ABB ACS280, Firmware Manual, Page: 63 / 430

Program features 63
The following graph shows the trim increase in combined mode.
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, PID output can vary based on
the setpoint and actual.
At zero speed, the
40.05 Process PID trim output act
value depends on both
parameters
40.54 Set 1 trim mix
and
40.55 Set 1 trim adjust
. However, adjusting
40.54 Set 1 trim mix
near to zero speed will give quick correction.
Example :
If:
parameter
40.52 Set 1 trim selection
=
Speed
parameter
40.56 Set 1 trim source
=
PID output
parameter
30.12 Maximum speed
=
1500
rpm
parameter
40.53 Set 1 trimmed ref pointer
=
AI1 scaled
parameter
22.11 Ext1 speed ref1
=
AI1 scaled
parameter
12.20 AI1 scaled at AI1 max
=
1500
parameter
12.12 AI1 scaled value
=
750
(AI1 actual scaled value)
parameter
40.01 Process PID output actual
=
100
(limited to 100)
parameter
40.54 Set 1 trim mix
=
0.1
parameter
40.55 Set 1 trim adjust
=
1
Then:
If
12.12 AI1 scaled value
is 0:
Par40.05 = (100/100) x {(1500 × 0.1) + [(1 – 0.1) × 0]} × 1
Par40.05 = 150
If
12.12 AI1 scaled value
is 750:
Par40.05 = (100/100) x {(1500 × 0.1) + [(1 – 0.1) × 750]} × 1
Par40.05 = 825
40.55 Set 1 trim adjust
40.53 Set 1 trimmed ref pointer 0
40.05 Process PID trim output act
40.54 Set 1 trim mix
Par 40.55
Par
40.54