JPH0361207B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a standard voltage and current generator used as a simulated signal power source for calibration, maintenance, and experimental research of measuring instruments.

The following three methods are known for displaying errors in measuring instruments.

(1) % of FS This specifies the error value with respect to the maximum scale value. In this case, the error value remains constant even if the input under measurement becomes small. This method is especially used for analog instruments, for example 1.5
It is used by names such as grade, 0.5 grade, etc.

(2) % of reading The error value for the indicated value is specified, and the error rate is the same regardless of the input value to be measured. Used in high-end digital display equipment.

(3) % of erading±% of FS This is the above
Display the error using a combination of (1) and (2). In this method, the error value defined by % of FS is often small and is generally used for digital displays. For reference, if the indicated value is A, the maximum scale value is B, and the error rate is C%, then in (1) the error value will be ±(A+B・C/100), and in (2) the error value will be ±(A・The error value is C/100). Also, (3)
C% of reading±C′% of FS, ±
(C・A/100)±(B・C′/100).

Conventionally, the generator side generates an output that makes the indicated value of the measuring device under test an ideal value, and this generated output value is applied to each error value calculation formula.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a generator having a deviation value setting function that can set a deviation value with respect to an instruction value and a deviation value with respect to a maximum value, either individually or simultaneously.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the accompanying drawings.

FIG. 1 schematically shows the operating panel of this standard voltage and current generator. That is, in the figure, 1 is an output setting value display section, 2 is a deviation value display section, 3a and 3b are deviation value setting knobs, 4 is a deviation mode switching knob, and 5a and 5b are related to the deviation mode switching knob 4. The mode indicator lamp flashes
6 is a deviation value polarity changeover switch, and 7 is an output division operation section. In this case, the output setting value display section 1 shows
For example, four display windows are provided corresponding to each digit, and arbitrary numerical values can be set in each of the display windows by operating a dial (not shown). In addition, the deviation mode switching knob 4 has four switching contacts from "0" to "". At the "0" position, the deviation value setting is canceled, at the "" position, the deviation method for the indicated value is used, and at the "" position, the maximum A deviation method for the value and a simultaneous deviation method for the indicated value and maximum value are set at the "" position, respectively. On the other hand, the output division operation section 7 includes a rotary knob 7a for setting the denominator A, and a push button 7b for selecting the numerator B.
Thus, an arbitrary divided output of set output x B/A can be obtained. In the illustrated example, if denominator A is set to "6" by operating rotary knob 7a, numerator B is selected by push button 7b, and 0, 1/6, 2/3, 3/ 6,4/
6, 5/6 division can be done arbitrarily.

FIG. 2 specifically illustrates the internal circuitry of this generator. In the same figure, 10 is the reference voltage
This is a reference voltage generation section that generates Vs, and this reference voltage generation section 10 includes an attenuator 11 and a first adder 1.
2 are connected in parallel. The attenuator 11 is
Fixed resistor _R1 and the deviation value setting knob 3a mentioned above,
3b, and _an operational amplifier 13 connected in parallel between _{the variable resistors VR 1 and} VR ₂ .
This attenuator 11 outputs a voltage −V〓 determined by (VR ₁ +VR ₂ )·Vs/R ₁ . This output voltage is applied to each terminal 6 of the deviation value polarity switch 6 described above.
In this case, a voltage of -V is directly applied to one terminal 6a, while a voltage of +V is applied to the other terminal 6b via the first inverting circuit 14. A voltage is applied.
Selected by this deviation value polarity switch 6 -
The voltage V is supplied to a first adder 12 and a second adder 17, which will be described later, via a first switch 15 and a second switch 16, which are controlled by the deviation mode switching knob 4. . That is,
The first switch 15 is the deviation mode switching knob 4.
The second switch 16 is connected to the output side of an OR gate 18 whose input terminals are the contacts "" and "", and the second switch 16 is connected to the output side of an OR gate 19 whose input terminals are the contacts "" and "". . Therefore, when the deviation mode switching knob 4 is set to the contact "", the first switch 15 is on and the second switch 16 is off; when the contact is set to "", the first switch 15 is turned off and the second switch 16 is turned on. The first adder 12 includes a well-known operational amplifier circuit 20, the output side of which is connected to a voltage divider 21 controlled by the output divider operating section 7 described above. This voltage divider 21
is made up of, for example, a slide resistor, and the divided voltage is supplied via a buffer circuit 22 and a second inversion circuit 23 to an input terminal of an operational amplifier circuit 24 constituting the second adder 17. The input terminal of the operational amplifier circuit 24 is connected to the deviation value polarity changeover switch 6 via the second switch 16 described above. The output side of this second adder 17 is the output terminal 25 of this generator.
It is becoming. In addition, reference numeral 26 is a reference voltage
Output voltage of attenuator 11 (deviation voltage) with respect to Vs
This is a display device that includes a digital voltmeter that allows you to directly read the percentage from the voltage ratio of V〓.

