CN105698663A - Single-end network cable length measurement device and method - Google Patents
Single-end network cable length measurement device and method Download PDFInfo
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- CN105698663A CN105698663A CN201610263632.6A CN201610263632A CN105698663A CN 105698663 A CN105698663 A CN 105698663A CN 201610263632 A CN201610263632 A CN 201610263632A CN 105698663 A CN105698663 A CN 105698663A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/02—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
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- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
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Abstract
The invention discloses a single-end network cable length measurement device and method. The device comprises an acquisition module, a multi-harmonic-oscillation circuit and a controller. The acquisition module comprises an analog switch, a standard capacitor and an under-measurement network cable acquisition module. Eight wire cores of one network cable are accessed to the multi-harmonic-oscillation circuit in turn so as to realize charge and discharge of the network cable forming the principle of capacitance. The controller processes and calculates the number of pulses outputted by the multi-harmonic-oscillation circuit within a certain period of time and calculates the capacitance value of the wire core through comparison with the number of the pulses outputted by one standard capacitor accessed to the multi-harmonic-oscillation circuit within the same period of time. Then the capacitance value of the cable per meter is divided by the measured capacitance value of the wire core so as to obtain the length of the wire core. Then the remaining seven wire cores are completely measured so as to obtain the length of the cable, and the obtained length of the eight wire cores can be compared so as to obtain the position of open circuit of the wire cores of the cable. The single-end network cable length measurement device and method have advantages of being accurate, high in efficiency and relatively low in cost.
Description
Technical field
The present invention relates to screening parameter measurement Research field, particularly to the apparatus and method of a kind of single-ended measurement length of mesh wire。
Background technology
Now on the market, measure netting twine (electric wire) length and be generally adopted three kinds of methods:
The first is the mode adopting tape measure directly to measure, it is necessary to the substantial amounts of artificial and time, efficiency is non-normally low, but computational accuracy is the most accurate。
The second is to adopt tourelle, carrys out computational length by calculating tourelle circumference and the rolling number of turns。This method can reduce artificial and time in a way, but inconsistent owing to often enclosing radius, and is calculate by the circumference of tourelle when calculating, and increases error so that with the number of turns and also and then increases。
The third is to adopt electric-resistivity method to utilize electronic measuring instrument to measure, and needs the two ends end to end of wire to be inserted into respectively on instrument, just can measure when adopting test in this way。If wire has been install the wire rod come into operation just cannot measure。
Except three of the above method, the electronic machine also having, by wire rod is sent impulse wave, then detects echo, calculates and calculates length of wires from being sent to the time receiving echo。This device must apply high-precision ADC or high speed FPGA process chip just can detect faint echo, therefore cost is of a relatively high。
Therefore, study a kind of accurately, high and lower-cost measurement length of mesh wire the apparatus and method of efficiency have great importance。
Summary of the invention
It is an object of the invention to the shortcoming overcoming prior art with not enough, the apparatus and method of a kind of single-ended measurement length of mesh wire are provided, no matter whether netting twine accesses network for it, the length of each core in netting twine can be measured easily, and then draw the length of netting twine and whether have core to open a way have accurately, efficiency is high and lower-cost advantage。
The purpose of the present invention is realized by following technical scheme: the device of a kind of single-ended measurement length of mesh wire, including acquisition module, multi-resonant oscillating circuit, controller, described acquisition module includes analog switch, standard capacitance and netting twine acquisition module to be measured, when measuring, netting twine to be measured is connected with netting twine acquisition module to be measured；Described standard capacitance is connected with multi-resonant oscillating circuit by analog switch with netting twine acquisition module to be measured, and described multi-resonant oscillating circuit output square wave is to controller；Controller, for controlling the switching of analog switch, calculates the number of square wave and calculates the length of netting twine to be measured。
Preferably, described netting twine acquisition module to be measured is provided with 8 ports and a core to be measured switching circuit, and 8 ports are connected with eight cores in netting twine to be measured respectively, and core to be measured switching circuit is for accessing analog switch by corresponding port。Such that it is able to each core is carried out measurement of length。
