JP2684917B2 - Recorder circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recorder circuit which records and measures a normal range of a voltage to be measured and a minute fluctuation portion.

[0002]

2. Description of the Related Art Conventionally, this type of recorder circuit has a structure as shown in FIG. That is, in FIG. 2, 20 denotes an input terminal of the measured voltages V _1, the normal range is applied to the input terminal 20 and 20 to be measured voltages V ₁ is measured by the recorder 21. 22 is a differential amplifier circuit for amplifying a minute variation of the measured voltages V _1, slight variation of the measured voltages V ₁ is amplified by the differential amplifier circuit 22 is measured by the recorder 23 .

[0003]

Since the conventional recorder circuit described above must be equipped with two recorders, the recorder 21 for measuring the normal range and the recorder 23 for measuring the minute variation, There are drawbacks that the recorder circuit becomes large and the manufacturing cost becomes high. Further, when the ratio of the minute fluctuation amount of the measured voltage V _{1 to} the maximum range is small, the purpose of the recorder 21 for the normal range measurement cannot be obtained, which is uneconomical.

The present invention has been made to solve the above-mentioned problems, and enables one recorder to measure the normal range and minute fluctuations of the voltage to be measured, thereby reducing the size and cost of the product. It is an object of the present invention to provide a recorder circuit which aims at

[0005]

In order to achieve the above object, the present invention is capable of recording and measuring an input voltage, and a common-mode amplifier circuit capable of amplifying and outputting a minute variation of a measured voltage. One recorder and a selector switch that can be selectively switched so that the measured voltage is directly used as the input voltage of the recorder or the output voltage of the in-phase amplifier circuit is used as the input voltage of the recorder. It is configured to have.

[0006]

According to the recorder circuit having the above construction, when the changeover switch is operated to directly set the measured voltage to the input voltage of the recorder, the normal range of the measured voltage is recorded and measured in the recorder. If the changeover switch is switched so that the output voltage of the common-mode amplifier circuit becomes the input voltage of the recorder, the expanded range corresponding to the minute fluctuation of the measured voltage is recorded and measured by the recorder.

[0007]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a recorder circuit of this embodiment.
In the figure, 1 is a non-inverting input terminal, 2 is an inverting input terminal,
3 is a changeover switch, 4 is a recorder, and 10 is an in-phase amplifier circuit. The non-inverting input terminal 1 is directly connected to the recorder 4 via the direct paths 5, 6 and 8 by the switching operation of the changeover switch 3, and the inverting input terminal 2 is directly connected to the recorder 4. Has been done. As a result, the measured voltage V ₁ applied to the input terminals 1 and 2 can be input to the recorder 4. The input voltage of the recorder 21 at full scale is 1/3, and 0 ≦ V ₁ ≦ V ₃ is set.

[0008] phase amplifier circuit 10 is for amplifying a minute variation [Delta] V ₁ of the measured voltages V _1, is formed by the error amplifier 11 and resistors 12, 13 of the resistance values R _1, R ₂ . Specifically, the non-inverting input terminal 1 is the error amplifier 1
1 is connected to the positive side and the inverting input terminal 2 is the reference battery 1
It is connected to the minus side via 4 and the resistor 12.
Further, the output side of the resistor 12 is connected to the output side of the error amplifier 11 via the resistor 13, and the output terminal 7 of the error amplifier 11 is connected to the recorder 4 via the changeover switch 3.

[0009] The reference cell 14 has a reference voltage E to set the output V ₀ which phase amplifier circuit 10 described above, the reference voltage E, the following equation (V _3/2) -E = _{(R 1 + R 2) /} R 1 · output V ₀ which phase amplifier circuit 10 when the measured voltage V ₁ is applied based on the (V ₁ -E) is selected to be V _3/2 There is. Therefore, the recorder 4 at this time indicates the position of 1/2 of the full scale, and this position is regarded as the virtual zero point,
The minute variation ΔV ₁ from this position is amplified by the in-phase amplifier circuit 10.

Next, the operation of this embodiment will be described.
When measuring the normal range of the measured voltage V ₁ applied to the input terminals 1 and 2, the changeover switch 3 is operated to
The terminals 6 and 8 are connected. As a result, the in-phase amplifier circuit 10 and the recorder 4 are electrically disconnected, and the input terminals 1 and 2 are directly connected to the recorder 4, so that the measured voltage V ₁ is directly input to the recorder 4. The recording is measured by the recorder 4.

[0011] On the other hand, very small variation ΔV ₁ of the measured voltage V ₁
When measuring, the changeover switch 3 is changed over to connect the terminal 7 and the terminal 8. As a result, the direct paths 5, 6 and 8 between the non-inverting input terminal 1 and the recorder 4 are cut off, and the in-phase amplifier circuit 10 and the recorder 4 are connected, so that the measurement target applied to the input terminals 1 and 2 is measured. slight variation ΔV ₁ of the voltage V ₁
Is amplified by the in-phase amplifier circuit 10 and recorded and measured by the recorder 4. If the reference battery E of the reference battery 14 is made variable, the range of the non-measurement voltage V ₁ may be widened,
It can be narrowed.

[0012]

As described above, according to the present invention, it is possible to easily measure the normal range of the voltage to be measured and the expanded range for minute fluctuations by using one recorder, so that the recorder circuit can be downsized. There is an excellent effect that the cost can be reduced and the product cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram showing a recorder circuit according to an embodiment of the present invention.

FIG. 2 is a circuit configuration diagram showing a conventional recorder circuit.

[Explanation of symbols]

 1 ... Inverted input terminal 2 ... Inverted input terminal 3 ... Changeover switch 4 ... Recorder 10 ... In-phase amplifier circuit 11 ... Error amplifier 12, 13 ... Resistor 14 ... Reference battery

Claims (1)

(57) [Claims] 1. A common-mode amplifier circuit capable of amplifying and outputting a minute fluctuation amount of a measured voltage, one recorder capable of recording and measuring an input voltage, and directly recording the measured voltage. And a selector switch capable of selectively switching the input voltage of the meter or the output voltage of the in-phase amplifier circuit to the input voltage of the recorder.