j5 Flashcards
whats a set point
the set point provides the informations to the controller about the desired value of the process
whats an actuator
the actuator alters the process variable
whats an open loop system
only one process variable is controlled an indicator and an operator are necessary to keep the process variable at a constant
closed loop system
control process variable is automatic
three things that an open loop control requires
requires an operator to monitor the process and operate controlling device, the operator requires a monitor to measure the value of the process, controlling device alter the actuator
discontinuous control system
full power is applied or removed to modify the process
in continuous control system
the process is controlled from very low power to full power
examples of control variables are
motor speed, liquid pressure, room temperature, liquid flow, liquid level, and position of a work piece for a machine
electrical out put signal standard is usually
4 ma to 20 ma direct current signal or 10ma to 50 ma
an actuator is
a device that converts a signal input to a mechanical motion
three types of servomechanisms
electrical hydraulic and pneumatic
