1, and when normal start-up is confirmed in the test mode S1, it transitions to an operation mode S2, and when an abnormality occurs in the operation mode S2, it returns to the test mode S1. If an abnormality diagnosis is performed in the inspection mode S1, the mode transitions to the warning mode S3, and when the abnormality diagnosis is recovered, the mode returns to the inspection mode S1 again.

[0042] [Inspection mode: Figure 5] Next, the inspection mode will be described with reference to Fig. 5. Fig. 5 is a process flow diagram in the inspection mode. When the inspection mode starts, an inspection preparation process (S11) is performed. The inspection preparation process first applies a voltage to the input port of the contact input device 1, activates an alarm at the output port of the contact output device 3, sets the actual contact relay circuit 31 to an alarm mode by connecting the AC contact, sets the monitoring relay circuit 35 to a monitoring mode by connecting the CB contact, and unmasks the contact information of the contact monitoring photocoupler 36. The unmasking will be described later.

[0043] Next, the process of the relay monitoring mode (S12) is performed to determine whether or not the contact monitoring photocoupler 36 is ON (S13), and if it is not ON (No), the process returns to S12. The process of the relay monitoring mode will be described later. If the contact monitoring photocoupler 36 is ON in the judgment process S13 (Yes), a self-check is performed within the contact output device 3 (S14), and it is judged whether the result is normal or not (S15). If it is normal (Yes), the mode shifts to the operation mode, and if it is not normal (No), the mode shifts to the alarm mode.

[0044] [Relay monitoring mode: Figure 6] The relay monitoring mode will be described with reference to Fig. 6. Fig. 6 is a process flow diagram in the relay monitoring mode. In the relay monitoring mode, as shown in Fig. 6, the actual contact relay circuit 31 is set to the alarm mode by connecting the AC contact, the monitoring relay circuit 35 is set to the monitoring mode by connecting the CB contact, the detection result of the contact monitoring photocoupler 36 is checked (S21), and the process ends. The detection result will be described in detail with reference to Figs. 9 and 10.

[0045] [Operation mode: Figure 7] The operation mode will be described with reference to Fig. 7. Fig. 7 is a process flow diagram in the operation mode. As shown in FIG. 7, the operation mode is entered by connecting the monitoring relay circuit 35 to the CA contact (S31), then a self-check is performed within the contact output device 3 (S32), and the mode then transitions to the relay monitoring mode (S33). If an abnormality occurs in the self-check or relay monitoring mode (Yes), the mode shifts to the inspection mode, and if no abnormality occurs (No), the process returns to step S32.

[0046] [Alarm mode: Figure 8] The alarm mode will be described with reference to Fig. 8. Fig. 8 is a process flow diagram in the alarm mode. In the alarm mode, as shown in FIG. 8, the monitoring relay circuit 35 is connected to the CA contact, and the contact monitoring photocoupler 36 is turned off to disable (mask) the output to the logic IC 38 (S41). Then, the actual contact relay circuit 31 is connected to the AC contact and set to the alarm mode (S42).

[0047] Next, a self-check is performed within the contact output device 3 (S43) to determine whether it is normal or recovered (S44). If it is not normal or recovered (No), the process returns to S43; if it is normal or recovered (Yes), the process ends.

[0048] [Test mode status table: Figure 9] Next, the state table of the inspection mode will be described with reference to Fig. 9. Fig. 9 is a diagram showing the state table of the inspection mode. 9 shows, as status items, the input to the photocoupler 11 of the contact input device 1, the cable 2, the real contact relay output of the real contact relay circuit 31, the mode of the monitoring relay circuit 35, the state (ON / OFF) of the contact monitoring photocoupler 36, and the determination content of the logic IC 38. Note that these status items are also common to Figs. 10 to 11. In the inspection mode shown in FIG. 9, (a) indicates that the photocoupler 11 is powered off, (b) indicates a normal connection state, (c) indicates that the cable 2 is not connected, and (d) indicates an abnormal state in which the actual contact relay circuit 31 has failed.

[0049] 9(a)-(d), the monitoring mode circuit 35 is in "monitoring mode" and connected to the contact monitoring photocoupler 36, and detection (inspection) is performed by the contact monitoring photocoupler 36. Since anything other than FIG. 9(b) is abnormal, the detection result is "OFF" and the judgment content is "abnormal." In FIG. 9(b), the detection result of the contact monitoring photocoupler 36 is "ON" and the judgment content is "normal connection."

[0050] In addition, in Figures 9(a) to (c), the real contact relay circuit 31 outputs an "alarm" before normal startup, and it can be determined that the real contact relay circuit 31 is normal, but in Figure 9(d), the real contact relay circuit 31 cannot output an "alarm" before normal startup, so it can be determined that the relay output of the real contact relay circuit 31 is abnormal.

[0051] [Operation mode status table: Figure 10] The operation mode state table will be described with reference to Fig. 10. Fig. 10 is a diagram showing the operation mode state table. In the operation mode, the actual contact relay circuit 31 is connected to the BC contact, and the monitoring relay circuit 35 is connected to the CB contact to enter the monitoring mode. However, the logic IC 38 recognizes that the contact monitoring photocoupler 36 is OFF.

[0052] FIG. 10(e) shows a normal state, in which the contact monitoring photocoupler 36 is OFF, but the logic IC 38 judges the connection to be "normal." Also, FIG. 10(f) shows a fault state in which the actual contact relay circuit 31 "cannot output an alarm", and the determination result is "abnormal".

