Chain: A term used to describe the linking of serval RS-232C
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.
An indication of the rate of decay of a signal to its steady
state value. Related to setting time.
Ratio: Ratio of actual damping to critical damping. Less than
one is an underdamped system and greater than one is an overdamped
Band: A range of input signals for which there is no system
The region or band of no response where an error signal will
not cause a corresponding actuation of the controlled variable.
The slow release of confined fluid to gradually reduce pressure
on the fluid.
The volume of fluid discharged by a pump in a given time, usually
expressed in gallons per minute(gpm).
To close the vent connection of a pressure control valve permitting
the valve to function at its adjusted pressure setting.
A logarithmic measurement of gain. If G is a system'sgain (ratio
of output to input), then 20 log G = gain in decibels (db).
Torque: The minimal torque present in n unenergized motor. The
detent torque of a step motor is typically about 1% of its static
Signal: A voltage or current that varies between two distinct
and fixed levels.
device used to convert Ac voltage in to DC pulses.
Current (DC): A steady level of electrical current, produced
by a power source e.g. battery, thermocouple etc. that flows in
only one direction in a circuit.
Digital Link(DDL): A digital feedback system used with servo
valve to allow the valve to communicate with a digital host device
such as a PLC or personal computers. The host device serially transmits
command signals to the valve, and position information is sent back
to the host which respond with an error correction signal.
A low amplitude, AC signal superimposed on the torque motor
or solenoid input to improve system resolution. Direct is expressed
by the direct frequency (Hz) and the peak-to-peak dither
Drive Servo: A high-torque, low speed servo motor with a high
resolution encoder or resolver intended for direct connection to
the load without going through a gearbox.
A passage in or a line from a hydraulic component which return leakage
fluid independently to reservior or to a vented manifold.
Acting Cylinder: A cylinder in which fluid force can be applied
to the movable element in either direction.
Cycle: For a repetitive cycle, the ratio of on time to total
Duty Cycle= On Time / (On Time + Off Time).
Breaking: A passive technique for stopping a permanent magnet
brush or brushless motor. The motor windings are shorted together
through a resistor which results in motor braking with an exponential
decrease in speed.