Technical information

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230V FX Series Positioning Drive Reference Manual
Compensation, Proportional
A control action which is directly proportional to the error signal of a feedback loop. It is used to improve
system accuracy and response time.
Compliance
The amount of displacement per unit of applied force. Opposite of stiffness.
Computer Numerical Control
A computer-based motion control device programmable in a numerical word address format. A Computer
Numerical Control (CNC) product typically includes a CPU section, operator interface devices, input/output
signal and data devices, software and related peripheral apparatus.
Continuous Path
(see Coordinated Motion.)
Control Systems or Automatic Control Systems
An engineering or scientific field that deals with controlling or determining the performance of dynamic
systems such as servo systems.
Coordinated Motion
Multi-axis motion where the position of each axis is dependent on the other axis such that the path and
velocity of a move can be accurately controlled. Required when generating circular or helical tool paths.
Coupling Ratio
The ratio of motor velocity to load velocity for a load coupled to a motor through a gear or similar
mechanical device.
Critical Damping
A system is critically damped when the response to a step change in commanded velocity or position is
achieved in the minimum possible time with little or no overshoot.
Daisy Chain
A term used to describe the linking of several serial communications devices in sequence such that a single
data stream flows through one device and on to the next. Daisy-chained devices usually are distinguished by
device addresses which serve to indicate the desired destination for data in the stream.
Damping
An indication of the rate of decay of an oscillating signal to its steady state value. Related to setting time.
Damping Ratio
Ratio of actual damping to critical damping. Less than one is an underdamped system and greater than one
is an overdamped system.
DC Drive
An electronic control unit for running DC motors. The DC drive converts AC line current to a variable DC
current to control a DC motor. The DC drive has a signal input that controls the torque and speed of the
motor. Usually used to describe a drive with an SCR output stage.
DC Servo Drive
A DC drive which incorporates the necessary compensation networks necessary to operate a servo system.
Usually has a transistorized PWM output but can also utilize SCR output devices.