CN85200586U

CN85200586U - Automatic non-contact range converter

Info

Publication number: CN85200586U
Application number: CN 85200586
Authority: CN
Inventors: 相小平
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-04-15
Filing date: 1985-04-15
Publication date: 1986-01-29

Abstract

The utility model relates to an automatic range converting system without contact points. The system provides an automatic converting function without contact points for the range of measuring instruments by using an electronic controlling attenuator matched with an amplitude discriminator and a set of logic controlling systems to replace the range converter of mechanical contact points of switches or electric relays. Adopting the special designed electronic attenuator, the system is suitable for any measuring instrument using an electromagnetic system meter.

Description

Automatic non-contact range converter

Native system is applicable to any range conversion of using the surveying instrument of pointer header, to replace the mechanical contact-type range conversion of hand switch or relay system.

In the prior art, be common as the gain control of operational amplifier with the Mos analog switch.It changes Amplifier Gain to insert different feedback resistances, but it can not be used for the higher occasion of voltage.Have a class to use the automatic range converting system of relay herein, this technology belongs to the contact converting system, the cost height, and reliability is low, uses wideless.

For improving reliability, the stability of the instrument of measuring, easy to use and raising competitiveness of product has designed native system.

Native system is made up of attenuator (1), attenuator (2), amplitude discriminator and a cover logic control system, sees Fig. 1.

Input voltage u is output as u behind attenuator (1) ₁Deliver to prime amplifier.The output u of preposition amplification ₂Deliver to attenuator (2).The output u of attenuator (2) ₃Deliver to main amplifier.(if necessary) can be directly exported in the output one tunnel of main amplifier, and the gauge outfit circuit is delivered in another road after wave detector detection, wave filter are in addition level and smooth be u ₄, promote gauge outfit deflection.

The output U of wave detector, wave filter ₄Except that being sent to the gauge outfit circuit, also deliver to an amplitude discriminator.This is a fenestra formula comparer.It is to being in the U of (being in the fenestra) between the upper and lower limit ₄The mode of value low to export (or high) level responds.The variation of this level is used for controlling a up-down counter: work as U ₄When dropping within the fenestra, counter is not counted, and the state of this hour counter makes corresponding range indicator (LED) light after decoding.The indicated range and the indicating value of gauge outfit can be read measured value in the time of thus.If U ₄Exceed the upper limit, then the amplitude discriminator control counter is made plus coujnt, and the output of code translator drives a high LED, and it decays one grade Electronic Control attenuator (1) or (2) simultaneously, makes u that is: ₁Or u ₃Decay one grade, thereby make U ₄Fall into fenestra, make the gauge outfit indicating value not surmount the full scale line.For U ₄During less than lower window edge, whole adjustment process is identical, and only direction is opposite.

If U after once adjusting ₄Still not in fenestra, then said process can continue to carry out automatically, until U ₄Till dropping in the fenestra.Read measured value by range indicator and gauge outfit indicating value again.

The bound of fenestra is to be provided with according to following principle: its upper limit is exactly to make gauge outfit completely carve the U of deflection ₄Value is limited to 1/ (K) U down ₄Wherein K is the multiplying power of adjacent two ranges.

If K=10 then overlaps between each range, dial plate is as long as a scale as if K ≠ 10, is then wanted two scales.

If attenuator (1) has the n shelves, attenuator (2) has the m shelves, and the result who then works in coordination makes total range number Z=n * m shelves.It can be more much more than waver gear, thereby stepping can be thinner, and reading is also more accurate.

Fig. 2 is attenuator (a 1) schematic diagram.Because it is positioned at input end, may be subjected to the impact of high pressure.Measuring high-tension occasion simultaneously also requires the electron device in the attenuator not to be damaged.So taked special design: it does not resemble the position that changes tap the common attenuator makes output obtain decay, but with the method that changes the following resistance value of voltage divider, promptly different ranges change rely on switch with on-off element under resistance R ₂Realize.Simultaneously output terminal is with nonlinear element (as diode etc.) pressure limiting, even input end adds thousands of volt voltages like this, pipe can not impacted yet.

Make K '=u/u ₁, K ' is the multiplying power between the adjacent second gear of attenuator (1).Then have:

K '=mk k---the multiplying power of the adjacent second gear of system

Being calculated as follows of attenuator (1) then:

R ₂=(R ₁)/(K '-1)-r r---the internal resistance of on-off element

·

R _2n＝ (R ₁)/((K′) ⁿ-1) －r

It should be noted that because the internal resistance r and the R of on-off element ₂Series connection.So require r little and stable.Otherwise can introduce error.Because the domestic Mos switching tube of having produced r＜5 Europe in batches is as long as select R ₂Much larger than r, again according to R ₂Value is determined R ₁, then the error of the temperature variation of pipe internal resistance r introducing is inappreciable, can conform with the accuracy requirement of pointer header fully.The on-off element of attenuator (1) is selected: as require AC/DC then can only use the Mos switching tube, as the measurement that only is used to exchange, then also available ambipolar pipe, as long as the C-e reversal connection, conducting resistance is also very little.R ₁The available raising amplifier gain of introducing of decay remedies.

