CN1218186C - Sensitive-element current-voltage characteristic measuring apparatus - Google Patents
Sensitive-element current-voltage characteristic measuring apparatus Download PDFInfo
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- CN1218186C CN1218186C CN 03125278 CN03125278A CN1218186C CN 1218186 C CN1218186 C CN 1218186C CN 03125278 CN03125278 CN 03125278 CN 03125278 A CN03125278 A CN 03125278A CN 1218186 C CN1218186 C CN 1218186C
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- sensitive element
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- output terminal
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Abstract
The present invention discloses a device for testing the volt-ampere characteristic of a sensitive element. The device is characterized in that a computer outputs a control signal through a parallel printing interface; the control signal is decoded by a decoder to control the channel switch and the voltage/current switch and read testing states, and the channel switch controls a switching switch K#-[n] so that a testing loop of the n sensitive element is switched into conduction; meanwhile, the control signal output through the parallel printing interface is decoded by the decoder to control a testing voltage which is needed by the output of a program-controlled power supply; and an intelligent multimeter is controlled by an RS232 serial interface to switch testing shifts, and read testing data is input into the computer. The device is fully automatic and carries out multi-station simultaneous measurement; the device can process the data into sensing sensitive element parameters needed by users. The adoption of an overcurrent detection protective circuit in the device enhances the security and extends the service life of the device.
Description
Technical field
The present invention relates to a kind of static volt ampere proving installation of sensitive element, this device is particularly suitable for the test of thermistor static volt ampere.
Background technology
Volt-ampere characteristic is the key property of sensitive element.Promptly in 25 ℃ still air, be added in the voltage of sensitive element two exits and reach relation between the electric current under the thermally equilibrated steady state conditions, be i.e. the voltage-current characteristics of sensitive element under actual working state.This characteristic has reflected the situation under sensitive element in working order.The artificial point-to-point measurement record of multimeter is mainly used in domestic test to volt-ampere characteristic at present, uses artificial then or computer carries out data processing.This method of testing inefficiency, and be difficult to avoid because the sum of errors mistake that manual measurement caused has had a strong impact on the static volt-ampere test of sensitive element, and become the bottleneck problem that domestic sensitive element product further develops.
Summary of the invention
The object of the present invention is to provide a kind of sensitive element volt-ampere characteristic proving installation.This proving installation can carry out at a high speed, continuously, automatically, the test of multistation.
For achieving the above object, the solution that the present invention takes is: computing machine is exported control signal by parallel printer interface, this control signal switches by decoder for decoding control channel and voltage/current switches, and the read test state, passage switching controls passage change-over switch K
nMake the test loop conducting of n sensitive element, simultaneously, the test voltage that the control signal of parallel printer interface output needs by the output of decoder for decoding control programmable power supply again, control intelligent multimeter switch test shelves by the RS232 serial line interface, and the data of read test are imported computing machine.
Advantage of the present invention is:
1. full automation does not need manual intervention just can carry out multistation and measures simultaneously.
2. adopt over-current detection holding circuit, the security and the serviceable life of having improved proving installation.
3. utilize this device can carry out data processing and carry out automatic curve plotting, feel for the user intuitively, be convenient to operation.
Description of drawings
Fig. 1 is the structured flowchart of a kind of embodiment of the present invention.
Fig. 2 adds the structured flowchart that detects holding circuit automatically among Fig. 1.
Fig. 3 is the physical circuit figure of a kind of embodiment of programmable power supply among Fig. 1.
Fig. 4 is the physical circuit figure that detects a kind of embodiment of holding circuit among Fig. 2 automatically.
Fig. 5 is a process flow diagram of measuring control program.
