CN112648176B

CN112648176B - Liquid injection system based on FPGA (field programmable Gate array) control diaphragm pump and liquid injection control method thereof

Info

Publication number: CN112648176B
Application number: CN202011529078.4A
Authority: CN
Inventors: 牛勇涛; 陈禾如
Original assignee: Zhongshan Chuangyi Biochemical Engineering Co ltd
Current assignee: Zhongshan Chuangyi Biochemical Engineering Co ltd
Priority date: 2020-12-22
Filing date: 2020-12-22
Publication date: 2022-06-24
Anticipated expiration: 2040-12-22
Also published as: CN112648176A

Abstract

The invention discloses a liquid injection system based on an FPGA (field programmable gate array) control diaphragm pump and a liquid injection control method thereof, wherein the liquid injection system comprises an upper computer for sending an instruction for opening one path of liquid injection, an FPGA control module electrically connected with the upper computer for receiving the instruction of the upper computer, and a solenoid valve switch and a diaphragm pump controlled by the FPGA control module. Because the FPGA is adopted to generate PWM pulse to control the rotating speed of the direct current motor on the diaphragm pump when receiving the command, the ideal liquid injection speed is achieved. The FPGA simultaneously opens and closes the diaphragm pump and the corresponding electromagnetic valve, so that the aim of high-precision liquid injection is achieved.

Description

Liquid injection system based on FPGA (field programmable Gate array) control diaphragm pump and liquid injection control method thereof

Technical Field

The invention belongs to the field of medical examination equipment, and relates to a liquid injection system based on an FPGA (field programmable gate array) control diaphragm pump and a liquid injection control method thereof.

Background

The pump is a machine for conveying fluid or pressurizing fluid, and the injection pump and the plunger pump are generally used at present for injection, the injection pump is composed of a motor and a driver thereof, a sample injector, a screw rod, a bracket and the like, the injection pump is provided with a screw rod and a nut which move in a reciprocating manner, and the screw rod mainly moves to push the sample injector to move at a constant speed and slowly inject liquid in the sample injector to a required position. The plunger pump is divided into two representative structural forms of an axial plunger pump and a radial plunger pump, and consists of an electrical appliance part, a power end, a hydraulic end and a transmission part. Both of these pumps are relatively complex in structure and relatively expensive. In the external diagnosis class project of current medical instrument, it is higher to pouring into reaction reagent precision, and most instruments all adopt the plunger pump to accomplish the high accuracy and annotate liquid in comparison, to some instruments that need to pour into multiple reagent, then need a plurality of plunger pumps of chooseing for use that correspond, can greatly increased the cost of instrument like this. In particular, in many testing procedures of medical instruments (such as blood testing), a reagent needs to be injected to measure a certain value, so as to help a doctor to perform diagnosis. The injection amount of the reaction reagent often determines the accuracy and precision of the detection result. In order to improve the accuracy and precision, most medical instruments adopt a plunger pump mode to control the injection precision. The actual types of blood to be injected are more in blood detection, and the use of a plunger pump can greatly increase the cost of the instrument.

Disclosure of Invention

In order to solve the above technical problems, an object of the present application is to provide a liquid injection system for controlling a diaphragm pump based on an FPGA, and the system and the technique achieve the same high-precision liquid injection requirement by mainly using the way that the FPGA generates a PWM pulse to control the diaphragm pump.

According to an aspect of the present application, in order to achieve the above technical effects, the present application provides the following technical solutions:

design a annotate liquid system based on FPGA control diaphragm pump, include: the liquid injection control system comprises an upper computer, an FPGA control module and a diaphragm pump, wherein the upper computer is used for sending and opening one of the liquid injection instructions, the FPGA control module is electrically connected with the upper computer and used for receiving the instructions of the upper computer, the solenoid valve switch and the diaphragm pump are controlled by the FPGA control module, meanwhile, the FPGA control module generates PWM pulses of the circuit, the PWM pulses can be reflected on IO pins of the FPGA, the IO pins and a triode base are connected to control a triode to be opened and closed according to the change of the high level and the low level of the IO pins, an emitting electrode of the triode is connected with a grounding resistor, and a control signal of an NMOS pipe is led out between the emitting electrode of the triode and the grounding resistor to control the rotating speed of the diaphragm pump.

In order to obtain better technical effect, the invention also has the following technical characteristics:

in some embodiments, the ground resistor has a resistance of 10k ohms to counteract some noise interference and to help reduce the effect of "load variations" on the output voltage.

In some embodiments, the IO pin may show a periodic variation of high and low levels (3.3V/0V) measured by an oscilloscope, and a triode NPN connected to the IO port is accurately turned on and off by the variation of the high and low levels.

In some embodiments, the collector of the transistor is connected to a 5V power supply, and the level of the PWM signal generated after passing through the transistor becomes 5V/0V.

