Temperature loggers are extremely versatile in multi-physics systems and have penetrated into virtually every industry. System classification is also complex. In embedded systems, the real-time multitasking mechanism is implemented by a background task management program that runs after startup. The application runs on this manager program. The background performs tasks such as resource management, message management, task scheduling, and exception handling according to the requirements of each task. Its primary purpose is to schedule all available resources for real-time control tasks. There are two major types of real-time systems: soft real-time systems and hard real-time systems. The purpose of the soft real-time system is to make each task run as fast as possible, and does not require limiting how long a task must be completed. In hard real-time systems, tasks must not only be performed without errors but also on time. Most real-time systems are a combination of the two. For a complex task system, the choice of task scheduling mode is a key point of its system architecture. Paperless recorders have multi-level interface management and high real-time response requirements, and it is imperative to select a system task scheduling model that is suitable for this. 1, the characteristics of real-time multi-tasking recorder The usual real-time multitasking operating systems are relatively large and are not suitable for real-time systems composed of single-chip microcomputers (80C320). Due to the limited computing power and memory of the SCM, real-time operating systems are required to be simple, practical, efficient, and reliable. As far as the recorder is concerned, its tasks and functions are foreseen, and the memory and file management system can be simplified or even cancelled [1]. Because the task's memory requirements are explicit, fixed and independent storage area allocation schemes can be used without the need to control and allocate via the OS. Therefore, a real-time multitasking operating system can be simplified as a scheduling module based on task scheduling and clock interrupt management. There are four kinds of task status in the recorder: running, ready, waiting, suspending, and the sleeping status is merged into waiting without any distinction. 2, the division of tasks, organization and scheduling 2.1 Division of tasks In the real-time multi-tasking system of single-chip microcomputer, the key to realize the real-time multi-task mechanism is to decompose the system function into each task module reasonably. The principle of dividing the task: the function is relatively independent, and can be divided into a task with a program that is executed by other programs at the same time. However, the task division cannot be too fine, otherwise it will increase the system overhead of task switching, reduce the system efficiency and affect the real-time nature of the system response. The literature [2] pointed out that close tasks should be merged as far as possible to reduce the communication between tasks. Considering the task's real-time performance and execution time, the recorder's ten tasks can be divided into three categories: (1) High-priority tasks: processing of uploading sampling values ​​by the lower computer, virtual channel organization, and alarm processing. This type of task requires high real-time performance, and the execution time is <0.1s. If the sampling value processing task is used, the recorder needs to save the sampled value as historical data. The time stamp is added during the save process. The sampled value is correct and the time-stamped record is invalid. of. (2) Low-priority tasks: key response, display, PID control, flow totalizer. The execution time of such tasks is <0.2s, and the real-time performance of the tasks is generally required. If the key responds to the task, a delay of 0.5s can be tolerated. (3) Background tasks: store, print, and communicate with the supervisor (PC). The execution time of such tasks is >1s, which requires the lowest real-time performance. Graphite Part,Other Graphite Parts,High Purity Graphite Part,High Strength Graphite Part Henan Carbon Road New Material Technology Co., Ltd , https://www.kyisostaticgraphites.com