JPS61165117A - Program control device - Google Patents

Abstract

PURPOSE:To reset exactly an electronic controlling circuit even in case when an electric conduction is executed again after the short time cut-off of a power source, by applying a reset signal, in a period in which an input voltage of a constant-voltage circuit exceeds a voltage for outputting a set voltage. CONSTITUTION:When a normally opening switch 7 and 9 of an operating witch 5 are brought to a closing operation, an AC voltage is applied between power source lines 11, 13, it is converted to DC, and a voltage V0 is applied between power source lines 16A, 16B. An output voltage V1 of a constant-voltage circuit 18 is stabilized to a constant voltage V1r, when the voltage V0 exceeds Vr. On the other hand, a constant-voltage diode 26 of an initializing circuit 25 conducts, when the voltage V0 has reached Vr, a transistor 28 is turned on, and a reset terminal 22r of an electronic control circuit 22 rises to a high level. After reset has been ended, and read of a selecting signal is ended, an output terminal O2 is varied to a high level, a relay coil 38a of a relay 38 is conducted electrically and energized, and the power source line 11 is connected to power source terminal 2 through a relay armature 38a and self-held.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a reset terminal of the electronic control circuit for a period from the lower limit of the output voltage of the constant voltage circuit or the operation guaranteed voltage of the electronic control circuit to the set voltage of the constant voltage circuit upon power-on. Reset signal to! This invention relates to a program control device that can be used.

Conventionally, the initialization circuit that resets the electronic control unit when the power is turned on detects the output voltage of the constant voltage circuit, and when the output voltage of the constant voltage circuit is detected to be a predetermined voltage that is slightly lower than the set voltage of the constant voltage circuit when the power is turned on. For example, a switching transistor is activated to start charging a capacitor in a time constant circuit, and the voltage generated between the terminals of this capacitor is supplied to a reset terminal of an electronic control circuit. For a predetermined period of time until the lower threshold level of the reset terminal of the control circuit is exceeded, the electronic control circuit assumes a reset state. However, in this configuration, the capacitor of the time constant circuit discharges after the power is cut off, so the predetermined 11. - It takes a long time, so if the power is turned off after a short period of time,
Immediately after re-energizing, the voltage between the terminals of the capacitor may already exceed the lower threshold level of the reset terminal of the electronic control circuit, and in this case, the electronic control circuit may not be reset and malfunction may occur.

The present invention has been made in view of the above-mentioned nakazuke, and its first aspect is
The object of the present invention is to provide a program control device that is equipped with an initialization circuit that can reliably reset an electronic control circuit even when the power is turned on again after being cut off for a short time, and that does not cause malfunction.

