JP4415384B2 - DIGITAL OUTPUT DEVICE AND DIAGNOSIS METHOD USING DIGITAL OUTPUT DEVICE - Google Patents

Description

  The present invention relates to a digital output device that controls connection and disconnection between various devices and a power source, and more particularly to a digital output device and a diagnosis method that can appropriately diagnose the mounting state of a device to be controlled and the state of its own device.

  FIG. 10 is a block diagram illustrating a configuration of a digital output device that controls connection and disconnection between field devices arranged in a plant and a power source.

  A digital output device 40 shown in FIG. 10 is a device that controls connection and disconnection between the external power source 2 that is an operation power source of the field device 1 such as a solenoid valve, a relay, and a lamp, and the field device 1 by a switch 45. . The digital output device 40 is provided with a multi-channel circuit for connecting the field device 1 and controls the field device 1 individually for each channel. Although only one channel is shown in FIG. 10, the number of switches 45 corresponding to each channel is provided, and on / off of each switch 45 is controlled by an output signal from the output control unit 51. As a result, the field device 1 of the corresponding channel is individually controlled.

Japanese Patent Laid-Open No. 10-021156

  However, the conventional digital output device cannot perform abnormality diagnosis such as detection of abnormality of wiring on the field device side or failure of the digital output device. Further, in a digital output device that controls field devices, it is necessary to perform abnormality diagnosis without stopping the operation of the plant, and it is necessary to perform abnormality diagnosis by a method that does not affect the field device.

  An object of the present invention is to provide a digital output device and a diagnostic method capable of appropriately diagnosing the mounting state of a device to be controlled and the state of its own device.

The digital output device of the present invention detects the current value of the current flowing through the switch as a comparison result with a plurality of levels in the digital output device that controls connection / disconnection between the power source and the device by turning on / off the switch Detected by the current value detecting means, the voltage detecting means for detecting the voltage output to the device, and the current value detecting means when the switch is on and when the switch is off. Diagnosing means for diagnosing whether the switch is on-fixed or off-fixed based on the detected current value and the voltage detected by the voltage detecting means.
According to this digital output device, diagnosis is performed based on the current value detected by the current value detection means when the switch is on and when the switch is off, and the voltage detected by the voltage detection means. Therefore, it is possible to appropriately diagnose the mounting state of the device to be controlled and the state of its own device without using another device for diagnosis. It is also possible to perform diagnosis with the device in use or without using the device.

  A switch bypass circuit that is provided in parallel with the switch and allows a predetermined current to flow when the switch is off, and the current value detection means can detect the current flowing through the switch bypass circuit. Good.

  Provided in parallel with the output wiring to the device, provided with a device bypass circuit for bypassing the device and flowing a predetermined current when the output wiring is interrupted, the current value detection means, The current flowing through the circuit may be detectable.

  The voltage detection means may detect a voltage as a comparison result with a plurality of levels.

  The diagnosis unit may diagnose whether or not the output wiring to the device is disconnected or short-circuited.

Same digital output device of the present invention, the connection between the power source and the plurality of devices, the cutting, comprising a plurality of switches independently controlled, which is connected via a separate output lines to said plurality of devices In the digital output device having a plurality of channels configured, the plurality of channels are output toward the device, current value detection means for detecting a current value of the current flowing through the switch as a comparison result with a plurality of levels. A voltage detection means for detecting a voltage to be detected, a current value detected by the current value detection means when the switch is turned on and when the switch is turned off, and a voltage detected by the voltage detection means together they are composed of a diagnostic means for performing a diagnosis based, and switches switching means for switching the state of the switch in one of the channels, Serial when switching the state by switching the switching means, characterized in that it comprises a impact detection means for detecting the presence or absence of effects on the output lines in the other channels, the.
According to this digital output device, since the presence or absence of an influence on the output wiring of another device when the state is switched by the switch switching means is detected, the output wiring between channels corresponding to each switch is short-circuited, etc. Can be detected efficiently.

