JPH0778007A - Analog signal processor for programmable controller - Google Patents

Abstract

PURPOSE:To prevent the time delay from the input to the output of an analog quantity from increasing by converting the signal from a controlled system from analog to digital, performing arithmetic operation by a method that the programmable controller indicates, and generating an analog output. CONSTITUTION:The sequence process part 11 of a CPU unit 10 mounted on a programmable controller(PC) main body executes a sequence program stored in a sequence program memory 12. An analog signal processor for PC, e.g. an analog input/output unit 14, on the other hand, is provided to the PC main body detachably and the process part 15 of this analog input/output unit 14 administers the whole operation of the analog input/output unit 14. Then the conversion output of an A/D conversion part 17 which converts the analog input signal inputted from the controlled system 1b into a digital signal is operated according to an indication from the PC main body and the analog output based upon the arithmetic result is outputted by a D/A conversion part 19 and an analog output part 1a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an analog signal processing device for a programmable controller which is mounted on a programmable controller body and controls an analog voltage or an analog current.

[0002]

2. Description of the Related Art A conventional technique will be described. FIG.
FIG. 3 is a configuration diagram of a programmable controller (hereinafter referred to as a PC) using a conventional analog input / output unit. In the figure, 170 is a CPU unit of a PC attached to the main body of the programmable controller, 171 is a sequence processing unit for processing a sequence program, 172
Is a sequence program memory for storing a sequence program, 173 is an interface unit for exchanging data with the analog input / output unit, 174 is an analog input / output unit, 175 is a processing unit for managing the overall operation of the analog input / output unit, 176 is an A / D conversion value memory for the analog input / output unit 175 to transfer the A / D conversion value to the CPU unit 170, and 177 is used when the CPU unit 170 transfers the D / A conversion value to the analog input / output unit 175. A D / A conversion value memory 178, an A / D conversion unit 178 for converting an analog quantity into a digital value,
9 is an analog input section, 17a is a D / A conversion section for converting a digital value into an analog quantity, 17b is an analog output section, 1
Reference numeral 7c is an object to be controlled in this control system, and 17d is a switch unit for setting the offset value and the gain value of the A / D conversion unit 178 and the D / A conversion unit 17a of the analog input / output unit 174.

FIG. 19 is a diagram showing an example of a sequence program for controlling this system. In the figure, reference numeral 181 denotes A / A from the analog input / output unit 174.
After reading the D-converted value and calculating the value to be D / A converted by arithmetic processing, the A / A of the analog input / output unit 174 is calculated.
Sequence program to be written in the D conversion value memory, 18
Reference numerals 0 and 182 are sequence programs for other processing.

Next, the operation will be described. First, the analog input signal from the controlled object 17c is converted to A / D
The operation up to storage in the converted value memory unit 176 will be described. An analog signal indicating the state of the controlled object 17c is input to the analog input section 179 and then converted into a digital value by the A / D conversion section 178. The A / D converted value is written in the A / D converted value memory 176. This series of processing is sequentially repeated by the processing unit 175, and the digital conversion value of the analog signal amount input to the analog input unit 179 is sequentially stored in the A / D conversion value memory 176.

Next, the operation of the sequence processing unit 171 for fetching the A / D converted digital value, performing arithmetic processing, and writing the result in the D / A converted value memory 177 will be described. The sequence processing unit 171 processes the analog input / output unit program 181 shown in FIG. 19 while repeatedly processing the first step to the last step of the program stored in the sequence program memory 172. The value that is A / D converted by the analog input / output unit program 181 is read from the A / D converted value memory 176, and the D / A converted value is calculated by a program that executes a functional expression that combines four arithmetic operations, It is written in the D / A converted value memory 177.

By the way, after the analog input / output unit program 181 is once executed, there is a time interval until the analog input / output unit program 181 is executed next. This interval corresponds to the cycle time until the sequence processing unit 171 processes from the first step to the last step of the sequence program and returns to the processing of the first step again, and the cycle time increases as the size of the sequence program increases. Also becomes longer. Processing unit 1
Reference numeral 75 is a process for periodically reading the digital value written in the D / A conversion value memory 177, converting it into an analog amount by the D / A conversion unit 17a, and then outputting it to the controlled object 17c via the analog output unit 17b. Is repeated.

Next, the setting of the offset value and the gain value of the A / D converter 178 and the D / A converter 17a will be described. First, the offset value and the gain value of the A / D conversion unit 178 are set from the outside by the analog input unit 17
The offset value setting voltage 0V and the gain value setting voltage 10V are applied to 9 and the offset setting switch (not shown) and the gain setting switch (not shown) of the switch unit 17d are turned ON in each case. As a result, the converted output of the A / D conversion unit 178 is stored in the offset / gain storage unit 1c as an offset value and a gain value. To set the offset value and the gain value of the D / A conversion unit 17a, connect a voltmeter to the analog output unit 17b,
The output voltage of the analog output unit 17b is set to 0V when the offset value is set and 10V when the gain value is set by the up / down switch (not shown) of the switch unit 17d.
Adjust so that When the voltage is adjusted to 0V, the offset setting switch of the switch unit 17d stores the input value of the D / A conversion unit 17a as an offset value in the offset / gain storage unit 1c, and when the voltage is adjusted to 10V, the switch unit 17d. The input value of the D / A conversion unit 17a is stored as a gain value in the offset / gain storage unit 1c by the gain setting switch.

[0008]

The conventional analog input / output unit 174 executes only the process of converting the analog input amount from the controlled object 17c into a digital value and the process of converting the digital value into an analog output amount. And the calculation process for determining the analog output amount with respect to the analog input amount is P
The C CPU unit is doing this. Therefore, the delay time until the analog output amount changes with respect to the change of the analog input amount largely depends on the time required for the A / D conversion and the D / A conversion, as well as the cycle time for processing the sequence program. Also, the larger the sequence program, the longer this delay time becomes, and the controlled object 1
There is a problem that it is difficult to control 7c at high speed and with high precision.

