JPH02244202A - Control device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an adjustment device that outputs a control signal for adjusting, for example, a furnace temperature to a target value. It is something.

[Prior Art] For example, a control device that adjusts the furnace temperature, etc. to a target value feeds back measurement data such as the furnace temperature to the control device, compares it with the target value in its internal calculation circuit, and adjusts the deviation. The temperature of the furnace or the like to be controlled is adjusted to the target temperature by calculating the control data obtained.

In recent years, such control devices have been increasingly digitized to improve calculation accuracy, and the measurement data that is analog input is first converted to digital values, the control data is calculated using the digital values, and then this is used again for analog control. The control target is controlled by converting it into a signal.

[Problems to be Solved by the Invention] However, once analog input measurement data is converted into digital values, the measurement data input to the arithmetic circuit becomes discrete and the resolution becomes discontinuous. There is a problem in that it becomes difficult to precisely control the object to be controlled, and particularly when the measurement data fluctuates rapidly, it becomes even more difficult to precisely control discontinuous portions.

Therefore, the present invention has been made in view of the above-mentioned problems, and by determining a deviation control signal for a deviation below ILsB when converting an analog input into a digital value, the controlled object can be adjusted to a target value. It is an object of the present invention to provide an adjustment device that can finely control and improve controllability.

[Means to solve the problem]

In order to achieve the above object, the first invention of the present invention is as follows:
An adjustment device that outputs a control signal for adjusting an analog input to a target value, comprising an A/D conversion circuit that converts the analog input into a digital value, and a digital value converted by the A/D conversion circuit. an arithmetic circuit that compares it with the target value and calculates a digital control value corresponding to the difference between the two values;
a first D/A conversion circuit that converts the digital control value into an analog value as a main control signal; and a second D/A conversion circuit that converts the digital value converted by the A/D conversion circuit into an analog value.
a D/A conversion circuit, a differential amplifier that calculates a deviation between the analog value converted by the second D/A conversion circuit and the analog input, and a deviation that calculates a deviation control signal corresponding to the deviation. The present invention is characterized in that it includes an arithmetic circuit and an addition circuit that adds the main control signal and the deviation control signal and outputs the control signal.

Further, a second invention is an adjustment device that outputs a control signal for adjusting an analog input to a target value, comprising an A/D conversion circuit that converts the analog input into a digital value;
a first D/A conversion circuit that converts a digital value converted by the A/D conversion circuit into an analog value; and a first D/A conversion circuit;
a differential amplifier that calculates a deviation between the analog value converted by the conversion circuit and the analog input and re-inputs the deviation to the A/D conversion circuit; an arithmetic circuit that compares a corresponding digital value and a digital deviation corresponding to the deviation with the first target value and calculates a digital control value and a deviation digital control value corresponding to the difference between the two values; and the arithmetic circuit. a second D/A conversion circuit that converts the digital control value outputted from the arithmetic circuit into an analog value and uses it as a main control signal; The present invention is characterized in that it includes a third D/A conversion circuit that generates a control signal, and an addition circuit that adds the main control signal and the deviation control signal and outputs the control signal.

[Function] In the first invention, an analog input is converted into a digital value by an A/D conversion circuit, inputted to a calculation circuit, and compared with a target value to calculate a digital control value corresponding to the difference between the two values. Ru. This digital control value is then converted into an analog value by a first D/A conversion circuit to obtain a main control signal. On the other hand, the digital value converted by the A/D conversion circuit is converted into an analog value by the second D/A conversion circuit, and the deviation between this analog value and the analog input is determined by the differential amplifier. A deviation less than ILsB can be obtained when converting an input into a digital value. Then, a deviation calculation circuit calculates a deviation control signal corresponding to this deviation, which is added to the main control signal in an addition circuit and output as a control signal. Therefore, it becomes possible to control the controlled object narrowly with respect to the target value.

Further, in the second invention, after the analog input is converted into a digital value by the A/D conversion circuit, this digital value is converted into an analog value by the first D/A conversion circuit, and the differential lamp converts the analog input into a digital value. The deviation between the value and the analog input is determined and the l used when converting the analog input into a digital value.
The deviation less than or equal to the LSB is re-inputted to the A/D conversion circuit.