Next, this invention will be explained. First, when the deviation mode switching knob 4 is set to contact ``'', the first
When the switch 15 is turned on, the display lamp 5b that displays the deviation value (% of reding) with respect to the indicated value lights up, and the deviation method with respect to the indicated value is activated. That is, as mentioned above, a deviation voltage of -V determined by (VR <sub>1</sub> +VR <sub>2</sub> )·Vs/R <sub>1</sub> of the attenuator 11 is applied to one terminal 6a of the deviation value polarity switch 6, and Since a deviation voltage of +V〓 is applied to the other terminal 6b via the inverting circuit 14, by selectively switching the respective contacts 6a and 6b, the deviation voltage of −V〓 or +V〓 can be changed to the second terminal 6b. 1 adder 12. Therefore, the output terminal 25 connected to the output side of the first adder 12 receives V <sub>1</sub> =B/A due to the division ratio B/A set by the output division operation section 7.
An output voltage of (Vs±V〓) will appear.
On the other hand, when the deviation mode switching knob 4 is switched to the contact ``'', the second switch 16 is turned on and the deviation value (% of
The display lamp 5a indicating FS) lights up, and the system is switched to the deviation method from the maximum value. According to this, the reference voltage Vs is divided in the voltage divider 21 by the division ratio B/A set by the output division operation section 7 described above, resulting in B/A·Vs. This divided voltage B/A·Vs is input to the second adder 17 via the buffer circuit 22 and the second inversion circuit 23, and in this adder 17, the deviation value polarity changeover switch 6 switches the second switch 16 to the second adder 17. It is added to the deviation voltage -V〓 or +V〓 supplied via. Therefore, from the output terminal 25, V ₂ =
A voltage of B/A・Vs±V is output. moreover,
When the deviation mode switching knob 4 is switched to the contact ``'', the first and second switches 15, 1 are turned on by the open signal supplied via the OR gates 18, 19.
6 are both turned on, and each indicator lamp 5
a and 5b are also lit, and a simultaneous deviation method for the indicated value and the maximum value is performed. That is, according to this,
As mentioned above, from the first adder 12, V ₁ =Vs±
A voltage V 〓 is output, and this voltage V ₁ is divided into a predetermined value B/A by a divider 21 and then passed through a buffer circuit 22 and a second inverting circuit 23 as described above. It is input to the adder 17 of No. 2.
Then, in this adder 17, it is added to the deviation voltage -V〓 or +V〓 supplied from the deviation value polarity changeover switch 6 via the second switch 16,
Therefore, from the output terminal 25, V ₃ =B/A×
A voltage of (Vs±V〓)±V〓, that is, a voltage including a deviation value from both the indicated value and the maximum value, is output. In addition, in this example, % of
In the case of reading±% of FS, the error rate for the indicated value and the error rate for the FS value are the same, but one more attenuator 11 is added, and the switch 15,
16 to each attenuator 11, the above error rate can be changed arbitrarily.

Here, with reference to FIG. 3, an example of a case where a measuring instrument is actually inspected or calibrated using this standard voltage/current generator will be explained. In the same figure,
Let A be this standard voltage and current generator, and B be a measuring instrument to be inspected or calibrated. For example, if the full scale voltage of the measuring instrument B is 100V, the value on the output setting display section of the generator A is set to 100.00, and a reference voltage Vs of 100V is applied to the measuring instrument B. Then, operate the deviation value setting knobs 3a and 3b (see Figure 1) to change the deviation voltage V〓, and set the reference voltage and the deviation voltage (Vs± Read V〓) and check if the error is within the tolerance. At that time, according to this generator A,
By simply selecting the mode position """""" with the deviation mode switching knob 4 shown in Fig. 1, you can select the deviation method for the indicated value, the deviation method for the maximum value, and the indicated value. and the simultaneous deviation method for the maximum value can be set very easily.

Also, a rotary knob 7a and a push button 7b (see Figure 1)
By setting the output voltage division value by
For example, the output voltage can be stepped up or down in 20V increments, and the error rate relative to the indicated value at each step can also be checked.

As is clear from the above description of the embodiments, according to the present invention, by operating the deviation mode switching knob, the deviation methods for the indicated value and the maximum value can be easily set individually or simultaneously. Further, the range of the upper and lower limits of the deviation, the deviation value, and each deviation method can be easily and easily confirmed on the operation panel. Note that an output terminal other than the above-mentioned output terminal 25 may be provided on the output side of the first adder 12, and the deviation value with respect to the instruction value may be output from that output terminal.

[Brief explanation of drawings]

Fig. 1 is a diagram schematically showing the operation panel of a generator according to the present invention, Fig. 2 is a circuit diagram of this generator, and Fig. 3 is a schematic diagram for explaining the usage state of this generator. . In the figure, 1 is the output setting display section, 2 is the deviation value display section, 3a and 3b are the deviation value setting knobs, 4 is the deviation mode switching knob, 5a and 5b are the mode display lamps, 6 is the deviation value polarity switching switch, 7 is an output dividing section, 10 is a reference voltage generating section, 11 is an attenuator, 1
2 and 17 are adders, 14 and 23 are inversion circuits, 1
5 and 16 are switches, 21 is a divider, and 25 is an output terminal.

Claims (1)

[Claims] 1 a reference voltage generation section, attenuation means for attenuating the reference voltage of the reference voltage generation section to obtain a predetermined deviation voltage, polarity switching means including an inverting circuit for inverting the polarity of the deviation voltage, and the reference voltage a first voltage that adds the deviation voltage supplied from the polarity switching means;
an adding means, a voltage dividing means for dividing the output voltage from the first adding means into a predetermined value, and a second adding means for adding the divided voltage from the voltage dividing means and the deviation voltage from the polarity switching means. a first switch means and a second switch means respectively connected between the polarity switching means and the first and second addition means; A standard voltage and current generator comprising: a deviation mode switching control means for alternately or simultaneously controlling conduction with a second switch means.