CN201532230U

CN201532230U - Digital capacitance type material-level transmitter

Info

Publication number: CN201532230U
Application number: CN2009201107250U
Authority: CN
Inventors: 彭光正
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-08-10
Filing date: 2009-08-10
Publication date: 2010-07-21
Anticipated expiration: 2019-08-10

Abstract

A digital capacitance type material-level transmitter includes a multivibrator, a monostable trigger, a filter, a singlechip system, a pressure flow converter and a probe; both the multivibrator and the monostable trigger are formed by a 7555 stage peripheral device, the filter is realized through RC two-stage filtering, the singlechip system is realized through a M68HC908JK3 singlechip minimum system, the pressure flow converter is realized through a pressure flow conversion chip XTR110, and the height of material to be detected is measured by measuring the dielectric constant of a capacitor formed a transmitter probe and capacitor walls. The material-level transmitter has the advantages of simple structure, reliable circuit, easy manufacture, high measuring precision, low cost, strong antijamming ability and flexible calibration.

Description

The digit capacitance level position transducer

Technical field

The utility model relates to a kind of height of materials measuring instrument, and the utility model relates to a kind of digit capacitance level position transducer more specifically, measures the height of tested material by the measuring transducer probe and the size of the capacitor specific inductive capacity of chamber wall formation.

Background technology

At present, the used digit capacitance level position transducer of China from Germany and U.S.'s import, costs an arm and a leg mostly.And that the level position transducer of domestic production mostly is greatly is analog, antijamming capability and demarcate dirigibility all not as good as digital.For this reason, it is very necessary designing and make the digit capacitance level position transducer voluntarily.

Summary of the invention

The purpose of this utility model is to overcome the deficiencies in the prior art, and the digit capacitance level position transducer that a kind of antijamming capability is strong, demarcation is flexible, cheap is provided.

The technical solution of the utility model is achieved in that

A kind of digit capacitance level position transducer, measure the height of tested material by the measuring transducer probe and the size of the capacitor specific inductive capacity of chamber wall formation, it comprises multivibrator, monostalbe trigger, wave filter, Single Chip Microcomputer (SCM) system, the baric flow conversion, probe, the multivibrator output amplitude, the square wave that cycle and dutycycle are all certain, this square wave is done the input of monostalbe trigger, monostalbe trigger is also exported square wave, its amplitude, cycle is consistent with input, dutycycle is directly proportional with the capacitance of the probe of a variation, the DC voltage of gained is directly proportional with capacitance behind filter filtering, is converted to the electric current output that is directly proportional with the capacitance of popping one's head in through Single Chip Microcomputer (SCM) system and baric flow.Wherein multivibrator and monostalbe trigger are made of 7555 grades of peripheral components of a slice respectively, wave filter adopts the filtering of RC secondary to realize, Single Chip Microcomputer (SCM) system adopts the M68HC908JK3 single-chip minimum system to realize, the baric flow conversion adopts baric flow conversion chip XTR110 to realize.

This practicality is new for compared with prior art novel, and following good effect is arranged:

1, the utility model is simple in structure, circuit is reliable;

2, the utility model is easy to making, measuring accuracy height;

3, the utility model is cheap;

4, the utility model antijamming capability is strong;

5, the utility model is demarcated flexibly.

Description of drawings

Fig. 1 is the utility model structure collectivity block diagram.

Fig. 2 is the utility model test section circuit diagram.

Fig. 3 is the utility model numeral transmission circuit partial circuit figure.

Fig. 4 is the utility model baric flow conversion portion circuit diagram.

Fig. 5 does not have the part layout for the utility model circuit board.

Fig. 6 is the utility model board top surface wiring diagram.

Fig. 7 is the utility model circuit board bottom surface wiring diagram.

Among the figure: 1-multivibrator, 2-monostalbe trigger, 3-wave filter, 4-Single Chip Microcomputer (SCM) system, the conversion of 5-baric flow, 6-probe.

Embodiment

Describe the utility model most preferred embodiment in detail below in conjunction with accompanying drawing:

By shown in Figure 1, the digit capacitance level position transducer, mainly by multivibrator 1, monostalbe trigger 2, wave filter 3, Single Chip Microcomputer (SCM) system 4, baric flow conversion 5, probe 6 are formed.

