CN114941615A - Pump control device and method and liquid chromatography pump - Google Patents
Pump control device and method and liquid chromatography pump Download PDFInfo
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- CN114941615A CN114941615A CN202210613448.5A CN202210613448A CN114941615A CN 114941615 A CN114941615 A CN 114941615A CN 202210613448 A CN202210613448 A CN 202210613448A CN 114941615 A CN114941615 A CN 114941615A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B17/00—Pumps characterised by combination with, or adaptation to, specific driving engines or motors
- F04B17/03—Pumps characterised by combination with, or adaptation to, specific driving engines or motors driven by electric motors
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/02—Stopping, starting, unloading or idling control
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/06—Control using electricity
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
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- Mechanical Engineering (AREA)
- General Health & Medical Sciences (AREA)
- Analytical Chemistry (AREA)
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- Immunology (AREA)
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- Health & Medical Sciences (AREA)
- Control Of Positive-Displacement Pumps (AREA)
Abstract
本发明公开了一种泵的控制装置、方法及液相色谱泵，其中，泵的控制装置包括前止点和编码器，泵的控制方法为：S1，每间隔一段固定时间采集一次编码器的读数，并计算采集间隔读取的编码器读数差值；S2，判断泵的柱塞杆的运动状态；当泵的柱塞杆处于匀速运动状态时，当一个采集间隔读取的编码器读数差值小于理论最小差值时，编码器向泵发出电信号指令，使泵停止运行；当泵的柱塞杆处于匀加速运动状态时，当最新编码器差值小于当前运行最小编码器读数差值时，编码器向泵发出电信号指令，使泵停止运行，本发明具有结构简单成本低精度高的优点，可以准确确定柱塞杆的零点位置，确保柱塞杆的运动曲线精确匹配，实现超高效色谱泵流速的监测和反馈控制。
The invention discloses a pump control device, a method and a liquid chromatography pump, wherein the pump control device includes a front dead center and an encoder, and the pump control method is: S1, collecting the data of the encoder every fixed time interval. read, and calculate the difference between the encoder readings read at the acquisition interval; S2, judge the movement state of the plunger rod of the pump; when the plunger rod of the pump is in a state of uniform motion, when the difference between the encoder readings read at a collection interval When the value is less than the theoretical minimum difference, the encoder sends an electrical signal command to the pump to stop the pump; when the plunger rod of the pump is in a state of uniform acceleration, when the latest encoder difference is less than the current running minimum encoder reading difference When the encoder sends an electrical signal command to the pump to stop the pump, the present invention has the advantages of simple structure, low cost and high precision, can accurately determine the zero position of the plunger rod, ensure the exact matching of the movement curve of the plunger rod, and realize the super Monitoring and feedback control of high-efficiency chromatography pump flow rates.
Description
Technical Field
The invention relates to the field of liquid chromatography, in particular to a pump control device and method and a liquid chromatography pump.
Background
The highest working pressure of an ultrahigh pressure plunger pump of the ultra-high performance liquid chromatograph is more than 80-100MPa, and the precision of the pump directly determines the qualitative repeatability of the system. In order to overcome flow rate fluctuation, a mode of serially connecting double plungers or parallelly connecting double plungers is generally adopted, stable output of the flow rate of the working liquid is realized by accurately controlling motion curves of the two plungers, and pressure fluctuation caused by liquid compression and the like is overcome by dynamically performing compression compensation. In order to achieve accurate infusion without pressure fluctuations, the zero position of the plunger rod needs to be accurately determined at pump initialization. The plungers are aligned with reference to the zero point, and position control is performed by a stepping motor or a servo motor as an initial value of the motion curve. When the pump works, the liquid pressure needs to be detected by the pressure sensor and is accurately matched with the motion curve of the plunger rod, and the flow rate is monitored and feedback controlled through the conversion relation between the pressure and the flow rate. Therefore, accurate positioning and position control of the plunger zero point are a key technology of the ultrahigh pressure plunger pump.
