JPH0477326B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a measurement power supply failure signal output circuit for a measuring instrument such as a data recording device that continuously records data on natural phenomena such as brightness and illuminance over a long period of time.

Conventional configuration and its problems In recent years, when designing tunnel lighting,
It has become necessary to continuously record outdoor luminance values and vertical illuminance values at tunnel entrances over a long period of time. A power failure compensation type data recording device is used as a device for recording such signals. This data recording apparatus requires unmanned operation, and therefore the operation status of the data recording apparatus is often monitored by remote monitoring control. Therefore, a data recording device is required to have a function of reliably informing the outside of the failure state of the device.

A conventional power failure output circuit for a measuring instrument such as a data recording device will be described below.

Fig. 4 shows the power supply unit and power failure output circuit of a conventional data recording device, where 1 is the measurement power supply unit, 2 is the power failure detection circuit, 3 is the failure signal output control circuit, and 4 is the failure output. It is a DC power supply for use.
The measurement power supply 1 further includes a measurement DC constant voltage power supply 1.
a, charging control circuit 1b, rechargeable battery 1
c, relay contact (A contact) 1d, reverse current blocking diode 1f, voltage converter 1e, power supply detection circuit 1g,
Consists of relay 1h. Power failure detection circuit 2
shows an example configured with a relay 2a. Further, the failure signal output control circuit 3 is an example composed of a relay 3a and relay contacts 3b and 3c.

The operation of the conventional power failure detection circuit configured as described above will be described below with reference to waveforms at various parts in FIG. Generally, DC power supplies used for measuring instruments etc. have a large capacity capacitor connected to the output stage to stabilize the output voltage.
It is designed to avoid sudden changes in load.
Therefore, when the input of the DC power source is turned on, this capacitor is charged, so the rise of the output voltage is delayed, and when it is turned off, the capacitor is discharged, so the output voltage is maintained for a while. In this way, an operation delay occurs in the output voltage with respect to the power input. Power input (typically commercial frequency
(AC100V is used) is applied in parallel to the measurement power supply section 1 and the fault output DC power supply 4. In the measurement power supply unit 1, the measurement DC constant voltage power supply 1a converts the voltage into a DC voltage _V1 necessary for the measurement operation of the data recording device. The output of the measurement DC constant voltage power supply 1a is 3
One is supplied to the charging control circuit 1b. The charging control circuit 1b includes a current limiting resistor _R1 ,
Consisting of a reverse current blocking diode _D1 , it controls the charging current to the battery 1c, and when the battery is operating, the charge on the battery is controlled by the DC constant voltage power supply 1 for measurement.
Prevent backflow to a. The second output of the measurement DC constant voltage power supply 1a is supplied to the voltage converter 1e, and is converted to a voltage level _V2 necessary for the measurement circuit system. Generally, the voltage V ₁ is set higher than the voltage V ₂ necessary for the measurement circuit to charge the battery 1c, and is converted to the voltage V ₂ by the voltage converter 1e. FIG. 4 shows an example in which a forward voltage drop of a rectifying diode _D2 is used as a voltage converter, but this is a general form. The output of the charging control circuit 1b is connected to the battery 1c through a relay contact (a contact of the relay 1h). Further, a backflow blocking diode 1f is connected between the output of the charging control circuit 1b and the output of the voltage converter 1e so that the charging control circuit 1b side serves as an anode. This backflow blocking diode 1f supplies charge from the battery 1c to the measurement circuit system when the battery is in operation, and separates the charging operation of the battery 1c and the power supply to the measurement circuit system during power input (AC100V) operation, and is used for measurement. A power supply path is secured from the DC constant voltage power supply 1a to the measurement circuit system through the voltage converter 1e. The voltage _V2 of the measurement circuit system is applied to the voltage detection circuit 1g, and when the voltage _V2 is higher than the voltage determined by the constant voltage diode _D3 , the transistor Q is turned on and the relay 1 is turned on.
h to close relay contact 1d. As a result, it is possible to charge the battery when there is power input, and it is possible to supply power from the battery when the battery is in operation. When the voltage V ₂ becomes lower than the voltage determined by the voltage regulator diode D ₃ , the base current of the transistor Q is limited by the resistor R ₂ , and as a result, the transistor Q is turned off, relay 1h is turned off, and relay contact 1d is opened. Disconnect battery 1c from the power circuit. In this way, the voltage detection circuit 1g operates to prevent over-discharge of the battery 1c and to prevent the supply voltage _V2 to the measurement circuit system from dropping too much.