  The switch switching unit may switch the state of the switch only for a short period of time that does not affect the device.

The digital output device of the present invention includes a plurality of switches that independently control connection and disconnection between a power source and a device, and has a dual circuit configuration on the control side and the standby side with respect to the device. In the output device, the control side and standby side circuits detect a current value detecting means for detecting a current value of the current flowing through the switch as a comparison result with a plurality of levels, and a voltage output to the device. Diagnosis based on the voltage detection means, the current value detected by the current value detection means when the switch is on and the switch is off, and the voltage detected by the voltage detection means First diagnostic means to be executed, switch control means for controlling on / off of the switch, and a switch fixing hand for forcibly fixing the switch to the off side during standby When, the said switch control means by function, diagnosing the switch control means based on the state of the output signal at the switch control means when securing forced off side switch by the switch securing means And 2 diagnostic means.
According to this digital output device, when the switch is forcibly fixed to the OFF side by the switch fixing means, the switch control means is functioned to diagnose the switch control means, so that the control on the control side is affected. The switch control means can be diagnosed without any problems.

The diagnostic method of the present invention is a diagnostic method using a digital output device that controls connection / disconnection between a power source and a device by turning on / off the switch. A step of detecting as a comparison result, a step of detecting a voltage output to the device, and a current value detecting means when the switch is on and when the switch is off. And a step of diagnosing whether or not the switch is locked on or off based on the detected current value and the voltage detected by the voltage detection means.
According to this diagnostic method, since the diagnosis is performed based on the current value and voltage detected when the switch is on and when the switch is off, another device for diagnosis is used. Therefore, it is possible to appropriately diagnose the mounting state of the device to be controlled and the state of its own device. It is also possible to perform diagnosis with the device in use or without using the device.

The diagnosis method of the present invention includes a plurality of switches that independently control connection and disconnection between a power source and a plurality of devices, and the same configuration connected to the plurality of devices via independent output wirings In the diagnostic method using a digital output device having a plurality of channels, a step of detecting a current value of a current flowing through the switch as a comparison result with a plurality of levels in the plurality of channels, A step of detecting a voltage to be output; a current value detected by the current value detection means when the switch is turned on and when the switch is turned off; and a voltage detected by the voltage detection means together and a step of performing a diagnosis based, the step of switching the state of the switch in one of the channel, the switch When switching the state by the step of switching the state, characterized in that it comprises the steps of: detecting the presence or absence of effects on the output lines in the other channels.
According to this diagnosis method, since the presence or absence of an influence on the output wiring of another device when the state is switched is detected, an abnormality such as a short circuit of the output wiring between channels corresponding to each switch is efficiently performed. Can be detected.

  According to the present invention, for example, the diagnosis is performed based on the current value detected by the current value detection means when the switch is on and when the switch is off, and the voltage detected by the voltage detection means. Therefore, it is possible to appropriately diagnose the mounting state of the device to be controlled and the state of its own device without using another device for diagnosis. It is also possible to perform diagnosis with the device in use or without using the device.

  FIG. 1 is a block diagram functionally showing a digital output device according to the present invention.

  In FIG. 1A, the current value detecting means 101 detects the current value of the current flowing through the switch. The voltage detection means 102 detects the voltage output toward the device. Diagnosis means 103 performs diagnosis based on the current value detected by the current value detection means when the switch is on and when the switch is off, and the voltage detected by the voltage detection means.

  In FIG.1 (b), the switch switching means 105 switches the state of the switch corresponding to one apparatus. The influence detection unit 106 detects whether or not there is an influence on the output wiring of another device when the state is switched by the switch switching unit 105.

  In FIG. 1C, the switch 111 controls connection and disconnection between the power source and the device. The switch control unit 112 controls on / off of the switch 111. The switch fixing means 113 forcibly fixes the switch 111 to the off side during standby. The diagnosis means 114 diagnoses the switch control means 112 by causing the switch control means 112 to function when the switch fixing means 113 is forcibly fixing the switch to the OFF side.

