CN105353695A - Feedback event driven type analog signal frequency conversion acquisition circuit and acquisition method - Google Patents

Abstract

The invention discloses a feedback-type event-driven analog signal frequency conversion acquisition circuit, including a sensor, a low-pass filter, a voltage follower, an analog-to-digital converter, a first comparator, a second comparator, and a first digital-to-analog converter , the second digital-to-analog converter and the core controller; the invention can automatically adjust the sampling frequency according to the catastrophe situation, and can monitor the slow changes in the early stage and the conditions of the inducing factors for the catastrophe process of the geological body, so as to facilitate the study of the long-term catastrophe of the geological disaster Response; it can also effectively monitor the dynamic situation at the time of the disaster in time, which is conducive to the study of the transient dynamic characteristics of the disaster and facilitates the monitoring and early warning of disasters. It can minimize the power consumption of the system through the adaptive sampling rate adjustment, maximize the battery life of the system, and is more suitable for the practical application of the complex environment in the field.

Description

A feedback-type event-driven analog signal frequency conversion acquisition circuit and collection method

technical field

The invention relates to a geological acquisition circuit, in particular to a feedback event-driven analog signal frequency conversion acquisition circuit and acquisition method.

Background technique

The common problems of intelligent monitoring instruments in the field geological disaster monitoring process are as follows: (1) under severe weather conditions, such as long-term rainfall, haze, etc., monitoring instruments will stop running due to insufficient solar energy and battery power supply; ( 2) In the process of automatic monitoring of many geological disaster information, because the sampling rate of the acquisition circuit is set too low, it is impossible to capture the rapid change process of geological disasters immediately and completely at the time of emergency events such as the landslide acceleration and slipping stage, and the monitoring of disasters Both early warning and scientific research lead to the loss of a large amount of useful information; or because the sampling rate is set too high, resulting in a huge amount of data, under normal circumstances there is no catastrophe in the geological body or when the catastrophe is very small, the worthless data is lengthy, causing unnecessary data analysis and extraction. At the same time, it will consume more resources of the system, increase the cost and power consumption of the system, and the battery life of the instrument will drop sharply. For the catastrophe process of geological bodies, on the one hand, we need to pay attention to the slow changes in the early stage and the inducing factors, so as to facilitate the study of the long-term catastrophe response of geological disasters; Monitoring and early warning.

Contents of the invention

The purpose of the present invention is to provide a solution to the above-mentioned problems, which can automatically adjust the sampling frequency according to the catastrophe situation, reduce repetitive and lengthy data without losing the encrypted sampling data in the fast-changing stage, facilitate analysis and real-time early warning, through self-adaptive The sampling rate adjustment maximizes the reduction of system power consumption, maximizes the endurance of the system, and is more suitable for the practical application of the complex environment in the field. It is a feedback-type event-driven analog signal frequency conversion acquisition circuit.

In order to achieve the above object, the technical solution adopted by the present invention is as follows: a feedback-type event-driven analog signal frequency conversion acquisition circuit, including a low-pass filter, a voltage follower, an analog-to-digital converter, a first comparator, a second a comparator, a first digital-to-analog converter, a second digital-to-analog converter and a core controller;

The input end of the low-pass filter is connected to a sensor, and the output end is divided into three paths, which are respectively connected to the positive end of the voltage follower, the positive end of the first comparator, and the negative end of the second comparator. The sensor is a displacement sensor or a pressure sensor. sensor;

The two output terminals of the core controller are respectively connected to the negative terminal of the first comparator and the positive terminal of the second comparator through the first digital-to-analog converter and the second digital-to-analog converter,

The output terminals of the first comparator and the second comparator are connected with an OR logic operator, or the output terminal of the logic operator and the output terminal of the voltage follower are respectively connected with the trigger input terminal and the signal input terminal of the analog-to-digital converter;

The output of the analog-to-digital converter is divided into two paths, which are respectively connected to the core controller through an interrupt line and a data line. The core controller is also provided with a state control output, which is connected to the analog-to-digital converter through the state controller The input terminal is connected;

The core controller is also connected with a clock circuit, an RS232 communication interface circuit and a data storage unit.

