CN112165330A - Method for improving channel calibration effect of PLC analog input module - Google Patents
Method for improving channel calibration effect of PLC analog input module Download PDFInfo
- Publication number
- CN112165330A CN112165330A CN202011213624.3A CN202011213624A CN112165330A CN 112165330 A CN112165330 A CN 112165330A CN 202011213624 A CN202011213624 A CN 202011213624A CN 112165330 A CN112165330 A CN 112165330A
- Authority
- CN
- China
- Prior art keywords
- analog input
- input signal
- curve
- value
- channel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/10—Calibration or testing
- H03M1/1009—Calibration
- H03M1/1014—Calibration at one point of the transfer characteristic, i.e. by adjusting a single reference value, e.g. bias or gain error
- H03M1/1019—Calibration at one point of the transfer characteristic, i.e. by adjusting a single reference value, e.g. bias or gain error by storing a corrected or correction value in a digital look-up table
Abstract
The invention provides a method for improving the channel calibration effect of a PLC analog input module, which adopts the technical scheme that the method comprises the following steps: and obtaining an analog input signal curve, dividing the signal curve into regions, calibrating the regions, and checking and calibrating the effect. Obtaining an analog input signal curve, which is used for drawing an expected value of a certain type of analog input signal in a complete measurement interval into a curve; dividing a signal curve into a plurality of sections which can be approximately considered to be linear according to the slope of the curve; a step of inter-zone calibration for taking the different zones f separatelyi(X)=aiX+biCalibrating a plurality of sampling points in the interval according to a least square method to obtain a mapping relation between a channel original acquisition value and a calibrated value in the corresponding interval; a step of checking the calibration effect, which is used to convert the calibrated channel to the original collection value of the analog input signal according to the mapping relation of the channel to different intervals to the calibrated value, and compare the calibrated value with the expected valueThen the obtained product is obtained. The invention can effectively improve the channel calibration effect of the analog input signal which is obviously nonlinear in a certain interval without increasing the calculation complexity, so that the calibrated value converted from the original acquisition value according to the mapping relation can better meet the expectation.
Description
Technical Field
The invention belongs to the technical field of industrial process control, and particularly relates to a method for improving the channel calibration effect of a PLC analog input module.
Background
The PLC analog input module adopts ADC/DAC with good linearity as an analog-digital/digital-analog conversion chip at present, but the channel needs to be calibrated due to the fact that specific hardware of a channel circuit adopts the difference between individual inherent characteristics of components. The purpose of calibration is to find a mapping relationship between the original collected values and the calibrated values of a certain channel, so as to minimize the sum of the absolute values of the differences between the original collected values and the calibrated values of the channel at a plurality of sampling points. In practical engineering application, for convenient calculation, a mapping relation corresponding to the minimum sum of squares of the above differences is found, i.e., a least square method is adopted.
The method for calibrating the channel of the conventional PLC analog input module comprises the following steps: on the premise that the linearity of the ADC/DAC is good, assuming that a linear mapping relationship exists between the original acquisition value and the calibrated value, which is denoted as f (x) = aX + b, the channel is calibrated at a plurality of sampling points according to the least square method using the mapping relationship. However, this approach has limitations: in the actual measurement process after calibration, when a certain type of analog input signal is obviously nonlinear in a certain interval, the measurement result of the channel calibrated according to the assumed linear mapping relation in the obviously nonlinear signal interval sometimes does not meet the expectation.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a method for improving the channel calibration effect of a PLC analog input module without increasing the calculation complexity.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method for improving the calibration effect of a PLC analog input module channel comprises the following steps: and acquiring an analog input signal curve, dividing the signal curve into regions, calibrating the regions, and checking the calibration effect.
Wherein the step of obtaining the analog input signal curve plots expected values of a type of analog input signal over a complete measurement interval.
The step of dividing the signal curve divides the curve of the analog input signal into a plurality of sections which can be approximately considered to be linear according to the slope of the curve.
The step of calibrating among the different sections respectively adopts fi(X) = aiX + biAnd calibrating a plurality of sampling points in the interval according to a least square method to obtain a mapping relation between the channel original acquisition value and the calibrated value in the corresponding interval.
The step of checking the calibration effect converts the calibrated original acquisition value of the channel to the analog input signal into a calibrated value according to the mapping relation of the channel to different intervals, and compares the calibrated value with an expected value.