  Embodiments 1 and 2 of the digital output device according to the present invention will be described below with reference to FIGS.

  FIG. 2 is a block diagram illustrating the configuration of the digital output device according to the first embodiment.

  A digital output device 10 illustrated in FIG. 2 is a device that controls connection and disconnection between the field device 1 and an external power source 2 that is an operation power source of the field device 1 such as a solenoid valve, a relay, and a lamp. The external power source 1 is connected between the ground terminal 11 and the power supply voltage terminal 12 of the digital output device 10, and the field device 2 is connected between the ground terminal 13 and the output terminal 14 of the digital output device 10.

  As shown in FIG. 2, the digital output device 10 includes a switch 15 provided between the power supply voltage terminal 12 and the output terminal 14, and a current value detection circuit that detects the current value of the current output from the output terminal 14. 16, an external power supply voltage monitoring circuit 17 that monitors the voltage at the power supply voltage terminal 12, a voltage level comparator 18 that compares the voltage at the output terminal 14 with the comparison voltage, and a comparison voltage monitoring circuit 19 that monitors the comparison voltage. And a switch 20 for selecting a comparison voltage to be applied to the voltage level comparator 18, and signals from the current value detection circuit 16, the external power supply voltage monitoring circuit 17, the voltage level comparator 18, and the comparison voltage monitoring circuit 19, An output control unit 21 for controlling the switch 15. The output control unit 21 includes a processor, an input / output port, and the like.

  The digital output device 10 is provided with a circuit of a plurality of channels for connecting the field device 1 and controls the field device 1 individually for each channel. Although only one channel is shown in FIG. 2, the output terminal 14 and the switch 15 are provided in the number of channels corresponding to each channel, and the field device of the corresponding channel by turning on / off each switch 15. 1 is controlled individually. Each switch 15 is controlled by an output signal (ON / OFF) output from the output control unit 21.

  As shown in FIG. 2, in the digital output device 10, a high resistance Roff for flowing a minute current (leakage current) when the switch 15 is off is connected in parallel with the switch 15. An internal load resistor R is connected between the ground terminal 13 and the output terminal 14, that is, in parallel with the field device 1 serving as a load. The internal load resistor R is provided for detecting disconnection.

  In order to guarantee the soundness of diagnosis, which will be described later, the output control unit 21 uses the external power supply voltage monitoring circuit 17 to check whether or not the voltage level of the external power supply 2 is within a specified range. Further, the output control unit 21 uses the comparison voltage monitoring circuit 19 to check whether or not the comparison voltage serving as the reference voltage in the voltage level comparator 18 is within a specified range.

  FIG. 3 is a diagram showing a level determination criterion for the current read back value RDBK (I) output from the current value detection circuit 16. The level determination is executed in the output control unit 21. As shown in FIG. 3, the current read back value RDBK (I) is divided into “off level”, “on level”, and “high level” from a low level to a high level. These correspond to the normal range when the output is off (switch 15 is off), the normal range when the output is on (switch 15 is on), and the abnormal range, respectively.

  Next, the operation of the digital output device 10 will be described.

  During normal operation, the switch 15 is turned on and off according to the output signal output from the output control unit 21. When the switch 15 is turned on, the corresponding field device 1 is connected to the external power source 2. Further, when the switch 15 is turned off, the corresponding field device 1 is disconnected from the external power source 2. Thereby, on / off of the field device 1 of each channel is controlled.

The digital output device 10 can make a diagnosis on the presence or absence of the following states.
(1) Short circuit: A short circuit between the output terminal 14 and the ground in each channel.
(2) Disconnection: disconnection of output wiring from the output terminal 14 to the field device 1 or output wiring from the ground terminal 13 to the field device 1.
(3) Short circuit between channels: Short circuit between channels in the output wiring from the output terminal 14 to the field device 1.
(4) ON failure: A state in which the switch 15 is fixed to ON.
(5) Off failure: A state in which the switch 15 is stuck off.
(6) Overcurrent: A state in which the output current value exceeds the normal range and shows a high current value due to a cause other than a short circuit or a short circuit between channels.
(7) Internal failure: Other abnormal conditions.

