Solutions Manual – Process Dynamics
and Control, 4th Edition (2016) by Dale
Seborg
Process Control - a system that combines measuring materials and controlling instruments into
an arrangement capable of automatic action.
Process Control System - requires more than measuring and controlling the physical and
chemical characteristics of a process material
Variable - a value measured by an instrument
Process variable - the dependent variable that is to be controlled in a control system. Ex.
Temperature, pressure, level and flow.
Control variable or Manipulated variable - the independent variable used to adjust the
process(dependent) variable. Typical examples are flow rate of steam used to heat a process,
the flow rate of a refrigerant used to control a process, and the amount of reagent required to
neutralize a wastewater stream.
Setpoint - the desired value at which the process should be controlled and is used by the
controller for comparison with the process variable.
Low-water fuel cutoff - a level measuring device that shuts down a boiler when the water level
drops below the lowest allowed level.
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, Process automation - process involving batch and continuous flow of liquids, gases, and bulk
solids. Common operation include chemical reactions, cooling and heating and mixing and
separating products. Places priority on process safety, process uptime, high capital investment,
long plant lifetimes, and data management and product traceability.
Factory automation - refers to processes usually involving the piece flow of product. Typically
used in the manufacturing of discrete products. Places priority on production speed, low cost,
real-time processing and flexibility.
Primary element - the sensing device that detects the condition of the process variable.
Examples include thermocouples, pressure gauges, level gauges, and flowmeters.
Control element or controller - a device that compares a process measurement to a setpoint
and changes the control variable to bring the process variable back to the setpoint. This is
accomplished by sending a signal to the final element. Signal may be air pressure, electric
current, voltage or digital signal with atleast one other signal.
Final element - a device that receives a control signal and regulates the amount of material or
energy in the process. Examples include control valves, hydraulic pistons, variable-speed drives,
relays, pumps and dampers.
Measuring element - a device that establishes a scaled value for the measured process variable.
i.e. temperature transmitter is a measuring element that converts a thermocouple voltage to a
scaled temperature value.
Fieldbus networks - are digital communication protocols that are optimized for use in the
process automation industries.
Device networks - are digital protocols optimized for use in factory automation industries.
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and Control, 4th Edition (2016) by Dale
Seborg
Process Control - a system that combines measuring materials and controlling instruments into
an arrangement capable of automatic action.
Process Control System - requires more than measuring and controlling the physical and
chemical characteristics of a process material
Variable - a value measured by an instrument
Process variable - the dependent variable that is to be controlled in a control system. Ex.
Temperature, pressure, level and flow.
Control variable or Manipulated variable - the independent variable used to adjust the
process(dependent) variable. Typical examples are flow rate of steam used to heat a process,
the flow rate of a refrigerant used to control a process, and the amount of reagent required to
neutralize a wastewater stream.
Setpoint - the desired value at which the process should be controlled and is used by the
controller for comparison with the process variable.
Low-water fuel cutoff - a level measuring device that shuts down a boiler when the water level
drops below the lowest allowed level.
1
, Process automation - process involving batch and continuous flow of liquids, gases, and bulk
solids. Common operation include chemical reactions, cooling and heating and mixing and
separating products. Places priority on process safety, process uptime, high capital investment,
long plant lifetimes, and data management and product traceability.
Factory automation - refers to processes usually involving the piece flow of product. Typically
used in the manufacturing of discrete products. Places priority on production speed, low cost,
real-time processing and flexibility.
Primary element - the sensing device that detects the condition of the process variable.
Examples include thermocouples, pressure gauges, level gauges, and flowmeters.
Control element or controller - a device that compares a process measurement to a setpoint
and changes the control variable to bring the process variable back to the setpoint. This is
accomplished by sending a signal to the final element. Signal may be air pressure, electric
current, voltage or digital signal with atleast one other signal.
Final element - a device that receives a control signal and regulates the amount of material or
energy in the process. Examples include control valves, hydraulic pistons, variable-speed drives,
relays, pumps and dampers.
Measuring element - a device that establishes a scaled value for the measured process variable.
i.e. temperature transmitter is a measuring element that converts a thermocouple voltage to a
scaled temperature value.
Fieldbus networks - are digital communication protocols that are optimized for use in the
process automation industries.
Device networks - are digital protocols optimized for use in factory automation industries.
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