Preferably, described multi-resonant oscillating circuit includes 555 intervalometers, the first resistance, the second resistance, charge and discharge capacitance, described 555 intervalometers include the first comparator and the second comparator, arrange high activation threshold value in the first comparator, arrange low activation threshold value in the second comparator；In measurement process, charge and discharge capacitance being carried out discharge and recharge, if the voltage in charging process in multi-resonant oscillating circuit reaches high activation threshold value, then the first comparator is output as low level, and multi-resonant oscillating circuit output sets to 0, and charge and discharge capacitance discharges；When the voltage in multi-resonant oscillating circuit in discharge process reaches low activation threshold value, then the second comparator is output as low level, and multi-resonant oscillating circuit output puts 1, and a discharge and recharge completes a rectilinear oscillation, exports a square wave。
Further, described device includes range handover module, for regulating the resistance of the first resistance in multi-resonant oscillating circuit, the second resistance。So that device can carry out the measurement of random length netting twine。
Preferably, between described multi-resonant oscillating circuit sum counter, it is provided with pre-filtering block, for the square wave of multi-resonant oscillating circuit output is carried out deburring process。
Preferably, described device includes LCD display module, is connected with controller, for showing the data when pre-test。
Preferably, described device includes keyboard input module, is connected with controller。Thus realizing man-machine interaction more easily。
A kind of method of the device based on above-mentioned single-ended measurement length of mesh wire, including step:
One end of netting twine to be measured is connected with netting twine acquisition module to be measured, standard capacitance is first accessed multi-resonant oscillating circuit by analog switch, multi-resonant oscillating circuit output square wave is to controller, controller calculates the square wave number n1 that certain time internal standard electric capacity is corresponding, then netting twine acquisition module to be measured is accessed multi-resonant oscillating circuit by analog switch, multi-resonant oscillating circuit output square wave is to controller, and controller calculates the square wave number n2 that in the identical time, netting twine to be measured is corresponding；Represent the capacitance of standard capacitance according to n1/n2=C2/C1, C1, obtain the electric capacity C2 that netting twine to be measured is corresponding；According to L=C2/CPCalculate the length L, wherein C that obtain cablePCapacitance for unit length。Wherein CPThe actual measurement of test of many times can be passed through obtain。
Preferably, eight cores in described netting twine to be measured are connected with netting twine acquisition module to be measured respectively through port, and above-mentioned 8 cores are measured length respectively；Presetting a length threshold, find core length maximum, if the difference of the length measurements of other cores and core length maximum exceedes length threshold, then this core is opened a way, and obtains open circuit according to the length measurements of core and position occurs。
Preferably, described device is provided with different gears according to the length of netting twine to be measured, before measurements, first select a gear, gear information is converted to control signal and is sent to range handover module by controller, and range handover module regulates the resistance of the first resistance, the second resistance in multi-resonant oscillating circuit according to control signal。By arranging different gear, it is possible to making measurement more accurate, application scenario is wider。
The present invention compared with prior art, has the advantage that and beneficial effect:
The present invention only needs one end of connected with network cable, and no matter whether netting twine accesses network, all can obtain the length of netting twine at once。Complete machine cost is low, easy to operate, it is possible to measures easily and needs the netting twine how long prepared to be replaced, and is particluarly suitable for netting twine and installs and use when changing。The present invention can also measure the particular location of netting twine open circuit simultaneously, and error is in 2 meters。Have accurately, efficiency is high and lower-cost advantage。
Accompanying drawing explanation
Fig. 1 is the schematic diagram adopting capacitance method to carry out length of mesh wire measurement。
Fig. 2 is the structure principle chart of device described in the present embodiment。
Fig. 3 is the hardware circuit diagram of device described in the present embodiment。
Fig. 4 is the workflow diagram of device described in the present embodiment。
Fig. 5 is the circuit diagram of the present embodiment 555 intervalometer。
Fig. 6 is the circuit diagram of the present embodiment multi-resonant oscillating circuit。
Detailed description of the invention
Below in conjunction with embodiment and accompanying drawing, the present invention is described in further detail, but embodiments of the present invention are not limited to this。
Embodiment 1
