SU1150491A2 - Level indicator - Google Patents

Abstract

Level on avt. St. ff 900120, characterized in that, in order to increase the measurement accuracy, an intermediate level value storage register is entered into it, with its code code associated with the code output of the second reversible counter, control input with control signal circuit, and output - with a code input of the first reversible counter.

Description

The invention relates to a measurement technique and can be used in the petrochemical industry to measure the levels of liquid media. According to the main author. St. P 900120 known gauge with multi-frequency sensor. The device contains a sensor connected to the first co-mutation circuit, which is connected to the first reversible counter through two logical circuits, and to the second switching circuit that is connected to the second reversible counter, a control signal processing circuit and a memory block connected between each other and switching circuits and reversible counters, a frequency shaping circuit connected to the switching circuits, a level register and a section number register connected to a section number counter, a trigger, an overflow circuit, a connected output with the level and section indication registers, the section counter, and the inputs with the output of the first reversible counter and the level register input, the trigger input connected to the output of the second reversing counter connected to the first reverse counter, and the trigger output connected to the second circuit switching and inputs of logic circuits lj. I Level gauges with multi-sectional frequency sensors are used to measure the level of the media; sections that can be end-to-end joined together. The use of a multisection sensor with end-to-end sections reduces the metal consumption of the primary converter, but requires a special information processing algorithm, different from that for the sensor with overlapping sections. When the butt-end sections of the sensor are connected, the error in converting the level to frequency at the level of the medium located at the junction of the sections is i2%, which allows the sensor to make a conclusion whether it is full or in part only in one i-th section. This ambiguity determines the following processing algorithm. information coming from the sensor with sections butt: a sign of the degree of filling of the section (empty, partially 912 full, full) is formed as a result of the summation of levels in the i-th and back-(i + 1) -th sections of the sensor. The code value of the monitored medium in each L-th section is taken offset N c -i-100. As a result, the possibility of obtaining negative level values is eliminated and the sign of the degree of filling of the section is formed, allowing to distinguish levels in the case of partially filled and empty sections of sensor 2j. The drawbacks of the level gauge are faults when working with a butt-joint multisection frequency sensor, as a result of which the level gauge transmitter may miss several full sections. The purpose of the invention is to increase the accuracy in determining the number of completely filled sensor sections and to extend the functionality of the computational converter, i.e. the creation of a level gauge capable of processing information coming from multisectional sensors, which sections are connected both end-to-end and overlap. This goal is achieved by the fact that the intermediate level value storage register is entered into the gage, the code input of which is connected to the code output of the second reversible counter, the control input to the control output circuit, and the code input of the first reversible counter. The drawing shows a block diagram of the proposed level gauge. The device contains a control signal generation circuit 1, two circuits 2 and 3 co-installations, a frequency formation circuit 4 f (y, and (, 2, two logic circuits AND 5 and 6, a coefficient memory block 7, reversible counters 8 and 9, trigger 10, overflow indication circuit 11, level 12 register, counter 13 and number 14 register 14, intermediate level value storage register 15. Measuring f, j and compensation f 2, - channels of a multi-section sensor 16 are connected to switching circuits 2 and 3. Outputs circuits 3 are connected to the counting inputs of the reversible counter 9, and circuits 2 - to the inputs ble AND circuits 5 and 6, respectively associated with their outputs

3

summing and subtracting the inputs of the reversing counter 8. The inputs fo and foj of the frequency shaping circuit 4 connected to the reference frequency bus fg and the Qg bus of the control signal generation circuit 1 are connected to the inputs of circuits 2 and 3.

The outputs Q, 0, Qj 1 are connected to the coefficient memory block 7, and the output QI to the storage register 15 of intermediate level values. The outputs Ng of block 7 of the memory coefficients are connected to the code inputs of the counter 8, which are connected with their respective codes to the corresponding code inputs of the second reversible counter 9, the level register 12 in the section and the overflow sign circuit 11. The bus borrowing the reversible counter 9 is connected to the trigger 10, and the code output of the counter 9 is associated with the code inputs of the register 15 for storing intermediate level values associated with its code outputs with the code input of the reversing counter 8. The single output of the trigger 10 is connected to the inputs of circuits 2 and 3 switching and logic circuits 5 and 6. One output (Vj) of the overflow indication circuit 11 is connected to the counter 13 of the number of sections associated with the register 14 of the number of sections, the second (Pzagr section register) - to the input of the register 14 of the number of sections, and the third and fourth (register level and zero level setting) - to register inputs 12 level.

The output qj of circuit 1 is connected to the reversible counter B, qg to the reversible counter 9 and trigger 10, q ' to the counter 13 of the number of sections, circuit 11 overflow, q, to the storage register 15 of intermediate level values. Outputs and q, circuits 1 are connected to a level sensor 16 to ensure its synchronous operation with a computational transducer of the level gauge.

The output result is removed from the register 1 of the number of sec1; ii, in which the code of the number of completely filled sections is stored, and the register 12 is set inside the current section. The calculation sequence control is a control signal generation circuit 1 having the classical structure of a synchronous type control device.

504914

The basis of the proposed level gauge is a cyclical interrogation. During the time of the dash sections, starting with the first one, the interrogation of the (i + 1) -th section of the intermediate code of the NH level in it, and the code of the level of the NM section in it. pe1 "Att„ J, + NH. "P", with the formation of the signal V- 1, if the level H is 100%, or 10 signals q dgr register sections; qsorp level register, if О i Н «tOO%, or q, q ™ signals of section register and zero level register setting, if Н 0%.

f5 During the entire sensor polling cycle, the number of completely filled sections N and the level Hz, inside the empty or partially filled (pC + 1) -th section, is determined. The value of level 20 in each section is sequentially generated at the output of the reversible counter 8.

