Application Control; Application Macros; Process Pid Control - ABB ACS850 Manual

70 Program features

Application control

Application macros

See chapter Application macros

Process PID control

There is a built-in PID controller in the drive. The controller can be used to control
process variables such as pressure, flow or fluid level.
In process PID control, a process reference (setpoint) is connected to the drive
instead of a speed reference. An actual value (process feedback) is also brought
back to the drive. The process PID control adjusts the drive speed in order to keep
the measured process quantity (actual value) at the desired level (setpoint).
The simplified block diagram below illustrates the process PID control.
AI1
AI2
Process
• • •
actual
values
D2D
FBA
For a more detailed block diagram, see page 364.
Quick configuration of the process PID controller
1. Select a setpoint source
2. Select a feedback source and set its minimum and maximum levels
fbk1 src, 27.05 PID fbk1
used, also set parameters
max and 27.08 PID fbk2
3. Set the gain, integration time, derivation time, and the PID output levels
PID gain, 27.13 PID integ
27.19 PID minimum).
4. PID controller output is shown by parameter
the source of, for example,
(page 89).
Setpoint
(27.01 PID setpoint
max, 27.06 PID fbk1
27.02 PID fbk
min.
time, 27.14 PID deriv
21.01 Speed ref1 sel
Process
PID
sel).
min). If a second feedback source is
func, 27.04 PID fbk2
time, 27.18 PID maximum
04.05 Process PID
or 24.01 Torq ref1
(27.03 PID
src, 27.07 PID fbk2
(27.12
and
out. Select it as
sel.