The device of the single-ended measurement length of mesh wire described in the present embodiment for as if Fig. 1 shown in netting twine, netting twine has 8 cores, the present embodiment adopts capacitance method to carry out the measurement of length of mesh wire, if user confirms that netting twine is no problem, it is intended merely to the length measuring netting twine, so can arbitrarily take the measurement of one of them core, by other seven core ground connection, using the measured value length value as netting twine。If user does not confirm that netting twine is either with or without open circuit, so can take turns to access device described in the present embodiment by the 8 of a netting twine piece core, measure the length obtaining every core, if 8 core length are in certain range of error, so it can be assumed that netting twine is normal, if wherein one or several threads core length compare with core maximum, exceed certain limit value, then it is assumed that these cores occur in that open circuit, core length owing to currently calculating refers to the link length to open circuit, then just can directly obtain the position of open circuit。It is particularly suitable for netting twine and measurement length of mesh wire when changing is installed。
The device of a kind of single-ended measurement length of mesh wire of the present embodiment includes acquisition module, multi-resonant oscillating circuit, controller, LCD display module and keyboard input module, and controller adopts cpu controller to realize。Below in conjunction with Fig. 2,3,5,6, its concrete structure is illustrated。
Described acquisition module includes analog switch, standard capacitance and netting twine acquisition module to be measured, the electric capacity of standard capacitance is known, it is C1, netting twine acquisition module to be measured is provided with 8 ports and a core to be measured switching circuit, when measurement, 8 ports are connected with eight cores in netting twine to be measured respectively, and the break-make of 8 ports is to switch circuit by core to be measured to complete, when to detect one of them core, just only this core is turned on。Standard capacitance is connected with an input of analog switch respectively with netting twine acquisition module to be measured, and analog switch is connected with cpu controller, selects conducting standard capacitance or netting twine acquisition module to be measured according to the control signal of cpu controller。The outfan of analog switch is connected with multi-resonant oscillating circuit。
Owing to the capacitance of the common 5 class netting twines of length one meter probably only has about 49pF, if being only difficult to precisely measure out the size of electric capacity by the single discharge and recharge time, and test random error also can be relatively larger。Oscillating circuit is utilized to treat the repeatedly discharge and recharge of survey line core thus obtaining the more accurate discharge and recharge time so the present embodiment adopts。
Referring to Fig. 5, the present embodiment oscillating circuit adopts 555 intervalometers, and 555 contain two the first comparator A1, the second comparator A2。A1 reference voltage (high activation threshold value) isThe reference voltage (low activation threshold value) of A2 isWhenTime, A2 is output as 1；Work as UTL< during Ucc, A2 is output as 0, then make R-S trigger put 1。Work as UTH< during Ucc, A1 is output as 1；UTH> Ucc time, A1 is output as 0, makes R-S trigger reset。5 ends are voltage controling end, by an external reference power source, thus it is possible to vary upper and lower evoked potential value, the not used time, can pass through a 0.01uF shunt capacitance ground connection。4 ends are for triggering reset terminal, and the used time should not connect high level。In a word, 555 intervalometers be equivalent to one can analog voltage control upset R-S trigger。
With the schematic diagram of the multi-resonant oscillating circuit of 555 intervalometer compositions referring to Fig. 6。Multi-resonant oscillating circuit includes 555 intervalometers, the first resistance R1, the second resistance R2, charge and discharge capacitance C。As Vc because C charging is risen to by power onTime, the first comparator A1 is output as low level, makes the output of R-S trigger set to 0, and T turns on, and electric capacity C is discharged by T；When Vc because electric capacity electric discharge and reduce to slightly belowTime, the second comparator A2 is output as low level, make R-S trigger output put 1, T cut-off, electric capacity C continue charging until Vc slightly aboveTime, trigger is turned to again 0, thus completing a rectilinear oscillation。
Its frequency of oscillation can calculate by below equation:
F=1.43/ (R1+2R2) C；
So when resistance R1 and R2 is known, as long as the frequency of oscillation f measuring output just can obtain capacitance C。
According to multi-resonant oscillating circuit pulse computing formula f=1.43/ (R1+2R2) C, when R1 and R2 is fixing, C is increasing, and f will be more and more less, and square-wave cycle is increasing, after C reaches certain value, can cause that square wave does not observe。In order to be effectively increased the measurement range of device described in the present embodiment, it is provided with a range handover module, this range handover module is connected with cpu controller, for regulating the resistance of the first resistance R1 in multi-resonant oscillating circuit shown in Fig. 6, the second resistance R2, such that it is able to avoid the situation that square wave can't detect。
The square wave of the present embodiment multi-resonant oscillating circuit output first passes through the enumerator entering back in cpu controller after a pre-filtering block is filtered and counts。Pre-filtering block is for carrying out deburring process to the pulse square wave of multi-resonant oscillating circuit output, to ensure the accuracy that subsequent data processes。