The conventional analog input / output unit 17
In the case of control using 4, the calculation process for determining the analog output amount with respect to the analog input amount is performed by the PC sequence program. When performing the calculation by this sequence program, a plurality of constant parameters in the function formula are set. In order to make the determination, there has been a problem that the analog input amount and the analog output amount have to be back-calculated in advance based on the relation between them to obtain them.

The conventional analog input / output unit 17
In No. 4, the offset value and the gain value could only be set to fixed values for each analog input channel or analog output channel. In the analog input / output unit 174, it is general that either 0-10V or 4-20mA is used as the specified condition voltage or specified condition current of the offset value and gain value of each channel. Therefore, the manufacturer of the unit sets the offset value and the gain value by either 0-10V or 4-20mA before shipping, but the user sets the offset value and the gain value by the specified condition different from the manufacturer's setting. You may want to set and use a value. In this case, the user has to set the offset value and the gain value again.

The conventional analog input / output unit 174 is also used.
In setting the offset value and gain value of the analog input channel, the voltage for offset value setting and the voltage for gain setting, or the current for offset setting and the current for gain setting are input from the outside. After being applied to the channel, a predetermined switch equipped in the unit was turned on to store the offset value and the gain value. On the other hand, when setting offset and gain values for analog output channels, increase or decrease the voltage or current output by the switch equipped on the unit, and then turn on another specified switch to set the offset value. And gain values were stored respectively. That is, there has been a problem that manual operation of the switch is required to set the offset value and the gain value of both the analog input channel and the analog output channel.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to prevent an increase in the time delay from the input to the output of an analog amount.

It is another object of the present invention to facilitate setting of a functional expression showing the relationship between the analog input amount and the analog output amount.

Another object is to easily set or change the offset value and the gain value.

Another object is to easily set the offset value or the gain value.

[0016]

A programmable controller analog signal processing device according to the present invention is a programmable controller analog signal processing device detachably provided in a programmable controller main body which operates based on a sequence program. A / D conversion means for converting an analog input signal input from an object into a digital signal, and an operation means for performing an operation on a converted output of the A / D conversion means by a predetermined functional expression based on an instruction from the programmable controller main body. And an output means for outputting an analog output based on the arithmetic output of the arithmetic means to the controlled object.

Further, based on the coordinate information sent from the programmable controller main body, the coordinate information indicating a plurality of points on the coordinate where one axis is an analog input amount and the other axis is an analog output amount. A function formula calculating means for calculating a function formula showing a predetermined number of straight lines connecting a plurality of points is provided.

Further, it has a selecting means for selectively outputting either the command value from the programmable controller main body or the arithmetic output of the arithmetic means based on the instruction from the programmable controller main body, and the output means is based on the selective output of the selecting means. The analog output is output to the controlled object.

Further, a plurality of storage means for storing the offset value and the gain value of the A / D conversion and the offset value and the gain value of the D / A conversion are provided, and the storage means selected from the plurality of storage means is stored. The offset value and the gain value are set based on the contents.

Further, a voltage reading unit or a current reading unit capable of reading the converted output of the D / A converting unit according to a command from the programmable controller main body, and a predetermined voltage value or current value is output based on the command from the programmable controller main body. , A constant voltage power supply or constant current power supply for inputting this output to the A / D conversion means, and A / D when the constant voltage power supply or constant current power supply outputs a predetermined voltage value or current value.
The converted output of the D conversion means is written in the storage means as an offset value or gain value of the A / D conversion, and the input value to the D / A conversion means based on the read output of the voltage reading means or the current reading means from the programmable controller main body. A command to increase or decrease the value is issued, and the input value when the predetermined voltage value or the predetermined current value is read by the voltage reading unit or the current reading unit is written in the storage unit as an offset value or gain value for D / A conversion. And means.

[0021]

The analog signal processing device for a programmable controller according to the present invention is based on an instruction from the programmable controller main body with respect to the conversion output of the A / D conversion means for converting the analog input signal input from the controlled object into a digital signal. The calculation means performs a calculation according to a predetermined functional expression, and outputs an analog output based on the calculation result to the control target.

Further, based on the coordinate information sent from the programmable controller main body, the coordinate information indicating a plurality of points on the coordinate having one axis as an analog input amount and the other axis as an analog output amount, The function formula calculating unit calculates a function formula indicating a predetermined number of straight lines connecting a plurality of points.

Further, based on the command from the programmable controller main body, the selecting means selectively outputs either the command value from the programmable controller main body or the arithmetic output of the arithmetic means, and the output means controls the analog output based on this selective output. Output to the target.

Further, a plurality of storage means for storing the offset value and the gain value of the A / D conversion and the offset value and the gain value of the D / A conversion are provided, and the storage means selected from the plurality of storage means are provided. The offset value and the gain value are set based on the stored contents.

Further, when the constant voltage power supply or the constant current power supply inputs a predetermined voltage value or current value to the A / D conversion means based on a command from the programmable controller main body,
The writing output writes the converted output of the A / D conversion means to the storage means as an offset value or gain value of the A / D conversion, and the conversion of the D / A conversion means read by the voltage reading means or the current reading means. A command to increase or decrease the input value to the D / A converting means is issued from the programmable controller main body based on the output, and the D / A converting means when the converted output of the D / A converting means reaches a predetermined voltage value or a predetermined current value. The input value of is written in the storage means by the writing means as an offset value or gain value for D / A conversion.

[0026]

【Example】

Example 1. FIG. 1 is a block diagram of a control system using an analog input / output unit according to the present invention. In the figure, 10 is a CPU unit of a PC mounted on the programmable controller main body, 11 is a sequence processing unit for processing a sequence program, 12 is a sequence program memory for storing the sequence program, 13
Is an interface unit for exchanging data with the analog input / output unit, and 14 is an analog signal processing device for a programmable controller mounted on the programmable controller main body, for example, an analog input / output unit. Reference numeral 15 is a processing unit that manages the overall operation of the analog input / output unit 14, 16 is a dual port memory for exchanging data with the CPU unit 10 of the PC, and 17 is A / D conversion that converts an analog amount into a digital value. Means, for example, an A / D converter. 18 is an analog input section, 1
9 is a D / A converter that converts a digital value into an analog quantity,
Reference numeral 1a is an analog output unit, 1b is a controlled object, and 11c is an offset / gain storage unit that stores an offset value and a gain value. The arithmetic means is embodied by the processing unit 15, and the output means is composed of the D / A conversion unit 19 and the analog output unit 1a.

