Liquid helium Dewar liquid volume calculation method and system based on Siemens PLC

Abstract

The invention discloses a Siemens PLC-based liquid helium Dewar liquid volume calculation method and system, which are applied to the technical field of low-temperature control, and the method comprises the steps: obtaining the data of a liquid helium Dewar tank capacity meter and the data of a liquid level meter; calculating based on the data of the liquid helium Dewar tank capacity meter and the data of the liquid level meter to obtain the liquid helium Dewar liquid volume; and the liquid level meter data and the liquid volume of the liquid helium Dewar are displayed through an upper computer.

Description

Technical Field

[0001] The present invention relates to the field of cryogenic control technology, and in particular to a method and system for calculating the liquid volume of a liquid helium dewar based on a Siemens PLC. Background Art

[0002] PLC control system is a new generation of industrial control device formed by introducing microelectronic technology, computer technology, automatic control technology and communication technology on the basis of traditional sequential controller. Its purpose is to replace relays, execution logic, timing, counting and other sequential control functions, and establish a flexible remote control system. It has the characteristics of strong versatility, easy use, wide adaptability, high reliability, strong anti-interference ability and simple programming.

[0003] Generally, the cyclic scanning working mode is adopted, and the interrupt working mode is added in some large and medium-sized PLCs. After the user completes the debugging of the user program, the program is written into the PLC memory through the programmer, and the input signal of the field and the controlled actuator are connected to the input end of the input module and the output end of the output module respectively. Then the PLC working mode is selected as the running working mode, and the subsequent work is completed by the PLC according to the user program.

[0004] The liquid helium dewar tank capacity table is a table in which the dewar manufacturer uses 3D scanning technology to scan the dewar liner and obtain the point cloud data of the tank. This scanning process does not require contact with the tank, and a large amount of 3D coordinate data can be obtained in a short time, so as to completely reconstruct the 3D model of the tank. The acquired point cloud data is preprocessed to protect denoising, filtering, registration and other operations to improve the accuracy and integrity of the point cloud data. Based on the preprocessed point cloud data, the 3D model is reconstructed using relevant software. After the model is established, the various indicators of the tank can be checked and analyzed. The shape, size, position, flatness and other parameters of the tank can be detected, and the volume and weight of the tank can also be calculated. The liquid helium dewar tank capacity table is a data table related to the liquid level and volume obtained based on 3D scanning technology.

[0005] The liquid level gauge of the liquid helium dewar in this application is the AMI1700 series liquid level gauge. The AMI1700 liquid level meter is a precision instrument that uses a capacitive level sensor as input and can provide measurement and control for monitoring liquids. Since the height of the 10000L and 20000L dewars is relatively high, a single capacitive level sensor cannot meet the full-scale measurement, and two capacitive level sensors are finally used. This installation method increases the difficulty of PLC programming of the dewar liquid helium level and volume.

[0006] In view of the above problems, the present application proposes a method and system for calculating the liquid volume of a liquid helium dewar based on Siemens PLC. By associating the liquid helium dewar tank capacity table data with the dewar level gauge data, a volume calculation program is written to reduce the error in the liquid helium volume calculation. Summary of the invention

[0007] The purpose of this application is to provide a method and system for calculating the liquid volume of a liquid helium dewar based on a Siemens PLC, aiming to solve the technical problem that errors are easily generated when calculating the liquid volume of a liquid helium dewar in the prior art.

[0008] To achieve the above objectives, this application provides the following technical solutions:

[0009] The present application provides a method for calculating the liquid volume of a liquid helium dewar based on Siemens PLC, comprising:

[0010] Obtain the data of the liquid helium Dewar tank capacity table and the liquid level gauge;

[0011] Calculate based on the data of the liquid helium Dewar tank capacity table and the liquid level gauge data to obtain the liquid volume of the liquid helium Dewar;

[0012] The liquid level gauge data and the liquid volume of the liquid helium Dewar are displayed by a host computer.