A common control device for an ultra-high performance chromatographic pump determines the zero position by adopting a photoelectric switch and adopts the open loop position control of a stepping motor. The plunger rod driving mechanism is provided with a light barrier, and the position when the plunger rod moves to the position when the light barrier blocks the photoelectric switch is used as the plunger rod zero point. The mode depends on the assembly error of the light blocking sheet and the photoelectric switch, the control precision is low, and the plunger rods are easy to be out of synchronization. In addition, the influence of dust on long-term operation is large, another common pump control device for the ultra-high performance chromatography adopts a grating ruler and a servo motor to perform position measurement and feedback control, and has the disadvantages of high cost, complex structure and control and low reliability.
Disclosure of Invention
In order to solve the above-mentioned deficiencies in the prior art, the present invention aims to provide a pump control device, a pump control method, and a liquid chromatography pump, wherein the method has high precision and small error.
The technical scheme adopted by the invention for solving the technical problems is as follows:
the control device of the pump according to the embodiment of the present invention includes: the front dead point is used for preventing the plunger rod of the pump from sliding, can be a flange, a stop block or a stop lever, and determines the limit distance of the movement of the plunger rod of the pump by stopping the advance of a plunger rod seat or a driving mechanism of the pump to stop the advance of the connected or contacted plunger rod; the encoder collects the running speed of the pump, compares the running speed with the running speed and analyzes the running speed, and can send an electric signal instruction to the pump so as to determine the relative position of the stepping motor of the pump.
In some embodiments, a filter is also included to prevent encoder readings from fluctuating.
In some embodiments, the encoder is a magnetic encoder or an opto-electronic encoder.
The control method of the pump according to the embodiment of the invention comprises the following steps: s1, collecting the reading of the encoder at a time at intervals of a fixed time, and calculating the difference of the readings of the encoder at a collection interval; s2, judging the motion state of the plunger rod of the pump; s2-1, when the plunger rod of the pump is in a uniform motion state, comparing the reading difference value of the encoder read at one acquisition interval with the theoretical minimum difference value, and when the reading difference value of the encoder read at one acquisition interval is smaller than the theoretical minimum difference value, the encoder sends an electric signal instruction to the pump to stop the pump from running; s2-2, when the plunger rod of the pump is in the state of uniform acceleration motion, comparing the difference value of the latest encoder with the reading difference value of the current running minimum encoder, and when the difference value of the latest encoder is smaller than the reading difference value of the current running minimum encoder, sending an electric signal instruction to the pump by the encoder to stop the pump from running.
According to the control method of the pump, the encoder is used for feeding back the running speed of the pump, when the running speed fed back by the encoder deviates from the theoretical speed, the plunger rod of the pump is determined to impact a front dead center, the encoder sends an electric signal to the pump to stop the running of the pump, the plunger rod is further stopped to continue to move, and further strong impact is avoided.
In the embodiment of the invention, during the stage of the constant motion of the plunger rod, when D (D is the latest encoder difference value) is less than D t (D t Theoretical value), the moving speed of the plunger rod can be judged to deviate from the theoretical speed, the plunger rod can be considered to be impacted, and the encoder sends out an electric signal to stop the pump.
It will be appreciated that D t ＝D max E, wherein D max Changing the reading value of the encoder corresponding to each sampling time interval into a theoretical value for the theoretical speed of the plunger rod; g is a proportionality coefficient.
During the uniform acceleration stage of the plunger rod, when D is less than D min (D mmin Minimum encoder reading difference for current operation), the moving speed of the plunger rod can be judged to deviate from the theoretical speed, the plunger rod can be considered to be impacted, and the encoder sends out an electric signal to stop the operation of the pump.