FIG. 2 shows the dual port memory 16 of FIG.
FIG. In the figure, 20 is an A / D conversion value memory that stores a digital value obtained by converting an analog input amount, and 21 is a CPU that has a digital value for analog output.
A CPU D / A conversion value memory written by the sequence processing unit 11 of the unit 10, and a calculation result storage memory 22 for storing a value calculated by the processing unit 15 of the analog input / output unit 14 from the analog input amount based on a functional expression. , 23
Is a D / A output permission memory in which information indicating whether or not to permit the output of analog output is stored, and 24 is which of the offset value and the gain value stored in the offset / gain storage unit 11c is selected. Offset / gain selection memory that stores information indicating
The output switching memory stores information that specifies which of the A / A converted value memory 21 and the operation result storage memory 22 outputs the value, and 26 is a constant that stores the constant parameter A in the function formula. Parameter A memory, 27 is a constant parameter B for storing constant parameter B in the function formula
It is a memory.

28 is an analog input amount 1 memory, 29 is an analog output amount 1 memory, 2a is an analog input amount 2 memory, 2b is an analog output amount 2 memory, 2c is an analog input amount 3 memory, 2d is an analog output amount 3 memory. And
A value indicating the relationship between the analog input amount and the analog output amount is stored. 2e selects A / D conversion or D / A
A / D, D that stores information to select or specify conversion
/ A conversion memory, 2f is an offset command memory in which information indicating whether to store an offset value is stored, 2g is a gain command memory in which information indicating whether to store a gain value is stored, 2h is D An output down command memory 2i for storing information indicating whether to increase the analog output amount while the offset / gain of the A / A converter is being set, 2i is D
The output down command memory stores information indicating whether or not to reduce the analog output amount during offset / gain setting of the / A converter.

FIG. 3 is a diagram showing a sequence program executed by the sequence processing unit 11. In the figure, 30 is an instruction to write the numerical value -1 to the internal register D0 of the CPU, 31 is an instruction to write the numerical value 4000 to the internal register D1, 32 is a constant parameter for the values stored in the internal register D0 and the internal register D1, respectively. A command for writing to the A memory 26 and the constant parameter B memory 27, and a command for writing 33 to the D / A output permission memory 23 are information for permitting D / A output.

Next, the operation will be described. When the device 34, which is turned on once after the power is turned on, is turned on, the sequence processing unit 11 executes the instruction 30, the instruction 31, and the instruction 32 in FIG. 3, and the numerical values are stored in the constant parameter A memory 26 and the constant parameter B memory 27, respectively. 1, 4000 are written as constant parameter A and constant parameter B.
Thereafter, while the control start device 35 is ON, the instruction 33 writes information for permitting D / A output to the D / A output permission memory 23.

FIG. 4 is a flow chart of processing executed by the processing unit 15 of FIG. In the figure, 40 is A in FIG.
A process of loading the digital value converted by the / D conversion unit 17, a process of writing the acquired A / D conversion value in the A / D conversion value memory 20, and a reference number 42 in the constant parameter A memory 26 and the constant parameter B memory 27. A process of fetching the stored constant parameter A and constant parameter B, 43 is a process of calculating y = Ax + B using the constant parameter A and constant parameter B with the A / D converted value as x, and 44 is a calculation result Process y for writing y in the calculation result storage memory 22, 45 is the D / A output permission memory 2
The process of reading the contents of No. 3 and judging whether the contents are the information permitting the D / A output, the process of setting 46 of the result y in the D / A conversion unit 19 as a value for analog output Is.

The processing section 15 of the analog input / output unit is
Processing is performed according to the flow chart shown in FIG. First,
The processing unit 15 determines the analog input amount input to the analog input unit 18 by the process 40, the process 41, and the process 42 as A.
The / D conversion unit 17 converts it to a digital value and writes it in the A / D converted value memory 20, and also reads out the constant parameter A and the constant parameter B from the constant parameter A memory 26 and the constant parameter B memory 27. take in. Next, in process 43, the analog input amount x converted into the digital amount obtained in process 40 is substituted into the functional expression y = Ax + B to calculate the analog output amount y. Then, the value of y is stored in the calculation result storage memory 22 by the process 44.

Next, in process 45, it is determined whether or not the contents stored in the D / A output permission memory 23 are information permitting D / A output. If not, the process returns to step 40 and D / A
If it is information that permits output, the y of the calculation result is output as an analog output amount through the D / A conversion unit 19. According to the first embodiment, the processing time from the input to the output of the analog amount does not depend on the execution cycle of the sequence program, so that the processing time is prevented from increasing.

Example 2. FIG. 5 is a diagram showing the relationship between the analog input amount and the output amount when control is performed by the analog input / output unit in another embodiment of the present invention. In the figure, the horizontal axis is the analog input amount, the vertical axis is the analog output amount, and the numbers on each axis are the analog input amount or output amount of each axis indicating the positions of points A, B, and C on the graph, in parentheses. Is a digitized value of those analog quantities.

FIG. 6 is a diagram showing a sequence program stored in the sequence program memory 12 of the CPU unit 10 of the PC. In the figure, 60 is a CPU
An instruction to write the number 0 to the internal register D0 of the unit 10, 61 to write a number 4000 to the internal register D1, 62 to write a number 1000 to the internal register D2, 63 to write a number 2000 to the internal register D3, 64 Is an instruction to write a numerical value 4000 to the internal register D4, 65 is an instruction to write a numerical value 500 to the internal register D5, 66 is a numerical value stored in the internal register D0 to the internal register D5, respectively, for the analog input amount 1 memory 28 and analog output. Ability 1 memory 29, analog input amount 2 memory 2a, analog output amount 2 memory 2b, analog input amount 3 memory 2c, analog output amount 3 memory 2
Reference numeral 67 is a command for writing in d, and 67 is a command for writing information for permitting D / A output in the D / A output permitting memory 23. The functional formula calculating means is embodied by the processing unit 15.

