ABB ACS560, Firmware Manual

Page: 56 / 514

56 Program features
The below graph shows the PID trim output in direct mode throughout the speed
range. A fixed trim speed reference is added throughout the speed range.
Note: In the above graph, it is assumed that the PID output is limited/stable at 100.
This is for understanding purpose only. In real case scenario, PID output can vary
based on the setpoint and actual.
Example
If,
Par. 40.52 Set 1 trim selection = Speed
Par. 40.56 Set 1 trim source = PID output
Par. 30.12 Maximum speed = 1500 rpm
Par. 40.01 Process PID output actual = 100 (limited to 100)
Par. 40.55 Set 1 trim adjust = 0.5
Then,
Proportional
The proportional method is suitable for applications where tension control is required
throughout the speed range but not near to zero speed.
In this mode, the PID trimmed output ( 40.05 Process PID trim output act ) is relative to
the reference selected by parameter 40.53 Set 1 trimmed ref pointer and with 40.01
Process PID output actual or 40.03 Process PID setpoint actual .
It is recommended that the speed reference selected in 40.53 Set 1 trimmed ref
pointer and the reference source selected in 22.11 Ext1 speed ref1 and 40.53 Set 1
trimmed ref pointer are same. This is required to make the proportional mode active.
In most of the use cases, the process speed reference is connected in 40.53 Set 1
trimmed ref pointer . For example, if EXT1 control mode is used and the reference
40.0
5
P
roc
es
s P
ID
tr
im
o
utput a
ct
40.55 Set 1 trim adjust
Drive speed reference
0
Par40.05
100
100
----------
 
 
1500 0.5
 
=
Par40.05 750 =