JPH06233550A - Instruction input system of inverter - Google Patents

Abstract

PURPOSE:To prevent malfunction due to the abnormality of an instruction input circuit without increasing a hardware amount by a method wherein an instruction is changed in such a way that it is changed from ON to OFF, and from OFF to ON continuously and a correct instruction is judged on the basis of a plurality of ON-instructions or it is confirmed that the input instruction circuit has been set to an OFF state and a control processing operation is performed. CONSTITUTION:A control circuit repeatedly performs a prescribed input processing operation at intervals of a prescribed time t3 on the basis of the processing operation of a CPU, and an external contact X is constituted in such a way that the state of the contact is changed from ON to OFF and from OFF to ON continuously. At this time, when the external contact X is closed, for example, at a read timing T3, FLAG=1 is set. Then, when the external contact X is open at a second timing T4, FLAG=2 is set. In addition, when the external contact X is turned on at a read timing T5, a prescribed control processing operation is performed. Thereby, a correct instruction can be input by only a normal instruction input circuit which can output in an either ON of OFF state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a command input system for an inverter device, and more particularly to a command input system for an inverter device used for drive control of an AC motor.

[0002]

2. Description of the Related Art In an inverter device for controlling the drive of an AC motor, a DC input supplied from a DC power supply unit is converted into AC by an inverter circuit, and an AC output of this inverter circuit is output through an output line. Is generally used, and the AC motor is controlled by the AC output control by the inverter circuit.

Conventionally, commands such as the operation, inching, emergency stop, and control switching of the AC motor by this type of inverter device are performed by the circuit shown in FIG. 5, for example. In FIG. 5, command signals for emergency stop, operation, inching, speed setting, etc. are indicated by switches S1 to S3 and speed setter S.
It is input by the command input circuits 101 to 103 or the A / D converter 104 by e. The input command signals are input to the control circuit 120 via the input port 111 or directly. The control circuit 120 includes a bus line 121 to which the command signal is input, and the bus line 1
21 and CPU 122 and ROM 123 respectively connected to
And RAM 124 and the like. Control circuit 120
Controls the base current of the transistor inverter 140 via the base drive circuit 130 in accordance with the input command signal based on the processing operation in the CPU 122, thereby controlling the drive of the AC electric motor M.

An example of processing in the control circuit mainly composed of the CPU is as shown in FIG.
The command data from S3 is input, and when these inputs are stabilized, processing such as emergency stop, operation, and inching are sequentially executed.

Further, in this type of inverter device, there is a risk of malfunction due to noise from an external circuit or the like or chattering at the external contacts of the switches S1 to S3, and it is necessary to prevent them. Therefore, for example, as the command input circuits 101 to 103 as described above, an insulating circuit such as a photocoupler 105 is provided between the external contact X and the input port 111 as shown in FIG. 7A, or as shown in FIG. A configuration in which a filter circuit such as the Schmitt trigger circuit 106 is inserted is generally adopted. Further, in addition to these configurations, a configuration is adopted in which the command data is input, that is, the command data is read into the input port as described above, is repeated a plurality of times until the input stability can be confirmed.

[0006]

However, in the above-mentioned conventional configuration, when the external contact is in the same state as when the command input circuit is deteriorated or damaged, the inverter device may operate unexpectedly. There is a problem of causing. That is, in the configuration of FIGS. 7A and 7B, the phototransistor that is the secondary-side transistor that constitutes the photocoupler 105, or the Schmitt trigger circuit 106.
When the output terminal of 1 becomes ON and becomes active, erroneous command data is output to the input port 111. As a result, there is a fear that the inverter device may run out of control.

In order to prevent the above-mentioned inconvenience, as shown in FIG. 8, two command input circuits for command data to the input port 111 by the external contact X are provided and duplicated, and the command input circuits are also duplicated. There is a method in which the AND condition of is calculated by hardware or software, and when the two command input circuits are both ON, it is regarded as a correct command. However, in the case of this method, there is a drawback that the amount of hardware required increases with the duplication.

It is an object of the present invention to prevent erroneous processing due to erroneous command data input due to an abnormality in the command input circuit without causing an increase in the amount of hardware as described above. To provide a method.

[0009]

According to a command input method of an inverter device of the present invention, a command signal from at least one external contact is input to a control circuit of the inverter device through a predetermined command input circuit, and the control circuit is provided. In an inverter device for performing a predetermined control process based on the command signal, the control signal performs the control process when the command signal is changed to ON, OFF, ON state and the state change is correctly input. Is characterized by.

The above-mentioned state change may be carried out by the external contact itself, or an abnormality detection that causes such a state change between the external contact and the command input circuit in response to ON of the external contact. It may be configured to provide means.

