JPH0719162B2 - Adjuster - Google Patents

Description

The present invention relates to an adjusting device that outputs a control signal for adjusting, for example, a furnace temperature or the like to a target value.

[Prior Art] For example, an adjusting device that adjusts a furnace temperature or the like to a target value feeds back measured data such as the furnace temperature to the adjusting device and compares the measured data with the target value in an internal arithmetic circuit to respond to the deviation. The control data is calculated to adjust the furnace to be controlled to the target temperature.

In recent years, such an adjusting device has been digitized to improve the calculation accuracy, and the measured data which is an analog input is once converted into a digital value, the control data is calculated with the digital value, and then the analog control is performed again. It is converted into a signal to control the controlled object.

[Problems to be Solved by the Invention] However, once the measured data that is an analog input is once converted into a digital value, the measured data that is input to the arithmetic circuit becomes discrete and the resolution becomes discontinuous. There is a problem that it becomes difficult to control the object finely, and particularly when the measurement data fluctuates significantly, it becomes more difficult to control the discontinuous portion finely.

Therefore, the present invention has been made in view of the above-mentioned problems, and by obtaining a deviation control signal for a deviation of 1 LSB or less when converting an analog input into a digital value, a control target is set to a target value. It is an object of the present invention to provide an adjusting device that can be controlled finely and can improve controllability.

[Means for Solving the Problems] In order to achieve the above object, the first invention of the present invention is
A controller for outputting a control signal for adjusting an analog input to a target value, the A / D conversion circuit converting the analog input into a digital value, and the digital value converted by the A / D conversion circuit. An arithmetic circuit for comparing the target value with a digital control value corresponding to the difference between the two values; a first D / A conversion circuit for converting the digital control value into an analog value to obtain a main control signal; A second D / A conversion circuit for converting the digital value converted by the A / D conversion circuit into an analog value, and a deviation between the analog value converted by the second D / A conversion circuit and the analog input And a deviation calculation circuit that calculates a deviation control signal for the deviation that is the output of the differential amplifier; a main control signal and the deviation control signal are added to obtain the control signal. And an adder circuit for outputting It is.

A second aspect of the present invention is an adjusting device that outputs a control signal for adjusting an analog input to a target value, which includes an A / D conversion circuit that converts the analog input into a digital value.
A first D / A conversion circuit for converting a digital value converted by the / D conversion circuit into an analog value, and a deviation between the analog value converted by the first D / A conversion circuit and the analog input is obtained. A differential amplifier for re-inputting the deviation into the A / D conversion circuit, and a digital value for the analog input output from the A / D conversion circuit and the deviation as the output of the differential amplifier. A digital deviation value and a digital input value are compared with the target value to calculate a digital control value corresponding to the difference between the two values and a deviation digital control value, and a digital control value output from the calculation circuit. Second to convert to analog value and use as main control signal
D / A conversion circuit, a third D / A conversion circuit for converting the deviation digital control value output from the arithmetic circuit into an analog value to obtain a deviation control signal, the main control signal and the deviation And an addition circuit for adding the minute control signal and outputting the control signal.

[Operation] In the first invention, the analog input is converted into a digital value by the A / D conversion circuit and input to the arithmetic circuit, compared with the target value, and the digital control value corresponding to the difference between the two values is calculated. . Then, the digital control value is converted into an analog value by the first D / A conversion circuit to obtain the main control signal. On the other hand, the digital value converted by the A / D conversion circuit is the second value.
Is converted to an analog value by the D / A conversion circuit of and the deviation between this analog value and the analog input is obtained by the differential amplifier,
A deviation of 1 LSB or less when converting the analog input to a digital value is obtained. Then, the deviation calculation circuit calculates an analog deviation control signal for the deviation output from the differential amplifier, and this is added to the main control signal by the adder circuit and output as a control signal. Therefore, it becomes possible to finely control the controlled object with respect to the target value.

In the second invention, after the analog input is converted into a digital value by the A / D conversion circuit, the digital value is converted into the first digital value.
Is converted to an analog value by the D / A conversion circuit of and the deviation between this analog value and the analog input is obtained by the differential amplifier,
A deviation amount of 1 LSB or less when the analog input is converted into a digital value is re-input to the A / D conversion circuit. Then, the digital value for the analog input and the digital deviation for the deviation that is the output of the differential amplifier are input to the arithmetic circuit as digital input values, which are compared with the target value to correspond to the difference between the two values. The digital control value and the deviation digital control value are calculated. The calculated digital control value is converted into an analog by the second D / A conversion circuit to be the main control signal, and the deviation digital control value is converted into analog by the third D / A conversion circuit to generate the deviation A control signal is added, and both signals are added by an adder circuit and output as a control signal. Therefore, the controlled object can be controlled more finely with respect to the target value.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the adjusting device according to the invention.