Embodiment
As shown in Figure 1, computing machine 1 is by parallel printer interface 3 output control signals, and this control signal switches 7 by switching 6 of code translator 2 encoded control passages and voltage/current, and the read test state, and passage switches 6 control channel change-over switch K
nMake the test loop conducting of n sensitive element, simultaneously, the test voltage that the control signal of parallel printer interface 3 outputs needs by 5 outputs of code translator 2 encoded control programmable power supplys again, control intelligent multimeter 8 switch test shelves by RS232 serial line interface 4, and the data of read test are imported computing machine 1.
N is the number of sensitive element in the proving installation, for one or more, measures when this device has been realized multistation.
In above-mentioned Fig. 1, sensitive element is an example with thermistor PTCR only, is easy to find out, to other sensitive element, all is suitable for as light activated element, humidity-sensitive element etc.
We can take the three-level protective measure in proving installation, and first order safeguard measure is that the incoming end at programmable power supply 5 is connected to air automatic switch K; Second level safeguard measure is to be connected to fuse FU in the test loop of every sample
nThird level safeguard measure is software protection, promptly surpasses minimum current I when program detects certain channel current
MinTwice the time, by parallel printer interface 3 control channel change-over switch K
nAutomatically cut off this test loop.
Switch for the automatic control that realizes voltage, designed programmable power supply 5 as Fig. 3.Programmable power supply 5 is a transformer, its elementary two termination power-frequency voltages, and the two ends of tested sensitive element are received in secondary output.Transformer adopting scale-of-two output, i.e. 1V, 2V, 4V ..., 512V etc. are by the program control output of binary coding realization test voltage, when having only relay J
1When closed, output voltage is 1V; Work as relay J
N1, J
N2, J
N3, J
N4, J
N5When closed, output voltage is (2
(n1-1)+ 2
(n2-1)+ 2
(n3-1)+ 2
(n4-1)+ 2
(n5-1)) V.Such as, only need ten relays can realize the voltage output of 1V to 1023V.
In order to make this proving installation safer reliable, in the test loop of sensitive element, be connected to over-current detection holding circuit 9, as shown in Figure 2.
Fig. 4 is the physical circuit figure of a kind of embodiment of over-current detection holding circuit 9, and its structure is that the positive input terminal of first operational amplifier 11 passes through resistance R
1Receive sensitive element and sampling resistor R
0Tie point, by two voltage stabilizing diode Z that oppositely connect
1, Z
2Ground connection, output terminal and negative input end join, and by diode D
1, variable resistor R
2Ground connection.The positive input terminal of second operational amplifier 12 is received variable resistor R
2The mobile terminal, negative input end inserts the output terminal by the D/A converter 10 of computer parallel interface 3 controls, D/A converter 10 output comparative voltage U, second operational amplifier, 12 output terminals pass through resistance R
3Receive the emitter-base bandgap grading of controllable silicon SCR, the plus earth of controllable silicon SCR.The anode of an input termination controllable silicon SCR of the illuminator of photoelectrical coupler 13, another input end is by light emitting diode D
2, K switch
1Connect power positive end, an output head grounding of the illuminator of photoelectrical coupler 13, another output terminal passes through resistance R
4Connect power positive end, by diode D
3Connect chip for driving 14 input ends, corresponding output terminal P gauge tap K
nIn this Fig. 4, sensitive element also is to be example with thermistor PTCR only.
In order to strengthen the antijamming capability of over-current detection holding circuit 9, at diode D
1Negative pole and ground between be connected to capacitor C
1
Over-current detection holding circuit 9 also can be another kind of circuit form, and what its structure and Fig. 4 were unique is not both, and the comparative voltage U that is provided by direct voltage source is provided the negative input end of second operational amplifier 12.
In the foregoing circuit, code translator 2 can be selected HT-12D for use, intelligence multimeter 8 can be selected FLUKE45 for use, D/A converter 10 can be selected MAX531 for use, first operational amplifier 11, second operational amplifier 12 can be selected TL082 for use, photoelectrical coupler 13 can be selected TLP521 or 6N136 for use, and chip for driving 14 can be selected ULN2004 or MC1413, K switch for use
nCan select relay J QX-10F or JTX for use.