Next, the third output of the measurement DC constant voltage power supply 1a is applied to the power supply failure detection circuit 2. FIG. 4 shows an example in which the power failure detection circuit 2 is constituted by a relay 2a that operates based on the voltage _V1 . When the power supply is turned on (see Fig. 5A), when the output of the measurement DC constant voltage power supply 1a, that is, the voltage drops, the relay 2a is turned on at voltage _V3 after time _t1 has elapsed. This is because the change in the output voltage of the measurement DC constant voltage power supply 1a is delayed as shown in waveform b in Figure 5, and the relay 2a
This is because the open circuit voltage _V4 is lower than the sensing voltage _V3 and operates with hysteresis. Similarly power input
When OFF (see Figure 5 A), after time _t2 , the voltage
Relay 2a turns OFF at _V4 . The operating state of the relay is shown in waveform C in Figure 5. Here, t ₁ and t ₂ are generally not equal in many cases due to the characteristics of the DC constant voltage power source for measurement and the characteristics of the relay.

On the other hand, the power input (AC 100V) is applied to the fault output DC power supply 4, causing a delay in the operation of the fault output DC power supply 4, as shown in FIG. 5D. The output (voltage V ₅ ) of the fault output DC power supply 4 is sent to the fault signal output control circuit 3 to drive the relay 3a. At this time, due to the operating characteristics of the relay 3a, the output of the relay 3a has a delay of _t3 when the power input is ON and _t4 when the power input is OFF, as shown in FIG. relay 3
A is connected to relay contact 3b (a contact), and relay 2a is connected to relay contact 3c (b contact). Furthermore, relay contacts 3b and 3c are connected in series and output a fault signal.

If the measurement DC constant voltage power source 1a fails and its output voltage _V1 becomes zero, the relay contact 3c is closed. At this time, if there is a power input, the relay contact 3b closes and outputs a failure signal. on the other hand,
When the power input turns OFF, relay contact 3b opens,
3c is closed and no fault signal is output. Further, during normal operation, relay contact 3b is closed and relay contact 3c is open, and similarly no failure signal is output. in this way,
Considering the state of the power input, a failure signal is output only when the DC constant voltage power supply for measurement has failed and there is a power input.

However, in the above configuration, if the load resistance of the measurement DC constant voltage power supply 1a is small and the load resistance of the failure output DC power supply 4 becomes large, and the output response becomes slower than that of the measurement DC constant voltage power supply 1a, With respect to the ON/OFF operation of the power supply input, the output change of the fault output DC power supply 4 is delayed with respect to the output change of the measurement DC constant voltage power supply 1a, so the delay time shown in Fig. 5 is t ₁ < t ₃ , t ₂ <t ₄ . As a result, a failure signal is output for a time (t ₄ −t ₂ ) when the power supply is turned off (waveform T shown in FIG. 4), causing false detection in remote monitoring control and the like. Furthermore, there is also a method of turning on/off the output end of the fault output DC power supply using the output of the measurement DC constant voltage power supply. in this way,
Similarly to the above, if the response of the fault output DC power supply is slower than that of the measurement DC constant voltage power supply,
An erroneous fault signal is output when the power input is interrupted.
In addition, there is a method of connecting the output of the DC power supply for fault output to the output of the DC constant voltage power supply for measurement via a rectifier, and reducing the output of the DC power supply for fault output when the output of the DC constant voltage power supply for measurement decreases. can also be considered. In this method, the output of the fault output DC power supply is forcibly reduced while the fault output DC power supply remains in operation, so there is a problem in that the load on the fault output DC power supply is heavy.

Purpose of the Invention The present invention solves the above-mentioned problems, and aims to provide a power supply failure signal output circuit that eliminates the load on the DC power supply for failure output and prevents instantaneous failure signal output when power input is interrupted. shall be.

