CN203148375U

CN203148375U - Plastic thickness measurement apparatus based on plane capacitance sensor

Info

Publication number: CN203148375U
Application number: CN 201320089761
Authority: CN
Inventors: 李安阳; 徐凯; 尹武良; 王奔
Original assignee: Changzhou Zhaoneng Electronic Science & Technology Co Ltd
Current assignee: Changzhou Zhaoneng Electronic Science & Technology Co Ltd
Priority date: 2013-02-27
Filing date: 2013-02-27
Publication date: 2013-08-21
Anticipated expiration: 2023-02-27

Abstract

The utility model relates to a plastic thickness measurement apparatus based on a plane capacitance sensor, which belongs to the field of a capacitance sensing technology. The plastic thickness measurement apparatus based on a plane capacitance sensor is used for detecting the thickness of a plastic film. The plastic thickness measurement apparatus based on a plane capacitance sensor comprises a sensor, D/A and A/D converting circuits, a one-chip microcomputer and a host computer. The sensor is a plane capacitance sensor comprising three metal electrodes, wherein one is an excitation electrode, and the other two are reception electrodes; the excitation signal generated by the one-chip microcomputer is loaded on the excitation electrode after DA conversion and power amplification; the signal received from the two reception electrodes is sent to the one-chip microcomputer after signal conditioning and AD converting; the one-chip microcomputer sends the obtained capacitance values C12 and C13 between the excitation electrode and the two reception electrodes to the host computer; the host computer compares the obtained capacitance values to the relation curve of a preselected stored capacitance ratio and the thickness of the plastic film to achieve thickness detection to the plastic film. The plastic thickness measurement apparatus based on a plane capacitance sensor is advantageous in that the usage is simple, measurement is rapid, and cost is low.

Description

A kind of plastics measuring thickness device based on planar capacitance sensor

Technical field

The utility model belongs to the capacitive sensing techniques field, relates to a kind of device and detection method of plastic foil detecting thickness.

Background technology

Plastic foils such as Polyvinylchloride, tygon, polypropylene are used very extensive at aspects such as industry, agricultural and packagings for foodstuff, output is very big, and description is a lot.One of most important quality index of finished product plastic foil must be controlled in process of production during thickness.

The method of plastics thickness probing both at home and abroad has four kinds: the one, and there is thicknessmeter to detect, robot calculator carries out Automatic Control, though this method accuracy is higher, the electronics of the method and plant equipment complexity, expensive, use seldom; Two are based on artificial on-line monitoring, manual shift control, and cost saving, effect is remarkable, is general urgent the employing, but testing result varies with each individual, and scattered property is very big, can not reflect the quality of production comprehensively.Three kinds is the beta thickness gauge that grows up the fifties, that technology has become is ripe, accuracy is also better, but exist radioactive ray to the harm of workman's human body, use and maintenance technology requirement height, price is expensive, and response speed waits shortcoming slowly, and at last a kind of is the infrared gauge that grows up the seventies, though it has overcome some shortcomings of beta thickness gauge, its adaptive faculty is relatively poor.

The utility model content

The purpose of this utility model is to overcome the deficiencies in the prior art, proposes a kind of simple quick and lower-cost plastic foil detecting thickness device and method.The technical solution of the utility model is as follows:

A kind of plastics measuring thickness device based on planar capacitance sensor, be used for the detection of plastic foil thickness, comprise sensor, D/A and A/D change-over circuit, single-chip microcomputer and host computer, described sensor is planar capacitance sensor, formed by 3 metal electrodes that are evenly distributed on search coverage top sustained height, one is exciting electrode, two other is receiving electrode, be carried on the exciting electrode after the pumping signal process DA conversion that single-chip microcomputer produces and the power amplification, the signal that receives from two receiving electrodes is respectively through being admitted in the single-chip microcomputer after signal condition and the AD conversion, single-chip microcomputer is with the capacitance C12 between the exciting electrode that obtains and two receiving electrodes, C13 sends into host computer, by host computer the capacitance ratio of itself and preliminary election storage is compared with the relation curve of plastic foil thickness, realize the thickness detection of plastic foil.