[0013] Furthermore, the step of calculating based on the data of the liquid helium Dewar tank capacity table and the liquid level gauge data to obtain the liquid volume of the liquid helium Dewar specifically includes the following steps:

[0014] The liquid level gauge data is divided into integers and decimals; the integer is associated with the data of the liquid helium dewar tank capacity table, that is, the volume V1 is obtained; the decimal is multiplied by the difference between the upper and lower parts of the preset scale to obtain the volume V2;

[0015] The liquid volume of the liquid helium Dewar is the sum of the volume V1 and the volume V2.

[0016] Furthermore, the liquid level meter data includes:

[0017] Convert the measured value of the level gauge to 0-100% operating value;

[0018] The operation value is multiplied by the length of the capacitive level sensor to obtain the level meter data.

[0019] The present application proposes a liquid helium dewar liquid volume calculation system based on Siemens PLC, including: a global data block, a data acquisition module, an FC function block, and a host computer display module;

[0020] The global data block is used to store the data of the liquid helium dewar tank capacity table;

[0021] The data acquisition module obtains the liquid level meter data through the liquid level meter;

[0022] The FC function block receives the liquid level gauge data transmitted by the data acquisition module, and calculates the liquid volume of the liquid helium Dewar based on the liquid level gauge data and the data of the liquid helium Dewar tank capacity table;

[0023] The global data block is connected to the data acquisition module through the internal communication mechanism of the PLC, the data acquisition module is connected to the FC function block through the internal communication mechanism of the PLC, and the host computer display module is connected to the PLC through the communication interface of the PLC to obtain the liquid level meter data and the liquid volume of the liquid helium Dewar for display.

[0024] Furthermore, the global data block is a Siemens PLC global data block, which acquires and stores data of the liquid helium dewar tank capacity table according to the liquid helium dewar tank capacity table.

[0025] Furthermore, the host computer display module is used to add the liquid level meter data and the liquid volume of the liquid helium Dewar to the variable table of WinCC, and display them based on the host computer display module.

[0026] The present application provides a device, comprising a processor and a memory coupled to the processor, wherein the memory stores program instructions for implementing a method for calculating the liquid volume of a liquid helium Dewar based on a Siemens PLC; the processor is used to execute the program instructions stored in the memory to implement a method for calculating the liquid volume of a liquid helium Dewar based on a Siemens PLC.

[0027] The present application provides a storage medium storing program instructions executable by a processor, wherein the program instructions are used to execute a method for calculating the liquid volume of a liquid helium dewar based on a Siemens PLC.

[0028] The present application provides a method and system for calculating the liquid volume of a liquid helium dewar based on Siemens PLC, which has the following beneficial effects:

[0029] (1) By adopting a method of associating the liquid helium Dewar tank capacity table data with the Dewar liquid level gauge data, the accurate calculation of the liquid helium volume is achieved; compared with the traditional method of calculating the volume by multiplying the percentage of the Dewar liquid level gauge by the geometric dimensions, the present application is more accurate in processing the nonlinear relationship between the liquid level change and the volume change, thereby reducing the calculation error;

[0030] (2) In the computing system proposed in the present application, the real-time monitoring and display of the liquid level and volume of the liquid helium dewar are realized through the cooperation of the PLC and the WinCC host computer, so that the operator can grasp the status of the liquid helium dewar at any time, thereby improving the real-time performance and safety of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flow chart of a method for calculating the liquid volume of a liquid helium Dewar based on Siemens PLC according to Example 1 of the present application;

[0032] Figure 2 This is a schematic diagram of the structure of a liquid helium Dewar liquid volume calculation system based on Siemens PLC in Example 2 of the present application;

[0033] Figure 3 This is a schematic diagram of the PLC global data block of the 10000L liquid helium dewar of Example 2 of the present application;

[0034] Figure 4 This is a schematic diagram of the FC function blocks of Example 2 of the present application;

[0035] Figure 5 This is a schematic diagram showing the display of the liquid level gauge data and the liquid volume of the liquid helium Dewar of the WinCC host computer in Example 2 of the present application;

[0036] Figure 6 It is a schematic diagram of the liquid volume curve of 10000L and 20000L liquid helium Dewar in Example 2 of the present application;

[0037] Figure 7 This is a schematic diagram of the structure of a conventional liquid helium dewar according to Example 2 of the present application;

[0038] Figure 8 This is a schematic diagram of the device structure of Example 3 of the present application;

[0039] Fig. 9 This is a schematic diagram of the storage medium structure of Example 4 of the present application. DETAILED DESCRIPTION

[0040] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0041] The following is an analysis of the solutions in the prior art in combination with related technologies.

