阅读说明：本技术 高精度柱箱温度控制系统 (High-precision column box temperature control system ) 是由 李硚华 于 2020-12-17 设计创作，主要内容包括：本发明涉及气相色谱仪领域,具体涉及一种高精度柱箱温度控制系统。该系统包括依次连接的：加热模块、采集模块、CPU；加热模块、采集模块采用多路设置,多路加热模块、采集模块以柱箱中的色谱柱为中心分布；其中：CPU将多路采集模块采集到的温度进行平均,若多路采集模块采集到的温度与平均值的温差大于第一预设值,则控制多路加热模块进行单点控温；若多路采集模块采集到的温度与平均值的温差小于第二预设值,则控制多路加热模块取平均值进行单独控温；同时CPU采用自适应PID算法综合六路数据在CPU中快速计算并调整参数,从而实现对气相色谱仪的精准控温。(The invention relates to the field of gas chromatographs, in particular to a high-precision column box temperature control system. The system comprises the following components which are connected in sequence: the system comprises a heating module, an acquisition module and a CPU; the heating module and the acquisition module are arranged in a multipath manner, and the multipath heating module and the acquisition module are distributed by taking a chromatographic column in the column box as a center; wherein: the CPU averages the temperatures acquired by the multi-path acquisition modules, and if the temperature difference between the temperatures acquired by the multi-path acquisition modules and the average value is larger than a first preset value, the multi-path heating modules are controlled to perform single-point temperature control; if the temperature difference between the temperature acquired by the multi-path acquisition module and the average value is smaller than a second preset value, controlling the multi-path heating module to take the average value for independent temperature control; meanwhile, the CPU integrates six paths of data by adopting a self-adaptive PID algorithm to quickly calculate and adjust parameters in the CPU, so that the accurate temperature control of the gas chromatograph is realized.)

1. The utility model provides a high accuracy post case temperature control system which characterized in that, including connecting gradually: the system comprises a heating module, an acquisition module and a CPU; the heating module and the acquisition module are arranged in a multi-path mode, and the multi-path heating module and the multi-path acquisition module are distributed by taking a chromatographic column in the column box as a center; wherein:

the CPU averages the temperatures acquired by the plurality of paths of acquisition modules, and if the temperature difference between the temperatures acquired by the plurality of paths of acquisition modules and the average value is larger than a first preset value, the CPU controls the plurality of paths of heating modules to perform single-point temperature control; if the temperature difference between the temperature acquired by the plurality of paths of acquisition modules and the average value is smaller than a second preset value, controlling the plurality of paths of heating modules to take the average value for independent temperature control; meanwhile, the CPU adopts a self-adaptive PID algorithm to synthesize six paths of data to quickly calculate and adjust parameters in the CPU.

2. The high-precision column box temperature control system according to claim 1, further comprising an acquisition chip connected between the acquisition module and the CPU, wherein the acquisition chip changes the channel by the following configuration method:

when each channel change command is sent, continuously executing SYNC and WAKEUP, and ignoring the DRDY level state; writing RDATA command read data after the SYNC command, the WAKEUP command and the DRDY command meet the condition that the time interval is greater than the minimum time interval 24/72000000S; the above operations are performed each time a channel is changed; the synchronization moment occurs 33.51ms after the SYNC command in the single channel, and the WAKEUP command occurs in the rising edge of the first SCLK clock written by the WAKEUP command in the multi-channel due to the fact that the WAKEUP command is immediately behind the SYNC command, so that the data acquired at the moment do not need to be discarded due to the fact that the synchronization is executed in the single channel; write SYNC, then enter the WEAKUP command.

3. The high-precision column box temperature control system according to claim 2, wherein the collection chip employs an ADS1256 high-precision ADC.

4. The high accuracy column box temperature control system of claim 1, wherein said first predetermined value is 0.1 ℃ and said second predetermined value is 0.05 ℃.

5. The high-precision column box temperature control system according to claim 1, wherein the heating modules and the collection modules are arranged in 6 ways, and the 6 ways of the heating modules and the collection modules are uniformly distributed by taking a chromatographic column in the column box as a center.

6. The system of claim 1, wherein the CPU employs a master control chip with a highest dominant frequency of 1.8G.

7. The system of claim 6, wherein the master control chip transmits data using a USB3.0 interface.

8. The high accuracy column box temperature control system of claim 1, wherein the resistors used in the circuitry of the temperature control system are high accuracy, low temperature drift resistors.