According to another aspect of the present invention, there is provided a command input method for an inverter device in which a command signal from at least one external contact is input to a control circuit of the inverter device through a predetermined command input circuit, and the command is issued in the control circuit. In an inverter device for performing a predetermined control process based on a signal, a determination means is provided for turning the command input circuit into an OFF state regardless of the state of the external contact, and when the OFF state is correctly input, the control circuit is It is characterized by performing control processing.

[0012]

According to the first aspect of the invention, the operation of the command input circuit is confirmed by the above-described change in the state of the command signal, that is, the command input circuit determines that the command is correct based on a plurality of ON commands. In the case of a malfunction, the control circuit does not perform erroneous control processing, and the above-mentioned runaway operation or the like is reliably prevented.

According to the second aspect of the present invention, the control circuit is erroneous by confirming that the command input circuit is in the OFF state by the discrimination means as described above, that is, by confirming the operation of the command input circuit. Control processing is prevented.

[0014]

EXAMPLES Examples of the present invention will be described in detail below.

(Embodiment 1) FIGS. 1 and 2 are explanatory views of the operation in the command input system of the embodiment of the present invention. The basic circuit configuration itself in this embodiment is the same as that shown in FIG.
Although the configuration is substantially the same as that described above, the operation at each external contact X and the processing operation of the control circuit 120 are different as follows. For convenience of explanation, reference numerals of the respective constituent elements in FIG. 5 and FIG. 7 are used in the following explanation. Further, the external contact X is an example of one contact of an input for a command such as operation control switching (the above switches S1 to S3 for each operation control etc.).

In FIG. 1, the control circuit 120 repeatedly performs a predetermined input process at intervals of a constant time t3 to generate a command for switching operation control or the like. The external contact X is
When, for example, the switch S1 is turned on, it is turned on.
(With command), OFF (without command), ON (with command)
And is configured to change the state of its contacts. In this case, the external contact X has the time t1, t
ON, OFF, ON as described above between 2 and t3
It is controlled by itself or an external device so that the state changes. These times t1, t2, t3 are t1 =
It is set so that t2 = t3. Further, the timing of the above-mentioned state change, that is, each timing of ON, OFF, and ON, is set to read timings T1, T2, ... Of the command signal from the external contact for input processing in the control circuit 120, as shown in FIG. For example, as shown in the figure, the read timing T1 is at the center of the times t1, t2, and t3.
It is set to come to T2, ...

An example of a flow chart of the above-mentioned input processing in the control circuit 120 is shown in FIG. In this case, the internal data in the control circuit 120 is provided with a flag FLAG as shown in the figure, and the flag FLAG changes to 1 and 2 each time there is a command from the external contact X, whereby the external contact X is turned ON → Generates commands for internal operation / control switching, etc., by switching from OFF to ON.

Next, this input process will be described with reference to FIG. This input process is performed by the state of the flag FLAG (FLAG
= 0, 1, 2) and the state of the external contact X (X = ON,
OFF), the reading is performed at each reading timing.
If there is no command from the external contact X, the flag F
Since LAG is 0 and the external contact X is OFF, the processing command remains OFF.

On the other hand, when the external contact X is turned on at the read timing T3 in FIG. 1, FLAG = 1 is set. Next, when the external contact X is turned off at the read timing T4, FLAG = 2 by the input processing of FIG.
Is set. Further read timing T5 following these
When the external contact X is turned on, the processing command is turned on and a predetermined control processing is performed.

In this embodiment, FLAG = 1 when the external contact X is in the same state as when it is turned on due to deterioration or damage of the command input circuit. However, in this case, since the external contact X does not have the OFF state following the ON state, FLAG = 0 at the next read timing, and the processing command remains OFF, so that the control process corresponding to the command is not performed.

According to the command input system of the first embodiment configured as described above, the correct command can be input only by the normal command input circuit that can output in either the ON or OFF state, and the hardware is 2 as in the conventional example
It is possible to prevent erroneous command generation due to an abnormality in the command input circuit without duplication and a redundant configuration.

(Second Embodiment) Next, a command input system according to a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, a relay Ry and a contact Y that can be controlled by the CPU 122 are provided to supply a command signal that changes the state as in the first embodiment to the command input circuit, thereby confirming the operation of the command input circuit. A predetermined control process is performed.

In FIG. 3, the command signals from the external contacts X1 and X2 are input via the photo coupler 105 to the input port 1.
11 and a bus line 121 (not shown). The input side of these photocouplers 105, that is, the photocoupler 10
A contact Y is provided in the electric power supply path to the photodiode 105 a that constitutes the element 5. The contact Y is turned on when the relay Ry is energized.

The relay Ry is connected to the phototransistor 151b on the output side of the photocoupler 151,
A control signal from a control circuit 120 (not shown) (see FIG. 5) is output to the photodiode 105a on the input side via the output port 112. Then, by making the photodiode 151a conductive and turning on the phototransistor 151b by this control signal, the relay Ry is energized and the contact Y can be controlled from OFF to ON or from ON to OFF. The ON / OFF control of the contact Y by such a control signal is CP
U122 performs the same as the state change of the external contact X in the first embodiment.