As a preference: the core controller is a microcontroller, ARM processor or FPGA.

A feedback event-driven analog signal frequency conversion acquisition method, comprising the following steps:

(1) Build a feedback-type event-driven analog signal frequency conversion acquisition circuit;

(2) The sensor samples once and sends it to the core controller, and the core controller presets the threshold values of the first comparator and the second comparator according to the sampling value, and feeds them into the first comparator and the second comparator;

(3) Sensor sampling is divided into three channels after being filtered by a low-pass filter, one of which is sent to the analog-to-digital converter through a voltage follower, and the other two are sent to the first comparator and the second comparator to match the preset Thresholds are compared,

If the threshold is not exceeded, it will be sampled regularly and recorded and stored according to the preset sampling interval;

If the sampled value monitored by any comparator exceeds the preset threshold, the following operations are performed:

(a) Trigger or logic operator output high level;

(b) The high level controls the analog-to-digital converter to start the conversion function, and performs analog-to-digital conversion on the sampling value sent into the analog-to-digital converter through the voltage follower. After the conversion, the output interrupt wakes up the core controller, and reads the analog The converted sampling value of the digital converter is recorded and stored;

(c) The core controller according to the formula To calculate the correction threshold, where ΔV _i is the correction threshold, V _i and V _i-1 are the current sampling value and the last sampling value respectively, k is the control coefficient obtained according to the test and debugging data, Δt _i is the current sampling time and the last sampling value The difference at one sampling time;

(4) Feed the modified threshold into the first comparator and the second comparator, and repeat the above step (3).

As a preference: in step (2), the value of the sensor sampling once is V _i , then the preset thresholds in the first comparator and the second comparator are respectively V _i +ΔV and V _i −ΔV _i .

Compared with the prior art, the present invention has the advantages that: the present invention is a feedback-type event-driven analog signal frequency conversion acquisition circuit and acquisition method proposed for the working characteristics and existing problems of field geological disaster monitoring instruments, which can Automatically adjust the sampling frequency, and monitor the slow changes and inducing factors in the early stage of the catastrophe process of geological bodies, which is convenient for studying the long-term catastrophe response of geological disasters; it can also effectively monitor the dynamic situation at the time of catastrophe in time, which is conducive to research The transient dynamic characteristics of catastrophe facilitate disaster monitoring and early warning.

The present invention is based on the formula Calculate the correction threshold. It can be seen from the formula that the embedded control program of the core controller needs to correct the value of ΔV _i according to the change rate ratio between each sampling value and the last sampling value. The faster the growth rate, the smaller the ΔV _i . The greater the sampling density, the better the ability to capture the complete process of rapid changes. Moreover, due to the adoption of an adaptive sampling rate adjustment method, the power consumption of the system is minimized, the battery life of the system is maximized, and it is more suitable for practical applications in complex environments in the field.

Description of drawings

Fig. 1 is a functional block diagram of the present invention;

Fig. 2 is a schematic diagram of trigger sampling in the present invention;

Fig. 3 is a sampling diagram of the prior art;

Fig. 4 is a sampling diagram of the present invention.

In the figure: 1. Voltage follower; 2. First comparator; 3. Second comparator; 4. Analog-to-digital converter; 5. First digital-to-analog converter; 6. Second digital-to-analog converter; 7. 8. Clock circuit; 9. RS232 communication interface circuit; 10. Data storage unit; 11. Low-pass filter.

detailed description

The present invention will be further described below in conjunction with accompanying drawing.