Below in conjunction with Fig. 4 over-current detection being protected despreading circuit 9 is described in further detail.
During test, over-current detection holding circuit 9 reads sample resistance R by what do not stop
0The voltage at two ends and preset threshold value voltage U compare, in case overcurrent takes place, cut off the test loop K switch immediately
n
Over-current detection is to go here and there sample resistance R in test loop by detection
0The voltage at two ends is realized.Sample resistance R
0Resistance very little, be 1 Ω, R
1Be current-limiting resistance.During pressurization, for a test loop, the output terminal P of code translator 2 correspondences in the test loop
0Be high level, the driving loop of chip for driving 14 correspondences is connected, corresponding K switch
nClosure, an output terminal P of photoelectrical coupler 13 at this moment
1Be high level.When thermistor PTCR component breakdown, the test loop current surge, thus make sampling resistor R
0Both end voltage increases, Z
1, Z
2Be two voltage stabilizing diodes that oppositely connect, the voltage clamp of first operational amplifier, 11 positive input terminals in 0～10V, is damaged first operational amplifier 11 to prevent too high voltage.First operational amplifier 11 is connected into voltage follower, has very high input resistance, and the function with next stage circuit and the isolation of previous stage circuit is arranged.The output of first operational amplifier 11 is by diode D
1, capacitor C
1Behind the rectifying and wave-filtering, by variable resistor R
2Dividing potential drop output is as the relatively input of second operational amplifier 12.This voltage is compared with the overcurrent protection action threshold voltage U that second operational amplifier, 12 negative input ends preset, and is bigger, is output as high level, triggers controllable silicon SCR and maintenance.At this moment, light emitting diode D
2Luminous indication, photoelectrical coupler 13 work are with output terminal P
1Drop-down is low level, diode D
3Conducting, with chip for driving 14 input pins drop-down be low level, thereby make corresponding test loop K switch
nDisconnect, cut off test loop, realized overcurrent protection.Threshold voltage U to the D/A converter programmed settings, need not manual shift by program.
Under the proper testing state, sample resistance R
0The voltage at two ends is less.So variable resistor R
2Pressure-dividing output voltage less than overcurrent protection action threshold voltage U, second operational amplifier 12 is output as low level, controllable silicon SCR can not trigger, thereby the illuminator of photoelectrical coupler 13 can be not luminous, its output terminal P
1Be high level, diode D
3Oppositely end.Pressurized control is by the output terminal P of code translator 2 correspondences
0Decision, over-current detection holding circuit 9 can not exert an influence to pressurized state.Keep conducting because controllable silicon SCR triggers the back, drop to when approaching zero up to controllable silicon SCR main circuit voltage or electric current, controllable silicon SCR is just turn-offed.Therefore, after each time a collection of element test being finished, before beginning the next group element begun test, must cut-off switch K
1Or,, make the over-current detection holding circuit of each test loop all be in the test pressurized state so that controllable silicon SCR is ended by the software reset.
In order to realize the powerful software systems with friendly user interface based on WINDOWS, we adopt the VC6.0 programming.Fig. 5 is a process flow diagram of measuring control program.During this device operation, at first detect the connection of intelligent multimeter, and require the user as required multimeter to be provided with.Then test parameter is provided with.Follow system initialization.Be provided with after the current test voltage, detect holding circuit and whether move, if holding circuit is moved then system reset, data deposit, end of test (EOT) entirely; If holding circuit is action not, check and arrive not pressing time that do not arrive pressing time; again detect the holding circuit action not; arrive pressing time, and measuring sensor both end voltage and flow through the electric current of element detects the highest voltage that is provided with then and arrives not; if do not arrive; then circulation is measured, until arriving the highest voltage that is provided with, system reset; the data deposit finishes to measure, return.