If when the electric voltage frequency of measuring was higher, attenuator should have indemnifying measure.Can on each resistance, make the dividing potential drop relation of AC impedance still be K ' by shunt capacitance.CALCULATION OF CAPACITANCE is as follows:

C ₁′＝（K′＋1）C ₁C ₁′＝C ₂∥C _i

Wherein:

·

C _n′＝〔（K′） ⁿ＋1〕C ₁C _n′＝C ₂n∥C _i

Attenuator (2) can adopt conventional tapered potentiometer structure to see Fig. 3 owing to do not relate to high-tension conversion.Only conversion is with on-off element.At this moment because the on-off element two ends are all earth-free, so can only use Mos switching tube or Mos analog switch.Though analog switch r is bigger, as long as the enough height of amplifier input impedance just can not produce error.

The highest one grade and minimum one grade at range also are provided with limit circuit, if input voltage is higher than the most high-grade higher limit or produce conversion during less than the lower limit of deep low gear, prevent unnecessary state to stop this moment.

Amplitude discriminator, logic control door, pulse producer all are custom circuits, can be according to equipment situation flexible design.Counter, code translator all have integrated product, need not design.

Compare with present widely used mechanical switch formula weight journey conversion regime, native system has following advantage:

1) belong to noncontact system, stable, reliable, noiselessness, contactless bad phenomenon, the life-span is essentially the mission life (millions of hours) of device, has been far longer than contact system.

2) structure is small and exquisite flexibly, and the installation site is unrestricted.Make instrument can make single plate structure.There are not the lead external parts.

Increased dirigibility for the complete machine general structure design.And be convenient to streamline production.

3) automatic conversioning broad, easy to use, alleviate user's manual switchover trouble, also avoided careless manipulation that the performance of beating of gauge outfit overload is resembled.

4) available binary code presets range, but long-distance remote control changes range.

According to different needs, realize the best way of native system:

1) the range number is few, but measuring voltage is higher, adds amplitude discriminator, logic control system composition with attenuator (1).

2) the range number is few, during measuring voltage not high (less than the voltage breakdown of on-off element): add amplitude discriminator, logic control system with attenuator (2).

3) the range number is many, the measuring voltage height: with attenuator (1), (2) cooperate and add amplitude discriminator again, logic control system is formed.

4) the range number is many, measuring voltage not high (defining with (2)): cooperate with two attenuators (2) to add amplitude discriminator, logic control system composition again.

Can form different measuring systems flexibly, the decay multiplying power of every kind of combination will require redesign according to difference like this:

With the system of an attenuator, multiplying power is K for only.

For the system with two attenuators, second multiplying power is K, and first multiplying power is K '.

The drawing explanation:

Fig. 1: 1-attenuator (1) 2-prime amplifier 3-attenuator (2) 4-main amplifier 5-wave detector and wave filter 6-amplitude discriminator and logic control system.

Fig. 2: attenuator (1) structure.

Fig. 3: attenuator (2) structure.

Fig. 4: amplitude discriminator and logic control system structure: A-amplitude discriminator B-control gate C-pulse producer D-up-down counter E-code translator F-range indicator.

Claims

1, the automatic range converting system of surveying instrument, this system have a variation with the gauge outfit both end voltage by amplitude discriminator (fenestra comparer) and logic control system [6], and the automatic conversion of range is realized in control attenuator [1], [3].It is characterized in that:

A, described attenuator [1] are Electronic Control attenuators that can bear high voltage, insert the following resistance of different voltage dividers with analog switch and realize conversion.

B, described attenuator [1] have one to make it the capacitance compensation network that not influenced by frequency change.

C, described attenuator [3] are the series connection step attenuators of an analog switch control.

2, according to the described system of claim 1, the system that it is characterized by is made of with logic control system (6) attenuator (1), (3).

3, according to the described system of claim 1, the system that it is characterized by is made of with logic control system (6) the identical attenuator (3) of inequality group of structure of two attenuation coefficients.

4, according to the described system of claim 1, the system that it is characterized by is made of an attenuator (1) and logic control system (6).

5, according to the described system of claim 1, the system that it is characterized by is made of an attenuator (3) and logic control system (6).

6, according to claim 1,2,3,4,5 described systems, it is characterized in that:

Stop counter to add counting (or subtracting counting) when a, described logic control system (6) have an energy to be in the highest one grade (or minimum one grade) according to range, and when measured value is within the fenestra value, stop the control gate circuit (B) of rolling counters forward.

B, described logic control system (6) have a continuous impulse generator (C).