9. The high-precision column box temperature control system according to claim 1, wherein a high-precision reference power supply is selected as a reference voltage source in the temperature control system, and the high-precision column box temperature control system is a linear stabilized power supply with ultralow quiescent current less than 1A, precision less than +/-0.11%, noise of 30 μ VRMS and fast transient response.

10. The system of claim 1, wherein the column casing is made of gold-plated hollow oxygen-free copper.

Technical Field

The invention relates to the field of gas chromatographs, in particular to a high-precision column box temperature control system.

Background

In the prior art, a temperature control system is formed by a single PT100 platinum resistor and a heating rod, a 16-bit ADC is adopted, and the temperature control is realized by a conventional PID algorithm of a single chip microcomputer. However, due to the uneven distribution of the volume and temperature of the column box from the heating core area to the periphery and the pure hysteresis and complexity of the heating equipment, the difficulty of controlling the high-precision temperature of the column box of the gas chromatograph is high, so that the retention time of a gas chromatograph is too long, the gas chromatograph is inaccurate in nature, and the performance of the gas chromatograph is affected.

Disclosure of Invention

The embodiment of the invention provides a high-precision column box temperature control system, which at least solves the technical problem that the existing column box temperature control is difficult.

According to an embodiment of the present invention, there is provided a high-precision column box temperature control system, including: the system comprises a heating module, an acquisition module and a CPU; the heating module and the acquisition module are arranged in a multipath manner, and the multipath heating module and the acquisition module are distributed by taking a chromatographic column in the column box as a center; wherein:

the CPU averages the temperatures acquired by the multi-path acquisition modules, and if the temperature difference between the temperatures acquired by the multi-path acquisition modules and the average value is larger than a first preset value, the multi-path heating modules are controlled to perform single-point temperature control; if the temperature difference between the temperature acquired by the multi-path acquisition module and the average value is smaller than a second preset value, controlling the multi-path heating module to take the average value for independent temperature control; meanwhile, the CPU adopts a self-adaptive PID algorithm to synthesize six paths of data to quickly calculate and adjust parameters in the CPU.

Further, the column box temperature control system also comprises an acquisition chip, the acquisition chip is connected between the acquisition module and the CPU, and the acquisition chip adopts the following configuration method to change a channel:

when each channel change command is sent, continuously executing SYNC and WAKEUP, and ignoring the DRDY level state; writing RDATA command read data after the SYNC command, the WAKEUP command and the DRDY command meet the condition that the time interval is greater than the minimum time interval 24/72000000S; the above operations are performed each time a channel is changed; the synchronization moment occurs 33.51ms after the SYNC command in the single channel, and the WAKEUP command occurs in the rising edge of the first SCLK clock written by the WAKEUP command in the multi-channel due to the fact that the WAKEUP command is immediately behind the SYNC command, so that the data acquired at the moment do not need to be discarded due to the fact that the synchronization is executed in the single channel; write SYNC, then enter the WEAKUP command.

Furthermore, the ADS1256 high-precision ADC is adopted as the acquisition chip.

Further, the first preset value is 0.1 ℃ and the second preset value is 0.05 ℃.

Furthermore, the heating module and the acquisition module are arranged in 6 ways, and the 6 ways of heating module and acquisition module are uniformly distributed by taking the chromatographic column in the column box as the center.

Further, the CPU adopts a main control chip with the highest main frequency of 1.8G.

Further, the main control chip adopts a USB3.0 interface to transmit data.

Furthermore, the resistor used by the circuit in the temperature control system is a high-precision low-temperature drift resistor.

Furthermore, a high-precision reference power supply is selected as a reference voltage source in the temperature control system, and the reference voltage source is a linear voltage-stabilized power supply with ultralow quiescent current less than 1A, precision less than +/-0.11%, noise 30 mu VRMS and fast transient response.

Further, the material in the column box is gold-plated hollow high-conductivity oxygen-free copper.

In the high-precision column box temperature control system in the embodiment of the invention, a CPU averages the temperatures acquired by a plurality of paths of acquisition modules, and if the temperature difference between the temperatures acquired by the plurality of paths of acquisition modules and the average value is larger than a first preset value, controls a plurality of paths of heating modules to perform single-point temperature control; if the temperature difference between the temperature acquired by the multi-path acquisition module and the average value is smaller than a second preset value, controlling the multi-path heating module to take the average value for independent temperature control; meanwhile, the CPU integrates six paths of data by adopting a self-adaptive PID algorithm to quickly calculate and adjust parameters in the CPU, so that the accurate temperature control of the gas chromatograph is realized.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:

FIG. 1 is a block diagram of a high accuracy column box temperature control system of the present invention;