Great advantage of the present utility model is not contact plastic foil, do not influencing under the prerequisite of production run, surveys plastic foil thickness quickly and easily, and the state of monitoring plastic films production lines is produced machine authentic communication is provided for further regulating.Relative additive method, this technology is more practical and convenient, and is fast simple, and cost is lower, is one of plastics thickness detecting strategy that has feasibility.

Description of drawings

Fig. 1 is the plastic foil detecting thickness structure drawing of device based on capacitive transducer of the present utility model;

Fig. 2 is capacitive transducer principle rough schematic of the present utility model.

Embodiment

Fig. 1 is the sniffer structured flowchart that draws according to an embodiment of the present utility model.Comprise capacitive transducer, D/A and A/D change-over circuit, power amplification and signal conditioning circuit, single-chip microcomputer, host computer 5 parts.

Capacitive transducer adopts 3 groups of identical battery lead plates to constitute, and electrode is made by metal light paper tinsel, and thickness is 0.001-1mm, and electrode size, spacing can be surveyed the corresponding adjustment of plastic foil thickness according to breaking.3 groups of electrodes are positioned at tested plastic foil top, and electrode plane is parallel with plastic foil.One of them battery lead plate is as excitation, and two other electrode utmost point is as detecting electrode, as shown in Figure 2.

If the capacitance that the electrode 1 among Fig. 1 and Fig. 2 and electrode 2 form is C12, the capacitance that electrode 1 and electrode 3 form is C13.Utilize the measurement of chip microcontroller capacitance C12, C13.Single-chip microcomputer provides the logical sequence of original excitation signal, control entire circuit for pole plate, and finishes the data communication with host computer.

The AD9754 chip is connected single-chip microcomputer and capacitor plate with the AD9240 chip, realizes D/A and A/D conversion, and the AD9754 chip is connected between single-chip microcomputer output interface and the exciting electrode, and the AD9240 chip is connected between receiving electrode and the single-chip microcomputer input interface.Single-chip microcomputer is by USB and upper machine communication, and host computer can show capacitance C12, C13 and the plastic foil one-tenth-value thickness 1/10 D of on-line measurement in real time, and has data storage function.

Concrete measuring method comprises following key step:

(1) capacitive transducer with detecting devices is fixed in above the plastic foil, placing smooth back switches on to equipment, send the excitation instruction by host computer to single-chip microcomputer, single-chip microcomputer is by measuring equivalent capacitance value C12, the C13 between the induced voltage calculating pole plate that detects the utmost point utmost point, and be real-time transmitted to the host computer preservation, and capacitance is presented on the VC interface of host computer;

(2) should use the same method the different plastic foil of thickness is surveyed, can obtain the equivalent capacity C13 of a series of different-thickness plastic foil correspondences and the ratio of equivalent capacity C12; Can obtain relation curve between plastics thickness D and the corresponding C13/C12 by three sample interpolation and standardization.

(3) deposit relation curve in host computer, and should use the same method to the plastic foil of unknown thickness and to measure capacitance ratio C13/C12.Host computer can be tried to achieve plastic foil thickness D by reverse calculating, and shows the plastic foil one-tenth-value thickness 1/10 of surveying at the VC interface.

Claims

1. plastics measuring thickness device based on planar capacitance sensor, be used for the detection of plastic foil thickness, comprise sensor, D/A and A/D change-over circuit, single-chip microcomputer and host computer, it is characterized in that, described sensor is planar capacitance sensor, formed by 3 metal electrodes that are evenly distributed on search coverage top sustained height, one is exciting electrode, two other is receiving electrode, be carried on the exciting electrode after the pumping signal process DA conversion that single-chip microcomputer produces and the power amplification, the signal that receives from two receiving electrodes is respectively through being admitted in the single-chip microcomputer after signal condition and the AD conversion, single-chip microcomputer is with the capacitance C12 between the exciting electrode that obtains and two receiving electrodes, C3 sends into host computer, is realized that by host computer the thickness of plastic foil detects.