Then, the digital input value of the digital value corresponding to the analog input and the digital deviation corresponding to the deviation is inputted to the arithmetic circuit, and this is compared with the target value and the digital control value and deviation corresponding to the difference between the two values are input. A minute digital control value is calculated.

This calculated digital control value is converted into an analog signal by a second D/A conversion circuit and used as a main control signal, and the deviation digital control value is converted into an analog signal by a third D/A conversion circuit and converted into a deviation signal. Both signals are added by an adder circuit and output as a control signal. Therefore, it becomes possible to control the controlled object even more precisely with respect to the target value.

【Example] An embodiment of the present invention will be described below based on the drawings.

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

First, to explain the configuration of the adjustment device, in the figure, l is an input terminal to which analog input such as measurement data detected from the controlled object is fed back, and input terminal l is connected to the A/D converter via input amplifier 2. It is connected to the conversion circuit 3. 1
0 is an arithmetic circuit.

20 is a first D/A conversion circuit, and the output terminal of the first D/A conversion circuit 20 is connected to one input terminal of the addition circuit 4. 5 is an output terminal for control signals.

On the other hand, the output line of the A/D conversion circuit 3 is branched, and a second D/A conversion circuit 21 is connected to the branch line.

The output terminal of the second D/A conversion circuit 21 is connected to one input terminal of the differential amplifier 6, and an analog input is manually input to the other input terminal. 7
is a deviation calculation circuit whose output terminal is connected to the other input terminal of the adder circuit 4.

The adjustment device is configured as described above and has an input terminal l.
The manually input analog input is amplified to a predetermined level and standardized by the input amplifier 2, and then sent to the A/D conversion circuit 3.
It is converted into a digital value and input to the arithmetic circuit IO. In the arithmetic circuit lO, the input digital value is compared with the target value by PID control, and a gain control gl value corresponding to the difference between the two values is calculated, and this digital control value is converted into the first D/A conversion circuit 20 It is converted into an analog value and applied 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 converted into an analog value by the second D/A conversion circuit 21, and the difference between this analog value and the analog input is obtained by the differential amplifier 6. The deviation below the ILSB (least bit) when converting the analog human power into a digital value is determined.

The deviation calculation circuit 7 calculates a deviation control signal corresponding to this deviation, which is added to the main control signal by the addition circuit 4 and outputted from the output terminal 5 as a control I signal. In this way, since the control signal also includes the deviation control signal, the controlled object is precisely controlled with respect to the target value.

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

In FIG. 2, the same or equivalent components as those 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. and.

A first line is connected to a branch line branching off from the output line of the A/D conversion circuit 3.
A D/A conversion circuit 22 is connected thereto.

Further, the output terminal of the differential amplifier 6 for determining 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 point 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-inputted into the A/D conversion circuit 3.

Therefore, both the digital value corresponding to the analog input output from the A/D conversion circuit 3 and the digital deviation corresponding to the deviation are input to the arithmetic circuit 11. , a data hold function for temporarily holding this digital value, etc., 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
The output terminals of the one-car conversion circuits 23 and 24, which are D/A conversion circuits, are connected to the input terminals of the adder circuit 4, respectively.

The adjusting device of this embodiment is constructed as described above, and the multiplexer 8 is initially switched to one contact n side. The analog input input to the input terminal 1 is amplified to a predetermined level and standardized by the input amplifier 2, converted to a digital value by the A/D conversion circuit 3, and input to the arithmetic circuit 1O to be held. Also, at this timing, the multiplexer 8 is switched to the other contact point. 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 this analog value and the analog input is obtained by the differential amplifier 6 and the corresponding The deviation below the ILSB when converting an analog input into a digital value is calculated. Then, this deviation is inputted again to the A/D conversion circuit 3, and the arithmetic circuit l! to the previously held digital value.

A digital deviation corresponding to this deviation is further added.