FIG. 2 is a schematic circuit diagram of a six-path acquisition circuit in the high-precision column box temperature control system of the present invention.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

According to an embodiment of the present invention, there is provided a high-precision column box temperature control system, see fig. 1-2, comprising, connected in sequence: the system comprises a heating module, an acquisition module and a CPU; the heating module and the acquisition module are arranged in a multipath manner, and the multipath heating module and the acquisition module are distributed by taking a chromatographic column in the column box as a center; wherein:

the CPU averages the temperatures acquired by the multi-path acquisition modules, and if the temperature difference between the temperatures acquired by the multi-path acquisition modules and the average value is larger than a first preset value, the multi-path heating modules are controlled to perform single-point temperature control; if the temperature difference between the temperature acquired by the multi-path acquisition module and the average value is smaller than a second preset value, controlling the multi-path heating module to take the average value for independent temperature control; meanwhile, the CPU adopts a self-adaptive PID algorithm to synthesize six paths of data to quickly calculate and adjust parameters in the CPU.

In the high-precision column box temperature control system in the embodiment of the invention, a CPU averages the temperatures acquired by a plurality of paths of acquisition modules, and if the temperature difference between the temperatures acquired by the plurality of paths of acquisition modules and the average value is larger than a first preset value, controls a plurality of paths of heating modules to perform single-point temperature control; if the temperature difference between the temperature acquired by the multi-path acquisition module and the average value is smaller than a second preset value, controlling the multi-path heating module to take the average value for independent temperature control; meanwhile, the CPU integrates six paths of data by adopting a self-adaptive PID algorithm to quickly calculate and adjust parameters in the CPU, so that the accurate temperature control of the gas chromatograph is realized.

The column box temperature control system further comprises an acquisition chip, the acquisition chip is connected between the acquisition module and the CPU, and the acquisition chip changes a channel by adopting the following configuration method:

when each channel change command is sent, continuously executing SYNC and WAKEUP, and ignoring the DRDY level state; writing RDATA command read data after the SYNC command, the WAKEUP command and the DRDY command meet the condition that the time interval is greater than the minimum time interval 24/72000000S; the above operations are performed each time a channel is changed; the synchronization moment occurs 33.51ms after the SYNC command in the single channel, and the WAKEUP command occurs in the rising edge of the first SCLK clock written by the WAKEUP command in the multi-channel due to the fact that the WAKEUP command is immediately behind the SYNC command, so that the data acquired at the moment do not need to be discarded due to the fact that the synchronization is executed in the single channel; write SYNC, then enter the WEAKUP command.

The ADS1256 high-precision ADC is adopted as the acquisition chip.

Wherein the first preset value is 0.1 ℃, and the second preset value is 0.05 ℃.

Wherein, heating module, collection module adopt 6 ways to set up, and 6 ways heating module, collection module use the chromatographic column in the column box as the even distribution of center.

Wherein, the CPU adopts a main control chip with the highest dominant frequency of 1.8G.

The main control chip adopts a USB3.0 interface to transmit data.

The resistor used by the circuit in the temperature control system is a high-precision low-temperature drift resistor.

The reference voltage source in the temperature control system is a high-precision reference power source, and is a linear stabilized voltage power supply with ultralow quiescent current less than 1A, precision less than +/-0.11%, noise 30 mu VRMS and fast transient response.

Wherein, the material in the column box adopts gold-plated hollow high-conductivity oxygen-free copper.

Referring to fig. 1-2, the high-precision column box temperature control system of the present invention will be described in detail with specific embodiments:

the invention designs a high-precision column box temperature control system based on an ADS1256 acquisition chip, aiming at the problems that the temperature control system of a gas chromatograph column box has poor temperature control effect and low precision, thereby influencing the temperature control stability of the column box and further influencing the retention time of an instrument. The column box is a key component of the gas chromatograph, and the change of the temperature of the column box is one of the factors which directly influence the accuracy of the analysis data of the gas chromatograph, so that the improvement of the accurate measurement and control of the temperature control system of the column box is necessary to improve the overall performance of the gas chromatograph.

The design is based on an ADS1256 acquisition chip, a CPU main control chip with the highest dominant frequency of 1.8G, a related hardware circuit and a multi-path high-precision acquisition heating temperature control module are matched, and parameters are adjusted through a fuzzy self-tuning PID control algorithm, so that the precise temperature control of the gas chromatograph is realized.