  4 and 5 are diagrams showing a list of diagnostic contents. Hereinafter, the operation at the time of diagnosis will be described with reference to FIG. 4 and FIG. The following operations and determinations are executed according to the control of the output control unit 21.

(Level diagnosis when the output signal is on)
When the output signal output from the output control unit 21 is on, that is, when the switch 15 is controlled to be turned on, the voltage read back value RDBK (V) is “High level” and the current read back value RDBK (I ) Is “on level” (FIG. 3), it is normal. This corresponds to states A5 to A9 in FIG.

  When a short circuit ((1) above) occurs with the switch 15 turned on, the output terminal 14 and the ground are short-circuited, so the voltage read back value RDBK (V) becomes “Low level” and the current read back value RDBK. (I) becomes “High level” (FIG. 3). Therefore, it can be determined that the short circuit is abnormal. This corresponds to the state A1 in FIG.

  When the switch 15 is fixed off, the voltage read back value RDBK (V) becomes “Low level”, and the current read back value RDBK (I) becomes “off level” (FIG. 3). Therefore, it can be determined as an off-failure (above (5)). This corresponds to the state A2 in FIG.

  The voltage read-back value RDBK (V) is “High level”, but when the current read-back value RDBK (I) is “High level”, this can be determined as an overcurrent ((6) above). This corresponds to state A3.

  When the voltage read-back value RDBK (V) is “High level” but the current read-back value RDBK (I) is “Off level”, no current flows to the field device 1, that is, disconnection ((2) above) ). This corresponds to the state A4 in FIG.

(Level diagnosis when output signal is off)
When the output signal output from the output control unit 21 is off, that is, when the switch 15 is controlled to be turned off, the voltage read back value RDBK (V) is “Low level” and the current read back value RDBK (I ) Is “off level” (FIG. 3), it is normal. In this case, since a minute current (leakage current) flows to the field device 1 via the high resistance Roff connected in parallel with the switch 15, the voltage read back value RDBK (V) is not zero but is “Low level”. Become. This corresponds to the states B6 to B11 in FIG.

  In the case of disconnection (above (2)), the field device 1 does not function as a load between the output terminal 14 and the ground, and the impedance between the output terminal 14 and the ground rises to the internal load resistance R. As a result, the minute current that flows through the high resistance Roff flows through the internal load resistance R, so that the voltage read back value RDBK (V) becomes “High level”. For this reason, it can be determined that the disconnection is abnormal. The current read back value RDBK (I) is “off level”. This corresponds to the state B3 in FIG.

  When the switch 15 is fixed to ON, the voltage read back value RDBK (V) is “High level” and the current read back value RDBK (I) is “ON level” as in the normal state when the output signal is ON. Become. Therefore, it can be determined as an on-failure (above (4)). This corresponds to the state B2 in FIG.

  When the voltage read back value RDBK (V) is “High level” and the current read back value RDBK (I) is “High level”, this can be determined as an overcurrent (above (6)), and the state in FIG. Corresponds to B1.

  The voltage read back value RDBK (V) is “Low level”, but when the current read back value RDBK (I) is “High level”, this can be determined as an overcurrent (above (6)). This corresponds to state B4.

  The voltage read back value RDBK (V) is “Low level”, but when the current read back value RDBK (I) is “on level”, it can be determined that an excessive current flows due to some abnormality. This corresponds to the state B5 in FIG.

(Pulse diagnosis when output is on)
In the present embodiment, an abnormality that cannot be detected by the level diagnosis is detected by performing a diagnosis using an output pulse.