In some embodiments, the turn-on voltage Vgs of the NMOS tube is 5V, the led NMOS control line is connected to the Gate of the NMOS to control the NMOS, the switching speed of the NMOS tube is 20ns, and the long-time delay does not cause the stop time of the motor of the diaphragm pump to be too long, thereby causing unstable injection precision.

In some embodiments, the NMOS transistor is an IRF8788NMOS transistor.

Another object of the present application is to provide a liquid injection control method for a liquid injection system of a diaphragm pump based on FPGA, which includes the following steps:

a. the upper computer sends a command for starting a certain path of liquid injection;

b. after receiving the command, the FPGA control module can open a corresponding electromagnetic valve switch, and meanwhile, the FPGA control module can generate PWM (pulse width modulation) pulses of the path, and the generated PWM pulses can be reflected on an IO (input/output) pin of the FPGA control module;

c. the period change of high and low levels can be displayed by measuring the IO pin through an oscilloscope, and the triode connected with the IO port is opened and closed through the high and low level change;

d. a control signal of an NMOS (N-channel metal oxide semiconductor) tube is led out between an emitting electrode of the triode and a grounding resistor, a collector of the triode is connected to a 3V-5V power supply, the turn-on voltage Vgs of the NMOS tube is 3V-5V, and a led-out NMOS control line is connected to a Gate electrode of the NMOS to realize the control of the NMOS control line;

e. and finally, sending a command of closing a certain path of liquid injection by the upper computer, and simultaneously turning off the diaphragm pump and the electromagnetic valve of the path to finish the liquid injection.

Because the FPGA is adopted to generate PWM pulse to control the rotating speed of the direct current motor on the diaphragm pump when receiving the command, the ideal liquid injection speed is achieved. The FPGA module generates PWM pulses to control the diaphragm pump and then the electromagnetic valve is matched when receiving the command, the diaphragm pump and the corresponding electromagnetic valve are opened and closed by the FPGA at the same time, the purpose of high-precision liquid injection is achieved, and the cost of the diaphragm pump is far lower than that of a plunger pump, so that the cost of an instrument is greatly reduced.

Drawings

Fig. 1 is a schematic diagram of a frame of a liquid injection system of an FPGA-controlled diaphragm pump according to the present application.

Detailed Description

The present application will be described in further detail with reference to examples.

In order to open and close the diaphragm pump and the corresponding electromagnetic valve, the aim of injecting liquid with high precision to achieve an ideal liquid injection speed is achieved. The application discloses annotate liquid system of FPGA control diaphragm pump, include for sending open wherein annotate the host computer of liquid instruction all the way, be connected with the host computer and be used for receiving the FPGA control module of host computer instruction, and receive the solenoid valve switch and the diaphragm pump of FPGA control module control, FPGA control module produces the PWM pulse of this way simultaneously, this PWM pulse can react on FPGA's IO pin, at this moment IO pin and triode base are connected with the level change according to IO pin and are opened and close the triode, ground resistance is connected to the projecting pole of triode, draw forth the control signal control diaphragm pump rotational speed of NMOS pipe between triode projecting pole and the ground resistance.

The embodiment is that, firstly, the upper computer sends a command for starting a certain path of liquid injection through the USB 2.0. The FPGA control module can turn on a corresponding electromagnetic valve switch after receiving the command, meanwhile, the FPGA generates PWM pulses of the path, the generated PWM pulses can be reflected on an IO pin of the FPGA, the IO pin is connected to a base electrode of the triode, the IO pin can display periodic variation of high and low levels (3.3V/0V) through measurement of an oscilloscope, and the triode NPN connected with an IO port is turned on and turned off through the variation of the high and low levels. The emitter of the triode is connected with a grounding resistor with the resistance value of 10k ohm, a control signal of an NMOS (N-channel metal oxide semiconductor) tube is led out between the emitter of the triode and the grounding resistor, and the collector of the triode is connected to a 5V power supply. Since the selected NMOS transistor turn-on voltage Vgs is 5V. And connecting the extracted NMOS control line to a Gate of the NMOS to realize the control of the NMOS control line. The switching speed of the NMOS tube is 20ns, and the phenomenon that the stop time of the motor of the diaphragm pump is too long due to long-time delay is avoided, so that the liquid injection precision is unstable.

The diaphragm pump is used for injecting liquid and is driven by a direct current motor, the standard input voltage of the diaphragm pump is 24V, the rotating speed of the motor is 3000 rpm, and the aim of reducing the rotating speed of the motor is achieved through PWM control, so that the flow rate of liquid is reduced. If a potentiometer voltage division method is directly adopted, the rotating speed of the motor is unstable, so that liquid injection is not stable, the motor is an inductive element, reverse electromotive force can be generated in the operation process, the input voltage of the motor can be influenced, and the influence can be reduced by adopting a PWM control NMOS method. After a certain time, the upper computer sends a command to simultaneously turn off the diaphragm pump and the electromagnetic valve, and liquid injection is completed. Through repeated measurement and calculation, the PWM period generated by the FPGA is 1ms, and when the duty ratio is 80%, the liquid injection precision of the instrument is relatively high.