[0042] Commonly used methods for calculating the volume of a liquid helium dewar: First, calculate the volume of the liquid helium dewar liner according to the liquid helium dewar drawing and the geometric dimensions of the liner. Then calculate the volume by multiplying the percentage of the dewar level gauge by the geometric dimensions to obtain the volume of the liquid helium. Figure 7 It can be seen from the structure diagram of the liquid helium dewar that the inner tank is composed of upper and lower heads and a middle cylindrical part. When the liquid level is at the lower and upper heads, the liquid level change and volume change are not linear. Using the above calculation method will produce a large error.

[0043] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0044] Example 1

[0045] See also Figure 1 , is a flow chart of a method for calculating the liquid volume of a liquid helium Dewar based on Siemens PLC in Example 1 of the present application; the steps include:

[0046] S1: Get the data of the liquid helium Dewar tank capacity table and the liquid level gauge data.

[0047] In this embodiment, the volume corresponding to each scale is obtained according to the liquid helium dewar tank capacity table.

[0048] Liquid helium level meter data collection: The 4-20mA measurement value of the AMI level meter is converted into a 0-100% operation value, and then the operation value is multiplied by the preset length of the capacitive level sensor to obtain the scale value of the current liquid level. Since the liquid level change is a slow process, using the PLC scanning cycle as the sampling frequency will cause the measurement value to fluctuate greatly; in this embodiment, the sampling frequency of the level meter is set to 1 minute, so that the curve generated by the WinCC trend chart is smoother.

[0049] S2: Calculate based on the data of the liquid helium Dewar tank capacity table and the liquid level meter data to obtain the liquid volume of the liquid helium Dewar.

[0050] In this embodiment, Siemens Step7 software and S7-300 PLC module are used to write a volume calculation program by associating the data of the liquid helium Dewar tank capacity table with the liquid level meter data to reduce the error of liquid helium volume calculation. Specifically, the current liquid level meter data is divided into integers and decimals; the integer is directly associated with the data of the liquid helium Dewar tank capacity table, that is, the volume V1 is obtained; the decimal is multiplied by the difference between the current upper scale and the lower scale to obtain the volume V2. The liquid volume of the liquid helium Dewar is the sum of the volume V1 and the volume V2.

[0051] Furthermore, since the volume of the Dewar is 20,000L and the tank height is more than 3m, the maximum measurement range of a single antenna of the AMI level gauge is 2m. This time, two level gauge antennas of 2m and 1m are used for combined measurement. LI43000ad is a 2m level gauge, which measures the bottom level of the Dewar; LI4300au is a 1m level gauge, which measures the top level above 2m. Use the if statement to calculate the volume of liquid helium based on the two situations of the level at the bottom level gauge and the level at the top level gauge.

[0052] Since the AMI level meter feedback signal to the PLC fluctuates greatly, fluctuating 3-4 times per second with a plus or minus 2%, the measurement error of the liquid helium volume is large. In order to eliminate the error, the edge instruction is used to collect the level meter signal once every 1 second and save it in the array. Then the level meter signal is averaged to obtain an accurate measurement value.

[0053] Liquefaction rate calculation: Use edge instructions to collect the level gauge signal LI4300a_L_AVG once every minute. Use the bubbling algorithm to save 60 data of LI4300a_L_AVG within 60 minutes. Use the current LI4300a_L_AVG value to subtract the LI4300a_L_AVG value 60 minutes ago to get the value of LI4300a_LR liquid helium rate.

