JP2019002580A - Control device performing self-check of relay - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for performing a self-check of a relay capable of preventing erroneous determination of an abnormality of the relay at the time of a self-check for checking the welding of a relay. SOLUTION: A control circuit having a plurality of relays for controlling power supply to a load device is made to be in various circuit states by operating the relays under the condition that the load device does not operate. The check signal is output by detecting the current flowing inside at multiple points in the control circuit, and by checking whether the check signal is output according to a predetermined pattern in each circuit state, the relay can be used. In a control device that performs a self-check of a relay that determines whether or not it is operating normally, the pattern set to be used for determining an abnormality based on the check signal is the location where the check signal should be output and should be output. Set a pattern consisting of parts that are not, and parts that are ignored even if there is output. [Selection diagram] Fig. 6

Description

  The present invention relates to a control device that performs a self-check of a relay installed in a control circuit.

As described in Japanese Patent No. 4572168, in a control device that controls the operation of a boiler or the like, a plurality of relays are installed in the control circuit, and the route through which current flows is changed by switching the contact of each relay. The operating state of the load device is controlled. In this relay, the circuit is switched by moving the contact from one contact to the other by the action of an electromagnet and a spring to control the power supply to the load device. One contact may be fixed by welding due to heat or the like, and the contact may not be switched. When this contact welding occurs, the command from the control side is not properly transmitted to the load side, and correct control cannot be performed.

For this reason, the control unit performs a self-check to check if there is any abnormality such as contact welding in each relay at a time that does not affect operation, such as combustion preparations, and if an abnormality is confirmed, it locks out and performs actual operation. It is made possible to proceed to actual operation only when no abnormality is detected. In the self-check, the relay is operated by supplying current to the control circuit in a state where the load device is not activated, and it is confirmed that the current corresponding to the control state flows at the check points set in the control circuit. To do. Each operating state is reproduced in order, and in each state, if it can be confirmed that the current flows at the place where the current should flow and the current does not flow at the place where the current should not flow, it can be determined that the current is normal. When a current that is not flowing flows or when an expected current does not flow, it is determined that an abnormality has occurred.

However, when the above self-check is performed, the current flows in a portion where the current should not flow even though the relay is operating normally, and therefore, the welding of the relay may be erroneously determined.

Japanese Patent No. 4572168

  The problem to be solved by the present invention is that an unexpected current flow occurs even when the relay of the control circuit is normal during the self-check for checking the welding of the relay by flowing a current through the control circuit. It is an object of the present invention to provide a control device that performs a self-check of a relay that can prevent erroneous determination of an abnormality.

According to the first aspect of the present invention, various circuit states are obtained by operating the relay under a condition in which the load device does not operate with respect to a control circuit having a plurality of relays for controlling power supply to the load device. The check signal is output by detecting the current flowing in the control circuit at a plurality of locations in the control circuit, and it is confirmed whether the check signal is output in a predetermined pattern in each circuit state. In the control device that performs self-checking of the relay that determines whether the relay is operating normally, the pattern set for use in the determination of abnormality by the check signal is a place where the check signal should be output. In addition to the parts that should not be output, a self-relay of the relay is characterized in that a pattern consisting of parts that are ignored even if there is output is set. Control apparatus for performing Ekku.

By implementing the present invention, it is possible to improve the accuracy of abnormality determination at the time of self-check, and reduce the possibility of erroneous determination that an abnormality has occurred even though the relay is normal. it can.

Control circuit diagram in an embodiment of the present invention It is a control circuit diagram in the embodiment of the present invention, and is an explanatory diagram of how the current flows in the check step (2) It is a control circuit diagram in the embodiment of the present invention, and is an explanatory diagram of how the current flows in the check step (3) It is a control circuit diagram in the embodiment of the present invention, and is an explanatory diagram of how the current flows in the check step (4) It is a control circuit diagram in the embodiment of the present invention, and is an explanatory diagram of how current flows in the check step (5) The time chart which showed the relay operation condition in the Example of this invention, and the energization condition to a check signal

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 to FIG. 5 are control circuit diagrams in the embodiment of the present invention, and are explanatory diagrams of how the current flows in each check process, and FIG. 6 shows the relay operation status and the check signal in the embodiment of the present invention. It is a time chart which showed the electricity supply condition.

