JPH0744992B2 - Control device for gas clothes dryer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a controller for a gas clothes dryer having a self-diagnosis function.

2. Description of the Related Art As shown in FIG. 4, the circuit of a conventional control device for a gas clothes dryer is composed of a group of mechanical contacts. Reference numeral 1 is a solenoid valve that opens a gas passage when energized, 15a is a contact of a time switch, and 15b is a timer motor of the time switch, which controls the time. That is, the contact 15a is closed according to the time set by the user. Reference numeral 16 is an ignition switch that works in conjunction with the instrument plug, and energizes the igniter 19 at the time of ignition and energizes the motor 20 thereafter. Reference numeral 17 is a temperature control thermostat, which controls the solenoid valve 1 by opening at a first set temperature and closing at a second set temperature lower than the first set temperature.
This regulates the combustion of the gas. A door switch 18 cuts off the power supply to the motor 20 and the solenoid valve 1 so that it is safe to open the door during operation. As described above, the conventional controller for the gas clothes dryer only controls the load required for operation, and does not have the self-diagnosis function for the failure of the parts constituting the controller.

Problems to be Solved by the Invention In such a conventional configuration, the components constituting the circuit are not diagnosed during its operation, and the failure is dealt with after an abnormal state occurs. On the other hand, when a control method for easily performing fine control by using a microcomputer has come to be considered, the number of circuit components has increased and it has become necessary to perform self-diagnosis of them to improve the safety of the device.

The present invention has been made in view of the above problems, and an object thereof is to add a self-diagnosis function and to operate on the safe side when an abnormal state occurs to improve safety.

Means for Solving the Problems To achieve the above object, the present invention provides a solenoid valve that opens a gas passage when energized, first and second switching circuits that control energization of the solenoid valve, and the second invention. A check circuit for monitoring the voltage of the solenoid valve side terminal of the switching circuit, and a control means for controlling the output of the switching circuit in the order of the first switching circuit and the second switching circuit. Before the output, after the output to the first switching circuit, and further after the output to the second switching circuit, it is sequentially determined whether the output from the check circuit is a predetermined voltage, and it is not the predetermined voltage. In some cases, the switching circuit is controlled so that the solenoid valve is not driven.

Action With the above configuration, the control means detects the failure of the switching circuit controlling the solenoid valve by the check circuit, and when the check circuit is not at the predetermined voltage, the switching circuit determines that the switching circuit is faulty and shuts off the power supply to the solenoid valve. Unsafe conditions such as being released can be avoided.

EXAMPLES Examples of the present invention will be described below with reference to FIGS. 1 to 3.

In FIG. 1 showing the circuit configuration of this embodiment, 1 is an electromagnetic valve for opening and closing a gas passage, and one end of this electromagnetic valve 1 is connected to a first switching circuit 2 for controlling energization. A second switching circuit 3 for controlling energization is connected to the other end of the solenoid valve 1. The collector voltage of the transistor Q ₂ forming the second switching circuit 3 is monitored by the check circuit 4. The microcomputer 5 which outputs the energization control signal of the solenoid valve 1 has an output terminal P for outputting a signal to the first switching circuit 2, an output terminal SV for outputting a signal to the second switching circuit 3, and a signal from the check circuit 4. It has an input terminal CH for input.
The first switching circuit 2 outputs Q ₁ only when a pulse signal is output from the output terminal P of the microcomputer 5.
The safety circuit is configured to turn on and turn off Q ₁ when a signal of L level or H level is output, and to prevent energization of the solenoid valve 1 at the time of abnormality due to runaway of the microcomputer 5 or the like. Is. The operation will be described below. First, the output terminal P of the microcomputer 5
While the pulse signal is at the L level, the transistor Q ₃ is turned off, and the resistance R ₁ → capacitor C ₁ → diode
The charging current flows in the path of D ₂ → capacitor C ₂
C ₂ is charged. Next, while the output terminal P of the microcomputer 5 is at the H level of the pulse signal, the transistor Q ₃
Is turned on and the electric charge stored in the capacitor C ₁ by the charging current is discharged in the path of the capacitor C ₁ → transistor Q ₃ → resistor R ₂ → diode D ₁ → capacitor C ₁ . It charges the capacitor C ₂ In this case the capacitor C ₂ → resistor R ₃ → resistor
It is discharged as R ₄ or the base current of transistor Q ₄ . When a pulse signal is output from the output terminal P of the microcomputer 5, the above operation is repeated, and the resistances R ₁ , R ₃ and R of the capacitor C ₂ are set so that (charge current)> (discharge current). _When the value of ₄ is set, the terminal voltage of the capacitor C ₂ becomes enough voltage to turn on the transistor Q ₄ ,
This turns on Q ₁ . On the other hand, when the pulse signal is not output from the output terminal P of the microcomputer 5 and becomes L level or H level, the charging current to the capacitor C ₂ is blocked by the capacitor C ₁ having a DC blocking function, and the capacitor C ₂ is blocked. ₂ terminal voltage is a transistor
Q ₄ can not be turned on, the transistor Q ₁ is also not turned on. Therefore, the solenoid valve 1 is not energized. By the above operation, when the microcomputer 5 runs away and the output terminal P becomes L level or H level in the first switching circuit 2, the solenoid valve 1 is forcibly de-energized and the gas path is closed. It works to the side.

