Allen-Bradley PowerFlex User Manual

Process PI Loop 2-117
There are two ways the PI Controller can be configured to operate.
• Process Trim - The PI Output can be added to the master speed reference
• Process Control - PI can have exclusive control of the commanded
speed.
The selection between these two modes of operation is done in the [PI
Configuration] parameter.
Process Trim
Process Trim takes the output of PI regulator and sums it with a master
speed reference to control the process. In the following example, the master
speed reference sets the wind/unwind speed and the dancer pot signal is
used as a PI Feedback to control the tension in the system. An equilibrium
point is programmed as PI Reference, and as the tension increases or
decreases during winding, the master speed is trimmed to compensate and
maintain tension near the equilibrium point.
When the PI is disabled the commanded speed is the ramped speed
reference.
Master Speed Reference
10 Volts
0 Volts
Dancer Pot
[PI Feedback Sel]
Equilibrium Point
[PI Reference Sel]
+
Spd Cmd
Process PI
Controller
Linear Ramp
& S-Curve
+
+
+
PI Disabled
Speed Control
Spd Ref
PI Ref
PI Fbk
Slip Adder
Open
Loop
Slip
Comp
Process
PI

Allen-Bradley PowerFlex Specifications

General

Category	DC Drives
Manufacturer	Allen-Bradley
Series	PowerFlex
Communication Options	EtherNet/IP, DeviceNet, ControlNet
Protection Features	Overcurrent, Overvoltage, Undervoltage, Overtemperature, Short Circuit
Enclosure Type	NEMA 1, NEMA 12, NEMA 4/4X
Operating Temperature	0°C to 40°C (32°F to 104°F)
Storage Temperature	-40°C to 70°C (-40°F to 158°F)
Humidity	5% to 95% (non-condensing)
Altitude	Up to 1000m (3280 ft) without derating