  When the field device 1 of the corresponding channel is controlled to be in the on state, the output signal output from the output control unit 21 is in the on state, and the switch 15 is in the on state. In the pulse diagnosis, the output signal is turned off for a moment to turn off the switch 15 for a moment and generate a short off pulse at the output terminal 14. The time for turning off the switch 15 is a sufficiently short time that does not affect the field device 1 in operation, and then the output signal is returned to the on state.

  In this embodiment, when an off pulse is generated, the voltage read back value RDBK (V) and current read back value RDBK (I) of the own channel are monitored. At this time, the voltage read back value RDBK (V) of the other channel is monitored.

  FIG. 6 is a diagram showing a pulse waveform when pulse diagnosis is performed when the output is on.

  FIG. 6A shows a pulse waveform in a normal state. As shown in FIG. 6A, the switch 15 is turned off for a moment according to the output signal from the output control unit 21 in the normal state. For this reason, the voltage read-back value RDBK (V) of the own channel takes “off level” for a moment and then becomes “on level”. The voltage read-back value RDBK (V) of the other channel of the short-circuit partner is not affected, and the voltage read-back value RDBK (V) of the other channel is maintained at “High level”. This corresponds to the state A8 and the state A9 in FIG.

  FIG. 6B shows a pulse waveform in the case of a short circuit between channels (the above (3)). As shown in FIG. 6B, in the case of a short circuit between channels, the voltage read-back value RDBK (V) of the other channel of the short-circuit partner is affected, and the voltage read-back value RDBK of the other channel according to the change of the output signal. (V) becomes “Low level”. For this reason, it can be determined that an inter-channel short-circuit has occurred between the own channel and the corresponding other channel. This corresponds to the state A6 in FIG.

  FIG. 6C shows a pulse waveform in the case of an on-failure (above (4)) or a short circuit between channels. As shown in FIG. 6C, in the case of an on failure, the switch 15 cannot be turned off, so that the voltage read back value RDBK (V) of the own channel does not become “Low level” but “High level”. It will remain. This corresponds to the state A5 in FIG.

  In the case of a short circuit between channels, even if the switch 15 is turned off, the potential of the output terminal 14 of the own channel may not be sufficiently lowered due to the influence of the potential of the other party of the short circuit. In such a case, the voltage read back value RDBK (V) does not become “Low level” but remains “High level”. For this reason, in the case of FIG. 6C, it can be determined that there is an ON failure or a short circuit between channels (state A5 in FIG. 4).

  When the voltage read-back value RDBK (V) of the other channel of the short circuit partner is affected, and the voltage read-back value RDBK (V) of the other channel fluctuates from “Low level” to “High level” in accordance with the change of the output signal, It is not a short circuit between channels, but it can be determined that there is some abnormality. This corresponds to the state A7 in FIG.

(Pulse diagnosis when output is off)
When the field device 1 of the corresponding channel is controlled to be in the off state, the output signal output from the output control unit 21 is in the off state, and the switch 15 is in the off state. In the pulse diagnosis, the output signal is turned on for a moment, so that the switch 15 is turned on for a moment and a short on pulse is generated at the output terminal 14. The time for turning on the switch 15 is a sufficiently short time that does not affect the field device 1, and then the output signal is returned to the off state.

  In this embodiment, when an on-pulse is generated, the voltage read-back value RDBK (V) and current read-back value RDBK (I) of its own channel are monitored. At this time, the voltage read back value RDBK (V) of the other channel is monitored.

  FIG. 7 is a diagram showing a pulse waveform when pulse diagnosis is performed when the output is off.

  FIG. 7A shows a pulse waveform in a normal state. As shown in FIG. 7A, the switch 15 is turned on for a moment according to the output signal from the output control unit 21 in the normal state. For this reason, the voltage read back value RDBK (V) of the own channel takes “on level” for an instant, and then becomes “off level”. The voltage read-back value RDBK (V) of the other channel of the short-circuit partner is not affected, and the voltage read-back value RDBK (V) of the channel maintains “Low level”. This corresponds to the state B10 and the state B11 in FIG.

