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Chapter 8: Signal conversion - Coggle Diagram
Chapter 8: Signal conversion
Analog Electrical Signals
Voltage- to- current converter
The signals in process control are most often
transmitted as a current. It is often necessary to employ linear voltage to current converter
A voltage to current converter using an op amp
Current to voltage converter
At the receving end of the process control signal transmission system, it is often need to convert the current back to voltage.
V(out)=IR
Relay
Common conversion is to use the controller signal to activate a relay when a simple ON/OFF or two position control is sufficient.
Amplifiers
Often can provide necessary conversion of low energy control signal to high energy form
Serve for motor control, heat control, light level control and host of other industrial needs.
Motor control
Designed as packaged units that accepts low level DC signal directly to control motor speed
Digital To Analog Converter
DAC required when the digital output must provide a smooth control
Computer provides an input to DAC that then determines an appropriate analog input
Direct Action
New methods of final control have been developed that can be actuated directly by the computer.
A stepping motor interface easily to the digital signals that a computer outputs.
The objective of signal conversion is to
convert the low-energy control signal to a high energy signal
to
drive the actuator.