chapter 3 Flashcards
(42 cards)
is the technology by which a process or
procedure is accomplished without human
assistance”
Automation
Basic Element of an automated system
Power, Programs of instruction,
Control system
to accomplish the process and operate
the automated system
Power
to direct the process
Program of instructions
principal power source
electricity
– to actuate the instructions
Control system
“Set of commands that specify the sequence of steps in
the work cycle and the details of each step
Program of Instructions
processing steps are specified in a
Work cycle Program
examples of automated work cycles in
which decision making is required:
▪Operator interaction
▪Different part or product styles processed by the
system
▪Variations in the starting work units
Features of a Work Cycle Program
▪Number of steps in the work cycle
▪Manual participation in the work cycle
▪Process parameters
▪Operator interaction
▪Variations in part or product styles
▪Variations in starting work units
executes
the program of instructions.
Control element
causes the process to accomplish its
defined function, to carry out some manufacturing
operation
control system
Two types of control system
Open-loop control system, Closed-loop (feedback) control system
operates without the
feedback loop
. Open-loop control system
a system in
which the output variable is compared with an input
parameter, and any difference between the two is used
to drive the output into agreement with the input
Closed-loop (feedback) control system
Closed-loop (feedback) control system
▪Input Parameter (set point)
is the operation or function being controlled
(output value)
The process
is used to measure the output variable and close
the loop between input and output
A sensor
compares the output with the input and
makes the required adjustment in the process to reduce
the difference between them.
controller
is accomplished using one or more
actuators which are the hardware devices that physically
carry out the control actions
adjustment
Advanced Automation Functions
- Safety monitoring
- Maintenance and repair diagnostics
- Error detection and recovery
“Use of sensors to track the system’s operation and
identify conditions that are unsafe or potentially unsafe”
Safety Monitoring
▪To protect workers and equipment
▪Reasons for safety monitoring
▪Possible responses to hazards:
▪Complete stoppage of the system
▪Sounding an alarm
▪Reducing operating speed of process
▪Taking corrective action to recover from the safety
violation