An embodiment in which the present invention is applied to an oven will be described below with reference to the drawings. 1 and 2 are AC power supply terminals, 3 is a heater as a load provided in the oven body 4, and 5 is an operation switch, which is connected to a normally closed switch 6, a normally open switch 7.8, and normally open switches 9 and 10. Become. The operation switch 5 includes a first push button (not shown) that operates the normally open switch 6, a second push button that operates the normally open switch 7.9 in conjunction with the normally open switch 8. 1
0 is provided, and each switch 6 to 10 is operated only while each push button is operated, and returns to a steady state when the operation is completed. , inside the operation switch 5, the normally closed switch 6
One end of each of the normally open switches 7.8 is connected to one end of the normally open switch 7.8, and the other ends of each of the normally open switches 7.8 and one ends of each of the normally open switches 9 and 10 are commonly connected. Then, the other end of the normally closed switch 6 is connected to the power supply terminal 2, and the common connection point of the normally open switches 7 to 10 is connected to one end of the bidirectional three-terminal thyristor (hereinafter referred to as TRIAC) 12 via the power line 11. connect to,
The other end of the triac 12 is connected to the power terminal 1 via the heater 3 and the power line 13. 14 is a DC power supply circuit, and the primary coil 15a of the transformer 15 is connected to the power supply lines z and i3.
The secondary coil 15b of this transformer is connected between the input terminals 16a and 16b of the bridge rectifier circuit 16,
A smoothing capacitor 17 is connected between the positive and negative output terminals 16c and 16d of the bridge rectifier circuit 16,
Ground the negative output terminal 16d. 18 is a constant voltage circuit, which connects the collector of an NPN type power transistor 19 to the bridge rectifier circuit 16 via a positive power supply line 16A.
At the same time, the cathode of a constant voltage diode 20 for generating a reference voltage is connected to the base, and the anode of the constant voltage diode 20 is connected to the negative output terminal 16d of the bridge rectifier circuit 16 via the negative power supply line 16B. The emitter of the transistor 19 is connected to the power line 11 to maintain the H1 voltage V1 between the emitter of the transistor 19 and the negative power line 16B at a predetermined constant voltage, and the emitter of the transistor 19 is connected to the power line 11 to have the same potential. 2
Reference numeral 2 denotes an electronic control circuit composed of, for example, an LSI, which electrically stores and stores several control programs, for example, two, for controlling the temperature of the oven in relation to the elapsed time. The positive power terminal 22S of this is connected to the emitter of the transistor 19, and the negative terminal i1+ii terminal 22d is connected to the negative power line 16B=5-. The first selection terminal 22j is connected to the other end of the normally open switch 9, and the second selection terminal 221 (is connected to the other end of the normally open switch 1).
0, the clock input terminal 22c is branched into two, and one is connected to the secondary coil 1 of the transformer 15 via the resistor 23.
5b, and the other end is connected to the negative power supply line 16B via a capacitor 24. 25 is an initialization circuit for receiving a reset signal to the reset terminal 22r of the electronic control circuit 22, and includes a constant voltage diode 26 whose anode is connected to the negative power supply line 16B.
The cathode of the transistor 28 is connected to the positive power line 16A via the resistor 27, and the cathode of the voltage regulator diode 26 is connected to the base of the PNP transistor 28 via the resistor 29, and the emitter of the transistor 28 is connected to the positive power line 16A. The collector of the transistor 28 is connected to the reset terminal (-22r) and connected to the negative power supply line 16B via the resistor 30.The first and second output terminals 01 and O2 of the electronic control circuit 22 will be described later. stroking to output an output signal such as
The base of an NPN transistor 32 is connected to the output terminal o1 of the output terminal o1 through a resistor 31, and the base of an NPN transistor 34 is connected to the second output terminal 02 through a resistor 33, and the collector of the transistor 32 is connected to a resistor. 35 to the gate of the triac 12,
Both emitters of transistors 32 and 34 are connected to each other to form an NPN type transistor 36 for switching.
The emitter of the transistor 36 is grounded, and the base is connected to the collector of the transistor 28 of the initialization circuit 25 via a resistor 37.

38 is a relay as a second power-on circuit, in which a relay contact piece 38a is connected to the normally open switch 7.8 and the j112 column, one end of the relay coil 3.8b is connected to the power supply line 11, and the other end is connected to the transistor. Connected to 34 collectors. 39 is a thermistor for sensing the temperature inside the oven main body 4, one end of which is connected to the power supply line 11, and the other end is grounded via a resistor 4o. 41 is an A-D converter that converts an analog signal into a digital signal; its input terminal 41a is connected to the common connection point of the thermistor 39 and the resistor 40, and its output terminal 41b is connected to the input terminal 22i of the electronic control circuit 22. Connected. That is, the A-D converter 41 converts the analog signal voltage generated across the resistor 40 into a digital signal, and changes the resistance value of the thermistor 39 in accordance with temperature changes within the oven body 4. Since the voltage across the resistor 40 changes, the digital signal output to the output terminal 41b of the AD converter 41 changes in accordance with this voltage change.