Configuration of the Invention The present invention includes a power supply failure detection circuit that detects a failure of a DC constant voltage power supply for measurement connected to a power input;
A DC power supply for failure output connected to the power supply input, and a voltage reduction means connected in parallel to the DC power supply for failure output, which receives power input and rapidly reduces the output voltage of the DC power supply for failure output to zero only when the power supply input is cut off. and a failure signal output control circuit that outputs a failure signal from the output of the DC power supply for failure output and the output of the power supply failure detection circuit, and is connected in parallel to the DC power supply for failure output. This voltage reduction means prevents erroneous output of a failure signal when the power is turned off.

DESCRIPTION OF EMBODIMENTS FIG. 1 shows a configuration diagram of a power failure signal output circuit in an embodiment of the present invention. In FIG. 1, 1 is a measurement power supply unit, 2 is a power supply failure detection circuit, 4 is a failure output DC power supply whose output voltage response is slower than the measurement DC constant voltage power supply 1a in the measurement power supply unit 1, and 3 7 is a fault signal output control circuit, and 7 is a voltage reduction means. Here, the measurement power supply section 1, the power supply failure detection circuit 2, the fault output DC power supply 4, and the fault signal output control circuit 3 have the same configuration as in FIG. 4, and the details of the measurement power supply section 1 will be omitted.

FIG. 1 shows an embodiment of the voltage reduction means 7, which is connected in parallel to the fault output DC power supply 4 and includes a relay 7a which is operated by power input;
Load resistor R _L1 connected to the output of DC power supply 4 for failure output and relay contact 7b (b contact of relay 7a)
Consists of. Further, the load resistance R _L1 and the relay contact 7b are connected in series.

The operation of the power failure signal output circuit of this embodiment configured as described above will be explained with reference to the waveforms of each part in FIG. 2.

First, we will explain the operation when the power input goes from OFF to ON. When the power input is turned from OFF to ON as shown in Figure 2A, the output of the measurement DC constant voltage power supply 1a in the measurement power supply section 1 increases at a high speed as shown in Figure 2B, and the voltage V ₁ reach.
The output of the measurement DC constant voltage power supply 1a is sent to the power supply failure detection circuit 2. In the power failure detection circuit 2, the relay 2a operates when the input voltage reaches _V3 . This is because the open circuit voltage V ₄ of the relay 2a is lower than the impression voltage V ₃ . Therefore, relay 2a
Since the contact 3c is a B contact, it operates with a delay of _t1 from when the power is inputted, as shown in FIG. 2C. On the other hand, the power input to DC power supply 4 for failure output is ON.
At this time, the rising speed of the output voltage _V5 is slower than the rising speed of the output voltage _V1 of the measurement DC constant voltage power supply 1a.
Voltage reducing means 7 is connected in parallel to the fault output DC power supply 4.
is connected, but relay 7a operates at the same time as the power input is turned on, relay contact 7b (b contact of relay 7a) is opened, and load resistor R _L1 is disconnected from the fault output DC power supply output. That is, the voltage reduction means 7 does not operate when there is a power input, and only when there is no power input, the voltage reduction means 7 operates.
operates to lower the output of the fault output DC power supply, so the load resistor R _L1 consumes only the remaining charge of the fault output DC power supply, resulting in low power consumption. As a result, the fault output DC power supply output is directly applied to the fault signal output control circuit 3, resulting in a voltage waveform shown in FIG. 2D. The relay 3a in the fault signal output control circuit 3 is connected to the power input as shown in FIG.
It operates with a delay of _t3 from when it is ON. At this time, t ₃
>t ₁ holds true. Therefore, the failure signal output control circuit 3 does not output a failure signal when the power is turned on, as shown in FIG.