  FIG. 7B shows a pulse waveform in the case of a short circuit between channels (the above (3)). As shown in FIG. 7B, in the case of a short circuit between channels, the voltage read-back value RDBK (V) of the other channel of the short-circuit partner is affected, and the voltage read-back value RDBK of the other channel according to the change of the output signal. (V) becomes “High level”. For this reason, it can be determined that an inter-channel short-circuit has occurred between the own channel and the corresponding other channel. This corresponds to the state B9 in FIG.

  FIG. 7 (c) shows a pulse waveform in the case of an off-fault ((5) above) or a short circuit between channels. As shown in FIG. 7C, in the case of an off failure, the switch 15 cannot be turned on, so that the voltage read-back value RDBK (V) of the own channel does not become “High level” but “Low level”. Will remain. This corresponds to the state B7 in FIG.

  In the case of a short circuit between channels, even if the switch 15 is turned on, the potential of the output terminal 14 of the own channel may not be sufficiently increased due to the influence of the potential of the other party of the short circuit. In such a case, the voltage read back value RDBK (V) does not become “High level” but remains “Low level”. For this reason, in the case of FIG. 7C, it can be determined that there is an off failure or a short circuit between channels (state B7 in FIG. 5).

  When the voltage read-back value RDBK (V) of the other channel of the short circuit partner is affected and the voltage read-back value RDBK (V) of the other channel varies from “High level” to “Low level” in accordance with the change of the output signal, It is not a short circuit between channels, but it can be determined that there is some abnormality. This corresponds to the state B8 in FIG.

  As described above, in this embodiment, it is possible to detect an abnormality related to wiring such as a short circuit, a disconnection, a disconnection between channels, and a failure of a channel in the digital output device without using an external device. Further, when detecting an abnormality, the field device that is operating or stopped is not affected, so that the abnormality can be detected during operation of the plant.

  In the above embodiment, a plurality of comparison voltages are prepared, and the voltage read back value is obtained by the voltage level comparator 18, but the output control unit 21 uses the A / D converter as the digital value of the voltage of the output unit 14. May be entered. In this case, the output control unit 21 detects abnormality based on the input voltage read back value.

  FIG. 8 is a block diagram illustrating a duplex configuration of the digital output device according to the second embodiment. In this embodiment, an example in which the digital output device is duplicated is shown.

  As shown in FIG. 8, the ground terminals 11A and 13A, the output terminal 14A and the power supply voltage terminal 12A of the digital output device 10A on the control side are connected to the external power source 2 and the wiring to the field device 1 of each channel, and the standby side The ground terminals 11B and 13B, the output terminal 14B, and the power supply voltage terminal 12B of the digital output device 10B are connected in parallel.

  At the normal time, the control-side digital output device 10 </ b> A performs on / off control of the field device 1. When a failure or the like is detected in the control-side digital output device 10A, the control right is switched to the standby-side digital output device 10B. In this case, the standby-side digital output device 10B turns the field device 1 on and off. Take control. The location of the control right is recognized in each of the digital output device 10A and the digital output device 10B by a duplex control signal exchanged between the digital output device 10A and the digital output device 10B.

  FIG. 9 is a block diagram showing the configuration of the control-side digital output device 10A. About the structure similar to Example 1, illustration is partially omitted and the same code | symbol is attached | subjected to the same component. The standby-side digital output device 10B is configured in the same manner as the digital output device 10A.

  In FIG. 9, the duplex control circuit 31 is configured using a switching element such as a transistor, and is on / off controlled based on a duplex control signal. The duplex control circuit 31 is turned on at the normal time, that is, when the control right is in the digital output device 10A. In this case, the output signal (ON / OFF) from the output control unit 21A via the output circuit 32 is turned on. ), The switch 15 is on / off controlled. When the control right is handed over to the standby-side digital output device 10B, the duplex control circuit 31 is turned off in accordance with the duplex control signal. In this case, the switch 15 is turned on regardless of the output signal (on / off). Fix to the off side.

