PID Controller (Percent)

The function block PID-Controller (Percent) contains the following elements:

-     proportional term

-     integral term

-     differential term

-     integral wind-up avoidance logic

-     setup of controller output; with auto/manual selection

The controller can be tuned with the multipliers (Kr, Ki, Kd). The error input d (d=W-X) is set internally by the controller. It is limited within the range of -100 to 100. The controller output is limited within the range of 0 to 100.



Name I/O Type(s) Function
W I FLOAT Set point
X I FLOAT Controlled variable (sensor input)
Kr I FLOAT Proportional gain input
Ki I FLOAT Integral multiplier
Kd I FLOAT Differential multiplier
Yh I FLOAT Manual set input
H I BIT Manual mode
Slu o BIT Deviation limit reached -100
Slo O BIT Deviation limit reached 100
SYu O BIT Control limit reached (output is 0)
SYo O BIT Control limit reached (output is 100)
Y O FLOAT Controller output


Ki = 0 I-term is off
Kd = 0 D-term is off
H = 1 Manual mode - Yh is channeled directly to Y


The symbol indicates, whether the controller runs in automatic or in manual mode.