Next, the operation and effect of this embodiment configured as described in 1-1 will be explained with reference to the timing diagram shown in FIG. 2. Figure 2 (C) shows the voltage change, and Figure 2 (d) and (e) are the same as Figure 1.
The input/output signals of each input/output terminal of the electronic control circuit 22 are shown with number 1, and FIG. 2(f) shows on/off of the relay contact piece 38b of the relay 38, and FIG. 2(g) 2(h) shows a set temperature program which is one of the control programs stored in the electronic control circuit 22, and FIG. ) indicates the temperature change inside the oven body 4.

Now, when the operating switch 5, for example, the normally open switches 7 and 9, is turned on by suppressing the second push button (not shown) at time t1, the power supply line 11 or the normally open switch 7 is turned on. Power line 11, 1.3 connected to power terminal 2
By applying an AC voltage between them, the low voltage AC stepped down by the transformer 15 is converted to DC by the bridge rectifier circuit 16, and the positive and negative power lines 16A
.

16B, the voltage V between the power supply lines 16A and 16B. Since the capacitor 17 is charged when the power is turned on, it gradually increases as time passes, as shown by the solid line in FIG. 2(c). Then, the output voltage V1 of the constant voltage circuit 18 is V
When the voltage of o is lower than Vr, the voltage regulator diode 20
The voltage is V because it is cut off. The voltage is slightly lower than the voltage V.

However, when the voltage Vo exceeds Vr, the voltage regulator diode 20 breaks over and becomes conductive to change and adjust the base current of the transistor 19, so that the voltage V. When is less than Vr -1-, voltage v1 or Vr
The voltage V1r is stabilized at a constant voltage V1r, which is slightly lower than the voltage V1r. On the other hand, the constant voltage diode 26 of the initialization circuit 25 has a voltage of V. When reaches Vr (time t2), it breaks over and becomes conductive, turning on the transistor 28.
The reset terminal 22r of the electronic control circuit 22 is shown in FIG. 2(d).
As shown in the figure, the signal is kept at a low level from time t1 to t2, and rises to a high level at time t2. Also,
The electronic control circuit 22 has positive and negative power terminals 22s.
When the terminal voltage between 22d and 22d is within a few percent below Vlr, normal operation is performed.Since the operating type and voltage of the eye and lower limit are determined, voltage From the time when the lower limit guaranteed operation voltage Vrmin is reached (time t2'), the voltage Vi becomes Vl' (constant voltage circuit 18
Until the voltage reaches the set voltage (time t2), the low level signal applied to the reset terminal 22'r resets the state of the internal registers, etc., and the outputs of the output terminals 01 and o2 remain at low level. becomes. Now, the normally open switch 9 of the electronic control circuit 22 has been closed since time t1, but the first selection terminal 22'' of the electronic control circuit 22 is closed at time t1.
2, the resetting of the electronic control circuit 22 ends, and reading ends at time t3, which is a predetermined time elapsed from time t2, as shown in FIG. 2(g). That is,
The electronic control circuit 22 reads the selection signal, for example, twice between time t2 and time t3, determines that the reading results match, and finishes the reading to prevent erroneous reading due to causes such as switch chatter. I have to. Next, based on the selection signal whose reading is finished at time t3, the electronic control circuit 22 selects the stored 2
Start reading one of the control programs. The timing progression of the electronic control circuit 22 after time t2 is performed by counting the AC waveform sent to the clock terminal 22c of the electronic control circuit 22. Now,
After the electronic control circuit 22 finishes reading the selection signal at time t3, after a predetermined period of time has elapsed (time t4), the output terminal o2 is changed to high level and the transistor 34 is turned on, and at the same time, the transistor 36 is turned on at time t2.
changes from its base to a high level (see Figure 2 (d))
11. Since the relay coil 38a of the relay 38 is energized via the transistors 34 and 36, and a short time has passed since 11. 'j (time t4'), the relay contact piece 38a is closed (on) (time t4 to time 14- is the time required for switching the relay contact piece 38a).

After the relay contact piece 38a is closed at time t4- (time t5), the suppression of the second push button (not shown) of the operation switch 5 is released and the normally open switches 7 and 9 are opened. (off), the power line 11 is connected to the relay contact 38a.
The electronic control circuit 22 continues to be connected to the power supply terminal 2 via the power supply terminal 2 for so-called self-maintenance, and power is continuously supplied to the electronic control circuit 22.