Next, the operation will be described. The sequence processing unit 11 of FIG. 1 is a device 6 that is turned on once after power is turned on.
When 8 is turned on, the analog input amount 1 memory 28, the analog output amount 1 memory 29, the analog input amount 2 memory 2a, the analog output amount 2 memory 2 are instructed by the instruction 60 to the instruction 66.
b, a predetermined numerical value is written in each of the analog input amount 3 memory 2c and the analog output amount 3 memory 2d. Here, the numerical value to be written in the analog input amount 1 memory 28 and the analog output amount 1 memory 29 is a value indicating the position of the point A in FIG. 5, and when the digital conversion value of the analog input amount is 0, the analog value is the analog value 4000. Indicates that the output amount is output.

Similarly, the analog input amount 2 memory 2a, the analog output amount 2 memory 2b, the analog input amount 3 memory 2c, and the analog output amount 3 memory 2d indicate the positions of points B and C on FIG. Analog input amount 1 Memory 2
8, analog output amount 1 memory 29, analog input amount 2 memory 2a, analog output amount 2 memory 2b, analog input amount 3 memory 2c, and analog output amount 3 memory 2d
After setting the value of, the sequence processing unit 11 writes the information indicating the output permission from the analog input / output unit 14 in the D / A output permission memory 23 while the control start device 69 is ON.

FIG. 7 is a flow chart of the internal processing of the analog input / output unit. In the figure, 70 is a process of converting an analog input amount into a digital value, 71 is a process of writing the digital value converted by the process 70 into the A / D converted value memory 20, 72 is an analog input amount 1 memory 28, an analog output amount. 1 memory 29, analog input amount 2 memory 2a,
The process 73 of taking in the values of the analog output amount 2 memory 2b, the analog input amount 3 memory 2c, and the analog output amount 3 memory 2d, and generating a functional expression for calculating the analog output amount from the analog input amount, 73 is a process 72 A process of substituting the digital value converted in the process 70 into the functional expression generated in the process 70 to calculate a value for analog output, and 74 represents the result calculated in the process 73 in the calculation result storage memory 22.
Processing for storing the information in the D / A output permission memory 23 is determined whether or not the content of the D / A output permission memory 23 is information for permitting D / A output,
If not, the process returns to step 70, and if the information permits the D / A output, the process proceeds to step 76. In step 76, the D / A converter 19 converts the result calculated in step 73 into an analog output amount. Processing.

The processing section 15 of the analog input / output unit 14 of FIG. 1 is processed according to the flow chart shown in FIG.
In process 70, the analog amount input to the analog input unit 18 of FIG. 1 is converted into a digital value, and in process 71, the analog amount of FIG.
Of the A / D converted value memory 20. In the process 72, the analog input amount 1 memory 28, the analog output amount 1 memory 29, the analog input amount 2 memory 2a, the analog output amount 2 memory 2b, the analog input amount 3 memory 2c, and the analog output amount 3 memory 2d in FIG. Generate a functional expression from the written value.

First, a linear expression is obtained from the analog input amount 1 memory 28 and the analog output amount 1 memory 29, and the analog input amount 2 memory 2a and the analog output amount 2 memory 2b. By the sequence program of FIG. 6, analog input amount 1 memory 28, analog output amount 1 memory 29, analog input amount 2 memory 2a, analog output amount 2 memory 2b
Since the numerical values 0, 4000, 1000, and 2000 are written in each of them, y = (− 2) x + 4000 (functional expression 1) is obtained from these numerical values. Next, similarly, the analog input amount 2 memory 2a, the analog output amount 2 memory 2b, the analog input amount 3
Y = (− 0.5) x + 2500 (functional expression 2) is obtained from the numerical values written in the memory 2c and the analog output amount 3 memory 2d. In the functional expressions 1 and 2, x is a digital conversion value of the analog input amount, y is a calculation result,
It is a digital value that is converted into an analog quantity.

Next, in process 73, the analog input amount converted into the digital value obtained in process 70 is substituted into the functional expression generated in process 72 to obtain the analog output amount. First,
The analog input amount converted into a digital value is compared with the value written in the analog input amount 2 memory 2a. If the analog input amount converted into a digital value is less than the value of the analog input amount 2 memory 2a, The calculation is performed using the function expression 1, and if it is more than that, the calculation is performed using the function expression 2. In process 74, the calculation result obtained in process 73 is written in the calculation result storage memory 22. In the process 75, it is determined whether or not the information permitting the D / A output is written in the D / A output permission memory 23, and if it is written, the process 76.
If not, the process returns to step 70. In process 76, the result calculated in process 73 is input to the D / A conversion unit 19 in FIG. 1 to be converted into an analog amount, which is output to the controlled object 1b via the analog output unit 1a. As described above, according to the second embodiment, it is possible to easily set the functional expression indicating the relationship between the analog input amount and the analog output amount.

Example 3. As in the first or second embodiment described above, the analog input / output unit 14 calculates the analog output amount from the analog input amount without depending on the sequence program of the PC, and when outputting the analog output amount, it is started when the power is turned on. Sometimes, the analog output amount changes in an instant from the state in which there is no output to the output amount calculated from the analog input amount, which may give a shock to the controlled object 1b.
The purpose of the third embodiment is to prevent such a sudden change in the analog output amount at the time of starting. FIG. 8 is a diagram showing a sequence program of the CPU unit of the PC according to the third embodiment of the present invention. In the figure, 80 is an instruction to write the numerical value -1 to the internal register D0 of the CPU,
81 is an instruction to write a numerical value 4000 to the internal register D1 of the CPU, and 82 is a constant parameter A for the numerical values stored in the internal register D0 and the internal register D1, respectively.
An instruction to write to the memory 26 and the constant parameter B memory 27, 83 to write information to permit D / A output to the D / A output permission memory 23, and 84 to output M0 while the calculation result by the analog input / output unit 14 is output. ON
, 85 is a command for writing information for switching the output to the output switching memory 25, 86 is a command for writing an arbitrary value to be output as an analog output amount to the internal register D2, and 87 is a value written in the internal register D2. To C
This is an instruction to write in the D / A conversion value memory 21 for PU.
The selection unit is embodied by the processing unit 15.