Further, in the step of obtaining the curve of the analog input signal, the expected value of a certain type of analog input signal in the complete measurement interval can be obtained through actual measurement, or can be obtained through calculation of a description function of the analog input signal of the certain type.
Further, the step of dividing the signal curve into intervals may modify the boundaries of the respective intervals according to the result of the step of checking the calibration effect, or may continue to divide an interval into a plurality of smaller intervals.
Further, the step of calibrating the interval may arrange relatively denser sampling points in the section with the faster slope change according to the signal curve in the interval.
Compared with the prior art, the invention has the following beneficial effects:
the channel calibration effect of the analog input signal which is obviously nonlinear in a certain interval can be effectively improved without increasing the calculation complexity, so that the calibrated value converted from the original acquisition value according to the mapping relation can better meet the expectation.
Drawings
FIG. 1 is a schematic diagram of the steps of the technical scheme.
FIG. 2 is a schematic diagram of signal curve division.
Detailed Description
The invention is further illustrated with reference to the following figures and examples.
A method for improving the calibration effect of a PLC analog input module channel is disclosed, the steps of the technical scheme are shown in figure 1, and the method comprises the following steps: and acquiring an analog input signal curve, dividing the signal curve into regions, calibrating the regions, and checking the calibration effect.
The step of obtaining a curve of the analog input signal plots expected values of a type of analog input signal over a complete measurement interval.
The expected value of a certain type of analog input signal in the whole measurement interval in the step of obtaining the analog input signal curve can be obtained through actual measurement or through calculation of a description function of the analog input signal of the type.
The step of dividing the signal curve into a plurality of sections, which can be approximately considered to be linear, divides the curve of the analog input signal into a plurality of sections according to the slope of the curve. As shown in fig. 2, the analog input signal curve of this type can be divided into two intervals, i.e. interval 1 and interval 2, according to the slope of the curve.
The step of dividing the signal curve into intervals may modify the boundaries of the respective intervals according to the result of the step of checking the calibration effect, or may continue to divide an interval into a plurality of smaller intervals.
Step of calibrating the partitions by using f for different partitionsi(X) = aiX + biAnd calibrating a plurality of sampling points in the interval according to a least square method to obtain a mapping relation between the channel original acquisition value and the calibrated value in the corresponding interval. For the interval 1 and the interval 2 shown in FIG. 2, respectivelyBy using f1(X) = a1X + b1And f2(X) = a2X + b2To represent the mapping relationship between the channel raw acquisition value and the calibrated value of the interval.
The step of calibrating the interval may be arranged to arrange relatively denser sampling points in the segment with the faster slope change according to the signal curve in the interval.
The step of checking the calibration effect converts the calibrated channel to the original acquisition value of the analog input signal into a calibrated value according to the mapping relation of the calibrated channel to different intervals, and compares the calibrated value with an expected value. The original channel acquisition value falls in the range of the signal curve interval 1 by adopting a mapping relation f1(X) = a1X + b1Converting into a calibrated value; the original channel acquisition value falls in the range of 2 of the signal curve interval, and a mapping relation f is adopted2(X) = a2X + b2And converting into a calibrated value. The result of comparing the calibrated value with the expected value can be used in the step of dividing the signal curve into regions as the basis for adjusting the boundary of the region.
The present invention is not limited to the above-described embodiments, and any obvious modifications or alterations to the above-described embodiments may be made by those skilled in the art without departing from the spirit of the present invention and the scope of the appended claims.
Claims (4)
1. A method for improving the calibration effect of a PLC analog input module channel is characterized in that the method comprises the following steps: obtaining an analog input signal curve, dividing the signal curve into regions, calibrating the regions, and checking the calibration effect; wherein the content of the first and second substances,
the step of obtaining the analog quantity input signal curve draws the expected value of a certain type of analog quantity input signal in a complete measurement interval as a curve;
the step of dividing the signal curve into a plurality of sections which can be approximately considered to be linear is to divide the curve of the analog quantity input signal into a plurality of sections according to the slope of the curve;
the step of calibrating among the different sections respectively adopts fi(X) = aiX + biCalibrating a plurality of sampling points in the interval according to a least square method to obtain a mapping relation between a channel original acquisition value and a calibrated value in the corresponding interval;
the step of checking the calibration effect converts the calibrated original acquisition value of the channel to the analog input signal into a calibrated value according to the mapping relation of the channel to different intervals, and compares the calibrated value with an expected value.