It will be appreciated that D min ＝D th -D af Wherein D is th ＝D delt *n 1 In the stage of uniform acceleration motion of the plunger rod, the plunger rod moves at a uniform speed D max The maximum speed corresponding to the speed curve of the uniform acceleration stage of the plunger rod is also the final speed of the uniform acceleration stage of the plunger rod, the initial speed of the acceleration stage is 0, D delt Representing the magnitude of change, D, in the difference between readings of the encoder for each acquisition interval tn For the acceleration stage n 1 After a sampling interval, reading a theoretical value of a difference value by an encoder; d af ＝D max *e 1 Wherein D is af To fix the difference, e 1 Is a fixed proportionality coefficient; i.e. D mmin ＝D th -D af ＝D delt *n 1 -D af 。
It will be appreciated that before operation, D will be adjusted according to the above-described method and encoder-related parameters t 、D delt And D af And the calculation is completed in advance for the use of the reading interval acquisition processing of the encoder.
In some embodiments, the encoder reading difference in step S1 is filtered by a filter and output by the filter.
A liquid chromatography pump according to an embodiment of the invention comprises the control device as described hereinbefore.
According to the liquid chromatography pump disclosed by the embodiment of the invention, the control device is matched with the control method, so that the relative position of the stepping motor is determined, the limit distance of the movement of the plunger rod is further determined, the precision is improved, and the error is reduced.
From the above, the beneficial effects of the invention are as follows: the invention provides a device and a method for controlling an ultra-high-performance chromatographic pump, which overcome the defects of low precision and easy influence of dust of a common photoelectric switch positioning scheme, high cost of a grating ruler and a servo motor, complex structure and control and the like.
Drawings
FIG. 1 is a schematic structural view of a control device of the pump of the present invention;
FIG. 2 is a time-velocity diagram illustrating a uniform motion plunger rod finding a zero point in accordance with an embodiment of the present invention;
fig. 3 is a time-velocity diagram of zero point seek for an accelerated moving plunger rod in accordance with an embodiment of the present invention.
In the reference numerals, 1 is front dead center; 2. a pump; 21. a plunger rod; 22. a plunger rod seat; 23. a reciprocating drive mechanism; 24. a housing; 25. a stepping motor; 26. a pump head; 3. an encoder.
Detailed Description
The present application will be described in further detail with reference to the following drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant invention and are not to be construed as limiting the invention. It should be noted that, for the convenience of description, only the portions related to the present invention are shown in the drawings.
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.
A specific structure of a control device according to an embodiment of the present invention is described below with reference to fig. 1 to 3.
A control device of a pump according to an embodiment of the present invention includes a front dead center 1 and an encoder 3.
The front dead center 1 is used for preventing the plunger rod 21 of the pump 2 from sliding, and determines the limit distance for the movement of the plunger rod 21 of the pump 2. The encoder 3 collects the running speed of the pump 2, compares and analyzes the running speed, and sends an electric signal instruction to the pump 2 so as to determine the relative position of the stepping motor 25 of the pump 2.
The control method of the pump according to the embodiment of the invention comprises the following steps: s1, collecting the reading of the encoder 3 at a fixed time interval, and calculating the reading difference of the encoder 3 read at a collection interval; s2, determining the motion state of the plunger rod 21 of the pump 2; s2-1, when the plunger rod 21 of the pump 2 is in a uniform motion state, comparing the reading difference value of the encoder 3 read at one acquisition interval with the theoretical minimum difference value, and when the reading difference value of the encoder 3 read at one acquisition interval is smaller than the theoretical minimum difference value, the encoder 3 sends an electric signal instruction to the pump 2 to stop the pump 2 from running; s2-2, when the plunger rod 21 of the pump 2 is in the state of uniform acceleration motion, comparing the difference value of the latest encoder 3 with the reading difference value of the currently operated minimum encoder 3, when the difference value of the latest encoder 3 is smaller than the reading difference value of the currently operated minimum encoder 3, the encoder 3 sends an electric signal instruction to the pump 2 to stop the pump 2 from operating.
It will be understood that, since the speed has reached the maximum speed during the uniform movement phase of the plunger rod 21 and the speed is not changed, the driving speed can be expressed as:
v 1 ＝(f/c)*(mStep/sec)
＝(f/1000*c)*(mStep/ms)；
where f is the motor drive timer frequency, c is the timing interval of the maximum speed timer, mStep/ms is a dimension, mStep represents the number of sub-division steps, sec represents seconds, and ms represents milliseconds.
