Omron MX2 User Manual

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Glossary Section A-1
PID Loop Proportional – Integral-Derivative – A mathematical model used for process
control. A process controller maintains a process variable (PV) at a setpoint
(SP) by using its PID algorithm to compensate for dynamic conditions and
vary its output to drive the PV toward the desired value. For variable-fre-
quency drives, the process variable is the motor speed. See also Error.
Process Variable A physical property of a process that is of interest because it affects the qual-
ity of the primary task accomplished by the process. For an industrial oven,
temperature is the process variable. See also PID Loop and Error.
PWM Pulse-width modulation: A type of AC adjustable frequency drive that accom-
plishes frequency and voltage control at the output section (inverter) of the
drive. The drive output voltage waveform is at a constant amplitude, and by
"chopping" the waveform (pulsewidth- modulating), the average voltage is
controlled. The chopping frequency is sometimes called the Carrier Fre-
quency.
Reactance The impedance of inductors and capacitors has two components. The resis-
tive part is constant, while the reactive part changes with applied frequency.
These devices have a complex impedance (complex number), where the
resistance is the real part and the reactance is the imaginary part.
Rectifier An electronic device made of one or more diodes that converts AC power into
DC power. Rectifiers are usually used in combination with capacitors to filter
(smooth) the rectified waveform to closely approximate a pure DC voltage
source.
Regenerative Braking A particular method of generating reverse torque to a motor, an inverter will
switch internally to allow the motor to become a generator and will either store
the energy internally, deliver the braking energy back to the main power input,
or dissipate it with a resistor.
Regulation The quality of control applied to maintain a parameter of interest at a desired
value. Usually expressed as a percent (±) from the nominal, motor regulation
usually refers to its shaft speed.
Reverse Torque The torque applied in the direction opposite to motor shaft rotation. As such,
reverse torque is a decelerating force on the motor and its external load.
Rotor The windings of a motor that rotate, being physically coupled to the motor
shaft. See also Stator.
Saturation Voltage For a transistor semiconductor device, it is in saturation when an increase in
input current no longer results in an increase in the output current. The satura-
tion voltage is the voltage drop across the device. The ideal saturation voltage
is zero.
Sensorless Vector Control A technique used in some variable-frequency drives (featured in some other
Omron inverter model families) to rotate the force vector in the motor without
the use of a shaft position sensor (angular). Benefits include an increase in
torque at the lowest speed and the cost savings from the lack of a shaft posi-
tion sensor.
Setpoint (SP) The setpoint is the desired value of a process variable of interest. See also
Process Variable (PV) and PID Loop.
Single-phase power An AC power source consisting of Hot and Neutral wires. An Earth Ground
connection usually accompanies them. In theory, the voltage potential on
Neutral stays at or near Earth Ground, while Hot varies sinusoidally above
and below Neutral. This power source is named Single Phase to differentiate
it from three-phase power sources. Some Omron inverters can accept single
phase input power, but they all output three-phase power to the motor. See
also Three-phase.

Omron MX2 Specifications

General

Brand	Omron
Model	MX2
Category	Inverter
Language	English