When calculating the intermediate code level N ,,., In the i-th section, the level gauge realizes the dependence

fo,; - f "; f

 (H;) (1)

02; fj; f

where f, foj. are frequencies corresponding to zero.

level in the section;

f. if () is the frequency value of the working section of the sensor;

f. (f (U; E) is the current value of the frequency of the sensor’s correction section,

with simultaneous linearization carried out by approximating the function

H- 4Z;)

(2)

second degree polynomial

PjCZ.) - (ajZ- + a) Z, - + a (3)

Consider the operation of the device during one cycle of Tf-poll of the sensor.

For synchronous operation of the device by means of signals q and q, respectively, the counter 13 and the section counter in the multi-section sensor are zeroed at the beginning of the cycle and the frequencies f are connected to the input of the computation transducer of the level gauge, and fj ;, corresponding to the first section. During the Tx survey cycle, the first section of the sensor generates an intermediate code for the NHJ level of the first section in six cycles Q.J-Qg of the level meter operation. During this time, dependency (1) and polynomial (3) are implemented jointly. During the Q stroke; The code N ,, f, pon, is transferred to the storage register 15 of the intermediate level code. During the Tx polling cycle, the second Nn npowe level code also forms six cycles during the second section of the sensor, and the resulting N is computed in the cycle Q of the T cycle (the level code in the first section Ny pg NH, intermediate Ng, Control signals q , 0 are generated by the control signal generation circuit 1. Selection of codes proportional to the coefficients a, the approximating polynomial (3), is made by signals Q, Q, 0 of the code Nyj, through the generation of the code Cr.rrom by signal Qr. 9 is produced at the moments of arrival of signals q, and q respectively At the beginning of the first measure from the coefficient memory block through the reversible counter 8 and the reversible counter 9, the code Ng is written. , and the trigger 10 with the arrival of the Pulse q is set to one state. During the first clock cycle, the NO code is recorded from the counter 9 by the frequency pulses fo2- and fj- received by its subtractions and summations through the switching circuit 3 from the frequency shaping circuit 4. and the primary sensor, respectively, until the counter is zeroed 9. Here, f. f 2; . At the output of the trigger 10, a time interval of 2 is formed, with a duration of

N

Og

r, t, -,

foz;

5i

(10), which is filled with frequency pulses f. and, coming through the switching circuit 2 from the outputs of the circuit 4 and the primary sensor to the inputs of logic circuits 5 and 6. At the same time, the number-pulse codes n, f 01, t and n f, p, are input to the outputs, summing and subtracting inputs of counter 9, in which the sum of pc is generated, - - fo4 - f), (5) with (4) fob - at the beginning of the second clock cycle, the code is copied from counter 8 to counter 9, from which it is written off by frequency pulses before counter zeroing 9. At the output of the trigger 10, an interval is formed (-Ipci I which is filled in the AND 5 circuit with frequency pulses fj. On its output generates the number of pulses P2 2i 2g. Which is recorded in counter 8, forming the code RS, PC1 2i in it. At the beginning of the third clock cycle, rewritten into counter 9, and in counter 8 sets the code Nq 01, and similarly to the previous clock in counter 8 is formed code, -4 - N, p ,, N ,, (8) li In the fourth, fifth and sixth cycles, similarly to the first three clock cycles in counter 8, respectively, the codes fo are formed; - f "; tfci Рс) OZi 2., аГРГв П8) ТТ9Т (9) in (10), (10) in (11), expression (11) takes the form ".„ .. Mi. (in the seventh cycle, the code N. is rewritten into the storage register 15 of intermediate level values. During the next six cycles of operation, the code N is calculated as described above, the prom code is rewritten into the reversible counter 9, the NHJ code of the prom signal q, loaded from the register 15 into the reversible the counter 8, and by the signal q the code N "Ui" poMe from the counter 9 is recorded in the storage register 15 of intermediate level values. With the help of the trigger 10, the time interval H is formed, which is filled with the frequency pulses fg. 6. In code 8, a code is formed, Hi, .4 (. N7PC, "I {rve" At the end of the seventh cycle, the generated code of the level in the first section goes to overflow indication circuit 11. If NU, av, 100%, Fore ™ Route with „.„ al V; -,.. „™ the current content of counter 13 of the number of sections by 1. If Nf ,. f 0%, then with the arrival of the clock signal q, the signals of the section register q and jQIp are set, zero level register, as a result, the contents of the 12-level register are zeroed out, and the number of sections is transferred from the counter of 13 numbers of sections to the number of sections, the code of the number of completely filled sections. If O n; re- 100%, the level register and q signals are generated. the section register, as a result of which a level value in the section is transferred to the level 12 register, and a code for the number of completely filled sections is transferred to the number 14 register register 14. The process of generating a code level in each cycle is similar to that discussed above. After the first appearance of the resultant code O i N. 100% of the contents of counter 13 and registers 12 and 14 do not change before the beginning of a new survey cycle of the sensor sections. The proposed level gauge, in comparison with the known one, has wider functional possibilities, since it can act as a primary converter as a multisection sensor with end-to-end sections, and a multisection sensor with overlapping sections, and higher accuracy in the case of using a multi-section sensor, sections which are butt-joined.

Claims (1)

LEVEL on avt. St. No. 900120, characterized in that, in order to increase the accuracy of measurement, an intermediate level value storage register is entered into it, and its code input is connected to the code output of the second reversible counter, the control input is with a control signal generation circuit, and the output is with a code input first reverse counter.