The present embodiment, cpu controller is connected with LCD display module, keyboard input module, analog switch, pre-filtering block, range handover module respectively, and effect includes processing the instruction of keyboard input module input, controls range switching, switches cable to be measured and standard capacitance, the square wave of multi-resonant oscillating circuit output is counted, calculated the length of netting twine to be measured, length data and open circuit data are delivered to LCD display module and displayed etc.。
The principle that realizes of the present embodiment is:
First, the standard capacitance (assuming that its capacitance is C1, it is noted that as far as possible select high-precision electric capacity) of a known parameters being accessed multi-resonant oscillating circuit one frequency of generation is the square-wave pulse of f1。Then the pulse number in the counters count time t of cpu controller is utilized, it is assumed that for n1。
Secondly, disconnect the connection of known standard capacitance and multi-resonant oscillating circuit, netting twine to be measured is accessed and replaces standard capacitance, if the electric capacity that C2 is this netting twine to be measured, now multi-resonant oscillating circuit produces a frequency is the square-wave pulse of f2, also with the pulse number n2 in the counters count time t of cpu controller。
Relation according to multi-harmonic-oscillations output pulse frequency Yu electric capacity C: f=1.43/ (R1+2R2) C, can obtain: f1/f2=C2/C1。Because f1=n1/t, f2=n2/t, so n1/n2=C2/C1, therefore only it is to be understood that the value of n1, n2 and standard capacitance C1, it is possible to converse the value of electric capacity C2。
Again owing to the length of cable and its capacitance have relation: L=C2/CP, C in formulaPFor the capacitance of unit length, being a fixed value, these data can pass through big measurement, measures cable every meter institute capacitor value and obtains。By above-mentioned analysis it can be seen that the length of cable just can be calculated after calculating cable capacitance capacity to be measured。Due to CPBeing affected by the external environment little, the length of cable therefore calculated by the method has higher degree of accuracy。
Below in conjunction with Fig. 4, the process that implements of the present embodiment is illustrated。
1, when holding state, LCD display module " please press measurement button ", and measuring button can be the button on touch screen, it is also possible to be arranged in input through keyboard module, can certainly be arranged on the outer end of the present embodiment device as an independent button, this measurement button is connected with controller。
2, when user determines measurement, pressing this measurement button, which root core what controller first detected current detection is, if the 8th, illustrating that whole netting twine cable all detects complete, the information such as length data, open circuit data that directly exports displays on LCD display module。
If current netting twine to be measured wherein core is but without detecting, then begin to carry out normal process of measurement below。
3, in order to make measurement result accurate, user's approximate size according to current tested netting twine, select it to belong to 1-100m, be also above 100m, then select different gears。After this gear information is input to controller, controller sends signal to range handover module, and range handover module adjusts the resistance of the first resistance R1, the second resistance R2 in multi-resonant oscillating circuit according to signal。
4, according to current core is linked into multi-resonant oscillating circuit realize to formed capacitance principle netting twine carry out discharge and recharge。Cpu controller processes and calculates the pulse number of multi-resonant oscillating circuit output in certain time, and compares, by output pulse number in the time same with the standard capacitance accessing multi-resonant oscillating circuit, the capacitance calculating core。Then with the capacitance of every rice noodle cable divided by the core capacitance surveyed, current core length can be drawn。
Certainly, in actual applications, after the length of all 8 cores is all calculated, obtain eight core length being compared, comparative approach has a lot, such as can preset a length threshold, find core length maximum, the length measurements of other 7 cores is compared with core length maximum respectively, if the difference between the two exceedes length threshold, then judge that this core is opened a way, obtain open circuit according to the length measurements of core and position occurs。Then above-mentioned open-circuit position information is sent to LCD display module to display。Thus realizing open circuit detection。
Above-described embodiment is the present invention preferably embodiment; but embodiments of the present invention are also not restricted to the described embodiments; the change made under other any spirit without departing from the present invention and principle, modification, replacement, combination, simplification; all should be the substitute mode of equivalence, be included within protection scope of the present invention。
Claims (10)
1. the device of a single-ended measurement length of mesh wire, it is characterized in that, including acquisition module, multi-resonant oscillating circuit, controller, described acquisition module includes analog switch, standard capacitance and netting twine acquisition module to be measured, when measuring, netting twine to be measured is connected with netting twine acquisition module to be measured；Described standard capacitance is connected with multi-resonant oscillating circuit by analog switch with netting twine acquisition module to be measured, and described multi-resonant oscillating circuit output square wave is to controller；Controller, for controlling the switching of analog switch, calculates the number of square wave and calculates the length of netting twine to be measured。
