JPH0724817Y2 - Timer circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a timer circuit having both an instantaneous contact that operates simultaneously when an operating voltage for a timer is applied and a time-delayed contact that operates after the timer expires. It is a thing.

[Prior Art] FIG. 3 shows a conventional timer circuit, which includes a power supply circuit section 1 for supplying power as an operating voltage and a timer control circuit section 2.
And the drive circuit unit 3 and the like. An instantaneous contact relay coil Ry ₁ is connected to the power supply circuit unit 1 side, and this relay coil Ry ₁ is excited when a power supply voltage is applied. The diode D ₃ connected in parallel to the relay coil Ry ₁
It is for absorbing back electromotive force of relay coil Ry ₁ . In addition, the series circuit of the relay coil Ry ₂ for timed contacts and the transistor Q ₁ is connected to the power supply circuit unit 1 side via the diode D ₁ ,
The power supply capacitor C ₂ for the relay coil Ry ₂ is connected in parallel to the series circuit. Also, the relay coil Ry ₂
A diode D ₂ for absorbing back electromotive force is connected in parallel with. A time constant circuit of a resistor R ₁ and a capacitor C ₁ is provided between the base of the transistor Q ₁ and the timer control circuit section 2. Further, a series circuit of a resistor R ₃ and a transistor Q ₂ is connected in parallel to a series circuit of a relay coil Ry ₂ and a transistor Q _1, and the collector of the transistor Q ₁ is connected to the base of the transistor Q ₂ via a resistor R _2. Connected to.

Here, the transistor Q ₁ is a relay coil for timed contacts Ry ₂
, And transistor Q ₂ is for energizing resistor R ₃ . The resistor R ₃ is a resistor for keeping the current consumption constant even when the relay coil Ry ₂ does not operate. Capacitor C ₁ ,
C ₂ is for compensation of momentary power failure, and is for holding current of relay coil Ry ₂ . The diode D ₁ is for preventing reverse discharge current.

This timer circuit operates as follows. When power is applied, the power supply circuit unit 1 applies power to the instantaneous contact relay coil Ry ₁ as an operating voltage and is excited at the same time as power is applied, and the instantaneous contact turns on. At the same time, the capacitor C ₂ is charged via the diode D ₁ . Further, an L level signal is output from the timer control circuit section 2 to turn off the transistor Q ₁ , and the relay coil for time delay contact Ry
₂ is not excited. Transistor Q ₁ is off, so transistor Q ₂ is on and the value of resistor R ₃
The same current as the excitation of Ry ₂ is applied. After the timer control circuit section 2 has timed out, an H level signal is output, turning on the transistor Q ₁ . By the transistor Q ₁ is turned on, thus energizing the relay coil Ry ₂ charges from the capacitor C ₂ is discharged through the relay coil Ry _2. Further, the timer control circuit section 2 is timed to excite the relay coil Ry _{2 and} open the normally closed time delay contact 5 shown in FIG. 4 to shut off the power supply to the timer T. Power is cut off, relay coil
No power is applied to Ry ₁ .

By the way, in a timer circuit having both an instantaneous contact that operates at the same time when a timer operating voltage is applied and a time-definite contact that operates after the time-delayed operation, the following conditions are required when the power is cut off.

Instantaneous power failure time <Instantaneous contact holding time <Definite time contact holding time <Timer reset time ... Here, the instantaneous power failure time is a time that does not affect the operation of the timer even if there is a momentary power failure. Say. This condition is for preventing a malfunction at the time of restoration in the self-holding / self-restoring circuit as shown in FIG. In FIG. 4, a normally open type instantaneous contact 4 and a normally closed type timed contact 5 are shown.
And a timer T are connected in series, and a push-type switch SW ₁ is connected in parallel to the instantaneous contact 4. In this circuit, the switch SW ₁ is pushed to drive the timer T, and the momentary contact 4 is turned on to perform self-holding. After the timed operation, the timed contact 5 is turned off to end the timed operation. In this circuit, the following conditions are required for self-holding.

ON time of switch SW ₁ > Operating time of instantaneous contact 4 ………
In addition, in the circuit shown in FIG.
The input time of SW ₁ should be as short as possible. Incidentally, it is generally considered that the input time of the switch SW ₁ is about 20 msec.

By the way, the constants of the circuit shown in FIG. 3 are determined as follows. That is, the compensation time for the instantaneous power failure of the timer,
The holding time of the instantaneous contact when the operating voltage is cut off depends on the power circuit section 1.
It is determined by the capacity of the smoothing capacitor of. For timing the instantaneous contact and time limiting contact indicated by the condition, at the time of the operation voltage blocking resistance so that the driving transistor to Q ₁ time limiting contact relay coil Ry ₂ is turned on longer than the retention time of the instantaneous contact point R ₁ And the time constant of the capacitor C ₁ is determined. Further, the capacity of the capacitor C ₂ is determined so that the holding current of the relay coil Ry ₂ can be reliably obtained during the time when the transistor Q ₁ determined above is turned on when the operating voltage is cut off. At this time, the diode D ₁ is provided to prevent the discharge current of the capacitor C _{2 from} flowing into the relay coil Ry ₁ .