On the other hand, since the set temperature program as shown in FIG. 2(h) is read out at time t4, an output pulse synchronized with the power supply frequency is outputted to the output terminal 02 based on this, and the transistor 32 is periodically turned on. Therefore, the gate of the triac 12 is grounded through the i-transistors 32 and 36, so that the triac 12 is ignited and the heater 3 is energized to generate heat. Due to the heat generated by the heater 3, the temperature inside the oven body 4 increases by 1 as shown in FIG. As described above, the signal is converted into a digital signal by the A-D converter 41 and input to the input terminal 22i of the electronic control circuit 22. On the other hand, the electronic control circuit 22 constantly compares the temperature information given to the input terminal 22i with the temperature set in the temperature setting program and changes the timing of the firing pulse output to the output terminal 02 to phase the triac 12. The amount of heat generated by the heater 3 is controlled to be adjusted.

That is, when the temperature T1 is read out from the temperature setting program at time t4 as shown in FIG. 252(h), the temperature inside the oven main body 4 at that time is low as shown in FIG. Since the difference from the temperature T1 is large, the timing of the ignition pulse output to the output terminal 02 of the electronic control circuit 22 is set so that the heater 3 generates a high amount of heat. Then, when the temperature inside the oven main body 4 increases by -I and the difference from the temperature T1 decreases, the timing of the ignition pulse output to the output terminal 01 changes so that the amount of heat generated by the heater 3 decreases. Therefore, the temperature inside the oven main body 4 is set to the set temperature T1. After that, as time passes, the set temperature program changes the temperature from T1 to T2 (time ts'), and then to T2.
to T3 (time ty), but the electronic control circuit 22 changes the set temperature T2. to T3 (time ty) in the same manner as described above. Since the amount of heat generated by the heater 3 is adjusted by comparing T3 with the temperature inside the oven, the temperature inside the oven main body 4 is controlled according to the set temperature program. In addition to the set temperature □, the cooking end data is also stored in the set temperature program, and when the cooking ends after a predetermined period of time has elapsed from time t4, the output of the output terminal 02 is set to a low level and the transistor 34
By turning off the relay coil 38b, the relay contact piece 38a is reset (off) by cutting off the power to the relay coil 38b, and the power to the heater 3 and the electronic control circuit 22 is automatically cut off. Now, if you want to check the cooking status or add items to cook, use Tsutsushi! If it is desired to interrupt the process in the middle, the normally closed switch 6 of the operation switch 5 can be manually turned off by pressing a first push button (not shown). That is, for example, when the normally closed switch 6 is opened (off) at time t8, the supply of AC power between the power lines 11 and 13 is cut off, resulting in the voltage between the power lines 1'6A and 16B. gradually decreases due to discharge from the capacitor 17 and becomes the second
As shown in Figure (c), the voltage drops up and down to Vr at time t9. Then, the constant voltage diode 26 is cut off!・Run sister 28 is cut off and reset terminal 22
As r becomes low level, the transistors 3 and 6 are turned off, and the power to the relay coil 38b is cut off. As a result, relay contact j-38a is opened (off) operated.

Therefore, even if the first push button of the operation switch 5 is released and the normally closed switch 6 is turned back on (turned on) after time 1° (time tlO), the relay 38 will not operate again and the cooking will not start. Interrupted.

By the way, for example, when the normally open switches 7 and 9 are closed at time t1, the output terminal 02 immediately becomes a high level as shown by the two-dot chain line in FIG. Considering the case where the timing of the output of the electronic control circuit 22 is set so that the relay contact 38a is turned on as shown by the two-dot chain line, in this case,
), the normally open switches 7 and 9 are at time t.

