ABB ACS280 Firmware Manual page 60

60 Program features
The graph below shows the PID trim output in direct mode throughout the
speed range. A fixed trim speed reference is added throughout the speed range.
40.05 Process PID trim output act
0
Note: In the above graph, it is assumed that the PID output is limited or stable
at 100. This is for clarity only. In real life scenarios, the PID output can vary based
on the setpoint and the actual value.
Example:
If:
40.52 Set 1 trim selection
parameter
40.56 Set 1 trim source
parameter
30.12 Maximum speed
parameter
40.01 Process PID output actual
parameter
40.55 Set 1 trim adjust
parameter
then:
100

Par40.05
--------- -
=

100
Par40.05 750
=
Proportional
The proportional method is suitable for applications where tension control is
required throughout the speed range but not near zero speed.
In this mode, the PID trim output actual (parameter
output act
) is relative to the reference selected by parameter
trimmed ref pointer
PID setpoint actual
It is recommended that the speed reference selected in
pointer
and the reference source in
required to make the proportional mode active.
In most of the use cases, the process speed reference is connected in
1 trimmed ref pointer
Drive speed reference
= PID output
= 1500 rpm
= 0.5,

 1500  0.5

40.01 Process PID output actual
and with
.
. For example, if EXT1 control mode is used and the
40.55 Set 1 trim adjust
= Speed
= 100 (limited to 100)
40.05 Process PID trim
22.11 Ext1 speed ref1
40.53 Set 1
40.03 Process
or
40.53 Set 1 trimmed ref
are equal. This is
40.53 Set