Multivibrator 1 is output as all certain square wave of amplitude, cycle and dutycycle, and this square wave is done the input of monostalbe trigger 2.The output of monostalbe trigger 2 also is square wave, its amplitude, cycle are consistent with input, dutycycle is directly proportional with the capacitance Cx of the probe 6 of a variation, the DC voltage of gained and Cx also are the relations of direct ratio after wave filter 3 filtering, through Single Chip Microcomputer (SCM) system 4 and baric flow conversion 5, obtain the electric current output that is directly proportional with 6 the capacitance Cx of popping one's head in.Cx is the capacitance between the transmitter two-plate.By above analysis as can be known, electric current output Io is the relation that is directly proportional with the height of tested material.

Single Chip Microcomputer (SCM) system 4 is made up of the M68HC908JK3 single-chip minimum system of motorola inc, it is XTR110 that baric flow is changed 5 chips, can realize the hole capital after selling all securities demarcation by operation to button, the demarcation of buying securities with all one's capital, the parameter locking, parameter release and function such as reset, it will from the voltage of I/O mouth input through carry out again after the A/D conversion suitable processing then after the D/A conversion output dc voltage (scope is 1～5V), this DC voltage obtains electric current output Io after pressure/stream translation, the height of this electric current and tested material is the relation of direct ratio.

Multivibrator 1 and monostalbe trigger 2 are made of 7555 grades of peripheral components of a slice respectively, and components and parts are selected as follows: R1-10k; R2-2k; R3-5k; Rx-200k; C1-0.01; C2-0.01; C3-0.1; C4-0.01.

Baric flow conversion 5 is realized by a slice XTR110.XTR110 be aim at analog signal conversion design become the accurate converter of electric current by voltage transition.Metalfilmresistor network accurate in the sheet provides the ratio of the linear dependence from the input voltage to the output current, and its input voltage is 0～10V, and output current is 4～20mA.XTR110 is inner to also have an independent important parameter, i.e. the reference voltage of 10V output is commonly used to drive external circuit or as its 3 pin reference voltages input.Usefulness the 10V reference voltage is here exported and is driven operational amplifier in the actual design, reconciles two potentiometers and makes amplifier be output as 1～5V.

Fig. 4 is the circuit diagram that 0～10V input produces 4～20mA electric current.4 pin are voltage input end; 13 pin and 14 pin connect the S utmost point and the G utmost point of P-Channel MOSFET respectively; The D utmost point connects load, output current.The input of XTR110 is 1～5V in this utility model, is output as 4～20mA, the mode of connection:

3,4,9,10 connects common port, and pin 5 is input.

This transmitter probe 6 forms a capacitor with chamber wall.The size of the specific inductive capacity decision capacitance Cx of surface area, the distance between the two-plate and the tested material of capacitor plate (probe 6 and chamber wall).After probe 6 was fixedly installed on the chamber wall, when the specific inductive capacity of tested material was constant, capacitance Cx this moment only depended on the height of tested material, and was directly proportional with the thing position.By transmitter the electric capacity of measuring is converted to continuous 4～20mA simulating signal output.

Claims

1. digit capacitance level position transducer, comprise multivibrator, monostalbe trigger, wave filter, Single Chip Microcomputer (SCM) system, the baric flow conversion, probe, it is characterized in that: the multivibrator output amplitude, the square wave that cycle and dutycycle are all certain, this square wave is done the input of monostalbe trigger, monostalbe trigger is also exported square wave, its amplitude, cycle is consistent with input, dutycycle is directly proportional with the capacitance of the probe of a variation, the DC voltage of gained is directly proportional with capacitance behind filter filtering, is converted to the electric current output that is directly proportional with the capacitance of popping one's head in through Single Chip Microcomputer (SCM) system and baric flow.

2. digit capacitance level position transducer according to claim 1 is characterized in that: described multivibrator and monostalbe trigger are made of 7555 grades of peripheral components of a slice respectively.

3. digit capacitance level position transducer according to claim 1 is characterized in that: described wave filter adopts the filtering of RC secondary to realize.

4. digit capacitance level position transducer according to claim 1 is characterized in that: described Single Chip Microcomputer (SCM) system adopts the M68HC908JK3 single-chip minimum system to realize.

5. digit capacitance level position transducer according to claim 1 is characterized in that: described baric flow conversion adopts baric flow conversion chip XTR110 to realize.