[0054] S3: Displaying the liquid level meter data and the liquid volume of the liquid helium Dewar through a host computer.

[0055] In this embodiment, the liquid level meter data and the liquid volume of the liquid helium dewar are added to the variable table of WinCC and displayed based on the host computer; visual monitoring of the data is achieved, which facilitates the operator to monitor and manage the status of the liquid helium dewar in real time.

[0056] In summary, in Example 1 of the present application, the liquid volume calculation program is compiled by associating the liquid helium Dewar tank capacity table data with the Dewar liquid level gauge data to reduce calculation errors. This method improves the accuracy of liquid helium Dewar liquid volume calculation and helps to improve the accuracy of liquefier performance assessment.

[0057] Example 2

[0058] See also Figure 2 , is a structural schematic diagram of a liquid helium Dewar liquid volume calculation system based on Siemens PLC in Example 2 of the present application; including: a global data block, a data acquisition module, an FC function block, and a host computer display module;

[0059] The global data block is used to store the data of the liquid helium dewar tank capacity table;

[0060] The data acquisition module obtains the liquid level meter data through the liquid level meter;

[0061] The FC function block receives the liquid level gauge data transmitted by the data acquisition module, and calculates the liquid volume of the liquid helium Dewar based on the liquid level gauge data and the data of the liquid helium Dewar tank capacity table;

[0062] The global data block is connected to the data acquisition module through the internal communication mechanism of the PLC, the data acquisition module is connected to the FC function block through the internal communication mechanism of the PLC, and the host computer display module is connected to the PLC through the communication interface of the PLC to obtain the liquid level meter data and the liquid volume of the liquid helium Dewar for display.

[0063] In this embodiment, the global data block stores the data of the liquid helium dewar tank capacity table, and the association of the liquid level meter data with the data of the liquid helium dewar tank capacity table and the calculation of the liquid volume of the liquid helium dewar are completed based on the FC function block. The liquid level and volume variables are displayed through the upper computer display module, and a curve chart is generated. Therefore, the accuracy of the liquid helium dewar liquid volume calculation is improved, and good results are achieved in practical applications.

[0064] See also Figure 3 , which is a schematic diagram of the PLC global data block of the 10000L liquid helium dewar of Example 2 of the present application. The established global data block is the Siemens PLC global data block. According to the liquid helium dewar tank capacity table, the volume corresponding to each scale is obtained. Among them, LITER[1] stores the volume data of the liquid to 1 cm, and so on.

[0065] See also Figure 4 , which is a schematic diagram of the FC function block of Example 2 of the present application. The FC function block is used to associate the liquid level meter data with the data of the liquid helium Dewar tank capacity table one by one to calculate the liquid volume of the liquid helium Dewar. Among them, the FC713 function block calculates the liquid volume of 20000L liquid helium Dewar, and the FC714 function block calculates the liquid volume of 10000L liquid helium Dewar.

[0066] See also Figure 5 , which is a schematic diagram of the display of the liquid level gauge data and the liquid volume of the liquid helium Dewar of the WinCC host computer in Example 2 of the present application. Among them, LI5100c and LI5100d are 10000L Dewar liquid level gauges, LI5200c and LI5200d are 20000L Dewar liquid level gauges, and LI5100 and LI5200 are the liquid volumes of the liquid helium Dewar.

[0067] Example 3

[0068] See also Figure 8 , is a schematic diagram of the device structure of Embodiment 3 of the present application. The device 50 includes a processor 51 and a memory 52 coupled to the processor 51 .

[0069] The memory 52 stores program instructions for implementing the above-mentioned method for calculating the liquid volume of the liquid helium Dewar based on Siemens PLC.

[0070] The processor 51 is used to execute the program instructions stored in the memory 52 to implement a liquid volume calculation of the liquid helium Dewar based on Siemens PLC.

[0071] The processor 51 may also be referred to as a CPU (Central Processing Unit).