Next, the operation will be described. In the sequence processing unit 11, the device 88 which is turned on once after the power is turned on is turned on.
When it is N, the constant value -1, 4000 is written as the constant parameter A and the constant parameter B in the constant parameter A memory 26 and the constant parameter B memory 27 by the instruction 80, the instruction 81, and the instruction 82 of FIG. While 89 is ON, the information permitting D / A output is written in the D / A output permission memory 23, and the analog output is permitted.

Next, the instruction 85 controls whether the analog output is the value written by the sequence program or the value calculated in the analog input / output unit. That is, while the M0 signal is OFF, the output switching memory 25 is OFF (that is, the information designating to output the value written by the sequence program is written in the output switching memory 25), and the instruction 86,
The value output as the analog amount is written in the D / A conversion memory for CPU 21 by the instruction 87. When the M0 signal is turned on by the automatic control start device 8a, the output switching memory 25 is turned on (that is, the information designating to output the value calculated by the analog input / output unit 14 is written in the output switching memory 25). .

FIG. 9 is a flow chart of the processing executed by the processing unit 15 of FIG. In the figure, 90 is a process for fetching the digital value converted by the A / D conversion unit 21,
91 is the A / D converted value memory 2 for the imported A / D converted value
Processing for writing 0, 92 is a constant parameter A memory 26
And constant parameter B processing for fetching the constant parameter A and the constant parameter B stored in the memory 27, 93 substitutes the constant parameter A, the constant parameter B, and the A / D converted value into the functional expression y = Ax + B Then, it is a process of obtaining a digital value y to be output as an analog amount.

Reference numeral 94 is a processing for writing y obtained in the processing 93 in the operation result storage memory 22, and 95 is for reading the contents of the D / A output permission memory 23, and the read contents permit the D / A output. Processing for determining whether or not it is information to be processed, 96 reads the content of the output switching memory 25, and whether the read content is the information for outputting the value obtained in the processing 94, or the CPU unit 10 Processing for determining whether to output the value written in the CPU D / A converted value memory 21,
A process of D / A converting the contents of No. 2 and outputting as an analog amount, 98 is the contents of the D / A conversion value memory for CPU 21 being D
This is a process of A / A conversion and outputting as an analog amount.

The processing section 15 of the analog input / output unit 14 of FIG. 1 is processed as shown in the flow chart of FIG. First, in process 90 and process 91, the analog amount input to the analog input unit 18 of FIG. 1 is converted into a digital value and written in the A / D converted value memory 20. Next process 9
2. Using the constant parameter A and the constant parameter B set in the constant parameter A memory 26 and the constant parameter B memory 27 by the processing 93 and the processing 94, the functional expression y
The analog input amount converted into the digital value is substituted into = Ax + B, and the result y is written in the calculation result storage memory 22. In the process 95, the contents of the D / A output permission memory 23 are D / A.
Whether or not the information permits the A output is determined. If not, the process returns to the process 90 without outputting the analog amount, but if the information permits the D / A output, the process proceeds to the process 96.

In process 96, the contents of the output switching memory 25 are read. If it is the information indicating that the output switching memory 25 D / A converts the contents of the operation result storage memory 22 and outputs it by the instruction 85 of FIG. 8, the process proceeds to step 97, where the output switching memory 25 is the CPU D / A. If the information indicates that the contents of the converted value memory are D / A converted and output, the process 98
Proceed to. In process 97, the value calculated in process 93 and stored in the calculation result storage memory 22 is D / A converted and output as an analog amount. In process 98, the values written by the commands 86 and 87 in FIG. 8 are D / A converted and output as analog quantities. According to the third embodiment, D for CPU
Since the analog amount based on the content of the calculation result storage memory 22 can be output after the analog amount based on the predetermined digital amount stored in the / A converted value memory is output in advance, the analog output amount changes suddenly at the time of starting. Etc. can be prevented.

Example 4. Next, still another embodiment of the present invention will be described. FIG. 10 is a diagram showing an internal configuration of the A / D conversion unit 17 of FIG. In the figure, 100 is a V / F converter for converting an analog input voltage into a pulse train having a frequency proportional to the magnitude of the analog input voltage, and 101 is a pulse output from the V / F converter 100 within a fixed time. It is a counter that counts. FIG. 11 is a diagram showing an internal configuration of the D / A conversion unit 19 of FIG. In the figure, 110 is a gate circuit that outputs an input constant voltage amount while the gate control signal is ON. 11
Reference numeral 1 denotes an integrating circuit that integrates a constant voltage amount (pulse) that is a signal output from the gate circuit 110 and that is input at constant intervals, and converts it into a voltage amount.

FIG. 12 is a diagram showing the configuration of the offset / gain storage unit 11c of FIG. In the figure, 120 is a first A / D offset value memory that stores a first A / D conversion offset value, 121 is a first A / D gain value memory that stores a first A / D gain value, and 122 is a second A / D A second A / D offset value memory that stores the conversion offset value, a second A / D gain value memory 123 that stores the second A / D conversion gain value, and a first 124 that stores the first D / A conversion offset value. 1D / A offset value memory,
125 is a first D / A conversion gain value stored in the first D / A
A gain value storage memory, 126 is a second D / A offset value memory in which the second D / A conversion offset value is stored, 1
27 is the second D in which the second D / A conversion offset value is stored
/ A gain value memory. The first A / D offset value memory 120, the first A / D gain value memory 121,
First D / A offset value memory 124 and first D
The A / A gain value storage memory 125 constitutes one storage means, and the second A / D offset value memory 122 and the second A / D offset value memory 122
A / D gain value memory 123, second D / A offset value memory 126, and second D / A gain value memory 12
One storage means is constituted by 7.

FIG. 13 is a diagram showing a relationship between an analog amount and a digital value when 0-10 V is a voltage defining an offset value and a gain value and 4-20 mA is a current defining an offset value and a gain value. is there. The offset value is an analog amount when the digital value is 0, and the gain value is an analog amount when the digital value is 4000.