Alternatively, the step angle of the stepper motor 25 of the pump 2 is preferably 1.8 °, and the encoder 3 is preferably a 500-wire encoder 3, m 1 For dividing the motor into fine parts, so that the motor rotates one circle and drives the fine parts to have the number of fine parts of 200 m 1 And mStep. The encoder 3 count change is 2000cnt, it being understood that:
mStep/sec＝(2000/200*m 1 )*(cnt/sec)；
the speed fed back from the encoder 3 is
v 2 ＝(2000/200*m 1 )*v 1
＝[(10*f)/(c*m 1 )]*(cnt/sec)
＝[f/(c*m 1 *10)]*(cnt/ms)；
The above equation is the theoretical speed represented by the encoder 3 reading.
And collecting the reading of the encoder 3 at fixed time intervals, and performing calculation judgment once. Let the encoder 3 read acquisition interval be Δ t (ms).
The theoretical value of the change of the reading value of the encoder 3 in each sampling time interval of the encoder 3 is D max ，
Wherein D is max ＝v 2 *Δt
At theoretical speed corresponding to D max Is multiplied by a scaling factor e as a minimum threshold value D min The method comprises the following steps:
D min ＝e*D max ；
wherein the value range of e is 0-1, and the preferred value is 0.75-0.9.
As shown in FIG. 2, the actual reading change value D of the encoder is less than D during one encoder sampling time interval min When the movement speed of the plunger rod 21 deviates from the theoretical speed, the plunger rod 21 is determined to be impacted, and the encoder 3 sends out an electric signal to stop the operation of the pump 2.
It can be understood that the reading of the encoder 3 can only be an integer, and the ratio of the encoder 3 to the driving fine step is not an integer, and during operation, because of the existence of motor resonance, the speed fed back by the encoder 3 fluctuates around the theoretical speed, and in order to cope with the fluctuation of the reading of the encoder 3, the erroneous judgment is avoided, the difference value of the encoder 3 acquired each time needs to be filtered, and the output value of the filter is used as the judgment.
In some embodiments, D during the even acceleration phase of the plunger rod 21 max The maximum speed corresponding to the acceleration phase of the plunger rod 21, which is also the final speed of the acceleration phase, the acceleration is a, the initial speed of the acceleration phase is 0, and the time T of the entire acceleration phase acc (ms)：
t acc (ms)：
t acc ＝v 0 /a
＝(1000*v 0 )/a；
Since the acceleration is uniform and the acquisition intervals of each encoder 3 are the same, the acceleration is Δ t 1 (ms) then in the acceleration phase there are n acquisition intervals, resulting in:
n＝t acc /Δt 1 ；
theoretically, the variation of the difference between the readings of the encoder 3 at each acquisition interval is obtained as follows:
D delt ＝D max /n
＝(D mmax *Δt 1 )/t acc
＝D mmax *Δt 1 *a/1000*v 0 )(cnt)
in the formula, D delt Representing the variation of the difference in the readings of the encoder for each acquisition interval, D max For the theoretical speed, the reading changes by the theoretical value, Δ t, for each sampling interval of the encoder 1 Intervals are collected for readings.
D min ＝D th -D af Wherein D is th ＝D delt *n 1 In the stage of uniform acceleration of the plunger rod 21, the above-mentioned stage D of uniform velocity movement of the plunger rod 21 max The maximum speed corresponding to the speed curve of the uniform acceleration stage of the plunger rod 21 is also the final speed of the uniform acceleration stage of the plunger rod 21, the initial speed of the acceleration stage is 0, D delt Representing the variation, D, of the difference in readings of the encoder 3 for each acquisition interval th For the acceleration stage n 1 After a sampling interval, the encoder 3 reads the theoretical value of the difference; d af ＝D max *e 1 Wherein D is af To fix the difference, e 1 Is a fixed proportionality coefficient; i.e. D mmin ＝D th -D af ＝D delt *n-D t 。
As shown in FIG. 3, during the sampling process, when the latest encoder 3 difference D is less than the currently running minimum encoder 3 reading difference D min When the collision occurs, the pump 2 is immediately stopped.