[0072] The processor 51 may be an integrated circuit chip with signal processing capabilities. The processor 51 may also be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0073] Example 4

[0074] See also Fig. 9 , which is a schematic diagram of the structure of the storage medium of Example 4 of the present application. The storage medium of the embodiment of the present application stores a program file 61 that can implement all the above methods, wherein the program file 61 can be stored in the above storage medium in the form of a software product, including a number of instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) or a processor (processor) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, or a computer, a server, a mobile phone, a tablet, and other devices.

[0075] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, device, article or method including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, device, article or method. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the presence of other identical elements in the process, device, article or method including the element.

[0076] The above description is only a preferred embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

[0077] Although the embodiments of the present application have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the appended claims and their equivalents.

[0078] Of course, the present invention may have many other implementations. Based on this implementation, other implementations obtained by ordinary technicians in this field without any creative work are all within the scope of protection of the present invention.

Claims

1. A method for calculating the liquid volume of a liquid helium dewar based on Siemens PLC, characterized in that: include: Obtain the data of the liquid helium Dewar tank capacity table and the liquid level gauge; Calculate based on the data of the liquid helium Dewar tank capacity table and the liquid level gauge data to obtain the liquid volume of the liquid helium Dewar; The liquid level gauge data and the liquid volume of the liquid helium Dewar are displayed by a host computer.

2. The method for calculating the liquid volume of a liquid helium dewar based on Siemens PLC according to claim 1, characterized in that: The step of calculating based on the data of the liquid helium Dewar tank capacity table and the liquid level gauge data to obtain the liquid volume of the liquid helium Dewar specifically includes the following steps: The liquid level gauge data is divided into integers and decimals; the integer is associated with the data of the liquid helium dewar tank capacity table, that is, the volume V1 is obtained; the decimal is multiplied by the difference between the upper and lower parts of the preset scale to obtain the volume V2; The liquid volume of the liquid helium Dewar is the sum of the volume V1 and the volume V2.

3. The method for calculating the liquid volume of a liquid helium dewar based on Siemens PLC according to claim 1, characterized in that: The liquid level meter data includes: Convert the measured value of the level gauge to 0-100% operating value; The operation value is multiplied by the length of the capacitive level sensor to obtain the level meter data.

4. A system for calculating the liquid volume of a liquid helium dewar based on Siemens PLC according to claim 1, characterized in that: include: Global data block, data acquisition module, FC function block, host computer display module; The global data block is used to store the data of the liquid helium dewar tank capacity table; The data acquisition module obtains the liquid level meter data through the liquid level meter; The FC function block receives the liquid level gauge data transmitted by the data acquisition module, and calculates the liquid volume of the liquid helium Dewar based on the liquid level gauge data and the data of the liquid helium Dewar tank capacity table; The global data block is connected to the data acquisition module through the internal communication mechanism of the PLC, the data acquisition module is connected to the FC function block through the internal communication mechanism of the PLC, and the host computer display module is connected to the PLC through the communication interface of the PLC to obtain the liquid level meter data and the liquid volume of the liquid helium Dewar for display.

5. A liquid helium dewar liquid volume calculation system based on Siemens PLC according to claim 4, characterized in that: The global data block is a Siemens PLC global data block, which acquires and stores data of the liquid helium dewar tank capacity table according to the liquid helium dewar tank capacity table.

6. A liquid helium dewar liquid volume calculation system based on Siemens PLC according to claim 4, characterized in that: The host computer display module is used to add the liquid level meter data and the liquid volume of the liquid helium Dewar to the variable table of WinCC, and display them based on the host computer display module.

7. A device, characterized in that: The device includes a processor and a memory coupled to the processor, wherein the memory stores program instructions for implementing a method for calculating the liquid volume of a liquid helium Dewar based on a Siemens PLC as described in any one of claims 1 to 3; and the processor is used to execute the program instructions stored in the memory to implement a method for calculating the liquid volume of a liquid helium Dewar based on a Siemens PLC.

8. A storage medium, characterized in that: The method stores program instructions executable by a processor, wherein the program instructions are used to execute a method for calculating the liquid volume of a liquid helium Dewar based on a Siemens PLC as described in any one of claims 1 to 3.

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