Aerotech BM Series, Hardware Manual

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BM/BMS Series Hardware Manual Appendix A
www.aerotech.com A-3
Current Command
Motor driver or amplifier configuration where the input signal is
commanding motor current directly, which translates to motor
torque/force at the motor output. Brushless motors can be
commutated directly from a controller that can output current
phase A and B commands.
Current, Peak
An allowable current to run a motor above its rated load, usually
during starting conditions. Peak current listed on a data sheet is
usually the highest current safely allowed to the motor.
Current, rms
Root Mean Square. Average of effective currents over an
amount of time. This current is calculated based on the load and
duty cycle of the application.
Cycle
When motion is repeated (move and dwell) such as repetitive
back-and-forth motion.
DC Brushless Servo
A servomotor with stationary windings in the stator assembly
and permanent magnet rotor. (See AC Brushless Servo)
Deceleration
The change in velocity as a function of time.
Duty Cycle
For a repetitive cycle, the ratio of “on” time to total cycle time
used to determine a motor’s rms current and torque/force.
Dwell Time
Time in a cycle at which no motion occurs. Used in the
calculation of rms power.
Efficiency
Ratio of input power vs. output power.
Electronic Gearing
Technique used to electrically simulate mechanical gearing.
Causes one closed loop axis to be slaved to another open or
closed loop axis with a variable ratio.
Encoder Marker
Once-per-revolution signal provided by some incremental
encoders to accurately specify a reference point within that
revolution. Also known as Zero Reference Signal or Index Pulse.
Encoder Resolution
Measure of the smallest positional change which can be
detected by the encoder. A 1000-line encoder with a quadrature
output will produce 4000 counts per revolution.
Encoder, Incremental
Position encoding device in which the output is a series of
pulses relative to the amount of movement.
Feedback
Signal that provides process or loop information such as speed,
torque, and position back to the controller to produce a “closed
loop” system.
Flatness (of travel)
Measure of the vertical deviation of a stage as it travels in a
horizontal plane.
Force, Continuous
The value of force that a particular motor can produce in a
continuous stall or running (as calculated by the rms values)
condition.
Force, Peak
The maximum value of force that a particular motor can
produce. When sizing for a specific application, the peak force is
usually that required during acceleration and deceleration of the
move profile. The peak force is used in conjunction with the
continuous force and duty cycle to calculate the rms force
required by the application.
Friction
The resistance to motion between two surfaces in contact with
each other.
G.P.I.B.
A standard protocol, analogous to RS-232, for transmitting
digital information. The G.P.I.B. interface (IEEE-488) transmits
data in parallel instead of serial format. (See IEEE-488)