Module 1- Intro to Process Instrumentation Flashcards
Instrumentation Definition
a collection of instruments and their application for the purpose of observation measurement and control
Basic purpose of instrumentation is
to observe measure and control a pv also to obtain maximum output from the industry with minimum usage of materials
process variable definition
the variable/quantity being measured or controlled in the process
examples of pv
pressure, level, temperature, flow, electrical conductivity, pH, position, speed, density, mass etc.
setpoint definition
the desired value of the process variable
measured variable
electronic or pneumatic representation of the value of the pv
Process plant is
an arrangement of processing units arranged in a systematic order
Process plant objective
is to convert raw materials into a desired product by applying energy in a safe and cost effective manner.
(Main criteria for process Instrumentation)
In a successful process plant design instrumentation should address
Safety, Production and Environmental Standards
How should instrumentation address the Safety Criteria
the plant should allow for safe containment of process pressures,
construction materials should be able to withstand designed temperatures and chemical concentration
as well as
the control system should be capable of maintaining process parameters at designed points, providing for safe shut and fail safe capability
How should Instrumentation address the Production production criteria
quality and quantity of product should be maintained in order to maximize investment returns and
The designed product should meet or exceed original design expectations
How should instrumentation address the Environmental Criteria
The plant should comply with environmental regulations regarding air pollution and plant effluent as well as
Have instrumentation to monitor and control plant discharge
What are the main components of a control loop
process, measure, control and final control element
Define the Process component of the control loop
the physical system we are that we are trying to measure or control. it is a physical or chemical change of matter or energy eg water filtration system, molten melt casting system
Define the measurement component of the control loop
this component/block determines the current status of the process parameters, and send the information(measured pv signal) to the control block. this block includes the pse(primary sensing element) sensors and transmitters
Define the control component of the control loop
this component receives the information from the measurement instrument (measured pv signal) compares it to the programmed setpoint desired valued and signals the fce to take corrective action if necessary
1Define the Final Control Element(FCE) of the control loop
the device which acts to physical change the manipulated variable when signaled to by the controller. ie it controls the flow of materials to the process
Define an actuator
An actuator is a part of Final control device that causes physical change in the final control device when signaled to do so.
eg. valve actuator that opens or closes valve in response to controller signal
How are actuators usually powered
pneumatically, hydraulically, or electrically
Give 8 examples of parts of an actuator system
bellows, diaphragms, springs, gears, hydraulic pivot valves, pistons, electric motors.
What are the purposes of Instrumentation (I.C.R.A.M.)
Indicate
Control
Record
Alarm
Measure
Define Indicator
a human-readable device that displays information about the process and allows for taking measurements at a measure point at a measurement