  In the standby-side digital output device 10B, an operation reverse to that of the digital output device 10A is executed with respect to the duplex control signal.

  In FIG. 9, the output circuit read back unit 33 is a circuit that reads back the on / off state of the output circuit 32. The on / off read back unit 35 is a circuit that is provided in parallel with the voltage level comparator 18 and reads back the on / off state of the switch 15. The on / off read back unit 35 is configured using a photocoupler or the like.

  Next, the operation of the digital output device 10A will be described.

  When the control right is given to the digital output device 10A, the duplex control circuit 31 is on, and the switch 15 is on / off controlled according to the output signal (on / off) from the output control unit 21A.

  In this case, as in the first embodiment, a voltage read back value is output by the voltage level comparator 18, and the state (on / off) of the switch 15 is diagnosed in the output control unit 21A. In the present embodiment, the voltage at the output terminal 14 is also detected by the on / off read-back unit 35, and the output control unit 21A performs double diagnosis on the state of the switch 15 (on / off). As described above, the two-system read-back enables reliable diagnosis of the state of the switch 15 (ON / OFF).

  When the control right is given, the same operation is executed also in the digital output device 10B.

  When the control right is handed over to the digital output device 10B, the duplex control circuit 31 is turned off in accordance with the duplex control signal in the digital output device 10A, and the switch 15 is fixed to the off side regardless of the output signal (on / off). ing.

  In this embodiment, while the switch 15 is fixed to the OFF side, an output signal (ON / OFF) is output from the output control unit 21A, and the output of the output circuit read back unit 33 at that time is detected by the output control unit 21A. is doing. At this time, since the switch 15 is fixed to the OFF side by the control of the duplex control circuit 31, the operation at the time of detection does not affect the control from the standby side digital output device 10B to the field device 1. Since the output signal (ON / OFF) from the output control unit 21A can use an arbitrary pattern, activation of each channel from the output control unit 21A → the output circuit 32 → the output circuit read back unit 33 → the output control unit 21A Diagnosis is possible. In particular, it is possible to efficiently detect failures due to on-fixation and off-fixation inside the circuit. As a result, diagnosis over a wide range excluding the switch 15 can be performed, and the failure detection rate of the digital output device on the standby side (side without the control right), which has been a problem in the past, can be improved.

  While the control right is given to the digital output device 10B, the digital output device 10A cannot read back from the switch 15. However, when the control right is transferred to the digital output device 10A, the state of the switch 15 (on / off) is diagnosed by reading back by two systems as described above. Even if a failure occurs in one of the systems until then, the failure can be detected immediately.

  The scope of application of the present invention is not limited to the above embodiment. The present invention is not limited to controlling field devices, and can be widely applied to digital control devices that execute control of various devices.

1 is a block diagram functionally illustrating an information processing apparatus according to the present invention, where (a) is a block diagram illustrating one invention, (b) is a block diagram illustrating another invention, and (c) is another invention. FIG. FIG. 2 is a block diagram illustrating the configuration of the digital output device according to the first embodiment. The figure which shows the level determination reference | standard of electric current read-back value RDBK (I). The figure which shows the list of the diagnostic content. The figure which shows the list of the diagnostic content. The figure which shows the pulse waveform at the time of performing the pulse diagnosis at the time of output ON. The figure which shows the pulse waveform at the time of performing the pulse diagnosis at the time of output OFF. FIG. 6 is a block diagram illustrating a duplex configuration of a digital output device according to a second embodiment. The block diagram which shows the structure of the digital output device of the control side. The block diagram which shows the structure of the conventional digital output device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Current value detection means 102 Voltage detection means 103 Diagnosis means 105 Switch switching means 106 Influence detection means 111 Switch 112 Switch control means 113 Switch fixing means 114 Judgment means

Claims (10)