FIG. 2 shows waveforms at various parts of the circuit, and FIG. 3 shows a flow chart for self-diagnosis, and the operation will be described with reference to these figures. First, in step 6, the microcomputer output terminal P and
SV is set to L level, and the output of the check circuit in step 7 is judged. This is the interval of t ₁ shown in Fig. 2. If CH is at H level, Q ₁ is a short circuit or a failure of the first switching circuit corresponding to this, and the signal for driving the solenoid valve is not output. Go to step 13. Step 7
If CH is at L level, the process proceeds to the output of the P signal in step 8, the pulse signal is output as shown in FIG. 2, Q ₁ is turned on, and power is supplied to the solenoid valve. Then step 9
CH judgment of. This is the interval of t 2 shown in Fig. _2. If CH is at L level, the open failure of Q ₁ or the failure of the 1st switching circuit or the disconnection of the solenoid valve or the failure of Q ₂ corresponding to this is the failure. And step
The output from the 12 P terminal is reset to the L level, the power supply to the solenoid valve is cut off, and the process proceeds to step 13. Step 9
If CH is at H level, move to SV signal output of 10 to drive the solenoid valve. After that, the CH determination in step 11 is performed. This corresponds to the t ₃ section in Fig. 2, and if CH is at H level, Q ₂
Is an open failure, the P terminal L level is reset in step 12, and the process proceeds to step 13 in the next step. In step 11
If CH is not at H level and it is a signal obtained by inverting the SV pulse signal as shown in Fig. 2 during normal operation, the first and second switching circuits and solenoid valves are operating normally without failure. Then, move to the next step of Step 14. What separates the flow into step 14 and step 13 here is that step 14 is a branch for performing normal operation,
Step 13 is a branch for notifying that an abnormality has been recognized by self-diagnosis, and for performing control so that loads other than the solenoid valve are in an abnormal state. This branch shows an example of two systems, one for normal and one for failure,
When it is determined that there is a failure in each of the CH determinations in steps 7, 9, and 11, it is possible to branch to separate flows and perform individual processing.

EFFECTS OF THE INVENTION As is apparent from the above description of the embodiments, according to the present invention, two switching circuits for controlling solenoid valves are output with a time difference, and the failure of the switching circuit is detected by the output voltage of the check circuit between them. Since the diagnosis is performed and the solenoid valve is controlled so as not to be driven if there is an abnormality, failure can be prevented in advance and safety can be improved.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention, FIG. 2 is a waveform diagram of each part, FIG. 3 is a flowchart showing the same control,
FIG. 4 is a circuit configuration diagram of a conventional example. 1 ... Solenoid valve, 2 ... First switching circuit, 3 ...
Second switching circuit, 4 ... Check circuit, 5 ...
Microcomputer.

Claims (1)

[Claims] 1. A solenoid valve for opening a gas passage when energized, first and second switching circuits for controlling energization of the solenoid valve, and a check for monitoring a voltage of a solenoid valve side terminal of the second switching circuit. A circuit and control means for controlling the output of the switching circuit in the order of the first switching circuit and the second switching circuit, the control means before outputting to the switching circuit and outputting to the first switching circuit. After that, further, after the output to the second switching circuit, it is sequentially judged whether or not the output from the check circuit has a predetermined voltage, and when the voltage is not the predetermined voltage, the switching circuit is controlled so as not to drive the solenoid valve. Gas clothes dryer control device.