[Problems to be solved by the device] However, in the conventional circuit shown in FIG. 3, if the constants are determined as described above in order to satisfy the conditions, the capacity of the capacitor C ₂ will inevitably increase, so that the power supply is applied. At some time, the charging current supplied to the capacitor C ₂ through the diode D ₁ becomes large, so that the time required for the instantaneous contact relay coil Ry ₁ to reach the operating voltage becomes long. Therefore, since the input time of the switch SW ₁ shown in the condition becomes long, the switch SW ₁ for self-holding in FIG.
The lower limit of the input time of is restricted considerably.

The present invention has been made in view of the above points, and provides a timer circuit intended to operate with a short switch input time while satisfying the conditions.

[Means for Solving the Problem] The present invention is one in which a parallel circuit of a resistor for limiting a charging current and a diode arranged in a forward direction in the discharging direction of the capacitor is inserted in a charging / discharging path of the capacitor.

[Operation] The charging current is limited by the resistor when the capacitor is charged, and is discharged through the diode when the capacitor is discharged.

Embodiment 1 Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First
As shown in the figure, a parallel circuit of a resistor R and a diode D is inserted and connected in the charging / discharging path of the capacitor C ₂ .
In this embodiment, the capacitor C ₂ is inserted on the positive electrode side, but it may be inserted on the negative electrode side. As a result, the charging current of the capacitor C ₂ when the power is turned on is limited by the resistor R, so that more current is supplied to the relay coil Ry ₁ . Therefore, even when the capacitance of the capacitor C ₂ is the same as that in the conventional case of FIG. 3, the time required for the relay coil Ry ₁ to reach the operating voltage is shorter than in the conventional case. When the power is cut off, the capacitor C ₂ supplies a current to the relay coil Ry ₂ through the diode D, so that the resistance R does not affect the relay coil Ry ₂ . Therefore, the constants determined in the conventional FIG. 3 can be used as they are for the capacitor C ₁ , the resistor R ₁ , and the capacitor C ₂ . Therefore, it becomes possible to cope with a shorter input time of the switch SW ₁ while satisfying the above conditions.

(Embodiment 2) FIG. 2 shows another embodiment, in which a resistor R ₃ and a relay coil Ry _{2 are used.}
A parallel circuit of a resistor R and a diode D is inserted between the lines connecting to and. In order to keep the current consumption constant even when the relay coil Ry ₂ does not operate, R + R ₃ = the value of R ₃ shown in FIG. ₃ (almost the same value as the coil resistance of the relay coil Ry ₂ ) Determine R ₃ and.

[Advantage of the Invention] As described above, the present invention has a parallel circuit of a resistor for limiting the charging current and a diode arranged in the forward direction of the capacitor in the charging / discharging path of the capacitor. When the capacitor is charged, the charging current is limited by the resistor, and when the capacitor's charge is discharged, it is discharged via the diode, so that the relay coil for the instantaneous contact operates even if the capacitor has the same capacity as the conventional case. The time to reach the voltage is shorter than before, and the operating time of the instantaneous contact can be shortened.When the power is cut off, the capacitor supplies current to the relay coil for the time-delayed contact through the diode, so the effect of the resistance is not affected. Therefore, for the time constant circuit and the capacitor, the constants conventionally determined can be used as they are, and therefore, while satisfying the above conditions, Even if the switch input time is shorter, a reliable operation can be obtained.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is a circuit diagram of another embodiment of the present invention, FIG. 3 is an overall circuit diagram of a conventional example, and FIG.
The figure is a circuit diagram of a main part of the above. 4 is a momentary contact, 5 is a timed contact, Ry ₁ is a relay coil for momentary contact, Ry ₂ is a relay coil for timed contact, SW ₁ is a switch, C ₂ is a capacitor, R is a resistor, D is a diode, D ₁ is a diode , Q ₁ is a transistor.

Claims (1)

[Scope of utility model registration request] 1. A timer for a timed operation by operating a switch, and a momentary contact which operates simultaneously with application of an operating voltage of the timer and self-holds, and a timer after the timed operation which is connected in series with the timer and the momentary contact. A relay circuit for a momentary contact that is excited at the same time as the application of an operating voltage and a relay for a time-definite contact that is excited after the timer has timed out. A coil, a capacitor that is charged through a diode for preventing backflow when an operating voltage is applied, and serves as a power source for the relay coil for time delay contact, and a switching that is driven by the time delay contact output to excite the relay coil for time delay contact by an ON operation. The ON state of the switching element is maintained for longer than the holding time of the instantaneous contact when the element and the operating voltage are cut off. Equipped with a time constant circuit that closes the momentary blackout time that does not affect the timer operation even if there is a momentary power failure, the holding time of the instantaneous contact, the holding time of the timed contact, and the reset time of the timer. In a timer circuit that is set so that momentary power failure time <holding time of momentary contact <holding time of timed contact <return time of timer, a charging current limiting resistor is connected to the charging / discharging path of the capacitor. , A timer circuit characterized by inserting a parallel circuit with a diode in the forward direction in the discharging direction of the capacitor.