Claims (5)
1. sensitive element volt-ampere characteristic proving installation is characterized in that:
Computing machine (1) is by parallel printer interface (3) output control signal, and this control signal switches (6) by code translator (2) encoded control passage and voltage/current switches (7), and the read test state, and passage switches (6) control channel change-over switch k
n, make the test loop conducting of n sensitive element, simultaneously, the test voltage that the control signal of parallel printer interface (3) output needs by code translator (2) encoded control programmable power supply (5) output again,
Control intelligent multimeter (8) switch test shelves by RS232 serial line interface (4), and the data of read test are imported computing machine (1).
2. proving installation according to claim 1 is characterized in that: programmable power supply (5) is a transformer, its elementary two termination power-frequency voltages, and the two ends of tested sensitive element are received in secondary output.
3. proving installation according to claim 1 and 2 is characterized in that: be connected to over-current detection holding circuit (9) in the test loop of sensitive element.
4. proving installation according to claim 3 is characterized in that: the structure of over-current detection holding circuit (9) is that the positive input terminal of first operational amplifier (11) passes through resistance R
1Receive sensitive element and sampling resistor R
0Tie point, by two voltage stabilizing diode Z that oppositely connect
1, Z
2Ground connection, output terminal and negative input end join, and by diode D
1, variable resistor R
2Ground connection, the positive input terminal of second operational amplifier (12) is received variable resistor R
2The mobile terminal, negative input end inserts the output terminal by the D/A converter (10) of computer parallel interface (3) control, this D/A converter (10) output comparative voltage U, second operational amplifier (12) output terminal passes through resistance R
3Receive the emitter-base bandgap grading of controllable silicon SCR, the plus earth of controllable silicon SCR, the anode of an input termination controllable silicon SCR of the illuminator of photoelectrical coupler (13), another input end is by light emitting diode D
2, K switch
1Connect power positive end, an output head grounding of the illuminator of photoelectrical coupler (13), another output terminal passes through resistance R
4Connect power positive end, by diode D
3Connect chip for driving (14) input end, corresponding output terminal P gauge tap K
n
5. proving installation according to claim 3 is characterized in that: the structure of over-current detection holding circuit (9) is that the positive input terminal of first operational amplifier (11) passes through resistance R
1Receive sensitive element and sampling resistor R
0Tie point, by two voltage stabilizing diode Z that oppositely connect
1, Z
2Ground connection, output terminal and negative input end join, and by diode D
1, variable resistor R
2Ground connection, the positive input terminal of second operational amplifier (12) is received variable resistor R
2The mobile terminal, the comparative voltage U that is provided by direct voltage source is provided negative input end, output terminal passes through resistance R
3Receive the emitter-base bandgap grading of controllable silicon SCR, the plus earth of controllable silicon SCR, the anode of an input termination controllable silicon SCR of the illuminator of photoelectrical coupler (13), another input end is by light emitting diode D
2, K switch
1Connect power positive end, an output head grounding of the illuminator of photoelectrical coupler (13), another output terminal passes through resistance R
4Connect power positive end, by diode D
3Connect chip for driving (14) input end, corresponding output terminal P gauge tap K
n
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03125278 CN1218186C (en) | 2003-08-15 | 2003-08-15 | Sensitive-element current-voltage characteristic measuring apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03125278 CN1218186C (en) | 2003-08-15 | 2003-08-15 | Sensitive-element current-voltage characteristic measuring apparatus |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1488950A CN1488950A (en) | 2004-04-14 |
| CN1218186C true CN1218186C (en) | 2005-09-07 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 03125278 Expired - Fee Related CN1218186C (en) | 2003-08-15 | 2003-08-15 | Sensitive-element current-voltage characteristic measuring apparatus |
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|---|---|
| CN (1) | CN1218186C (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105004978B (en) * | 2015-08-10 | 2017-09-26 | 南京信息工程大学 | Multi-channel switch type surge protector dc breakdown voltage test device |
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2003
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| Publication number | Publication date |
|---|---|
| CN1488950A (en) | 2004-04-14 |
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