Next, the operation for setting the offset value and the gain value will be described for two cases of 0-10V and 4-20mA. First, the A / D converter 17
The setting of the offset value and the gain value of will be described. From the outside, voltage 0V, 1 is applied to the analog input section 18 of FIG.
0V, current 4mA, 20mA are sequentially input. The input voltage value is input to the V / F converter 100 in FIG. 10 via the analog input unit 18. A pulse having a frequency proportional to the input voltage value is applied to the V / F converter 1
00, and is counted by the counter 101. 4 mA and 20 mA input to the analog input unit 18
Are converted into pulses having frequencies corresponding to voltage values of 2 V and 10 V, respectively, and then input to the counter 101, and the number of pulses is counted. The pulse-converted value of 0 V is stored in the first A / D offset value memory 120 as the first offset value, and the pulse-converted value of 1 is stored.
The value of 0 V is stored as the first gain value in the first A / D gain value memory 121, the value of 4 mA is stored as the second offset value in the second A / D offset value memory 122,
The value of 20 mA is stored in the second A / D gain value memory 123 as the second gain value.

Next, the offset / gain value setting of the D / A converter 19 will be described. First, the processing unit 15 in FIG.
Indicates that the output voltage value of the analog output unit 1a is 0V which is the first offset value based on the command from the CPU unit 10.
The pulse width of the pulse having a constant cycle input as the gate control signal of the gate circuit 110 of FIG. 11 is adjusted so that Then, the digital value indicating the pulse width at that time is stored in the first D / A offset value memory 124 of FIG. Similarly, the voltage 1 as the first D / A gain value
A digital value indicating the pulse width of the gate control signal for outputting 0 V, 4 mA as the second D / A offset value, and 20 mA as the second D / A gain value, is stored in the first D / A gain value memory 125 of FIG. Second D / A
The offset value memory 126 and the second D / A gain value memory 127 respectively store them.

Next, the means for selecting the offset value and the gain value will be described. The CPU CPU 10 of the PC stores information indicating whether to select the first offset / gain value or the second offset / gain value in the offset / gain selection memory 24 shown in FIG. 2 by the sequence program. The first offset / gain value is the first A / D offset value, the first A / D gain value, the first D / D
An A offset value and a first D / A gain value, and the second offset / gain value is the second A / D offset value, the second A / D gain value, the second D / A offset value, and the second D / A gain. It shall consist of values. on the other hand,
The processing unit 15 of the analog input / output unit 14 of FIG.
Any one of the offset / gain value and the second offset / gain value is read from the offset / gain storage unit 11c shown in FIG. 12, the read offset value is a digital value 0, and the read gain value is a digital value. 40
A / A based on the relationship between analog quantity and digital value
Execute D conversion and D / A conversion. According to the fourth embodiment, it is possible to easily set or change the offset value and the gain value as described above.

Example 5. FIG. 14 is a diagram showing a system configuration in still another embodiment of the present invention. In the figure, 140 is a sequence processing unit of a CPU unit of a PC, 141 is a sequence program memory, 142 is an interface unit with an analog input / output unit, 143 is an interface unit, 144 is a processing unit of an analog input / output unit, and 145 is a CPU unit. A dual port memory for transmitting and receiving data to and from 146, an A / D conversion and analog input unit, 147, a D / A conversion and analog output unit, 148, a constant voltage current power supply device, and 149, a voltmeter. The interface unit 143 is provided for exchanging signals with the constant voltage current power supply device and the voltmeter. The voltage reading unit and the current reading unit are configured by the voltmeter and the interface unit 143, and the constant voltage power source and the constant current power source are configured by the constant voltage current power supply device 148 and the interface unit 143. The writing unit is implemented by the processing unit 144.

FIG. 15 shows the sequence program memory 14
2 is a diagram showing a sequence program stored in No. 1. FIG.
In the figure, 150 is the interface unit 143 of FIG.
A command to output a voltage of 0 V to the constant voltage current power supply device via a reference numeral 151 is an O / V selection memory 2e of FIG.
An instruction for setting to FF and indicating that the offset / gain of the A / D conversion unit is set.
This is a command to turn on the offset command memory 2f in FIG. 2 when a voltage of 0 V is applied to the / D conversion unit 146, and when the offset command memory 2f is turned on, as will be described later,
The converted output of the A / D converter at this time is stored as an offset value. The instruction 150, the instruction 151, and the instruction 152 are executed when the offset setting command device of the A / D converter is turned on.

Reference numeral 153 is an instruction to output a voltage of 10 V to the constant voltage current power supply device 148, and 154 is A / D and D in FIG.
/ A is a command to turn off the selection memory 2e.
When the D / D / A selection memory 2e is turned off, the offset / gain setting of the A / D converter is selected. Reference numeral 155 is an instruction to turn on the gain command memory 2g in FIG. 2 when a voltage of 10 V is applied to the A / D conversion unit 146. When the gain command memory 2g is turned on, A / The output of the D converter is stored as a gain value. The instruction 153, the instruction 154, and the instruction 15
5 is executed when the A / D gain setting command device is turned on.

Reference numeral 156 is an instruction for fetching a voltage value from the voltmeter 149, and 157 is an instruction for turning on the A / D, D / A selection memory 2e of FIG. When it is turned on, the offset / gain setting of the D / A converter is selected. 158 has a voltage value of 0V
In the above case, the instruction is to turn on the output down command memory 2i in FIG. 2. When the output down command memory 2i is turned on, the voltage value output from the D / A conversion unit decreases as described later. Reference numeral 159 is a command to turn on the output up command memory 2h when the taken-in voltage value is 0 V or less, and when the output up command memory 2h is turned on, the output voltage value from the D / A converter increases as will be described later. . Reference numeral 15a is a command for turning on the offset command memory 2f in FIG. 2 when the taken-in voltage value is 0V. When the offset command memory 2f is turned on, the D / A at that time is described as described later.
The input value of the conversion unit is stored as the offset value. Note that the instruction 156, the instruction 157, the instruction 158, and the instruction 15
9 and the instruction 15a are executed when the D / A offset setting command device is turned on.