In the digital output device that controls the connection and disconnection between the power supply and the device by turning the switch on and off,
Current value detection means for detecting the current value of the current flowing through the switch as a comparison result with a plurality of levels;
Voltage detection means for detecting a voltage output toward the device;
When the switch is on, and the switch detected current value by the current value detecting means when is off, and the voltage detecting means on fixed or of the switch based on the detected voltage by Diagnostic means for diagnosing the presence or absence of off-adhesion ;
A digital output device comprising: Provided in parallel with the switch, comprising a switch bypass circuit for flowing a predetermined current when the switch is off,
The digital output device according to claim 1, wherein the current value detection unit can detect a current flowing through the switch bypass circuit. Provided in parallel with the output wiring to the device, comprising a device bypass circuit for bypassing the device and flowing a predetermined current when the output wiring is interrupted,
The digital output device according to claim 1, wherein the current value detection unit is capable of detecting a current flowing through the device bypass circuit.   The digital output device according to claim 1, wherein the voltage detection unit detects a voltage as a comparison result with a plurality of levels.   5. The digital output device according to claim 1, wherein the diagnosis unit diagnoses the presence or absence of disconnection or a short circuit of the output wiring to the device. 6. Digital having a plurality of channels having the same configuration and having a plurality of switches for independently controlling connection and disconnection between a power source and a plurality of devices, and connected to the plurality of devices via independent output wirings In the output device,
The plurality of channels include a current value detection unit that detects a current value of a current flowing through the switch as a comparison result with a plurality of levels, a voltage detection unit that detects a voltage output toward the device, and the switch And diagnostic means for executing diagnosis based on the current value detected by the current value detection means and the voltage detected by the voltage detection means when the switch is off and when the switch is off. And
Switch switching means for switching the state of the switch in one channel;
An influence detecting means for detecting the presence or absence of an influence on the output wiring in another channel when the state is switched by the switch switching means;
A digital output device comprising: The digital output device according to claim 6, wherein the switch switching unit switches the state of the switch only for a short period of time that does not affect the device. In a digital output device comprising a plurality of switches for independently controlling connection and disconnection between a power source and a device, and having a dual circuit configuration on the control side and standby side for the device,
The control side and standby side circuits are:
Current value detecting means for detecting a current value of the current flowing through the switch as a comparison result with a plurality of levels;
Voltage detection means for detecting a voltage output toward the device;
A first diagnosis for executing diagnosis based on the current value detected by the current value detection means and the voltage detected by the voltage detection means when the switch is on and when the switch is off Means,
Switch control means for controlling on / off of the switch;
Switch fixing means for forcibly fixing the switch to the off side during standby;
A second controller for diagnosing the switch control means based on a state of an output signal in the switch control means by causing the switch control means to function when the switch is forcibly fixed to the off side by the switch fixing means; Diagnostic means;
A digital output device comprising: In the diagnostic method using the digital output device that controls the connection and disconnection between the power supply and the device by turning the switch on and off,
Detecting a current value of a current flowing through the switch as a comparison result with a plurality of levels;
Detecting a voltage output toward the device;
Based on the current value detected by the current value detection means when the switch is on and when the switch is off, and the voltage detected by the voltage detection means, Diagnosing the presence or absence of off-sticking;
A diagnostic method comprising: Digital having a plurality of channels having the same configuration and having a plurality of switches for independently controlling connection and disconnection between a power source and a plurality of devices, and connected to the plurality of devices via independent output wirings In the diagnostic method using the output device,
In the plurality of channels, a step of detecting a current value of a current flowing through the switch as a comparison result with a plurality of levels, a step of detecting a voltage output to the device, and the switch being turned on And performing a diagnosis based on the current value detected by the current value detection means and the voltage detected by the voltage detection means when the switch is off and when the switch is off,
Switching the state of the switch in one channel;
Detecting the presence or absence of an influence on the output wiring in another channel when the state is switched by the step of switching the state of the switch;
A diagnostic method comprising:

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