Types of Real Time System
Real time
It is the amount of time the system needs to finish all of its activities and provide an output in response to an input. The calculation of each job should take the same amount of time.
Instantaneous system
Systems that need to generate the right answer in the predetermined amount of time are known as real-time systems. If it goes above these time limits, the machine may malfunction or perform worse.
For instance, in an aircraft engine control system, the real-time control system must complete its work as planned by the operator or pilot within a certain time frame. If this is not done, control may be lost, potentially resulting in many fatalities.
Instantaneous program
A program whose operation accuracy is determined by the computation’s logical output and the speed at which the results are generated. A real-time clock that indicates the moment a job is executed or interrupted is a necessary for every real-time system.
- Real-time system types
- The real-time systems are separated into the following categories based on the clock and task execution process:
- Systems based on clocks
- Systems that are event-based
- Interactive platforms
- Real-time clock-based system
This system’s real time clock requires that job calculation be finished within the allotted time frame. Plant control systems comprise the majority of this category. For certain chemical processes, the clock might be in hours; for other control systems, it can be in milliseconds. As an example of feedback control for tank level, the real-time system should detect the tank’s level, process it using a control algorithm, and then open the valve in response to keep the level maintained. The three tasks—sampling input, processing, and output response—should be completed within the allotted time frame.
Either a continuous or discrete clock may be used. When operating in continuous mode, the system will finish the work in the allotted amount of time. This is the same continuous control technique as the tank level controller above. Discrete control systems are used in several chemical industries where chemicals must be introduced at predetermined intervals.
Real-time event-based system:
Certain plant systems need that actions be taken in response to specific occurrences rather than at predetermined intervals of time. For instance, if the liquid level in the tank reaches its maximum level, the control system must shut the value. Here, the action is event-based rather than time-based, and it is often used to show alarm circumstances and start alarm actions. Some examples of these situations include showing the high liquid level in the tank or the high liquid temperature, among other things. Event-based systems are often designed to require the system to react to a given event within a maximum amount of time. Interrupts are used by these systems to tell the real-time system when an action is needed. A few tiny systems employ polling, which is when the system checks in with the different sensors to see if anything needs to be done. These systems may have deadlines stated in terms of start or end times as they are essentially aperiodic jobs. For instance, the valve closure should activate after a certain amount of time after detecting the liquid level.
Interactive systems: Interactive systems are systems that combine clock- and event-based functionality to prioritize a task’s average execution time. This includes systems like automated teller machines, hotel reservation systems, airline booking systems, and so on. After receiving input from the operator or plant, this system starts the job and completes it in the typical amount of time. For instance, when you insert your card to withdraw cash from an ATM, the machine processes the transaction. In this instance, external atmospheric variables have no effect on the reaction time; instead, it is determined by network traffic and internal processing time.