Reference numeral 15b is an instruction to take in the voltage value of the voltmeter 149 of FIG. 14, reference numeral 15c is an instruction to turn on the A / D, D / A selection memory 2e of FIG. 2, and A / D, D / A selection. When the memory 2e is turned on, the offset / gain setting of the D / A converter is selected. Reference numeral 15d is a command to turn on the output down command memory 2i in FIG. 2 when the taken-in voltage value is 10 V or more, and the output down command memory 2i is O
When it becomes N, the voltage value output from the D / A conversion unit decreases as described later. 15e has a voltage value of 10V
It is a command to turn on the output up command memory 2h in the following cases, and when the output up command memory 2h is turned on, the output voltage value from the D / A conversion unit increases as will be described later.
Reference numeral 15f is an instruction to turn on the gain command memory 2g of FIG. 2 when the taken-in voltage value is 10V, and when the gain command memory 2g is turned on, the D /
The input value of the A converter is stored as a gain value. In addition,
Command 15b, command 15c, command 15d, command 15e, and command 15f are D / A gain setting command device O
It is executed when it becomes N.

16 and 17 show the processing unit 1 of FIG.
It is a flowchart which shows operation | movement of 44. In FIG. 16, 1
If the A / D and D / A selection memory 2e of FIG. 2 is OFF, the process proceeds to the process of setting the offset value and the gain value of the A / D conversion unit 60, and if it is ON, the offset of the D / A conversion unit. Process to set the value and gain value,
If the offset command memory 2f in FIG. 2 is ON, the processing proceeds to processing 162, and if it is OFF, the processing proceeds to processing 163. 162 is the processing of fetching and storing the offset value from the A / D conversion unit. 163 of FIG. Gain command memory 2g
If is ON, the process proceeds to step 164, and if it is OFF, the process returns to step 160, and 164 is a process of fetching and storing the gain value from the A / D conversion unit and returning to step 160.

In FIG. 17, reference numeral 165 indicates that if the output up command memory 2h shown in FIG.
If it is FF, the process proceeds to step 167, 166 is the process of increasing the output value to the D / A converter, and 167 is step 168 if the output down command memory 2i of FIG. The processing proceeds to processing 169, 168 is D
A process of lowering the output value to the A / A converter 169 is shown in FIG.
If the offset command memory 2f of is ON, processing 16a
If it is OFF, the process proceeds to process 16b.
Is a process of storing the input value of the D / A converter as an offset value, 16b is a process of proceeding to process 16c if the gain command memory 2g of FIG. 2 is ON, returning to process 160 if it is OFF, and 16c is D / A This is a process of storing the input value of the A conversion unit as a gain value and then returning to the process 160.

Next, the operation will be described. The processing unit 144 of FIG. 14 performs the processing shown in the flowcharts of FIGS. 16 and 17, and is controlled by the sequence program A / A of FIG.
D, D / A selection memory 2e, offset command memory 2
f, gain command memory 2g, output up command memory 2
h and A depending on the state of the output down command memory 2i
The offset / gain value is fetched and stored from the / D conversion unit, and the output value to the D / A conversion unit is increased / decreased, and the offset / gain value after adjusting the offset / gain value is stored. The values stored as the offset and gain values are the value counted by the counter 101 in FIG. 10 and the voltage 10V when the voltage 0V is applied from the constant voltage current device in the A / D converter. It is a value sometimes counted by the counter 101. Also, D
In the / A converter, a digital value indicating the pulse width of the gate control signal of the gate circuit 110 when the voltage of 0V is output, and the pulse width of the gate control signal of the gate circuit 110 when the voltage of 10V is output. Is a digital value indicating. According to the fifth embodiment, it is possible to easily set the offset value or the gain value in this way.

[0063]

As described above, the conversion output of the A / D conversion means for converting the analog input signal input from the controlled object into the digital signal is converted into a predetermined functional expression based on the instruction information from the programmable controller main body. Since the calculation means performs the calculation and outputs the analog output based on the calculation result to the controlled object, it is possible to prevent an increase in the time delay from the input of the analog amount to the output and to control the controlled object with high speed and high accuracy. effective.

Further, based on the coordinate information sent from the programmable controller main body, based on the coordinate information indicating a plurality of points on the coordinate where one axis is the analog input amount and the other axis is the analog output amount, Since the function formula indicating a predetermined number of straight lines connecting a plurality of points is calculated by the function formula calculating means, it is possible to easily set the function formula.

Further, based on the command from the programmable controller main body, the selecting means selectively outputs either the command value from the programmable controller main body or the calculation output of the calculating means, and the output means controls the analog output based on this selection output. Since it is output to the target object, there is an effect that it is possible to prevent an impact or the like on the control target object due to a sudden change in the output at the time of starting when the power is turned on.

Further, a plurality of storage means for storing the A / D conversion offset value and the gain value and the D / A conversion offset value and the gain value are provided, and the storage means selected from the plurality of storage means is stored. Since the offset value and the gain value are set based on the contents, there is an effect that the offset value and the gain value can be easily set or changed.

Further, when the constant voltage power supply or the constant current power supply inputs a predetermined voltage value or current value to the A / D conversion means based on a command from the programmable controller main body,
The writing output writes the converted output of the A / D conversion means to the storage means as an offset value or gain value of the A / D conversion, and the conversion of the D / A conversion means read by the voltage reading means or the current reading means. A command to increase or decrease the input value to the D / A converting means is issued from the programmable controller main body based on the output, and the D / A converting means when the converted output of the D / A converting means reaches a predetermined voltage value or a predetermined current value. Since the input value of is written in the storage means by the writing means as an offset value or gain value of D / A conversion,
There is an effect that the offset value or the gain value can be easily set.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing an analog input / output unit and a CPU unit of a PC according to the present invention.

FIG. 2 is a memory internal configuration diagram of the dual port memory in FIG.

FIG. 3 is a diagram showing a sequence program for controlling an analog input / output unit according to the first embodiment of the present invention.

FIG. 4 is a flowchart showing the internal processing of the analog input / output unit according to the first embodiment of the present invention.

