Rockwell Automation 1336E IMPACT Adjustable Frequency AC Drive User Manual V 1-4.XX - Manual (Page 349)

Control Block Diagrams B-11
Understanding Process Trim
Process trim lets you adjust the speed or torque of the motor. PTrim
Reference (parameter 49) contains the setpoint input for the processor
under control. PTrim Feedback (parameter 50) contains the input for
the process variable that is being controlled. These values are
compared. The regulator adjusts PTrim Output (parameter 48) so that
the difference between PTrim Reference and PTrim Feedback
approaches 0.
Figure B.1 shows the process trim cycle.
Figure B.1
Process Trim
The process trim PI (proportional integral) regulator takes inputs from
PTrim Preload (parameter 53), PTrim Ki (parameter 54), PTrim Kp
(parameter 55), and PTrim Select (parameter 51).
PTrim Select lets you select specific options for the process trim
regulator. The following options are available:
If bits 3 and 4 are both clear (0), PTrim Output (parameter 48)
becomes zero with the enable bit off and the integral term is
initialized at zero. If bits 3 and 4 are both set (1), option 3 (set output
option) takes priority.
file: Application
group: Process Trim
PTrim Reference
PTrim Feedback
Regulator PTrim Output
Motor
Process
To select
this option:
Set this
bit:
Trim the speed reference. 0
Trim the torque reference. 1
Configure as outer speed trim loop. Set bit 2 to pre-configure the PTrim
Reference (parameter 49) and PTrim Feedback (parameter 50) values to
use the speed ramp output and speed feedback signals.
2
Set output option. When you set bit 3, the output follows PTrim Preload
(parameter 53) with the process trim enable bit off. Rise of process trim
enable will preset the integral term of the process trim regulator to start the
PTrim Output (parameter 48) at the data input value.
3
Preset integrator option. When you set bit 4, PTrim Output is zero with the
process trim enable bit off. Rise of enable will preset the integrator as in
option bit 3.
4
Force ON trim limit option. When you set bit 5, the speed trim limit function
is always active. When clear (bit 5 = 0), the speed trim limiter is
automatically disabled.
5
Enable process trim. 6
Enable Encoder Switchover Mode 7