Ram: A device which converts mechanical force and motion into hydraulic fluid power.

Ramping: The acceleration and deceleration of a motor. May also refer to the change in frequency of the applied step pulse train.

Rated Torque: The torque producing capacity of a motor at a given speed. This is the maximum torque the motor can deliver to a load and is usually specified with a torque/speed curve.

Regenerative Circuit: An electronic signal of constant frequency and amplitude that has varying pulse width to control the level of power to the solenoid.

Regeneration: Usually refers to a circuit in a drive amplifier that accepts and drains energy produced by a rotating motor either during deceleration or free wheel shutdown.

Registration Move: Changing the predefined move profile that is being executed, to a different predefined move profile following receipt of an input or interrupt.

Repeatability: The degree to which the positioning accuracy for a given move performanced repetitively can be duplicated.

Resolution: The smallest positioning increment that can be achieved,. Frequently defined as the number of steps required for a motor's shaft to rotate one complete revolution.

Resolver: A feedback device with a construction similar to a motor's construction (stator and rotor). Provides velocity and position information to a drive's microprocessor or DSP to electronically commulate the motor.

Resonance: Designates the condition resulting from energizing a motor at a frequency at or close to the motor's natural frequency. Lower resolution, open-loop systems will exhibit large oscillations from minimal input.

Relay Logic: A system for controlling a machine or process based on the status of various interconnected relay.

Replenish: To add fluid to maintain a full hydraulic system.

Reservoir: A container for storage of liquid in a fluid power system.

Resolver: An electromagnetic feedback device which converts angular shaft position into analog signals can be processed in various ways, such as with an RDC (resolver-to-digital converter) to produce digital position information. There are two basic types of resolvers, transmitter and receiver. A transmitter type is designed for rotor primary excitation and stator secondary outputs. Position is determined by the ratio of the sine outputs amplitude to cosine output amplitude. A receiver type is designed for stator primary excitation and rotor secondary output. Position is determined by the phase shift between the rotor output signals and one of the primary excitation signals.

Resistance: The opposite to current flow offered by the component of an electrical circuit.

Return Line: A line used to carry exhaust fluid from the actuator back to sump.

Rotary Actuator: A device for converting hydraulic energy into rotary motion-a hydraulic motor.

Ringing: Oscillation of a system following a sudden change in state.

RMS Torque: For an intermittent duty cycle application, the RMS Torque is equal to the steady state torque that would produce the same amount of motor heating over long periods of time.

RS-232: A data communications standards that encodes a string of information on single line in a time sequential format. That standard specifies the proper voltage and time requirements so that different manufactures devices are compatible.