The technical scheme of the invention is based on ADS1256 high-precision ADC (acquisition chip), ADS1256 adopts the following configuration method to change the channel: when each channel change command is sent, SYNC and WAKEUP are continuously executed, and the DRDY level state is ignored. However, the three commands of SYNC, WAKEUP and DRDY should satisfy the condition that the RDATA command is written after a time interval greater than the minimum time interval 24/72000000S. The above operation is performed every time the channel is changed. The synchronous moment in single channel occurs 33.51ms after SYNC command, and in multi-channel, because WAKEUP command follows SYNC command, the synchronous moment occurs at the rising edge of the first SCLK clock written by WAKEUP command, and the data collected at the moment do not need to be discarded because of synchronization execution in single channel. Write SYNC, then enter the WEAKUP command. And 6 channels are adopted to respectively control the six heating modules and the six acquisition modules. The acquisition module comprises a temperature sensor and an acquisition circuit. Wherein, the six heating modules and the collecting module are evenly distributed in the column box at intervals. And transmitting the acquired data into a CPU, averaging the six paths of acquired data, respectively controlling the temperature at a single point if the temperature difference is greater than 0.1 ℃, and controlling the temperature independently by taking the average value if the temperature difference is less than 0.05 ℃. Six paths of data are synthesized in the CPU by a fuzzy PID control method (an adaptive PID algorithm) to quickly calculate and adjust parameters in the CPU. Because the transmission efficiency depends on the CPU of the main control chip, the USB3.0 interface is used for transmitting data, wherein the resistor used in the circuit adopts a high-precision and low-temperature drift resistor. The reference voltage source adopts a high-precision reference power supply, and meets the requirements that the ultralow quiescent current is less than 1A, the precision is less than +/-0.11%, the noise is 30 mu VRMS (10Hz to 100kHz), and the transient response is fast enough. The material in the column box is gold-plated hollow high-conductivity oxygen-free copper.

The key innovation points of the invention are at least as follows:

1. the column box adopts a six-path heating method, takes the chromatographic column as the center, and is uniformly distributed on the periphery of the chromatographic column, the obtained data are averaged, if the temperature difference is more than 0.1 ℃, the temperature is respectively controlled by single points, and if the temperature difference is less than 0.05 ℃, the average value is taken for independent temperature control.

ADS1256 changes channels using the following configuration method: when each channel change command is sent, SYNC and WAKEUP are continuously executed, and the DRDY level state is ignored. But three commands satisfy the read data of the RDATA command after more than a minimum time interval 24/72000000S. The above operation is performed every time the channel is changed. The synchronous moment in single channel occurs 33.51ms after SYNC command, and in multi-channel, because WAKEUP command follows SYNC command, the synchronous moment occurs at the rising edge of the first SCLK clock written by WAKEUP command, and the data collected at the moment do not need to be discarded because of synchronization execution in single channel. After writing SYNC, WEAKUP is written.

3. The parameters are quickly calculated and adjusted in the CPU by fuzzy PID integrated six-path data, the transmission efficiency depends on a main control chip, so that a USB3.0 interface is used for transmitting data, wherein the resistor adopts a high-precision low-temperature drift resistor.

4. The high-precision reference voltage source is a linear voltage-stabilized power supply which can meet the requirements that the ultralow static current is less than 1A, the precision is less than +/-0.11%, the noise is 30 mu RMS (10Hz to 100kHz), and the transient response is fast enough.

5. The material in the column box is gold-plated hollow high-conductivity oxygen-free copper.

The invention has the beneficial effects that:

the invention can improve the response time of the temperature control system and improve the sample measurement accuracy, and the technical scheme is more effective compared with the traditional means such as adding heat insulation cotton, and the like, and effectively solves the temperature control problem that the integral temperature of the chromatographic column is unstable due to the fact that the temperature measurement of a single platinum resistor is carried out and the temperature distribution of a column box cannot be accurately controlled.

According to the invention, through experiments, under the laboratory conditions, the long-term temperature control precision of the fluctuation of the temperature difference of the laboratory within the range of 3 ℃ is less than 0.006 ℃, the temperature difference of the inner edge of the column box and the core area is less than 0.001 ℃, the reproducibility of the retention time is less than 0.006%, and the maximum temperature rise rate is close to 280 ℃/min. And the real-time data of the temperature in the column box can be accurately known and controlled by reading the CPU data.

The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.

In the above embodiments of the present invention, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.

In the embodiments provided in the present application, it should be understood that the disclosed technology can be implemented in other ways. The above-described system embodiments are merely illustrative, and for example, a division of a unit may be a logical division, and an actual implementation may have another division, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, units or modules, and may be in an electrical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic or optical disk, and other various media capable of storing program codes.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.