Hormonal contraception is highly effective: when taken on the prescribed schedule, users of steroid hormone methods experience pregnancy rates of less than 1% per year. Perfect-use pregnancy rates for most hormonal contraceptives are usually around the 0.3% rate or less.
A programmable logic controller (PLC), or programmable controller is an industrial digital computer which has been ruggedised and adapted for the control of manufacturing processes, such as assembly lines, or robotic devices, or any activity that requires high reliability control and ease of programming and process fault diagnosis.
A PLC is primarily used to control machinery. Programs written for PLCs consists in simple terms on instructions to turn on and off outputs based on input conditions and the internal program. In this aspect, it is similar to a computer. Programmable Logic Controller, or PLC, is more or less a small computer with a built-in operating system (OS). This OS is highly specialized to handle incoming events in real time, i.e., at the time of their occurrence.