For example, a boiler is conceivable as a device that performs operation control. In modern boilers, the operation is performed only with the operation switch, and the subsequent operation is automatically performed by the operation control device. When an abnormality occurs, the automatic operation is performed such as detecting the abnormality and stopping the operation. There is a lot of control. The control circuit diagrams described in FIG. 1 to FIG. 5 are control circuits in which some functions in the operation control apparatus are extracted. The control circuit controls power supply to the load device, and describes the ignition device 1 and the pilot valve 2 as the load device. The ignition device 1 receives electric power supplied from the R phase and the S phase and generates sparks for ignition. The pilot valve 2 receives electric power supplied from the R phase and the S phase and opens the valve, and supplies fuel to the pilot burner. The power supply is performed, and operates when there is power supply from both the R phase and the S phase.

The control circuit is provided with a normally open relay K1 on the R phase inlet side and a normally open relay K2 on the S phase inlet side. A branch point from the R phase is provided at the secondary side of the relay K1, a detection circuit for the check signal CK1 is provided at the branch point, and a branch point from the S phase is also provided at the secondary side of the relay K2. A detection circuit for the check signal CK2 is provided at the branch point.

The control circuit is provided with a relay IG for controlling energization to the ignition device 1 and a relay PV for controlling energization to the pilot valve 2 in the R-phase side circuit. The relay IG switches between a route for supplying current to the ignition device 1 that is a load device and a route for supplying current to the detection circuit for the check signal CK3 without flowing the current to the ignition device 1, and normally the check signal CK3 The ignition device 1 is energized only when an ignition operation is performed. In the relay PV, the pilot valve 2 that is a load device and the detection circuit of the check signal CK4 are connected to the secondary side of the relay PV, and the contact of the relay PV is normally open to energize the pilot valve. In this case, the contact of the relay K2 is closed. When the contact of the relay K2 is closed, the pilot valve is energized and the check signal CK4 detection circuit is also energized.

When starting combustion with a boiler, a self-check is performed to inspect the welding of each relay while preparing for combustion. In the self-check, each relay is sequentially operated to be in various states, and it is confirmed whether a check signal corresponding to each state is output. The control circuit diagrams shown in FIGS. 1 to 5 describe the flow of current during the relay self-check, and the path through which the current flows is indicated by a bold line. FIG. 6 shows the state of each relay during the self-check and the output state of the check signal. When the relay is not operating, the column is blank, and when the relay is operating, a solid band is displayed. To fill in.

In the check signal column of FIG. 6, when a check signal is to be output, a solid band is entered in the frame, and when the check signal is not to be output, the frame is blank. Depending on the situation, a check signal is output. If there is a possibility of being done, a hatched band is entered in the frame. If the check signal is output as set during the self-check, it can be determined that each relay is operating normally, and if the check signal output is different from the setting, the control circuit It is determined that an abnormality has occurred. The output of the check signal is output at a place where it should be output, and can be determined to be normal if it is not output where it should not be output, but it should be output or should not be output. Not only the output but also in terms of control, there is a possibility of leakage current flowing, so there is a possibility of ignoring even if there is an output, and the above three ways are set.

A state in the self-check will be described. FIG. 1 shows an initial state in which the circuit is opened by both the relay K1 and the relay K2, and no current flows in the control circuit. This state is an initial state as well as a check step (1). In this case, since no current flows in the control circuit, if the relay K1 and the relay K2 are normal, none of the check signals CK1 to CK4 are output.

In this case, all the check signals are points where current should not flow. The control device confirms the output of the check signal. If no check signal is output as set, the process proceeds to the next step of the self-check. In this case, when the relay K1 is welded, a current flows from the R-phase side into the control circuit, and a current flows through the detection circuit for the check signal CK1, so that an output of the check signal CK1 is generated. Similarly, when the relay K2 is welded, a current flows from the S-phase side into the control circuit, and a current flows through the detection circuit for the check signal CK2, so that an output of the check signal CK2 is generated. If any one of the check signals is output, an abnormality has occurred, and normal control cannot be performed in the state where the abnormality has occurred. Therefore, the self-check is terminated and the control is locked out.

If no abnormality is detected in the check process (1), the process proceeds to the next check process. In the next check process (2), only the relay K2 is closed from the check process (1). When the relay K2 is closed, the S-phase circuit is connected, so that a current flows in the S-phase control circuit, and the check signal CK2 is output. At this time, since the R-phase relay K1 is open and no current flows from the R-phase side, no power is supplied from the R-phase to the ignition device 1 or the pilot valve 2, and these load devices do not operate. The check signals CK1, CK3, and CK4 connected to the control circuit on the R phase side are not output.

In this case, the detection circuit for the check signal CK2 is where the current should flow, and the detection circuit for the check signals CK1, CK3, and CK4 is where the current should not flow, and the controller checks whether the current is flowing as set. . If the output pattern of the check signal is different from the set pattern of the check process (2), an error occurrence is output, and if the output is in accordance with the set pattern, the next process of the self-check is performed. Move.