Embodiment 1: Referring to Fig. 1 and Fig. 2, a feedback-type event-driven analog signal frequency conversion acquisition circuit includes a low-pass filter 11, a voltage follower 1, an analog-to-digital converter 4, a first comparator 2, a second Comparator 3, the first digital-to-analog converter 5, the second digital-to-analog converter 6 and the core controller; the input end of the low-pass filter 11 is connected to a sensor, and the output end is divided into three paths, respectively connected to the voltage follower 1 The positive terminal, the positive terminal of the first comparator 2, and the negative terminal of the second comparator 3 are connected, and the sensor is a displacement sensor or a pressure sensor; the two output terminals of the core controller are respectively passed through the first digital-to-analog converter 5, The second digital-to-analog converter 6 connects the negative terminal of the first comparator 2 and the positive terminal of the second comparator 3, and the output terminals of the first comparator 2 and the second comparator 3 are connected with an OR logic operator 7, or logic The output terminal of the arithmetic unit 7 and the output terminal of the voltage follower 1 are respectively connected with the trigger input terminal and the signal input terminal of the analog-to-digital converter 4; Line and data line are connected with core controller, and described core controller is also provided with a state control output end, is connected with the input end of analog-to-digital converter 4 by state controller; Described core controller is also connected with clock circuit 8, RS232 communication interface circuit 9 and data storage unit 10, in the present invention, the core controller is microcontroller, ARM processor or FPGA.

The acquisition method of a feedback event-driven analog signal frequency conversion acquisition circuit is as follows:

(1) Build a feedback-type event-driven analog signal frequency conversion acquisition circuit;

(2) The sensor is sampled once, after the high-frequency noise is removed by the low-pass filter 11, after being converted into a digital signal by the voltage follower 1 and the analog-to-digital converter 4, it is sent to the core controller. The sampling value is V _i , and at the same time, the core controller sets two thresholds V _i +ΔV, V _i -ΔV _i , which are converted into analog signals by the first digital-to-analog converter 5 and the second digital-to-analog converter 6 respectively, and fed into the first comparator 2 and the second comparator 3;

(3) The sensor is sampled again, and is divided into three paths after being filtered by the low-pass filter 11, wherein one path is sent to the analog-to-digital converter 4 through the voltage follower 1, and the other two paths are sent to the first comparator 2 and the second comparator Compared with the preset threshold in device 3, since the two thresholds are V _i + ΔV and V _i - ΔV, that is to say, when the change of V _i reaches ΔV, no matter whether it is decreasing ΔV or increasing ΔV, it will It is monitored by the corresponding comparator, and the change at this time is divided into two situations:

If the threshold is not exceeded, regular sampling and record storage will be performed according to the preset sampling interval; for example, regular sampling once a day or once an hour, depending on the specific situation. The purpose of this is to reduce the amount of data on the one hand and facilitate storage and transmission And analysis, on the other hand facilitates the healthy running state of the present invention;

If the sampled value monitored by any comparator exceeds the preset threshold, the following operations are performed:

(a) trigger or logic operator 7 output high level;

(b) the high level controls the analog-to-digital converter 4 to start the conversion function, and performs analog-to-digital conversion on the sampling value sent into the analog-to-digital converter 4 through the voltage follower 1, and outputs an interrupt after the conversion to wake up the core controller, Read the sampled value after the conversion of the analog-to-digital converter 4, and record and store;

(c) The core controller according to the formula To calculate the correction threshold, where ΔV _i is the correction threshold, V _i and V _i-1 are the current sampling value and the last sampling value respectively, k is the control coefficient obtained according to the test and debugging data, Δt _i is the current sampling time and the last sampling value The difference at one sampling time;

(4) Feed the modified threshold into the first comparator 2 and the second comparator 3, and repeat the above step (3).

From the above scheme we can see that:

In the present invention, in order to save resources and reduce the system power consumption generated by the continuous sampling conversion of the analog-to-digital converter 4 clock, the clock of the analog-to-digital converter 4 is not started, and an external trigger mode is used to start a single conversion of the analog-to-digital converter 4 . In Figure 2, assuming that the sampling value of a certain time is V _i , the analog voltage value at the next moment may be greater or less than this sampling value V _i , we assume that the next sampling value greater than V _i is V _i+1 and less than V i The next sampling value of _i is V _i+1 ', then the core controller feeds back and outputs the values of V _i +ΔV and V _i -ΔV respectively through the first and second digital-to-analog converters 6 for the first and second comparisons Comparing with the device 3, whether it is increased or decreased, as long as it exceeds the range of V _i ±ΔV, the OR logic operator 7 will output a logic high level, triggering the analog-to-digital converter 4 to start conversion. The embedded control program of the core controller needs to correct the value of ΔV _i according to the change rate ratio between each sampling value and the last sampling value. The faster the growth rate, the smaller the ΔV _i and the greater the sampling density, the more rapidly changing complete process. And in the period when there is no major change or very slight change, the microcontroller will start the sampling of the analog-to-digital converter 4 at regular intervals according to the output of the clock circuit 8, such as sampling once a day or once every hour, depending on the specific situation. On the one hand, reducing the amount of data is convenient for storage, transmission and analysis, and on the other hand, it is convenient to detect the healthy operation status of the system.