2. The method of claim 1, wherein the step of obtaining the analog input signal curve includes obtaining an expected value of a type of analog input signal over a complete measurement interval by actual measurement or by calculation using a description function of the type of analog input signal.
3. The method of claim 1, wherein the step of dividing the signal curve into intervals modifies the boundaries of the corresponding intervals or continues to divide an interval into smaller intervals according to the result of the step of checking the calibration effect.
4. The method of claim 1, wherein the step of calibrating the plurality of zones arranges relatively denser sampling points in the zone with faster slope change according to the signal curve in the zone.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011213624.3A CN112165330A (en) | 2020-11-04 | 2020-11-04 | Method for improving channel calibration effect of PLC analog input module |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011213624.3A CN112165330A (en) | 2020-11-04 | 2020-11-04 | Method for improving channel calibration effect of PLC analog input module |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112165330A true CN112165330A (en) | 2021-01-01 |
Family
ID=73865527
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011213624.3A Pending CN112165330A (en) | 2020-11-04 | 2020-11-04 | Method for improving channel calibration effect of PLC analog input module |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112165330A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113311374A (en) * | 2021-07-28 | 2021-08-27 | 绅克半导体科技(苏州)有限公司 | Method for calibrating direct current parameters of multiple test channels of semiconductor test machine |
-
2020
- 2020-11-04 CN CN202011213624.3A patent/CN112165330A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113311374A (en) * | 2021-07-28 | 2021-08-27 | 绅克半导体科技(苏州)有限公司 | Method for calibrating direct current parameters of multiple test channels of semiconductor test machine |
| CN113311374B (en) * | 2021-07-28 | 2021-11-09 | 绅克半导体科技(苏州)有限公司 | Method for calibrating direct current parameters of multiple test channels of semiconductor test machine |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR970007351B1 (en) | Analog to digital converter | |
| CN108494402B (en) | TIADC system error estimation and compensation method based on sine fitting | |
| CN105049049B (en) | A kind of capacitors exchange method for improving gradually-appoximant analog-digital converter DNL/INL | |
| CN108365847B (en) | Calibration method for parasitic capacitance of charge type SAR-ADC | |
| CN112165330A (en) | Method for improving channel calibration effect of PLC analog input module | |
| CN105897266B (en) | A kind of gradual approaching A/D converter having digital mismatch repair ability | |
| CN104617953A (en) | Calibration system and method suitable for current source array in multichannel sectional type current steering DAC (digital to analog converter) | |
| CN102045067A (en) | Conversion and calibration algorithm for improving output signal-to-noise ratio of successive approximation (SAR) analog-to-digital converter (ADC) and ADC | |
| CN107196657A (en) | The row level analog-digital converter that monocline and Approach by inchmeal are combined | |
| CN103620964B (en) | Switch sequencing for code-range-specific linearity improvement in digital-to-analog converters | |
| CN103532554A (en) | Capacitor array and capacitor array layout design method | |
| CN102299715B (en) | Production line A/D (analog to digital) converter and digital correcting method with overflow marker position | |
| CN108809310A (en) | The passive band logical Delta-Sigma modulators based on time-interleaved SAR ADC | |
| CN112039528B (en) | Capacitor array logic control method in successive approximation analog-to-digital converter | |
| CN104135289A (en) | Method and device of calibrating column-level ADC (Analog to Digital Converter) with multiple reference voltage and single slope | |
| CN105245227B (en) | Digital calibrating method for imaging sensor row grade circulation A DC | |
| CN105049050A (en) | Electric charge reallocation method for successive approximation analog-digital converter | |
| CN104753533B (en) | One kind is classified shared binary channels flow-line modulus converter | |
| CN115021754A (en) | TIADC sampling time mismatch digital correction method and system | |
| Cen et al. | Design of capacitor array in 16-bit ultra high precision SAR ADC for the wearable electronics application | |
| CN112104370B (en) | High-precision analog-to-digital converter conversion speed improving circuit | |
| CN106209106A (en) | A kind of position round-robin method improving hybrid resistor capacitor type analog-digital converter dynamic property | |
| CN204376877U (en) | A kind of calibration system being applicable to current source array in multi-channel sectional-type current steering digital-to-analog converter | |
| CN106199115B (en) | A kind of baseline zero bias automatic correcting method of digital oscilloscope | |
| CN102638270B (en) | Design and method of domain layout of 14-bit integrated circuit DAC (Digital to Analog Converter) current source array |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |