DE1623883C - Method and arrangement for converting analog measured values into digital display values - Google Patents

Description

15. Arrangement according to the. \ N.sprüche4 and \ 1 characterized. da!> the subtraction training l4l consists of a hi>'..'."! - <ik-n multivibrator |. _; . | j" I ^ .41 with separate set and return lines, the V't / c input «^ n der, Au -.!: 'ig the discriminate (-rsc': - a! tung i3i. des ^ n return entry h to the Xu-tiang der Inipulsque.'e i9i the frequency /, '.jiu! de- .-en Visgans: ι ι * an d: n control input il9i of a cbcnia'lK mn dem. \ u -_; i: ig the discriminat.ir.-chah'.iiig ι3ι bewundeP- · :! lnipulstors (19. 20 . 211 ;; ngeschlns> en it. De- -i exit to auxiliary number: iiie ^r i6i drove!

Dk ί rtierung concerns an \ experienced to put into practice of a: \ slogen measured values in a finite or can be in a wide range in digital display erte and one to carry out this :, proceed: suitable Arrangement in which the measured values, if. s, e not a priori as DC voltages present, first converted into proportional or inversely proportional direct voltage, then according to the frequency variation method in Wcchselspav-Hingen implemented with the respective amplitude of the direct voltage, un assigned frequency and then can be converted into square-wave voltages while maintaining the frequency.

/.e 'of the invention it is. the advantages of the digital Ml-ivaertausgabe. namely high reading accuracy and speed, automatic storage of the results in printing units, etc. with those of the analog measured value acquisition, which in turn is faster and more economical than digital measured value acquisition. to combine and thereby already existing facilities through a high level of Adaptability to be considered.

For remote measurement in unoccupied participant circuits Offices it is already known to each measured value arising in the measurement order in the vacant office first of all there itself to be converted into a direct voltage with the measured value corresponding to the level and to use the DC voltage to control the frequency of a relaxation oscillator, its square waves after passing through a low pass to the measuring point and there in one of their current proportional to the respective frequency, which is displayed on the instrument of the measuring signal (German interpretation I 231 767). Since the measured values are here in analog form by a Ammeters are issued, their evaluation is slow and tiring and also with inaccuracies. which can be intensified by reading errors. The measured values can also not save and are not accessible to any automatic evaluation.

The task of the invention is zugrr.i.de. the Disadvantages of the aforementioned and similar analog measurement methods to be overcome without it being stated at the beginning of the 883

imagined giving up advantages. ■ -id through implementation of the analog measured values: in digital display values.

The method of the invention is characterized in that the square-wave voltages in the event that the DC voltages on which they are based belong to the Measured value are directly proportional, in a manner known per se during a by a clock pulse generator a certain time a counter controlling the display means are supplied as counting pulses and in the If the underlying DC voltages are inversely proportional to the measured value, a Apply the auxiliary counter from the duration until a certain number of these square-wave pulses arrive determined a time in which the Takiitn pulse generator The generated pulses are fed to the counter controlling the display means as counting pulses will.

The voltage frequencies carried out in the course of this N ^- experience * according to the frequency variation method on the one hand creates the prerequisites for analog-digital conversion, on the other hand it also allows remote transmission of the measured values without additional coding or similar s Aids. For secure transmission, e.g. B. via telecommunication lines, it is advantageous to _{assign the} corresponding DC voltages 0 b ' ^s ί «, frequencies /, to f _mjx , which are usually transmitted on such channels, to the measuring range 0 to A / mu. <°, for example, f \, to 500 Hz and f _{m ± lx} to 2500 Hz. In a further development of the method of the invention it is therefore provided that, during the voltage-frequency conversion, the measured value zero has a frequency other than zero; _{o is} assigned and whose influence on the counting result is switched off by appropriate presetting of the counter and or by subtracting this frequency / "from all frequencies of the band in question for the conversion To ·· -." mm before the counting.

Arrangements which convert measured values into direct voltages are known per se, as are voltage-frequency converters. An arrangement for carrying out the method of the invention assumes this prior art and is identified by means of a known transmitter, which supplies a direct voltage proportional to the respective measured value supplies a voltage-frequency converter connected to it known design, which generates an alternating voltage with the amplitude of the respectively supplied DC voltage assigned frequency

I _x (./η ύ L g / ,,. ,,)

gives off a known discriminator.

which converts the alternating voltages into square-wave voltages and they in the event that the underlying DC voltage is directly proportional to the measured value to the pulse input of a gate circuit whose static input with a pulse

to source of the frequency./, is connected. or they - ■ im Case that the underlying DC voltage is inversely proportional to the measured value Auxiliary counter supplies, the output of which is connected to the static input of the gate circuit. whose Pulse input in this case is connected to the output of a clock pulse generator of frequency /. and a counter which is connected to the output of the gate circuit and controls digital display means.

1 OZ.D

In the case. that the measured value zero cmc is assigned a frequency /, deviating from zero. is provided in a further development of this arrangement that for subtracting the frequency assigned to the measured value zero. /, between the discriminator circuit and the pulse input of the gate circuit or the auxiliary payer a subtraction circuit composed of one or more bistable Kippstul'en with two inputs and one output is provided, the first input with the output of the discriminator and the second input with a pulse source Frequency J _{0 is} connected.

If a large measurement range has to be dealt with, this is done with most data recorders by switching over the measurement ranges. The possibility of area switching remains with the method of the invention and the associated arrangement, since it is taken into account, provided it is done by a factor of 10 and even powers of 10, simply by moving the comma in the display. But to also change the measuring range by a different factor, e.g. B. two or three, is provided in a further development of the arrangement according to the invention that the static input of the gate circuit can be switched off from the pulse source of the frequency J ₁ and connected to a further pulse source of the frequency /, via retraining means for measuring range switching .

A particularly economical embodiment of the arrangement of the invention according to another development is characterized in that the impulses of the frequencies f _i7 . f · «nri /, are formed from frequency divider circuits known per se, all of which are controlled by the clock pulse generator of frequency /.

Usually several measurements are carried out one after the other carried out, which do not differ significantly in result. To avoid the display device must run up from zero to the final value every time. is in a further development of the express Arrangement between the counter and the display means a memory is provided which saves the previous result until the next result is completely received and then the value in the display device may only be changed slightly.

This means both the preparation of the meter for a new measurement and the correction of the display expires correctly according to a new result, another embodiment of the arrangement includes the Invention a control circuit that is used by the / to static input of the gate circuit is applied impulses and the resetting of the Controls the counter as well as the transfer of the counter reading into the memory.

According to a further development of the invention, this control circuit is equipped with means for presetting the counter to a value corresponding to the frequency to be deducted in order to eliminate the influence of the frequency f _{0 on the counting result.}

If the measured value is greater than the end value of the set measuring range, the counter capacity exceeded and this will trigger a false display. To prevent this from happening, contains a Further development of the invention, a multivibrator controlled by a counter, which when a certain upper limit value of the counter reading receives a signal and then an additional display means caused this counter reading to be identified.

Transducers emit direct voltages.

which are directly or inversely proportional to the measured value. The arrangement of the invention can provide a digital display in both cases if the inputs of the gate circuit are switched accordingly. Since the input switching of the circuit is difficult to implement in some cases, / .. B. if it is to be done by electronic means, another embodiment of the invention is characterized in that two gate circuits are provided, the outputs of which can be optionally connected to the counter and of which the switching means is made effective only for the square-wave voltages Kr frequency /, whose underlying DC voltages are directly pi-proportional to the measured value, while the second is made by Umscl '.' ¹ '-means only for the square wave voltages of the 1U qucnz f _x is made effective, the zugruiui.' DC voltages lying around the measured value vice versa; are proportional.

The at the voltage-frequency-Umsct / unu -; The following shift by the frequency / ,, which il.r <derives from the fact that very low frequencies are nu '. ^: can be transmitted, is to be taken into account according to the preceding either by presetting the counter or by supposing the frequency / band used for the conversion of all frequencies ti. An expedient embodiment of the invention provides. that the elimination of the tie: frequency L in the case of rectangular signals, the direct voltage is directly proportional to the measured value. preferably by presetting the counter via the control circuit uiui for square-wave voltages. whose underlying * DC voltage is inversely proportional to the measured value by subtracting the frequency / "in the

Subtraction circuit takes place.

The subtraction circuit has the task of subtracting square-wave pulses of frequency / ρ from all right-hand pulses of frequency f _n to f " _{ax arriving within a certain time.} According to a further development of the invention, this object is achieved in that the subtraction circuit consists of a bistable multivibrator with separate set / reset inputs, the set input of which is connected to the output of the discriminator circuit. whose

Reset input to the output of the pulse source of frequency / ₀ and its output to the control input of a pulse gate also connected to the output of the discriminator circuit, the output of which leads to the auxiliary payer.

The invention is described below with reference to one of the FIGS. 1 to 4 illustrated embodiment described and explained in their mode of operation. It means

F i g. 1 is a block diagram for an arrangement for

Carrying out the method according to the invention.

F i g. 2 one opposite F i g. 1 extended arrangement.

F i g. 3 one opposite F i g. 2 modified arrangement.

F i g. FIG. 4 shows an exemplary embodiment for one in the arrangements of FIG. 2 and 3 used subtraction circuit.

In the arrangement according to FIG. 1 the procedure is ongoing

showw

his \

port"·

to convert analog measured values into digital display bets as follows. A transducer or transmitter 1 converts the measured value Af ₁ . for example a resistance, a capacitance or a voltage, but also a distance. Winkclabwe.chung or a. can be, into a DC voltage L \ _v um. which is either directly or inversely proportional to the measured value M _{x. '} In one application, namely the examination of disturbed subscriber current crises in telephone networks, z. B. to measure shirt voltages in a range from zero to 35OV, furthermore resistance between zero and about 35 12. Lumnßskapatoren up to 7 αF and the resistance of the speech cores against each other and against Frde. Iu dun practically a range from zero to lnendh. For each measured value M _x , which is in a finite range /w.schu. 0 and M _{1MX is} measured, a proportional C , eichspa.nuni U _x between 0 and I _ and bc · jecon measured value, Wr for an infinitely large Ik cal% on 0 to oo, a DC voltage inversely proportional to the measured value Λ L, '- ^w ' ^ ⁿ ! _ And 0 (corresponding to the retrograde, proprboK scale of an ohmmeter, etc. ™ * η McB devices are never neglected. There are two ranges for external voltage and power supply capacities, and / was from 0 to 70 \ and «■ ·.:. Tcr> \ ': ~ »IniTi KmII and from ι) nis .OU nr

WMI V) UIS -'-> «» it.t "· ■ · r- Il f Zur Wuicr-

and from 0 to 7 _μ ΐ m in the other case: on. For VVuJer standing measurements there are even six ranges of r b, ^ V Ri ₁ IUn ₁₁ , which are graduated in such a way that the h -.- maximum output glcu voltage. The first range corresponds to the value 40 U. in the next range corresponds to the frequency range. So if this frequency range z. B. goes from 0 to f _{max is}

-τ

H) - HH)

"~ L, x

HHH))

and when the frequency range goes from / "to i" _un , AZ _{11111 is} J-10 · 100 · H) (K) I

• 10- 100 ·

As an example it is assumed that the frequencies J _{x are} between 0 and 2000 Hz. Then. if the final range value is 350 (approx. 350 V or 350 riF). the gate time T selected to ^ ₀₀₀ see = 175 msec. at

through the

a full-range value of 35 (e.g. 35 U) would be the

Gate time Tan itself 17.5 msec. But you need how

is explained further below - the frequency J _{2 is} not

to switch to ten times the value, but can

keep the same gate time of 175 msec if

one at the same time in the display for a shift

of the comma one place to the left. Through this

it is then also possible to fully utilize the entire display area.

During the gate time T, which is determined by the frequency /, of the pulse source 10. the square-wave pulses of the frequency f _{x reach} the counter 14, which controls the digital display device 16. If the gate time T. is assumed as above. 175 msec, "at this time at a frequency / ,,, of 2000 Hz 350 pulses or at a frequency / _x of 1000 Hz 175 pulses etc. enter the counter 14. However, 2000 Hz is the frequency mentioned above Example is assigned to the range end value of 350 V or 350 nF. 1000 FIz accordingly correspond to the range mean value of 175 V or 175 nF, etc. Consequently, the counter reading immediately reflects the measured value M _x . The counter 14 controls the digital display device 16. The consist of counter tubes or a printer that prints out the counter reading immediately.

If the earth resistance is to be measured in the range from 0 to 35 Ll instead of Frerrid voltages or line capacitances by the measuring value sensor 1, the measuring value sensor 1. is possibly by per se known ferrite control devices. switch accordingly. The new end-of-range value of 35 (U) instead of 350 (V or nF) can now be taken into account simply by the fact that when the transducer 1 is switched over, the decimal point in the display device 16 goes one further behind is switched to the left. Then, in the time T of 175 msec, 350 pulses at a frequency of 2000 Hz again enter the counter 14 if the measured value is 35 U, but they trigger the display 35.0 in the display device 16. Similarly, 175 pulses are generated at / _x = 1000 Hz

1 now on gt <

or "over arbitrarily wide nmu Vfirr ^ Hich"

will. If there is no transmission, the converter can! so interpreted. equal to square wave voltages
in the other case there will be ;,
Transmit voltages that are only transformed by a voltage disknminator 3 voltages. ^. _st

In the cases where v / o I _x - M ₁ - also auc * ■! * * _F one drives the square-wave voltages de. Frequen Λ

(via switch 5 1 in dergg »* ^ fJ ₁

the pulse input α ^e 'ner gate circuit ^ _ ^

static inputM via the switch 5 ^^ m ^ ^^ _{reach the} display value 17.5 reversed pulse source 10 of a frequency / 2 ^ver ^ "" ° ^e . _{dje converts into} 60 and so on. Of course you can change the relationships

Pulse source 10 gives square wave voltages a ^^ _{Me &} w * t M _x , reduction frequency Jf _x and

the just half period the Torschartunfc, To π _γ ne ^^ ^ _{currency different} p _{s and} be _1S, elswe.se the

in the other half-period, the goal scoring FC Torzeit T compared to the above calculation

The frequency /, this ^ nkspwunn ^ double. In this case, only half the counter reading is preferably selected so that the die_ ^u "J ^ View _{16n 65th} Or leads the ads nr.rhung 16

determining half-period T just ^de JVf, _{(f> which} is double the count and comes

from the range end value M ^ _{x of} the ueoe ^^ _mft ^ ^^ _{gate time T was ms special}

the ten, one hundred or one ^{thousand note} J _{;: L en Fr} «- is then an advantage. if the measured value is not constant and the door implementation is used - 309 634/437

but shows fluctuations, which are all the more evident appear in the display, the higher the frequency ^ and is therefore the repetition rate for successive measurements.

If the measuring device used as a sensor 1 is constructed so that it provides the measured value M _x reversed proporti -.nale output voltages U _x, after the voltage-to-frequency conversion sverden at the output of the discriminator 3 square wave voltages of the frequency / _V ~ obtained. (via the switch

5/1 in the position deviating from the state shown) is fed to an auxiliary counter 6, which determines a gate time T from the time up to the arrival of a certain number k of these square-wave pulses, in which the gate circuit? is open. For this purpose, the auxiliary counter6 is connected to the static input /? the gate switch? connected. At the impulse input «of the gate circuit? there is now a pulse source of constant frequency J ₁ (via switch 5/3), the pulses of which reach counter 14 during gate time T. The frequency / is chosen so that the product of the frequency / and the capacity k of the auxiliary counter 6 is equal to the product of the frequency range f _max or f _max ~ J ₀ used for the implementation and the numerical value M _{millcl of} the measured variable M. _x . which at the first implementation half of the maximum

delivered DC voltage. ™ ". Yields (or ten, hundred or thousand times it), is Wx = (La _x -Jo) ■ A / _m ," ,, (10 100 1000)].

The pulses of the frequency / run into the counter 14 during the time T 'determined by the auxiliary counter 6. In this measurement, the counter 14 is preset to a negative value which corresponds to the already defined numerical value M _mim . | or the ten. Hundreds or thousands of times that. Only when the counting pulses reach and exceed the preset value does the counter 14 start counting from 0 and control the display device 16 in a corresponding manner.

As an example it is assumed that the measured value M _{x is} a resistor. which can be between 0 and χ and an ohmmeter with six ranges is available as transmitter 1 for its measurement, whereby the

Value M _{milte [} , which supplies the output voltage "".

in the first area at 4012, in the second area at 40012, in the third area at 4 kl2, in the fourth area at 40ki2, in the fifth area at 400 ki2 and in the sixth area at 4 M12. The frequency conversion provides frequencies f _x between 0 and 2000 Hz, with the frequency 0 being the resistance cc in all areas, the frequency / ^ = 2000 Hz being the resistance 0 in all areas and the mean frequency ^ "" = 1000 Hz being the resistance M in question _{minel of} the set range, i.e. 4012 etc. is assigned.

With a three-digit display in the display device 16, the 4012 and 40 ki2 as 40.0.40012 and 4uO kl> displays as 400 and 4ki2 and 4 M12 as 4.00, the counter 14 is preset according to the above to which is easily done by taking the complement of 400 with respect to gives the entire meter range as a positive value in the meter before each new measurement, e.g. B. at a three-digit counter with the counter range (1) 000 the value 1000-400 = 600. The default setting can happen automatically if the switches 5/1 to 5/3 are flipped and thereafter These will be run by the same means that cause the previous advertisement to be deleted now operated manually or by a program control device.

With the assumed frequency range for / _v ίο of 20Ot) H? must be k · /, = 2000-400 = 800000 according to the previous explanations. Therefore let k, the capacity of the auxiliary counter6, be 100 and / ,. the frequency of the pulse source 8. churned to 8 kHz. If a resistance sun 40012 is measured in the 400-12 range, the voltage-frequency converter delivers 2 alternating voltages with a frequency of 10001 \ /. which occur at the output of the discriminator 3 as square-wave voltages. The auxiliary counter 6 opens the gate circuit 7 via the input / »until 100 pulses, i.e. 100 periods of this right voltage, have entered it, at 1000 H? so for 0.1 seconds. During this time of 0.1 seconds, S (K) pulses with the frequency /, of 8 kHz above the. Impulse input α of the gate circuit? in the counter 14. The first 400 pulses bring the counter sor. the pre-setting to the zero position, so that the counter reading is 400 at the end. That number win! displayed by the display device. On the other hand, if the measured resistance M _{x is} zero, the associated frequency is 2000 Hz and the gate time determined by the auxiliary counter 6 / accordingly only 0.05 seconds or 50 msec. During this time, only 400 pulses reach the counter 14 Analogously to this, a frequency /, of 667 Hz occurs at 80012, which causes a gate time T ' of 150 msec in which 1200 pulses from the pulse source 8 to the counter 14. They bring the counter 14 to the counter reading 800 and in this sense also actuate the display _{device 16. When switching to the area with M 1n} , - ,,,! = 4012 or 4Okl2, the above conditions remain, only the decimal point in the display device 16 is shifted from the start when the setting is made This measuring range is shifted by one place to the left. Likewise, when setting the range to the fourth and sixth measuring range (4k <2 and 4 MU), the decimal point is shifted by two places to the left s (12, k! 2, M12 etc.l can always be read on the area switch or, in the event of an automatic switchover by means of program control means, is given to the printing unit that is then connected as a display device by the means that effect this switchover.

In Fig. FIG. 2 shows an expanded arrangement in which the components of FIG. 1 identi see parts the same reference numerals as in F i g. I have. At the output of the discriminator 3 still occurs a square wave voltage of the frequency f _x which in one case is directly proportional to the measured value and in the other case is inversely proportional to the measured value. In contrast to before, however, the measured value is now 0 at f _x ~ M _x or the measured value α

a frequency J other than zero, for example 500 Hz and the respective Be

at fx ~~

from, for example, jg

rich end value is assigned a frequency / _TOI of, for example, 2500 Hz. This range is for both frequency conversion and a.:ch for long-distance transmission

3425

The alternating voltage is more favorable than the frequency range from 0 to 2000 Hz used in the example described above. 1 despite the Frequcnzverschicbung to / ;, (500 Hr.) Is maintained, is provided in the arrangement of Fig. 2 at the output of discriminator ^ a subtraction circuit 4, whose one input the square wave voltage of the frequency / _Λ and whose other Einganu a pulse sequence of the constant frequency / ₀ from a pulse source 9 is supplied. At the exit of the subtraction circuit 4, a square-wave voltage of the frequency L- / "occurs in any case. If ^ ₀ as assumed above 500 Mz is large and L is ₁₁₁ 250OHz that Ausuangsspannungen the SubtraktionsschaHung 4, ₅ frequencies between 0 and 2000 Hz have. This allows them in the same manner as in F i g. 1 described, can be further processed. The construction of a suitable Suh'.raktionskreis4 will be explained later with reference to FIG. 4 explained. '

In Fig. 2 is a further Impulsquellc 11 of the FRC Mucm // contain _3, "is anschlieBbar via a change-over switches selectively in place of the pulse source 10 of the frequency /, to the static input /) of the gate circuit. 7 The pulse source 10 loading is agreed by above the gate time T of gate circuit 7 according to the respective set Bere.chsendweri or its' eight, hundred or thousandfold msec is required, i.e. a frequency A of 2,856 Hz. The decimal notation was done simply by shifting the comma in the display device 16. The additional pulse source 11 now enables range switching in a ratio smaller than 10, for example by a factor of 2 or 3. As mentioned at the beginning, In addition to the named areas with the end values 35 and 350, measuring areas with the end values 7. 70 and 700 are required for measuring on disturbed subscriber groups h, namely z. B. a 7- ^ F-Bere.ch and a 70-V-area. For this purpose, the additional pulse source U gives a frequency /, of half the frequency f ,. i.e. 1.428 Hz., which corresponds to a doubling of the gate time T to 350 msec.

The frequencies f _x . / ". / 2 and /, are appropriately derived from a single, frequency-stable pulse source8 by scaling. In the numerical example given above, the pulse source supplies 8 alternating voltages of 8 kHz. By scaling down by a factor of 16 in stage 9, the frequency J ₀ of 500 Hz is obtained, which is scaled down by a factor of 175 in the stage, which results in the frequency /, of 2,856 Hz. In the stage Π controlled by stage 10, a reduction by a factor of 2 takes place, from which the frequency ^ of 1.428Hz results. . ....

Between the counter 14 and the display device 16 is in the arrangement of FIG. 2, a memory is used which stores the previous result in each case until the new result is completely contained in the counter 14. The counter 14 must of course be reset to zero or - at /, - _{v /} ^ - a value deviating from zero for each new measurement. The memory 15 now avoids. that the display device 16 is also reset and must always start up again. If, in order to eliminate errors, a measurement process is repeated several times, each new display value differs from the previous one; They may only appear in one or two places, and it is sufficient to correct these few places in the memory 15 and in the display device.

The point in time at which the counting result is transferred to the memory 15 is determined by a control circuit 13, which in turn is either activated by the pulse source 10 or 11 after the gate time 7 'has elapsed (at f _x ~ -M _x ) or the transfer Triggering signal from auxiliary counter

( ^at

when its counting capacity is exceeded. From which point the control circuit 13 is operated, a switch 5/2, which is connected to the Switches 5/1 and 5/3 when switching between the two types of measurement

f _x - W _x and J _x

is brought into the respectively applicable position. The control circuit 13 also resets the counter 14 to zero for measurements in which f _x ~ M _x , or the respective presetting of the counter 14 to the complement of the fixed value to be subtracted M _mille , or the tens, hundreds or Thousands of times that in measurements, ii ", those

f. - . '. is.

M _x

If the measured value is infinitely large when measuring resistance. it results in a DC voltage U _x of zero and, accordingly, a frequency J _x of 500 Hz (= / 0). _{As a result, the frequency / 0} - / ₀ occurs at the output of the subtraction circuit 4. so zero on. As a result, the auxiliary counter never reaches its capacity, and the gate circuit 7 remains open via its input /) continuously for counting pulses of the frequency /. The counter 14 could thus be acted upon by its counting capacity and continue counting indefinitely. In order to prevent this, a flip-flop 18 is connected to the output of the counter 14 which, when a defined highest count is reached, interrupts the count, triggers the transfer of the count to the memory and an additional display device 17 for displaying a feature "greater than" or caused. The highest display value is then stolen in the display device 16 and the information that this value has been exceeded in the device 17 conversion into proportional DC voltages and frequencies (/, - M ₁ ). can in the arrangement according to Fig .; can be displayed practically as often as required in the cycle of the frequency / ₂ or: / ₃ , since the control circuit 13 transfers the counting result to the memory 15 after each expiry of the gate time Tdetermined by the frequency J ₂ or / _{3 and} resets the counter 14 to zero Gate time T is followed by a time, as explained above. in which the gate circuit is blocked via input b. Then a new gate time T and so on begins. An operator thus came to the repetitive display in de

Track device 16 for any length of time and any fluctuations in the measured value that may occur capture. If the measuring sequence is controlled automatically, the program control device, which is then required anyway, is available the measuring time for each process and thus decides how many display values for each Measurement can be printed out.

Measured values that are inversely proportional during implementation Deliver DC voltages and frequencies

can also be displayed as often as required, since each time the capacity of the auxiliary counter 6 is reached, the counting result is passed through the control device 13 into the memory 15 and the counter 14 is again preset to the complementary value of the value to be subtracted. The cycle in which the display repeats, however, now depends on the frequency f _x and thus on the measured value itself.

The arrangement of FIG. 3 differs from the discussed arrangement according to FIG. ?. only in two points. Instead of a gate circuit 7, two gate circuits 7 1 and 7'2 are used here, one of which. 7 1. is applied only by square-wave voltages, the frequency of which is directly proportional to the measured value ( J \ ~ - M _x ). while the other. 7 2. is controlled by the auxiliary counter 6 of the square-wave voltages, the frequency of which is inversely proportional to the measured value

The output of one or the other circuit is optionally connected to the counter 14 via the switch 5 3. The arrangement of FIG. 3 looks more complex in the block diagram than that of FIG. 2. In the meantime, a gate circuit 7 1 or 7 2 generally only consists of a diode, a resistor and a capacitor, so that this additional expense is hardly significant. On the other hand, switching over on the output side (switch 5/3) can be implemented more easily by electronic means than switching over both inputs α and h of gate circuit 7.

In Fig. 3 are also the square-wave voltages. whose frequency is directly proportional to the measured value. The gate circuit 7/1 is fed directly via the changeover switch 51 and is not passed via the subtraction circuit 4. The subtraction of the frequency / ₀ from all frequencies /, takes place in the counter 14 by presetting the counter accordingly to the complementary value of the value to be subtracted, which is stored in a memory 13/1 to be queried by the control device 13 . The value to be subtracted corresponds to the quotient

4 °

45

55

.'ItIlU ~ JO

When the measured value zero assigned frequency / ₀ <\ s for example, 500 Hz and that of the full-scale value assigned frequency / _ΜΛΧ 250OHz and further if the gating time T corresponding to a Bcreiehsendwert of. "Selected 70 or 700 to .oO msec st. Must of Counter 14 can be preset so that the first Γϊ pulses bring the counter to zero. A Veisie'lKer counter would therefore have to be preset to 82: *. Be'i / ■ '"= ^r 500 Hz then run in 350 msec Γ5 pulses in the Counter 14 on. These bring the counter to (1) 000 and display 000. With / ,. = _s (K)!, ufer, in '-Ο msec S75 pulses into counter 14. You bring the counter to 825 - 875 = 11Γ .. "- \ _n iiezeiet in this case the end of the range ιX) Öde" r ~ "0.0 or" .00. if the comma is shifted to the left accordingly.

If several measuring ranges are provided sir.o. the do not differ from each other by a factor of 10. ..-. J 1 different presets in memory 13. : .- -.secures one of which each time you press ·> Measuring range switch activated j.v> approx.

In F ι ^ll 4 is an embodiment of door eir.e ■, ^Λ -

traktious' circuit 4 shown. It consists of, r,

bistable multivibrator with a set input: a reset input b and one from r ..;. ments 19. 20. 21 formed impulse gate, the shear input 19 is connected to the output <of the mu. brator. while being impulsive; to remove the discriminator 3. at which square-wave voltages of the frequency J _x occur. ! The output of the “discriminator .3 is more finely connected to input ii of the multivibrator, input b of the multivibrator is connected to the pulse qiK. ■ of the frequency ( _s) .

Pulses of the frequency / _t can only d; uin over ,; Capacitor 20 and diode 21 for auxiliary counting when resistor 19 is at the output. vi multivibrators positive or zero potential vortiiui. This is the case when the multivibrator over. its input <i is "set". On the other hand, the multivibrato is via its input. ¹ ", it must first be" set "again before the next pulse is passed on through the pulse gate.

The frequency / \ is, for example, 125OH /. the frequency./ ;, 500 Hz. At 1250 Hz, a pulse arrives at an interval of 0.8 msec. at 500 Hz every 2 msec. The first impulse at input a must first bring the multivibrator into the working position, ie "set" it. Fr vv is suppressed by the impulse gate. The second pulse (after 0.8 msec) reaches the auxiliary counter 6, as does the third pulse that arrives after 1.6 msec. After 2 msec the multivibrator is reset by the 500 Hz pulse. Therefore the fourth pulse (after 2.4 msec) is suppressed again, but it brings the multivibrator back into the working position. This allows the fifth impulse to pass through the impulse gate. The sixth pulse, which arrives after 4 msec, coincides with a reset pulse and is therefore not forwarded, but the seventh (4.8 msec) and eighth pulse (5.6 msec) can pass unhindered. The next pulse is suppressed because the multivibrator was reset before it arrived (after 6.4 msec) (after 6 msec). The tenth pulse vv, however, is transmitted. In this way, out of ten impulses, only six reach the counter and of 1250 impulses only 750. This corresponds to the difference /, -f ₀ . Of course, the subtraction circuit also works in the same way at every other frequency / and every other "zero" frequency / ₀ .

A major advantage of the method of the invention, that with the arrangements according to FIG

up to 4 is feasible. harbors : V. its ability to adapt to different reporting conditions and existing measuring devices. As has already been admonished, giver 1 is tension--. Resistance and capacity meter iw: e also other Mei'-ariordnunsienl of usual design can be seen, those at J-ii miles. i = .jr die der hrlinden \ 'Π intere ^^ ·' .- !. Me! - already for AnalogmeNSur.nei ";'.er-.venJet'.'. Earth here in the course of the Analog-Dignai-l' mv.andiung \ or-ατ, ϋΐηηΐί'η; voltage * -Frequency-L mse! / i :: ig eriaubi e- .. the Nkßwerte without infoπτ! a: ior.s ^ erlu ^ ι fornzuiihiegen At the receiving place stone then at the exit de · - [5isknrninators 3 still an Ar.aloe ^ ert

- A /, odei

M.

■ _in '"fden icderzcii can be cut back without impairing dr Oi-ifil- <n7ci" e if necessary. /. H. through Jinen parallel connected frequency-Siron -.- rmset ^ er rr »it n.ichsicschiiltciem ammeter. The frequencies / ... /: and t _:. 1 _:. can without notice through examination or a. \ erander: uerd - n -ο di'i * also the lor times to any Me: - bere.ch> enduerte adaptable> ind. The payer and the display device can finally be set up with such places as the particular display accuracy required.

1 sheet of drawings

Claims (1)

Patent claims: 1. Method for converting analog measured values, which can lie in a finite or infinite range, into digital display values, the measured values, unless they are present as direct voltages from the outset, first converted into proportional or inversely proportional direct voltages, then after the ι -, Frequency variation method converted into alternating voltages with the respective amplitude of the frequency assigned to the direct voltage and then while maintaining the frequency ^: r. Square-wave voltages are converted, characterized in that the square-wave voltages in the event that the DC voltages on which they are based are directly proportional to the measured value, in a manner known per se during a time determined by a clock pulse generator; In the event that the underlying DC voltages are inversely proportional to the measurement, an auxiliary / ähler ^ open, which determines a time from the duration up to the arrival of a certain number of these square-wave pulses in which the pulses generated by the clock pulse generator to the counter controlling the display means as a counter .-npulses are supplied. 2. The method according to part 1. characterized in that in the voltage-frequency conversion the measured value N'ill is assigned a non-zero frequency ^ and its influence on the number result by appropriate presetting of the counter and or by one made before the count Subtraction of this frequency /, from all frequencies of the band in question for the conversion / o .. .f _{max is} switched off. 3. Order to carry out the seduction "; according to claim 1, characterized by a known encoder (1). the one to the respective A voltage-frequency converter connected to it supplies the measured value proportional DC voltage (2) known type, which produces an alternating voltage with the amplitude of the respectively supplied DC voltage assigned frequency emits a known discriminator circuit (3). which converts the alternating voltages into square-wave voltages and feeds them - in the event that the underlying direct voltage is directly proportional to the measured value - to the pulse input α of a gate circuit (7) whose static input h is connected to a pulse source (10) of frequency / . or in the event that the underlying DC voltage is inversely proportional to the measured value, it is fed to an auxiliary counter (6), the output of which is connected to the static input b of the gate circuit (7). whose pulse input α fi.s in this case is connected to the output of a clock pulse generator (8) of the frequency /. as well as one at the output of the gate circuit (7) closed counter (".4). of the digital display means (161 controls (F i g. H-. - .1 -1 u s arrangement according to claim λ, characterized in that / ur subtraction of the frequency assigned to the MeH-VTt zero -r Γβι "iTine from one or more bistable Κφρ-stuf-n built subtraction circuit (4i ir.:; two fin.'änsien and one output provided, si their first output with the output u -. * discriminator * (3i and their second input iv.ä of a pulse source | 9i of frequency /, connect ;. ¹ ^ (H ig- -i- ,, JJ, s arrangement according to claim .1. thereby c. indicates that the static input ή d.-gate circuit | 7 | via switchover means H2i .-:: Measuring range switchover optionally from the ':. puKquelle (1Oi of the frequency /; dbschalvbar \, r, J to a further pulse source (11) of the frequency:. can be connected (F 1 g. 2). 6 arrangement according to claim 3 to .->. dadu:,. This identifies that the pulse sources (9. 10.!. of the frequencies / ,,. / _; and / _, from per se! i g. 2 |. 7. Arrangement according to claim 3 to 6. daduu ■ it denotes. ' that between the counter i14 and the display titles 16) a memory l! 5l \ o · seen is. S. Arrangement according to claim 7. marked.!:;., By a control circuit (13). those of the / i :: v. static input b of the gate circuit (7) reached ·, the pulses "is applied and the return position of the counter (14) as well as the transfer of the counter reading into the memory (15) controls. 9. Arrangement according to claim, characterized in that that to eliminate the influence of the frequency / "on the counting result the control circuit (131 with means (13 1) for presetting of the counter (14) is equipped to a value corresponding to the frequency to be deducted (Fig. 31. 10. Arrangement according to claim 3 to 9 characterized by a counter (14) controlled toggle switch (I81 certain upper limit value of the counter reading receives a signal and then an additional one Display means (17) to identify this counter reading. 11. Arrangement according to claim 3 to 10, characterized in that two gate circuits (7 1. 7 2) are provided, the outputs of which can optionally be connected to the counter (14) and of which the first (7 1) by switching means (5 / is 1) f only for the square wave voltages of the frequency _x made effective whose underlying DC voltages are directly proportional to the measured value, while the second (made 7.2) by switching means (5/1) nu ^r for the square wave voltages of the frequency effective J _x whose underlying DC voltages are inversely proportional to the measured value (Fig. 3). 12. The arrangement according to claim 3 to 11, characterized in that the switching off of the frequency /> at Rechted ::. mnnungen _h. whose underlying DC voltage directly corresponds to the measured value y 1 is proportional. preferably by appropriate Presetting of the counter il4i via the control circuit 113. 13 1) and for square-wave voltages. whose underlying DC voltage is the opposite of the measured value prop.ini.Mi.il; q. by sub- s traction of frequency /. in the suhi action circuit | 4 | he follows.