First, the configuration of the adjusting device will be described. In the figure, reference numeral 1 is an input terminal to which an analog input such as measurement data detected from a control target is fed back, and input terminal 1 is an A / D via an input amplifier 2. It is connected to the conversion circuit 3. Reference numeral 10 is an arithmetic circuit, and 20 is a first D / A conversion circuit. The output terminal of the first D / A conversion circuit 20 is connected to one input terminal of the adder circuit 4. Reference numeral 5 is a control signal output terminal.

On the other hand, the output line of the A / D conversion circuit 3 is branched, and the second D / A conversion circuit 21 is connected to the branched line. The output terminal of the second D / A conversion circuit 21 is connected to one input terminal of the differential amplifier 6, and the analog input is input to the other input terminal. Reference numeral 7 denotes a deviation calculation circuit, the output terminal of which is connected to the other input terminal of the addition circuit 4.

The adjusting device is configured as described above, and the input terminal 1
The analog input input from is amplified to a predetermined level by the input amplifier 2 and standardized, then converted into a digital value by the A / D conversion circuit 3 and input to the arithmetic circuit 10. In the arithmetic circuit 10, the input digital value is compared with the target value by PID control, the digital control value corresponding to the difference between the two values is calculated, and this digital control value is analogized in the first D / A conversion circuit 20. It is converted into a value and added to the adder circuit 4 as a main control signal.

On the other hand, the digital value converted by the A / D conversion circuit 3 is the second
Is converted to an analog value by the D / A conversion circuit 21 and the difference between the analog value and the analog input is obtained by the differential amplifier 6, and 1L when the analog input is converted to a digital value.
Deviation less than SB (minimum bit) is required. And
In the deviation calculation circuit 7, an analog deviation control signal for the deviation output from the differential amplifier 6 is calculated, and this is added to the main control signal in the addition circuit 4 to output the output terminal 5
Is output as a control signal. In this way, since the control signal also includes the deviation control signal, the control target is controlled with high precision and fineness with respect to the target value.

Next, FIG. 2 shows another embodiment of the adjusting device according to the present invention.

2 that are the same as or equivalent to those in the apparatus shown in FIG. 1 are designated by the same reference numerals.

In this embodiment, the input amplifier 2 is connected to one contact a of the multiplexer 8 and its common setting C is connected to the A / D conversion circuit 3. The first D / A conversion circuit 22 is connected to a branch line that branches the output line of the A / D conversion circuit 3. The output terminal of the differential amplifier 6 for obtaining the deviation between the analog value converted by the first D / A conversion circuit 22 and the analog input is connected to the other contact b of the multiplexer 8. In this way, by switching the contacts of the multiplexer 8, the deviation output from the differential amplifier 6 is re-input to the A / D conversion circuit 3.

Therefore, both the digital value of the analog input output from the A / D conversion circuit 3 and the digital deviation of the deviation output from the differential amplifier 6 are input to the arithmetic circuit 11. The arithmetic circuit 11 is also provided with a data hold function for temporarily holding the digital value and the like and a switching control function for switching the multiplexer 8 at a required timing. 23 is the second D / A conversion circuit, 24 is the third D / A conversion circuit, and both conversion circuits 23, 24
The output terminals of are connected to both input terminals of the adder circuit 4, respectively.

The adjusting device of this embodiment is configured as described above, and the multiplexer 8 is initially switched to one contact a side. Then, the analog input input from the input terminal 1 is amplified to a predetermined level by the input amplifier 2 and standardized, then converted into a digital value by the A / D conversion circuit 3, input to the arithmetic circuit 11 and held. ,Also,
At this timing, the multiplexer 8 is switched to the other contact b. On the other hand, the digital value converted by the A / D conversion circuit 3 is converted into an analog value by the first D / A conversion circuit 22, and the difference between the analog value and the analog input is obtained by the differential amplifier 6, The deviation of 1 LSB or less when converting the analog input to a digital value can be obtained. Then, this deviation is re-input to the A / D conversion circuit 3, and the arithmetic circuit 11 further adds the digital deviation corresponding to this deviation to the previously held digital value.

