ABB CL Series, Applications Manual

Page: 211 / 428

Wiring with the display system
208
1SVC 440 795 M1100
Contacts
DC01LI to DC32LI, value range of the manipulated variable
exceeded.
Coils
• DC01EN to DC32EN: Enable PID controller;
• DC01EP to DC32EP: Activate proportional component;
• DC01EI to DC32EI:
Activate integral component;
• DC01ED to DC32ED: Activate the differential
component;
• DC01SE to DC32SE: Activate the manual manipulated
variable
Memory requirement of the PID controller
The PID controller function block requires 96 bytes of
memory plus 4 bytes per constant on the function block
input.
Function of the PID controller function block
The controller operates on the basis of the equation of the
PID algorithm. According to this, the manipulated variable
Y(t) is the result of a proportional component, an integral
component and a differential component.
h The PID controller must be enabled so that it can work.
Coil DC…EN is active. If coil DC…EN is not active, the
entire PID controller is deactivated and reset. The
manipulated variable is set to zero.
The corresponding coils for the P, I and D components
must be active.
Example: If only coils DC…EP and DC…EI are activated,
the controller operates as a PI controller.
h The device calculates the manipulated variable every time
the scan time T
c
has elapsed. If the scan time is zero, the
manipulated variable is calculated every cycle.