The sampled encoder 3 difference value also needs to be filtered in the acceleration stage, and the filter output value is used as the judgment.
In the above embodiment, before each start-up, D needs to be adjusted according to the method and related parameters described above t 、D delt 、D af The advance calculation is done for use in the encoder 3 reading interval acquisition process.
Example 1
As shown in fig. 1, a liquid chromatography pump comprising: a housing 24; the stepping motor 25, the said stepping motor 25 is set up in the sidewall of the outer casing 24; a reciprocating drive mechanism 23, wherein the reciprocating drive mechanism 23 is positioned inside a shell 24, and the reciprocating drive mechanism 23 is powered by a stepping motor 25; a pump head 26, the pump head 26 being disposed on a side of the housing 24 away from the stepper motor 25; the plunger rod 21 is fixedly connected with the plunger rod seat 22, one end of the plunger rod 21 extends into the pump head 26, and the plunger rod seat 22 is driven by the reciprocating driving mechanism 23 to slide left and right, so that the plunger rod 21 is driven to slide left and right; a control device, the control device comprising: front dead center 1, where front dead center 1 is disposed between pump head 26 and housing 24, where front dead center 1 is used to prevent plunger rod 21 of pump 2 from sliding, and determine the limit distance for plunger rod 21 of pump 2 to move; encoder 3, encoder 3 sets up at step motor 25 installation shell lateral wall, the running speed of pump 2 is gathered to encoder 3 to compare the analysis, can send the signal of telecommunication instruction to pump 2, and then confirm the relative position of step motor 25 of pump 2.
Example 2
A liquid chromatography pump as described in embodiment 1, further comprising a filter for preventing fluctuation in encoder 3 readings.
The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of the invention according to the present application is not limited to the embodiments with specific combinations of the above-mentioned features, but also covers other embodiments with any combination of the above-mentioned features or their equivalents without departing from the inventive concept. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.
Besides the technical features described in the specification, other technical features are known to those skilled in the art, and are not described herein again in order to highlight the innovative features of the present invention.
Claims (6)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210613448.5A CN114941615A (en) | 2022-05-31 | 2022-05-31 | Pump control device and method and liquid chromatography pump |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210613448.5A CN114941615A (en) | 2022-05-31 | 2022-05-31 | Pump control device and method and liquid chromatography pump |
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| Publication Number | Publication Date |
|---|---|
| CN114941615A true CN114941615A (en) | 2022-08-26 |
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| CN202210613448.5A Pending CN114941615A (en) | 2022-05-31 | 2022-05-31 | Pump control device and method and liquid chromatography pump |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1340364A (en) * | 2000-08-16 | 2002-03-20 | 史密斯集团有限公司 | Pump for injector |
| US20120097026A1 (en) * | 2004-08-18 | 2012-04-26 | Waters Technologies Corporation | Piston Pump With Leak Diagnostic Port |
| CN107642472A (en) * | 2016-07-20 | 2018-01-30 | 北京普源精电科技有限公司 | Infusion pump and its self-test repositioning method with self-protection function |
| CN211448919U (en) * | 2019-12-31 | 2020-09-08 | 苏州同芯微流控技术有限公司 | Ultrahigh pressure industrial injection pump |
-
2022
- 2022-05-31 CN CN202210613448.5A patent/CN114941615A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1340364A (en) * | 2000-08-16 | 2002-03-20 | 史密斯集团有限公司 | Pump for injector |
| US20120097026A1 (en) * | 2004-08-18 | 2012-04-26 | Waters Technologies Corporation | Piston Pump With Leak Diagnostic Port |
| CN107642472A (en) * | 2016-07-20 | 2018-01-30 | 北京普源精电科技有限公司 | Infusion pump and its self-test repositioning method with self-protection function |
| CN211448919U (en) * | 2019-12-31 | 2020-09-08 | 苏州同芯微流控技术有限公司 | Ultrahigh pressure industrial injection pump |
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