Next, the operation when the power supply is cut off will be explained. When the power supply input is cut off (when the power supply input is OFF), the output of the measurement DC constant voltage power supply 1a rapidly decreases as shown in FIG. 2B. The output of the measurement DC constant voltage power supply 1a is connected to a power supply failure detection circuit. The relay 2a in the power failure detection circuit 2 operates when the input voltage reaches V ₄ (relay open voltage), and as a result, the relay contact closes with a delay of t ₂ from when the power input is OFF, as shown in Figure 2 C. Close 3c (b contact). On the other hand, when the power input is turned off, the relay 7a in the voltage reducing means 7
is turned OFF, the b contact of relay contact 7b (relay 7a) is closed, and the load resistor R _L1 is connected to the output of the fault output DC power supply 4, rapidly reducing the output power of the fault output DC power supply 4. As a result, the value of the load resistor R _L1 is selected so that the voltage drop rate of the output of the fault output DC power supply 4 is faster than the voltage drop rate of the measurement DC constant voltage power supply. The output of the fault output DC power supply 4 is applied to the fault signal control circuit 3, and the relay 3a operates with a delay of _t4 from when the power input is turned off, as shown in FIG. As a result,
t ₂ >t ₄ , and after relay contact 3b (a contact) is opened, relay contact 3c (b contact) is shorted.
Therefore, as shown in FIG. 2, no failure signal is output even when the power supply is cut off.

Another embodiment of the voltage reducing means 7 is shown in FIG.
In FIG. 3, when the power is turned on, relay 7a immediately operates, relay contact 7c (a contact of relay 7a) closes, and the fault output DC power output is transmitted to relay 3a. Therefore, the increasing characteristic of the output voltage of the fault output DC power supply when the power is turned on is directly applied to the relay 3a. On the other hand, when the power input is interrupted, relay 7a immediately turns OFF, and relay contact 7
c is open and the fault output DC power output is relay 3.
separated from a. As a result, the input voltage of the relay 3a becomes approximately equal to the waveform shown in FIG.
As shown in FIG. 2, no failure signal is output even when the power supply is cut off.

As described above, according to this embodiment, the power input
By providing a voltage reduction means that quickly brings the output of the DC power supply for failure output to zero when OFF, it is possible to prevent erroneous output of a power failure signal when the power supply input is cut off.

In the above embodiment, the measurement DC constant voltage power supply output V ₁
is input to the power failure detection circuit, but if the voltage V ₂ of the measurement circuit system is input to the power failure detection circuit, output of a failure signal can be prevented during battery operation.

Effects of the Invention The power failure output circuit of the present invention includes a DC constant voltage power source for measurement connected to a power input, a power failure detection circuit connected to the DC constant voltage power source for measurement, and a failure output connected to the power input. a DC power supply for fault output and a voltage reduction means connected in parallel to the DC power supply for fault output, which receives a power input and rapidly reduces the output voltage of the DC power supply for fault output to zero only when the power input is cut off; By providing a fault signal output control circuit that outputs a fault signal from the output and the output of the power supply fault detection circuit, the load on the DC power supply for fault output is eliminated and erroneous fault signal output is prevented when the power input (AC100V) is cut off. The practical effects are great.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a power failure signal output circuit according to an embodiment of the present invention, FIG. 2 is a waveform of each part of FIG. 1, FIG. 3 is another embodiment of the voltage reduction means, and FIG. 4 is a conventional one. The configuration diagram of the power failure signal output circuit of
These are the waveforms of each part in the figure. DESCRIPTION OF SYMBOLS 1...Power supply unit for measurement, 2...Power failure detection circuit, 3...Failure signal output control circuit, 4...DC power supply for failure output, 7...Voltage reduction means, 1a...DC constant voltage power supply for measurement , 1c...battery, 1h,
2a, 3a, 7a...Relay.

Claims (1)

[Claims] 1. A DC constant voltage power supply for measurement that receives power input and converts it into a DC voltage necessary for the measurement circuit, and a power supply failure detection circuit that detects a failure of the DC constant voltage power supply for measurement.
A fault output DC power supply connected to the power input and having an output response slower than the output response of the measurement DC constant voltage power supply, and a fault output DC power supply that receives power input and is connected in parallel to the fault output DC power supply and outputs a fault when the power input is interrupted. A voltage lowering means that immediately brings the output voltage of the DC power supply for measurement to zero, a circuit that performs a closing operation using the output of the DC power supply for fault output, and an output of the power supply failure detection circuit to detect whether the DC constant voltage power supply for measurement is normal or not. 1. A power supply failure signal output circuit for a measuring instrument, comprising: a failure signal output control circuit that connects in series a circuit that operates when open, and outputs a failure signal of the measurement DC constant voltage power supply.