[0053] Incidentally, when the cable 2 becomes "not connected (disconnected)" as shown in FIG. 10(g), it is determined to be "normally connected" since it is in the operation mode. However, in the operation mode, this is not the timing to issue an alarm (notification) that the cable 2 is not connected, so even if it is misidentified, it does not cause a problem. The problem arises with the timing of notifying the contact input device 1 when outputting an alarm in the case of AC contact connection of the actual contact relay circuit 31. Therefore, by temporarily switching to (returning to) the inspection mode, it is possible to check whether the cable 2 is disconnected. If it is necessary to monitor the connection destination, the system is controlled to periodically switch to the inspection mode.

[0054] [Alarm mode status table: Figure 11] The alarm mode state table will be described with reference to Fig. 11. Fig. 11 is a diagram showing the alarm mode state table. In the alarm mode, the actual contact relay circuit 31 is connected to an AC contact, and the monitoring relay circuit 35 is connected to a CA contact to set the operation mode (bypass). In this case, the logic IC 38 is turned OFF because no current flows through the contact monitoring photocoupler 36, and the judgment result is set to OFF and invalidated (masked). This is because, since it is masked, the monitoring relay circuit 35 is not in monitoring mode, and the detection result of the contact monitoring photocoupler 36 is not useful.

[0055] FIG. 11(h) shows the normal state, FIG. 11(i) shows the abnormal state in which the cable 2 is not connected (disconnected), and FIG. 11(j) shows the abnormal state in which the power supply of the contact input device 1 is OFF. Here, in the case of FIG. 11(i)(j), an abnormality cannot be detected, but as explained in the operation mode, the failure to detect the abnormality is not a problem and can be dealt with by periodically switching to the inspection mode.

[0056] [Effects of the embodiment] According to this monitoring device, a monitoring section is provided which controls an inspection mode in which the logic IC 38 of the contact output device 3 detects the current of the signal input from the contact input device 1 to perform an inspection to determine whether it is normal or abnormal, an operation mode during operation, and an alarm mode in which an alarm is issued, and which switches to the inspection mode at start-up or restart, and switches to the operation mode if the inspection is normal, and switches to the alarm mode if the inspection is abnormal. Depending on the state of the contact monitoring photocoupler 36 and the state of the photocoupler 11 of the contact input device 1 in each mode, the logic ICs 12, 38 can detect the start-up state of the connected device, whether the cable is connected, and a fault in the switch.

[0057] In particular, by having the host device acquire and analyze the judgment results of the logic IC 12 of the contact input device 1 and the logic IC 38 of the contact output device 3, various types of failures and the like can be comprehensively detected. [Industrial Applicability]

[0058] INDUSTRIAL APPLICABILITY The present invention is suitable for a contact output device and a monitoring device that are capable of detecting the start-up state of a connected device, the presence or absence of a cable connection, and a switch failure. [Explanation of symbols]

[0059] 1...contact input device, 2...cable, 3,3'...contact output device, 11...photocoupler, 12...logic IC, 13...logic level power supply (VccI2), 14...applied voltage (VccI1) power supply, 15...terminal, 16...terminal, 30a,30b,30c...terminal, 31...real contact relay circuit, 32...logic IC, 33...power supply (VccO), 34...power supply (VccO), 35...monitoring relay circuit, 36...contact monitoring photocoupler, 37...logic level power supply (VccI2), 38...logic IC, 100...main monitoring device (digital IO), 200...higher device, 310~340...various devices

Claims

1. A contact output device having a real contact, A terminal for a destination device to be connected to the switch; a first switch that controls the on / off of the switch and switches whether or not to output a signal input from the terminal; a detection circuit for detecting a current of a signal input from a contact input device using the terminal; a monitoring unit that performs contact monitoring for a signal input from the contact input device by detecting a current in the detection circuit and controls an operating mode; a second switch provided between the first switch and the detection circuit, for switching whether or not to output a signal from the first switch to the detection circuit; the monitoring unit controls an inspection mode in which a signal input from the contact input device is inspected by switching the first switch to output a signal from the terminal and the second switch to output the signal to the detection circuit, and the detection circuit detects a current of the signal to determine whether it is normal or abnormal; an operation mode in which the first switch is switched not to output a signal from the terminal and the second switch is switched not to output the signal to the detection circuit; and an alarm mode in which the first switch is switched to output a signal from the terminal and the second switch is switched not to output the signal to the detection circuit, and an alarm is issued; the monitoring unit transitions to the inspection mode at startup, and transitions to the operation mode if the inspection is normal, and transitions to the alarm mode if the inspection is abnormal; A contact output device characterized in that the monitoring unit is capable of detecting the startup state of the connected device, whether a cable is connected, and a fault in the switch based on the contact monitoring status in the inspection mode, the operation mode, and the alarm mode.

2. 2. The contact output device according to claim 1, wherein the monitoring unit operates in the operation mode and, if an abnormality occurs, transitions to the inspection mode, and, if an abnormality is detected in the inspection mode, transitions to the alarm mode.

3. 3. The contact output device according to claim 1, wherein the monitoring unit operates in an alarm mode, and when the monitoring unit recovers from an abnormality, the monitoring unit shifts to an inspection mode, and when the monitoring unit determines that the device is normal in the inspection mode, the monitoring unit shifts to an operation mode.

4. A monitoring device comprising a contact input device and the contact output device according to any one of claims 1 to 3.

5. 5. A monitoring system comprising a communication facility and a host device connected by the monitoring device according to claim 4.

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