SU754211A1 - System for remote measuring of liquid level - Google Patents

Description

The invention relates to the field of instrumentation, and in particular to information-measuring systems for remote measurement of the level of the product in land tanks or tanks of oil tankers.

Known measuring systems for monitoring the level of petroleum products, intended for remote measurement of the level of liquid in tanks. These systems include level gauges with an attachment for remote transmission of liquid level values that are connected by a communication line with information processing equipment [1].

A well-known system also includes a float-type level gauge, an analog-to-digital converter (ADC), a decoder, and a digital indicator [2].

A disadvantage of the known system is low reliability, due to the possibility of the occurrence of false information due to a failure in the circuit of one information bit of the ADC, leading to the appearance of an erroneous allowed code combination.

The purpose of the invention is to increase reliability.

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This goal is achieved by the fact that the proposed system for remote level measurement of a liquid is equipped with an automatic information accuracy control device ₅ connected to the decoder, made in the form of two AND elements, the first inputs of which are interconnected and connected to the decoder and the input of the HE element, the output of the latter is connected to the combined first inputs of the third and fourth elements are And, the second input of the first element And is combined with the second input of the fourth element And and is connected to another output of the decryptor ra and another element NOT, the output of which is connected to the combined second inputs of the second and third elements AND, the outputs of the first and second elements ¹⁵ AND are connected respectively to the first and second inputs of the memory element, both outputs of which are connected respectively to the third inputs of the third and fourth elements AND, and the exits of the latter with a signaling device.

The drawing shows a block diagram of the proposed system.

It consists of the device '1 automatic control of the reliability of information

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gage, float type 2 gauge, analog-to-digital converter 3 into a reflexive binary-decimal code, decoder 4, which translates the reflexive binary-decimal code into a decimal code, and digital indicator 5.

The device 1 of the automatic control of the accuracy of the information contains the elements N 6, 7, 8 and 9, the elements NOT 10 and 11, the element 12 of the memory and the signaling device 13.

The operation of the device 1 automatic control of the reliability of information is based on the following characteristic features of any reflex code. If at the moment of failure of one information bit of a code the number read from the ADC is even, then a failure will lead to a forbidden combination in the code or to an erroneously resolved code combination, but necessarily an odd one, and vice versa, an odd number can only be transformed into an even number. This feature is associated with the basic principle of building reflex codes, in which the values of two adjacent numbers differ in only one information bit. Therefore, in a multidigit reflex binary decimal code, the numbers “O” and “9” have the same code combination, and the decryption of such a code is based on the parity of the previous decimal place. ' The change of numbers, and, consequently, of parity, in all major decimal places is permissible only as a throw from the carry, which spreads when the significant digit in the lower decimal place changes from “9” to “0” or vice versa. Changing the parity in any high decimal if there are significant digits from 1 to 8 in the lower decimal is erroneous and signals a failure in one of the higher decimal places. An erroneous parity change in any decimal place leads to a change in the parity of all subsequent decimal places, so the automatic information control device 1 can be one, regardless of the number of decimal places, and must be connected to the decoder 4 of the second decimal data parity bus. To the second input of the automatic information accuracy control device, a signal is generated that is generated by the decoder 4 when the code combination of the numbers "9" and "0" appears in the lower decimal place. In this case, the device for automatic control of the reliability of information checks the operation of all the higher decimal places, except the younger, and therefore the measurement error can remain undetected only if one of the information bits fails in the lower decimal place. By type choice

reflex code this error can be reduced to a value equal to one of the lowest decimal place.

The device 1 automatic control of the accuracy of the information works as follows.

In the presence of a code combination of the numbers “0” and “9” in the lower decimal, decoder 4 generates a signal “1” that goes to the second input of the automatic control device 1 and prepares elements 6 and 7 for actuation and HE 10 blocks the AND elements 8 and 9. With an even number in the second decimal place in the decoder 4, the signal “0” is generated on the information bus of the parity signal, and with an odd number - the signal “1”. When the number in this digit changes from even to odd in decoder 4 on the parity information bus, and consequently, at the first input of the automatic control device 1, the signal from “0” changes to “1”. This triggers the element And 6, which sets the memory element 12 in a position in which at its output, connected to the element And 8, the signal will be formed "1", and at the other output signal "0". When changing the significant numbers in the low-order digit of the decoder 4 and moving to numbers from 1 to 8, the signal "1" at the second input of the automatic control device 1 disappears and elements 6 and 7 are blocked, and elements 8 and 9 through the element 10 are prepared to operate . However, of these two elements, And only element 8 is fully prepared for operation, since element 9 is blocked by a signal "0" from the output of memory element 12. If under these conditions a failure occurs, leading to an erroneous code combination and the associated change in the signal on the parity information bus, i.e. to change the signal from "1" to "0" at the first input of the automatic control device 1, then this signal through the element NOT 11 will trigger the element I 8 and, therefore, trigger the signal device 13. In the absence of a failure due to a change measured by the level gauge 2 levels of the product in the lower decimal place the code combination of the numbers "0" and "9" should appear again and again the decoder 4 will generate the signal "1", which will prepare the elements 6 and 7 for operation and will NOT block elements 8 and 9 through the element 10 In this case, in the second In the decimal number of a number in the decoder 4, an odd number will change to an even number, and the signal on the parity information bus will change from “1” to “O”. In this case, through the element NOT 11, the element AND 7 is triggered, which sets the memory element 12 to a position in which the signal “1” is generated at its output connected to the element 9 and the signal “0” at the other output. With further change of significant numbers in the youngest

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the discharge of the decoder 4 and the transition to numbers from 1 to 8, the signal at the second input of the automatic control device 1 disappears, and elements 6 and 7 are blocked, and elements 8 and 9 through the element 10 are prepared for operation. _five

However, of these two elements, And only element 9 is fully prepared for actuation, since element 8 is blocked by a signal "0" from the output of memory element 12. If under these conditions a failure occurs, leading to an erroneous code combination 10 and the associated change in the information signal the parity bus, i.e. signal to change from "0" to "1" at the first input of the automatic control device 1, this signal will trigger the AND gate 9, and consequently to ¹⁵ Switching times NIJ warning device 13. In the absence of failures in the further product change level measured by the level gauge 2, the sequence of operation of the device I automatic control of the reliability of information is repeated.

Claims (1)

Claim Remote Measurement System nya liquid levels ^25, comprising a float type level gauge, an analog-digital converter of the angle of rotation of the output shaft urs Nemerow in reflex code decoder and a digital display, characterized in that in order to increase reliability, it is provided with an automatic control of the reliability information, made in the form of two elements AND, the first inputs of which are interconnected and connected to the decoder and the input of the element NOT, the output of the last is connected to the combined first inputs the third And the fourth element And the second input of the first element And combined with the second input of the fourth element And and connected to another output of the decoder and another element NOT, the output of which is connected with the combined second inputs of the second and third elements And the outputs of the first and second elements And connected respectively with the first and second inputs of the memory element, both outputs of which are connected respectively with the third inputs of the third and fourth elements AND, and the outputs of the latter with a signaling device.