FIG. 5 is a diagram showing a relationship between an analog input amount and an output amount when controlled by an analog input / output unit according to a second embodiment of the present invention.

FIG. 6 is a diagram showing a sequence program for controlling an analog input / output unit according to a second embodiment of the present invention.

FIG. 7 is a flowchart showing the internal processing of the analog input / output unit according to the second embodiment of the present invention.

FIG. 8 is a diagram showing a sequence program for controlling an analog input / output unit according to a third embodiment of the present invention.

FIG. 9 is a flowchart showing the internal processing of the analog input / output unit according to the third embodiment of the present invention.

FIG. 10 is a diagram showing an internal configuration of an A / D converter of an analog input / output unit according to a fourth embodiment of the present invention.

FIG. 11 is a diagram showing an internal configuration of a D / A conversion unit of an analog input / output unit according to a fourth embodiment of the present invention.

FIG. 12 is a diagram showing a structure of a memory for storing an offset value and a gain value of an analog input / output unit according to a fourth embodiment of the present invention.

FIG. 13 is a diagram showing a relationship between an analog amount and a digital value of an analog input / output unit according to a fourth embodiment of the present invention.

FIG. 14 is a functional block diagram showing an analog input / output unit and a CPU unit of a PC for automatically adjusting and setting an offset value and a gain value of the analog input / output unit according to the fifth embodiment of the present invention.

FIG. 15 is a diagram showing a sequence program for automatically adjusting and setting an offset value and a gain value of an analog input / output unit according to a fifth embodiment of the present invention.

FIG. 16 is a flowchart showing the internal processing of the analog input / output unit according to the fifth embodiment of the present invention.

FIG. 17 is a flowchart showing the internal processing of the analog input / output unit according to the fifth embodiment of the present invention.

FIG. 18 is a functional block diagram showing a conventional analog input / output unit and a CPU unit of a PC.

FIG. 19 is a diagram showing a sequence program for controlling a conventional analog input / output unit.

[Explanation of symbols]

 10 PC CPU unit 11 Sequence processing unit 12 Sequence program memory 13 Interface unit 14 Analog input / output unit unit 15 Analog input / output unit processing unit 16 Dual port memory 17 A / D conversion unit 18 Analog input unit 19 D / A conversion unit 1a Analog output section 1b Control object 1c Offset / gain storage section 20 A / D conversion value memory 21 CPU D / A conversion value memory 22 Calculation result storage memory 23 D / A output permission memory 24 Offset / gain selection memory 25 Output Switching memory 26 Constant parameter A memory 27 Constant parameter B memory 28 Analog input amount 1 memory 29 Analog output amount 1 memory 2a Analog input amount 2 memory 2b Analog output amount 2 memory 2c Analog input amount 3 memory 2d Log output amount 3 memory 2e A / D, D / A selection memory 2f Offset setting command memory 2g Gain setting command memory 2h Output up command memory 2i Output down command memory 11c Offset / gain storage unit 100 V / F converter 101 Counter 111 Gate circuit 112 Integration circuit 120 First A / D offset value memory 121 First A / D gain value memory 122 Second A / D offset value memory 123 Second A / D gain value memory 124 First D / A offset value memory 125 First D / A Gain value memory 126 2nd D / A offset value memory 127 2nd D / A gain value memory 140 Sequence processing section 141 Sequence program memory 142 Interface section 143 Interface section 144 Analog input / output unit processing section 145 Dual port memory 146 A / D conversion unit 147 D / A conversion unit 148 Constant voltage current power supply device 149 Volt ammeter 170 PC CPU unit 171 Sequence processing unit 172 Sequence program memory 173 Interface unit 174 Analog input / output unit unit 175 Analog input Output unit processing unit 176 A / D conversion value memory unit 177 D / A conversion value memory unit 178 A / D conversion unit 179 Analog input unit 17a D / A conversion unit 17b Analog output unit 17c Control object 17d Switch unit

Claims (5)

[Claims] 1. An analog signal processing device for a programmable controller, which is detachably provided in a programmable controller main body that operates based on a sequence program, and which converts an analog input signal input from a control target object into a digital signal. Conversion means and this A
An arithmetic means for performing an arithmetic operation on a converted output of the / D conversion means by a predetermined functional expression based on instruction information from the programmable controller main body, and an output for outputting an analog output based on the arithmetic output of the arithmetic means to the control object. An analog signal processing device for a programmable controller, comprising: 2. The coordinate information sent from the programmable controller main body is based on coordinate information indicating a plurality of points on a coordinate where one axis is an analog input amount and the other axis is an analog output amount. 2. The analog signal processing device for a programmable controller according to claim 1, further comprising a function formula calculating means for calculating a function formula represented by a predetermined number of straight lines connecting a plurality of points. 3. A selection means for selectively outputting either a command value from the programmable controller main body or a calculation output of a calculation means based on a command from the programmable controller main body, and the output means is a selection output of the selection means. The analog signal processing device for a programmable controller according to claim 1 or 2, wherein a base analog output is output to the controlled object. 4. A plurality of storage means for storing an offset value and a gain value of A / D conversion and an offset value and a gain value of the D / A conversion are provided, and the storage means selected from the plurality of storage means. The analog signal processing device for a programmable controller according to claim 1, wherein the offset value and the gain value are set based on the stored contents. 5. A voltage reading unit or a current reading unit capable of reading the converted output of the D / A converting unit according to a command from the programmable controller main body, and a predetermined voltage value or current value output based on the command from the programmable controller main body. Of the constant voltage power supply or constant current power supply for inputting this output to the A / D conversion means, and the A / D conversion means when the constant voltage power supply or constant current power supply outputs a predetermined voltage value or current value. The converted output is written in the storage means as an offset value or gain value for A / D conversion, and
Based on the read output of the voltage reading means or the current reading means from the programmable controller body, the D /
A command to increase / decrease the input value to the A conversion means is issued, and the input value when the predetermined voltage value or the predetermined current value is read by the voltage reading means or the current reading means is an offset value or gain for D / A conversion. An analog signal processing device for a programmable controller according to any one of claims 1 to 4, further comprising: a writing unit that writes the value in the storage unit.