[ILM] 104A Flashcards
R->
G->
Y ->
W ->
C ->
main power
fan on/off - green
cooling - blue
heat - black
common - white
- open loop is
- closed loop is
- manual and has NO FEEDBACK
- automatic and has feedback
Internally powered
requires no power external to the system
pneumatic
operates by means of air pressure that a compressor supplies
electromechanical
operates by means of electricity and its components are connected by electrical wires
electronic
operates by means of electricity, but uses electronic elements, such as trasistors
hybrid
may contain components from any of the other categories and is also considered a power source-based system
control system modes
- on/off
- multi-position
- floating - (dead control zone)
- proportional or modulating
floating control
usually tri-state
- switch 1 is ON; switch 2 is OFF
- switch 1 is OFF; switch 2 is ON
- switch 1 is OFF; switch 2 is OFF
switch 1 & 2 are NEVER ON at the same time
proportional analog signal
0 to 10 vdc
2 to 10 vdc
4 to 20 maDC
Proportional (P) contains
no signal conditioning or algorithm
Proportional Integral (PI) contains
time algorithm
Proportional Integral Derivative (PID) contains
time and temperature algorithms
Miscommunication or inaccurate use or term causes
- unnecessary costs
- equipment damages
- civil litigation
- government intervention
- bodily injury to equipment users
the energy that the control system manipulates to cause a change in the controlled medium
control agent
a movable plate within a vessel or chamber that starts, stops, or varies the volume of air entering, leaving, or passing through that vessel or chamger
damper
a two position or on/off control system; non-variable
digital
a control system that is continuously variable
analog
direct acting
the output signal changes in the same direction that the controlled or measured variable changes
ex) an increase in resistance from an increase of temperature
reverse acting
the output signal changes in the opposite direction to the controlled or measured variable changes
ex) an increase in the controlled or measured variable results in a decreased output signal
low limit control
a device that normally monitors the condition of the controlled medium and interrupts system operation if the monitored condition drops below the desired minimum value
Peltier effect
cooling seats
resistance temperature detector (RTD)
a temp sensor that operates on changes in electrical resistance based on RTD temp changes
thermocouple
a device for measuring temp whenever 2 junctions of 2 dissimilar metals in an electric circuit are at different temperatures
thermistor
a heat sensitive resistor with a resistance change based on temp changes
transducer
an electronic pressure sensor utilizing piezoelectric counter emf to create measurable impedance in a control loop
electrical drawings
connection diagram
schematic diagram = ladder diagram
important point of schematic diagram
every line diagram or rung MUST have at least one load