No problem will occur if the normally open switches 7 and 9 are turned off at time t5-, as shown by the two-dot chain line in FIG. In this case, the selection input terminal 2 of the electronic control circuit 22
Since the normally open switch 9 is opened before the time t3 when reading the selection signal is completed, the electronic control circuit
2 can only read the selection signal, causing malfunctions. However, in this embodiment, after the reading of the selection signal is completed, the output terminal 02 changes to a high level and the relay 38 is activated. .

If it is turned on for only a short period of time, such as when it is turned off at time t5-, the power to the electronic control circuit 22 is cut off at time t5- and the operation is interrupted, so there is no risk of malfunction. If the operation time of the second push button of the operation switch 5 is too short, the operation can be repeated from the beginning.

In addition, if the voltage between the positive and negative power supply terminals 22s and 22d is lower than the guaranteed operation voltage Vrm[n, the electrician control circuit 22 will not operate stably and even if a reset signal is applied to the reset terminal 22r. Output end 7-
0. ．． Since it may output a high level at 0°, the transistors 32 and 34 connected to the output terminals ol and o2
may turn on when the voltage V1 is lower than VrIIlin. That is, this phenomenon occurs between time t1 and t2 and between time t9 and tlO, and the relay 38 is activated at time t2.
Normally open switch only for a short time due to previous actuation 7.
9, the electronic control circuit 22 may malfunction, or the relay 38 may operate after time t9, causing the electronic control circuit 22 to be reenergized even if the normally closed switch 6 is opened. This causes problems such as the heater being temporarily energized from time t9 to time t2 and from time t9 to time tto. However, in this embodiment, the initialization circuit 25
A transistor 36 turned on by the output of Therefore, between time t1 and t2 and between time t9 and tlG, the transistors 32 and 34
The gates of the relay 38 and the triac 12 are turned off by the transistor 36 regardless of whether the
- The various malfunctions described in (1) are reliably prevented.

In the embodiment L, the electronic control circuit 22 itself sets the timing from when the reset of the electronic control circuit 22 ends at time t2 until time t4 when the output terminal 02 outputs a high level, and the relay coil is activated at time t4. 38. For example, if a delay circuit is provided in the initialization circuit 25, etc., and the output from the delay circuit turns on/off the transistor 34, etc., the output of the electronic control circuit 22 is started. It is also possible to omit the terminal 02.

Further, in the above embodiment, for convenience of explanation, the effect when the normally open switches 7 and 9 are closed has been explained, but the same effect can be obtained when the normally open switches 8 and 10 are closed. Of course, a different temperature setting program is read out.

As is clear from the above description, the present invention is a program control device that is equipped with an initialization circuit that can reliably reset the electronic control circuit even when the power is turned off after being turned off for a short time, and that does not cause malfunction. can be provided.

[Brief explanation of the drawing]

The drawings show an embodiment in which the present invention is applied to an oven device, and FIG. 1 is a circuit diagram and FIG. 2 is a timing diagram. In the drawing, 3 is a heater (load), 5 is an operation switch, and 7.
8 is a normally open switch (first power supply circuit), 9.10 is a normally open switch (selection circuit), 14 is a DC power supply circuit, 18
is a constant voltage circuit, 22 is an electronic control circuit, 25 is an initialization circuit, 38 is a relay (second power-on circuit), 41
is an A-D converter.

Claims (1)

[Scope of Claims] 1. An electronic control circuit that stores a plurality of control programs for controlling a load, and selects one of the plurality of control programs in response to a selection signal to control the load; a constant voltage circuit which takes the output of the DC power supply circuit as an input and supplies power to the electronic control circuit; and detects the input voltage of the constant voltage circuit so that the input voltage is at least the output voltage of the constant voltage circuit. A program control device comprising an initialization circuit that applies a reset signal to a reset terminal of the electronic control circuit within a period from a value corresponding to the lower limit of the operation guaranteed voltage of the control circuit to a voltage equal to or higher than the voltage at which the constant voltage circuit outputs the set voltage. . 2. The initialization circuit has a switching circuit that is turned off by a reset signal thereof, and the switching circuit cuts off the output signal from the electronic control circuit, as set forth in claim 1. program control unit.