2. the device of single-ended measurement length of mesh wire according to claim 1, it is characterized in that, described netting twine acquisition module to be measured is provided with 8 ports and a core to be measured switching circuit, 8 ports are connected with eight cores in netting twine to be measured respectively, and core to be measured switching circuit is for accessing analog switch by corresponding port。
3. the device of single-ended measurement length of mesh wire according to claim 1, it is characterized in that, described multi-resonant oscillating circuit includes 555 intervalometers, the first resistance, the second resistance, charge and discharge capacitance, described 555 intervalometers include the first comparator and the second comparator, high activation threshold value is set in the first comparator, low activation threshold value is set in the second comparator；In measurement process, charge and discharge capacitance being carried out discharge and recharge, if the voltage in charging process in multi-resonant oscillating circuit reaches high activation threshold value, then the first comparator is output as low level, and multi-resonant oscillating circuit output sets to 0, and charge and discharge capacitance discharges；When the voltage in multi-resonant oscillating circuit in discharge process reaches low activation threshold value, then the second comparator is output as low level, and multi-resonant oscillating circuit output puts 1, and a discharge and recharge completes a rectilinear oscillation, exports a square wave。
4. the device of single-ended measurement length of mesh wire according to claim 3, it is characterised in that described device includes range handover module, for regulating the resistance of the first resistance in multi-resonant oscillating circuit, the second resistance。
5. the device of single-ended measurement length of mesh wire according to claim 1, it is characterised in that be provided with pre-filtering block between described multi-resonant oscillating circuit sum counter, for carrying out deburring process to the square wave of multi-resonant oscillating circuit output。
6. the device of single-ended measurement length of mesh wire according to claim 1, it is characterised in that described device includes LCD display module, is connected with controller, for showing the data when pre-test。
7. the device of single-ended measurement length of mesh wire according to claim 1, it is characterised in that described device includes keyboard input module, is connected with controller。
8. the method based on the device of the single-ended measurement length of mesh wire described in any one of claim 1-7, it is characterised in that include step:
One end of netting twine to be measured is connected with netting twine acquisition module to be measured, standard capacitance is first accessed multi-resonant oscillating circuit by analog switch, multi-resonant oscillating circuit output square wave is to controller, controller calculates the square wave number n1 that certain time internal standard electric capacity is corresponding, then netting twine acquisition module to be measured is accessed multi-resonant oscillating circuit by analog switch, multi-resonant oscillating circuit output square wave is to controller, and controller calculates the square wave number n2 that in the identical time, netting twine to be measured is corresponding；Represent the capacitance of standard capacitance according to n1/n2=C2/C1, C1, obtain the electric capacity C2 that netting twine to be measured is corresponding；According to L=C2/CPCalculate the length L, wherein C that obtain cablePCapacitance for unit length。
9. above-mentioned 8 cores are measured length by method according to claim 8, it is characterised in that eight cores in described netting twine to be measured are connected with netting twine acquisition module to be measured respectively through port respectively；Presetting a length threshold, find core length maximum, if the difference of the length measurements of other cores and core length maximum exceedes length threshold, then this core is opened a way, and obtains open circuit according to the length measurements of core and position occurs。
10. method according to claim 8, it is characterized in that, described device is provided with different gears according to the length of netting twine to be measured, before measurements, first select a gear, gear information is converted to control signal and is sent to range handover module by controller, and range handover module regulates the resistance of the first resistance, the second resistance in multi-resonant oscillating circuit according to control signal。
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| CN201610263632.6A CN105698663A (en) | 2016-04-25 | 2016-04-25 | Single-end network cable length measurement device and method |
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| CN201610263632.6A CN105698663A (en) | 2016-04-25 | 2016-04-25 | Single-end network cable length measurement device and method |
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| CN109100606A (en) * | 2018-07-12 | 2018-12-28 | 广州仪安电子有限公司 | Network wire crystal joint test method and network wire crystal joint test device |
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| WO2021093579A1 (en) * | 2019-11-12 | 2021-05-20 | 南京宏泰半导体科技有限公司 | Waveform measuring method |
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Application publication date: 20160622 |
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