Rockwell Automation WebPak 3000 DC Drive Application Workbook Version 1.1 - Manual (Page 96)

Glossary-4 WebPak 3000 Drive Application Workbook, Version 1.1
loop - A control scheme in which a reference input to a device is compared to a
feedback signal from the device for purpose of regulation. Any error is amplified to
affect the input to the device to reduce the error. All other “functions” in the loop can be
viewed as gain functions.
• inner loop - Also known as a “minor loop.”
• outer loop - Also known as a “major loop.”
losses - A motor converts electrical energy into mechanical energy, and in doing so,
encounters losses. These losses are all the energy that is put into a motor and not
transformed into usable power, but are converted into heat causing the temperature of
the windings and other motor parts to rise.
losses compensation - Provides the additional motor torque required to compensate
for the friction and windage losses of the motor and connected load.
motor full load torque - Torque developed when the motor is operating with full load
current and full field excitation.
open-loop system - A control system that lacks feedback.
overwind (or underwind) - Defines the direction of rotation of a center-drive winder.
Also referred to as “face in” or “face out” winding.
parallel control - A control strategy in which the output of two outer loops are used to
provide the input to an inner loop.
parameter - A value used to represent a drive or motor characteristic. There are three
types of parameters:
• configurable - Parameters that can be adjusted or changed only when the drive
is stopped.
• tunable - Parameters that can be adjusted or changed when the drive is running
or stopped.
• read only - Parameters that cannot be adjusted.
PI - Proportional-integral; when the transient response of a feedback control system is
considered satisfactory, but the steady-state error is too large, it is possible to
eliminate the error by increasing the system type. The system type can be increased
by operating on the actuating signal to produce one that is proportional to both the
magnitude and the integral of this signal resulting in improved system performance.
rated tension - The tension in the line when the drive is operating with motor rated
torque (motor rated current with rated field current) at full roll diameter.
reference rate - The rate of velocity change for the speed reference.
regulator - A piece of hardware or software that regulates a quantity such as voltage,
power, speed, etc., at a set value or between certain close limits.
scaling - The process of changing a quantity from one level to another level.
self-tuning - The adjustment of otherwise fixed parameters by an automatic
procedure (initiated manually) that calculates parameters based on data acquired
empirically and a pre-defined regulator-tuning algorithm.