In the next check step (3), only the relay K1 is closed. When the relay K2 closed in the check step (2) is opened and the relay K1 is closed, the current flowing on the S phase side of the control circuit is interrupted, and the current flows on the R phase side of the control circuit. When the relay K1 operates correctly, the check signal CK1 is output, and when the relay IG is in a position to close the contact on the non-ignition device which is the normal position, the check signal CK3 is output. Since the relay PV is open, the check signal CK4 is not output.

In this case, the check signals CK1 and CK3 are locations where current should flow, and the check signals CK2 and CK4 are locations where current should not flow. The control device confirms whether the current is flowing as set, and the check signal output pattern. Is different from the set pattern of the check process (3), an abnormality occurrence is output, and if the output is as set, the process proceeds to the next process.

In the next check process (4), the operation of setting the contact point of the relay IG to the ignition device side from the check process (3) is performed. When the contact of the relay IG is on the ignition device side, the current from the R-phase side flows to the ignition device, so that the output of the check signal CK3 is stopped. In this case, the current from the R phase flows to the ignition device 1, but since the S phase side is interrupted by the relay K2, there is no current flow from the S phase to the ignition device, and the ignition device 1 operates. Absent. Since the relay PV is open in terms of circuit, no current flows through the check signal CK4, and the check signal CK4 is not output.

However, when a current is sent from the R phase to a load device such as an ignition device, the current flowing in the ignition device flows to the S phase side circuit, flows through the S phase side circuit to the pilot valve 2, etc., and then In some cases, a leakage current may flow in the circuit around the R-phase side of the pilot valve. Since the relay PV is open, no current flows through the check signal CK4. However, the leakage current flows from the ignition device into the R-phase circuit via the S-phase circuit and the pilot valve. When this occurs, as indicated by the broken line in FIG. 4, a leakage current may flow to the detection circuit for the check signal CK4, and the check signal CK4 may be output due to the leakage current.

In this case, the check signal CK4 is output only when the relay PV closes the contact in terms of control. Therefore, the check signal CK4 is output in the check step (4) in which the operation of closing the contact of the relay PV is not performed. It is not a correct result. However, when a leakage current occurs as described above, the check signal CK4 is output even if there is no problem on the control circuit. Therefore, when the check signal CK4 is output, it is determined that an abnormality has occurred. If so, correct judgment cannot be made. For this reason, the output of the check signal CK4 in the above case is ignored, and even if the check signal CK4 is output, it is not determined that an abnormality has occurred. In the check pattern (4), the check signals CK1 and CK3 are places where the current should flow, the check signal CK2 is a place where the current should not flow, and the check signal CK4 is a place where the output is ignored even if there is an output. As for, it will not be abnormal even if current flows or not.

In the next check step (5), the relay IG is operated as a contact on the side where no current flows through the ignition device, and the relay PV is operated to close the contact. When the contact on the side other than the ignition device side is closed by the relay IG, the check signal CK3 is output. When the contact of the relay PV is closed, the current from the R-phase side flows to the check signal CK4, so that the check signal CK4 is output. Here, the check signals CK1, CK3, and CK4 are locations where current should flow, and the check signal CK2 is a location where current should not flow.

As described above, when a plurality of check processes are sequentially performed to determine abnormality of the control circuit, the output of the check signal is ignored even if there is an output in addition to the place to be outputted and the place not to be outputted. By setting the location, it is possible to prevent erroneous determination that an abnormality has occurred when no abnormality has occurred in the circuit due to the occurrence of leakage current.

The present invention is not limited to the embodiments described above, and many modifications can be made by those having ordinary knowledge in the art within the technical idea of the present invention.

1 Ignition device
2 Pilot valve K1 Relay K1
K2 relay K2
IG relay IG
PV relay PV

Claims (1)

For a control circuit having a plurality of relays that control the power supply to the load device, various circuit states are established by operating the relay under conditions where the load device does not operate, and the current flowing in the control circuit Is detected at multiple locations in the control circuit and a check signal is output, and the relay operates normally by checking whether the check signal is output according to a predetermined pattern in each circuit state. In the control device that performs the self-check of the relay for determining whether the check signal is present, the pattern set for use in the determination of the abnormality by the check signal is added to the location where the check signal should be output and the location where the check signal should not be output. A control device for performing a self-check of a relay, characterized in that a pattern consisting of portions to be ignored even if there is an output is set.

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