Refer to Fig. 3 and Fig. 4, Fig. 3 is a comparison diagram between the normal acquisition circuit data results and the sampling results of this patent. Conventional clock-driven sampling at a sampling frequency of 100Hz has 533,380 sampling points, while the event trigger method of the present invention only has 296 points, and can capture the entire process of displacement mutations. It can be seen that the present invention can be well applied in monitoring deformation parameters of loess landslides in the field.

Claims (4)

1. a feedback-type event-driven simulating signal frequency conversion Acquisition Circuit, is characterized in that:

Comprise low-pass filter, voltage follower, analog to digital converter, the first comparer, the second comparer, the first digital to analog converter, the second digital to analog converter and core controller;

Described low-pass filter input end connects a sensor, and output terminal is divided into three tunnels, and be connected with voltage follower anode, the first comparer anode, the second comparer negative terminal respectively, described sensor is displacement transducer or pressure transducer;

Two output terminals of described core controller connect the negative terminal of the first comparer and the anode of the second comparer respectively by the first digital to analog converter, the second digital to analog converter,

The output terminal of the first comparer, the second comparer connects one or logical-arithmetic unit, or the output terminal of the output terminal of logical-arithmetic unit and voltage follower is connected with the trigger input of analog to digital converter and signal input part respectively;

The output terminal of described analog to digital converter is divided into two-way, is connected with data line respectively by interrupt line with core controller, and described core controller is also provided with a state control output end, is connected with the input end of analog to digital converter by state controller;

Described core controller is also connected with clock circuit, RS232 communication interface circuit and data storage cell.

2. a kind of feedback-type event-driven simulating signal frequency conversion Acquisition Circuit according to claim 1, is characterized in that: described core controller is microcontroller, arm processor or FPGA.

3. a feedback-type event-driven simulating signal frequency-conversion collection method, is characterized in that: comprise the following steps:

(1) a kind of feedback-type event-driven simulating signal frequency conversion Acquisition Circuit is built;

(2) sensor sample is once, sends in core controller, is preset the threshold value of the first comparer, the second comparer by core controller according to this sampled value, and in feed-in first comparer, the second comparer;

(3) sensor sample, is divided into three tunnels after low-pass filter filtering, and wherein a road is sent in analog to digital converter through voltage follower, and two-way is sent in the first comparer, the second comparer and compared with predetermined threshold value in addition,

If do not exceed threshold value, then according to default sampling interval, timing sampling also records storage;

If the sampled value monitored in any one comparer exceedes predetermined threshold value, then proceed as follows:

A () triggers or logical-arithmetic unit exports high level;

B () described high level controls analog to digital converter and starts translation function, the sampled value sent into through voltage follower in analog to digital converter is carried out analog to digital conversion, export interruption after EOC and wake core controller up, read the sampled value after the conversion of analog to digital converter, and record stores;

C () core controller is according to formula calculate correction threshold, wherein, Δ V _ifor correction threshold, V _iand V _i-1be respectively current sample values and last time sampled value, k is the control coefrficient according to test adjustment data acquisition, Δ t _iit is the difference of current sample time and last sampling instant;

(4) by correction threshold feed-in first comparer, the second comparer, and above-mentioned steps (3) is repeated.

4. a kind of feedback-type event-driven simulating signal frequency-conversion collection method according to claim 1, it is characterized in that: in step (2), sensor sample value is once V _i, then the threshold value preset in the first comparer, the second comparer is respectively V _i+ Δ V, V _i-Δ V _i.