In this way, in the arithmetic circuit 11, the sum of the digital value corresponding to the analog input and the digital deviation corresponding to the deviation or each separate digital input value is compared with the target value by PID control, and the sum of the digital value corresponding to the analog input and the digital deviation corresponding to the deviation is compared with the target value. A digital control value corresponding to the difference and a deviation digital control ta value are calculated. This calculated digital control value is converted to analog in the second D/A conversion circuit 23 and used as the main control signal, and the deviation digital control value is converted to analog in the third D/A conversion circuit 24. A deviation control signal is obtained, and these two signals are added by an adder circuit 4 and outputted from an output terminal 5 as a control signal. Therefore, in this embodiment, a control signal close to the - layer target value is obtained, and it becomes possible to control the controlled object with even higher precision with respect to the target value. It is also possible to output the data using two high-precision D/A converters.

In addition, in both of the above-mentioned embodiments, the analog input such as measurement data manually inputted from the input terminal 1 works effectively on both those with large level fluctuations and those with small level fluctuations, and finely adjusts the target value. It is something that can be controlled.

[Effect of the invention J As explained above, according to the adjustment device of the first invention,
LSB when converting analog input to digital value
The following deviations are obtained using a differential amplifier, the deviation control signal corresponding to this deviation is calculated by Fi4 using a deviation calculation circuit, and this is added to the main control signal. This allows for a relatively simple circuit configuration. This has the effect that the controlled object can be controlled finely with respect to the target value, and controllability can be improved.

Further, according to the adjustment device of the second invention, the deviation below ILsB when converting an analog input into a digital value is determined by the differential amplifier, and this is re-inputted to the A/D conversion circuit, and then inputted to the arithmetic circuit. Input the digital input value of the digital value corresponding to the analog input and the digital deviation corresponding to the deviation, and check this! The digital control m value and the deviation digital control value corresponding to the difference between the two values are calculated by comparing with the 4 values, and after converting these into analog separately to make the main control signal and the deviation control signal, both signals are Since the control signal is obtained by adding the values of effective.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the adjusting device according to the invention, and FIG. 2 is a block diagram showing another embodiment of the invention. l... - Input terminal for analog input, 3... A/D conversion circuit, 4... Addition circuit, 5... Output terminal for control signal, 6... Differential amplifier, 7... Deviation Arithmetic circuit, 101
Eye... Arithmetic circuit, 20.21.22.23.24...
・D/A conversion circuit.

Claims (2)

[Claims] (1) An adjustment device that outputs a control signal for adjusting an analog input to a target value, comprising an A/D conversion circuit that converts the analog input into a digital value, and a control signal that is converted by the A/D conversion circuit. an arithmetic circuit that compares a digital value with the target value and calculates a digital control value corresponding to the difference between the two values; and a first D/A conversion that converts the digital control value into an analog value and uses it as a main control signal. a second D/A conversion circuit that converts a digital value converted by the A/D conversion circuit into an analog value, an analog value converted by the second D/A conversion circuit, and the analog input; a differential amplifier that calculates the deviation from the deviation, a deviation calculation circuit that calculates a deviation control signal corresponding to the deviation, and an addition circuit that adds the main control signal and the deviation control signal and outputs the control signal. An adjusting device comprising: (2) An adjustment device that outputs a control signal for adjusting an analog input to a target value, comprising an A/D conversion circuit that converts the analog input into a digital value, and an A/D conversion circuit that converts the analog input into a digital value. a first D/A conversion circuit that converts a digital value into an analog value;
a differential amplifier that calculates a deviation between the analog value converted by the D/A conversion circuit and the analog input and re-inputs the deviation to the A/D conversion circuit; A digital value corresponding to the analog input and a digital deviation corresponding to the deviation are compared with the target value, and a digital control value and a deviation digital control value corresponding to the difference between the two values are calculated. an arithmetic circuit; and a second D/D converter that converts the digital control value output from the arithmetic circuit into an analog value and uses it as a main control signal.
an A conversion circuit, a third D/A conversion circuit that converts the deviation digital control value output from the arithmetic circuit into an analog value as a deviation control signal, and the main control signal and the deviation control signal. and an adder circuit that adds the signals and outputs the control signal.