Application of Hongke PCA in Medical Equipment Industry

Application of PCAN interface card based on Hongke in hemodialysis machine

The number of patients with end-stage renal disease in China is huge and increasing year by year. Hemodialysis is a relatively mature alternative therapy, which can alleviate patients' symptoms and prolong patients' life. At present, China's hemodialysis machine market is mainly occupied by imported brands. The research and development of domestic hemodialysis machines with high quality and low price is not only the pursuit of China's medical enterprises, but also of great significance to the progress of science and technology and the development of medical undertakings.

Hemodialysis is to drain the blood in the body to the outside of the body through a dialyzer composed of countless hollow fibers. The blood and electrolyte solution (dialysate) with similar body concentration are inside and outside the hollow fibers, and exchange substances through dispersion / convection to remove metabolic waste in the body, maintain electrolyte and acid-base balance, and remove excessive water in the body.

Challenge

Shortcomings of traditional hemodialysis machine

In the actual treatment in the hospital, different modules need to be selected for treatment according to the situation of patients. After years of development, the function, safety performance and humanized design of domestic advanced models are comparable to those of foreign models, but domestic hemodialysis machines still have shortcomings. For example, most hemodialysis equipment does not have the functions of blood volume monitor, multiple sets of independent CPU systems and central networking. Although it has a variety of safety monitoring functions, the actual failure rate is high. Whether it is the appearance of the equipment, the principle of the hydraulic system of the machine, the design of parts, etc., there is a lack of innovation and lack of core competitiveness.

programme

Application and optimization of PCAN interface card based on Hongke in hemodialysis machine

In order to optimize the original prototype according to the new requirements and higher requirements, it is necessary to consider the system integrity, safety, accuracy and so on. Based on the above problems, Hongke PCA interface can be used to further R & D and optimization of hemodialysis machine.

Hemodialysis machine has many electronic control parts, which has high requirements for various indicators in the work of the machine. It needs an efficient and stable automatic control system to make dialysis run safely. Therefore, the control system of hemodialysis machine should meet the basic requirements of automatic control system, that is, stability, rapidity and accuracy.

For the control system of hemodialysis machine, its safety includes not only the control system itself, but also the executive parts controlled by the control system. When the control system has its own security, it should know the operation of the executive parts. When the actuator fails or does not work normally occasionally, the control system should be able to infer what parts have failed, what faults have occurred, what causes the faults and how to deal with them from the feedback of its components or according to the overall operation of the system.

Therefore, the functions of the control system structure of hemodialysis machine include: collecting the signals of various sensors to ensure the safety of dialysis; Control the movement of each pump to achieve accurate control of important parameters and meet the standard.

The control system of Hongke scheme can be divided into upper layer and lower layer. The upper layer is the main controller of upper computer and lower computer, and the lower layer is the motor and its driver, sensor module and three solenoid valve control boards. Its hardware structure is shown in the figure. The control system mainly includes the upper controller, the lower executive components and sensor modules. The upper computer is responsible for human-computer interaction function, obtaining medical staff instructions, displaying treatment parameters, etc. the main controller of the lower computer receives the instructions of the upper computer, completes the functions of the hemodialysis machine, and uploads the parameters to the upper computer. The motor, driver and solenoid valve are the executive components, The sensor acts as an information feedback component.

According to the requirements of the control system, the functions of each hardware module are divided as follows:

1) The host computer mainly realizes the human-computer interaction function, including guiding medical staff to carry out dialysis operation, displaying dialysis parameters in real time, providing maintenance personnel with maintenance platform, etc. The upper computer communicates with the main controller of the lower computer through CAN bus.

2) The main controller of the lower computer is used to realize the overall control of the hemodialysis machine, that is, collect sensor information such as temperature, conductivity and flow, control motors such as blood pump, degassing pump and flow pump, and control the drive of solenoid valve controller.

3) The motor and driver are the actuator of the control system, and the sensor module is the information acquisition device.

4) The solenoid valve controller is responsible for driving the solenoid valve and feeding back the status of the solenoid valve.

In this communication process, the can communication task is mainly responsible for the communication of devices on the CAN bus. We can give the highest priority to communication tasks to ensure that the control commands and parameters of the upper computer can be transmitted to the lower computer in time at any time. All communication between the upper computer and the lower computer is completed by this task, and other tasks can only contact the upper computer indirectly through this task. In the can receiving interrupt, it receives the data sent by the upper computer, caches the data, and triggers the can communication task by sending semaphore for analysis and execution.

HONGKE

Key characteristics of Hongke PCA interface card

high speed USB 2.0 adapter (compatible with USB 1.1 and USB 3.0)

two D-sub connectors are used to send and receive can FD and Lin messages (both are allocated by pins of can FD and LIN bus)

comply with can specification 2.0 A / B and FD

each can FD channel shall separate USB and Lin, with a maximum of 500V

can terminal can be excited by welding jumper

bus load measurement includes error frame and overload frame

induce error to generate can message for input and output

summary

The application and optimization of Hongke PCAN interface card in hemodialysis machine can meet the requirements of product stability, rapidity and accuracy. It can also be used with our handheld tester PCAN diag FD for various fault diagnosis, such as various fault diagnosis by processing CAN2.0 and can FD messages in the protocol layer, and oscilloscope function and voltage in the physical layer Resistance measurement function for fault diagnosis. At present, many manufacturers at home and abroad have used PCA interface card to upgrade their medical equipment. If you want to know more about PCA interface card, please contact Hongke for product information and trial opportunities.

Original title: [PCA medical application series] part6 application in hemodialysis machine based on Hongke PCA interface card

The source of the article: [WeChat official account: Guangzhou Rainbow Electronics Technology Co., Ltd.] welcome to add attention!