In this way, in the arithmetic circuit 11, by PID control, the sum of the digital value corresponding to the analog input and the digital deviation corresponding to the deviation or each different digital input value is compared with the target value, and both values are compared. A digital control value corresponding to the difference and a digital control value for the deviation are calculated. The calculated digital control value is converted into an analog by the second D / A conversion circuit 23 to be a main control signal, and the deviation digital control value is converted into an analog in the third D / A conversion circuit 24. The deviation component control signal is added, and both signals are added by the adder circuit 4 and output from the output terminal 5 as a control signal. Therefore, in this embodiment, a control signal closer to the target value can be obtained, and the control target can be controlled more finely with respect to the target value. The output from the arithmetic circuit 11 may be output by one high-precision D / A converter.

In both of the above-described embodiments, the analog input such as the measurement data input from the input terminal 1 effectively acts on both the one with a large level fluctuation and the one with a small level fluctuation, and finely controls the target value. I will get it.

[Effect of the Invention] As described above, according to the adjusting device of the first invention,
The difference of 1 LSB or less when converting the analog input to a digital value is found by the differential amplifier, and the analog deviation control signal for the deviation that is the output of the differential amplifier is calculated by the deviation calculation circuit and this is calculated. Since it is added to the main control signal, the control target can be finely controlled with respect to the target value with a relatively simple circuit configuration, and the controllability can be improved.

Further, according to the adjusting device of the second invention, the deviation amount of 1 LSB or less when converting the analog input into the digital value is obtained by the differential amplifier, and this is re-input to the A / D conversion circuit to be input to the arithmetic circuit. Inputs the digital value for the analog input and the digital deviation for the deviation that is the output of the differential amplifier as the digital input value, compares this with the target value, and outputs the digital control value corresponding to the difference between the two values. After calculating the deviation digital control value and converting each of these into an analog signal to form the main control signal and the deviation control signal, both signals are added to form the control signal, so that the control value is closer to the target value. A signal is obtained, the controlled object can be controlled more finely with respect to the target value, and the controllability can be further improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an adjusting device according to the present invention, and FIG. 2 is a block diagram showing another embodiment of the present invention. 1 ... Analog input terminal, 3 ... A / D conversion circuit, 4 ...
Adder circuit, 5 ... control signal output terminal, 6 ... differential amplifier,
7 ... Deviation arithmetic circuit, 10, 11 ... Arithmetic circuit, 20, 21, 22, 2
3, 24 ... D / A conversion circuit.

Claims (2)

[Claims] 1. An adjusting device for outputting a control signal for adjusting an analog input to a target value, comprising: an A / D conversion circuit for converting the analog input into a digital value; and a conversion by the A / D conversion circuit. An arithmetic circuit for comparing the digital value thus obtained with the target value to compute a digital control value corresponding to the difference between the two values, and a first D / C for converting the digital control value into an analog value to obtain a main control signal. An A conversion circuit, a second D / A conversion circuit for converting the digital value converted by the A / D conversion circuit into an analog value, and the analog value converted by the second D / A conversion circuit A differential amplifier that obtains a deviation from an analog input, a deviation calculation circuit that calculates a deviation control signal for the deviation that is the output of the differential amplifier, and the main control signal and the deviation control signal are added. And an adder circuit that outputs the control signal. An adjusting device characterized in that 2. An adjusting device for outputting a control signal for adjusting an analog input to a target value, the A / D converting circuit converting the analog input into a digital value, and the A / D converting circuit converting the analog input into a digital value. A first D / A conversion circuit for converting the converted digital value into an analog value, and a deviation between the analog value converted by the first D / A conversion circuit and the analog input is calculated, and the deviation is calculated as the A A differential amplifier for re-input to the / D conversion circuit, a digital value for the analog input output from the A / D conversion circuit, and a digital deviation amount for the deviation amount that is the output of the differential amplifier. An arithmetic circuit that compares the input value with the target value and calculates a digital control value and a deviation digital control value corresponding to the difference between the two values, and a digital control value output from the arithmetic circuit that is converted into an analog value. main A second D / A conversion circuit that uses a control signal; a third D / A conversion circuit that converts the deviation digital control value output from the arithmetic circuit into an analog value to generate a deviation control signal; An adjusting device comprising: a main control signal and an adder circuit for adding the deviation control signal and outputting the control signal.