An example of a flow chart of the above control processing and input processing of the control circuit 120 in the second embodiment is shown in FIG. In FIG. 4, X1 and X2 are external contacts X, respectively.
1, X2 means a command signal (command data) input to the control circuit 120 from the photo coupler 105 or the input port 111. Further, MX1 and MX2 are control circuits 120.
Means the discrimination data for external contact discrimination in
0 of MX1 and MX2 means an abnormal state, and 1 means a normal state. The abnormal state means that the photocoupler 105, which is a command input circuit, is abnormal due to a failure or the like.

Next, the operation of the second embodiment will be described with reference to FIG. In this case, when the inverter device is in operation, the control circuit 120 sequentially repeats the processing of PATH1 and PATH2 in FIG. 4 at a predetermined timing. Here, the contact Y at the start of processing is OFF, for example.
If it is in the state, the process of PATH2 is first performed.

In the processing of PATH2, command data X1,
X2 is read, and the discrimination data MX1 and MX2 are set to 1. Next read command data X
The ON and OFF states of 1 and X2 are detected respectively. In this case, since the contact Y is in the OFF state, the command data X
It is a normal state that both 1 and X2 are OFF.
Therefore, if the command data X1 and X2 are ON, it is determined that the photocoupler 105 is abnormal due to a failure or the like, and the determination data MX1 and MX2 are set to 0.
At the end of the processing of PATH2, the contact Y is controlled to be ON, and then the processing of PATH1 is performed.

In the processing of PATH1, first the command data X
1, X2 are read. Next read command data X
The AND condition of 1, X2 and the discrimination data MX1, MX2 is determined. Here, if the command input circuit is in a normal state, the discrimination data MX1 to MX2 in the above-mentioned PATH2.
Is set to 1, the command data X1 and X2 are O
If N, the AND condition is satisfied and the command data X
Predetermined control processes 1 and 2 based on 1 and X2 are performed. On the other hand, when the photocoupler 105 is abnormal due to a failure or the like, the determination data MX1 and MX2 are set to 0, so the AND condition is not satisfied and the control process is not performed. At the end of the processing of PATH1, the contact Y is controlled to be OFF, and then the processing of PATH2 described above is performed.

As described in the second embodiment, the contact Y is O
While confirming that the command signal is OFF in the FF state, by inputting only valid input as the command signal when the contact Y is ON and performing the predetermined control processing, the hardware is set to the same as in the conventional example. It is possible to prevent the generation of an erroneous command due to an abnormality in the command input circuit without duplicating the redundant configuration.

In addition, the method of the first embodiment requires a configuration for ON / OFF control of the external contact in synchronization with the read timing in the control circuit, but the method of the second embodiment turns the contact ON / OFF. There is an advantage that a desired function can be realized by a simple configuration of control, and the correctness of a large number of command input circuits can be determined by controlling one contact.

[0031]

As described above, according to the present invention, without increasing the amount of hardware in the inverter device,
It is possible to prevent an erroneous command processing operation due to an abnormality in the command input circuit.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of operation or processing timing of an external contact and a control circuit in a command input system according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing processing according to the first embodiment.

FIG. 3 is an explanatory diagram illustrating a main part of a circuit configuration of a command input system according to a second embodiment of the present invention.

FIG. 4 is a flowchart showing processing according to the second embodiment.

FIG. 5 is an explanatory diagram showing a conventional general configuration of a command input method in an inverter device.

FIG. 6 is a flowchart showing processing in a conventional command input method.

7A and 7B are explanatory views showing an improved example of a conventional command input method.

FIG. 8 is an explanatory diagram of a conventional command input method in which the system is duplicated.

[Explanation of symbols]

 101, 102, 103 ... Command input circuit 111 ... Input port 112 ... Output port 120 ... Control circuit 130 ... Base driver circuit 140 ... Transistor inverter 151 ... Photo coupler

Claims (2)

[Claims] 1. An inverter device in which a command signal from at least one external contact is input to a control circuit of an inverter device via a predetermined command input circuit, and the control circuit performs a predetermined control process based on the command signal. In the inverter command input method, the command signal is changed to ON, OFF, and ON, and the control circuit performs the control process when the state change is correctly input. 2. An inverter device in which a command signal from at least one external contact is input to a control circuit of an inverter device via a predetermined command input circuit, and the control circuit performs a predetermined control process based on the command signal. At the command input circuit regardless of the state of the external contact.
A command input method for an inverter device, characterized in that a determination means for setting an FF state is provided, and the control circuit performs the control process when the OFF state is correctly input.