PID (Proportional-Integral-Derivative) is a widely used control method today. PID formula made up by three main elements.
P: Proportional
I: Integral
D: Derivative
The PID algorithm, which has many articles about it, may vary depending on the manufacturer. Principal components are proportional, integral and derivative. The values of these components directly affect the operational characteristic.
Speed plc has 128 or 256 unit pid control block according to cpu type. With Input 1 parameter, PID block can be selected from 0 to 255. PID block will try to equalize Input 2(Set) and Input 3(Proses) values. To ensure this equality, the PID formula will be run over and over again in the period specified in the input 6 parameter.
Bu e?itli?i sa?lamak için input 6 parametresinde belirlenen periyotta PID formulünü tekrar tekrar çaly?tyracaktyr. For a correcty working PID control it is crucial that the formula run in equal time periods.
P, I, D values should be entered depending on the characteristics of the system to be controlled.
For example, P, I, D values of a heating operation reaching the set value in 3 hours and a heating operation reaching in 10 minutes must be very different. In the Speed Plc, you can use both constants and memory field elements in P, I, D values. So you can change these parameters at different times of the process or when the control is exposed to different effects. For example, Let's assume we heat a container with liquid inside. The PID block will increase the output value the first time the heating is turned on and reduce it as it approaches the set value. Assume that the desired temperature value is obtained with 20% output. Cold commodity will be entered into the tank as the process continues. The temperature will decrease with the commodity input and the PID, which detects the temperature drop, will start to increase the output value. To accelerate this increase and not to allow the temperature value to drop, we can change the values of P, I, D for a period of time and then restore it. Thus, it will react very quickly to the drop in temperature.
Input 1: Pid block number.
Input 2: Proses set value.
Input 3: Proses actual value.
Input 4: P(Proportional)
Input 5: I(Integral)
Input 6: D(Derivative)
Input 7: Period
Output: % output value.
Proportional Integral Derivative