In the medical apparatus and instruments, the part with the requirement on the injection precision is often adopted by a plunger pump method, and the places needing high-precision injection are more, so that the cost of the plunger pump is higher, and the cost of the whole machine is greatly increased. Therefore, a low-cost diaphragm pump is adopted. The liquid injection of the diaphragm pump is driven by a direct current motor carried by the diaphragm pump. By using PWM control, the effective value of the driving voltage of the diaphragm pump can be reduced, so that the purpose of reducing the rotating speed of the direct current motor is achieved. And the FPGA simultaneously opens or closes the motor and the electromagnetic valve of the diaphragm pump so as to control the liquid injection speed and precision. After receiving a command of starting liquid injection, the FPGA generates a PWM period and a duty ratio by an internal algorithm, and controls an IO pin of the FPGA to generate a PWM pulse signal. The PWM pulse signal controls the on and off of the triode, the PWM signal with the same period and duty ratio is generated in the later stage of the triode, and the level of the PWM signal generated after passing through the triode is changed into 5V/0V because the emitter of the triode is connected with the grounding resistor with the resistance value of 10k ohm and the collector of the triode is connected with the 5V power supply. The NMOS adopts IRF8788, the opening voltage of the NMOS is 4.5V at the lowest, so that the 5V voltage is connected to the Gate of the NMOS, the NMOS can be controlled to be correspondingly opened and closed, and the liquid injection speed of the diaphragm pump is controlled.

A control liquid injection method of a liquid injection system based on an FPGA control diaphragm pump comprises the following steps:

a. the upper computer sends a command for starting a certain path of liquid injection; b. the FPGA control module can open a corresponding electromagnetic valve switch after receiving the command, and simultaneously can generate PWM (pulse-width modulation) pulses of the path, and the generated PWM pulses can be reflected on an IO (input/output) pin of the FPGA control module; c. the period change of high and low levels can be displayed by measuring the IO pin through an oscilloscope, and the triode connected with the IO port is opened and closed through the high and low level change; d. a control signal of an NMOS (N-channel metal oxide semiconductor) tube is led out between an emitting electrode of the triode and a grounding resistor, a collector of the triode is connected to a 3V-5V power supply, the turn-on voltage Vgs of the NMOS tube is 3V-5V, and a led-out NMOS control line is connected to a Gate electrode of the NMOS to realize the control of the NMOS control line;

What has been described above are merely some embodiments of the present invention. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the inventive concept thereof, and these changes and modifications can be made without departing from the spirit and scope of the invention.

Claims

1. The utility model provides a annotate liquid system based on FPGA control diaphragm pump which characterized in that includes: the automatic liquid injection control device comprises an upper computer, an FPGA control module, a solenoid valve switch and a diaphragm pump, wherein the upper computer is used for sending and opening one path of liquid injection instructions, the FPGA control module is electrically connected with the upper computer and is used for receiving the instructions of the upper computer, the solenoid valve switch and the diaphragm pump are controlled by the FPGA control module, meanwhile, the FPGA control module generates PWM pulses of the path, the PWM pulses can be reflected on IO pins of the FPGA, the IO pins are connected with a base electrode of a triode to control the triode to be opened and closed according to the high-low level change of the IO pins, an emitting electrode of the triode is connected with a ground resistor, and a control signal of an NMOS pipe is led out between the emitting electrode of the triode and the ground resistor to control the rotating speed of the diaphragm pump.

2. The priming system of claim 1, wherein said ground resistor has a resistance of 10 kohms.

3. The priming system of claim 1 or 2, further comprising an oscilloscope for measuring the periodic variation of the high and low levels displayed by the IO pin.

4. The priming system of claim 1 or 2, wherein the collector of the transistor is connected to a 5V power supply, and the level of the PWM signal generated by the transistor becomes 5V/0V.

5. The priming system of claim 4, wherein the turn-on voltage Vgs of the NMOS tube is 5V, the NMOS control line is connected to the Gate of the NMOS to control the NMOS tube, the switching speed of the NMOS tube is 20ns, and the long-time delay does not cause the stop time of the motor of the diaphragm pump to be too long, thereby causing unstable priming precision.

6. The priming system of claim 1 or 2, wherein said NMOS transistor is an IRF8788NMOS transistor.

7. The liquid injection system control liquid injection method based on the FPGA control diaphragm pump is characterized by comprising the following steps of:

d. a control signal of an NMOS (N-channel metal oxide semiconductor) tube is led out between an emitter of the triode and a grounding resistor, a collector of the triode is connected to a 3V-5V power supply, the Vgs (voltage Vgs) of the NMOS tube is 3V-5V, and a led-out NMOS control line is connected to a Gate electrode of the NMOS so as to control the NMOS;