04 Automated Process Control by nasif123


  Automated Process Control

It is used extensively from oil refining, chemical
 processing, electrical generation to the food
 and beverage and pharmaceutical industries.

Deals with analog signals from sensors and
 meters, that are transmitted to specialized
 computers which cause the temperature,
 pressure, flow etc to be continually adjusted
  Automatic control systems are
  composed of three components:
 Sensors: measure some physical
  state such as temperature.

 Responders: a simple electrical or
  mechanical systems or special
  purpose digital controllers or general
  purpose computers

 Actuators: affect a response to the
  sensor(s) under the command of the
 Why Automated Control System?

Enable us to operate our
 processes in a safe and
 profitable manner.

All measured process
 variables are maintained
 at operator specified set
 point values.
  The old manual methods:
In the old manual process, scientists
walked around the lab recording data and
then manually entered all the data into a
Based on their analysis of this aggregated
data, they returned to each controller for
maximum effectiveness and best yield.
 Drawbacks of Manual Method
 This may lead to poorly controlled
  process variables and can exhibit
  large variability
 Lack of ability of simultaneous
  data collection
 Manual methods make FDA
  compliance difficult, and systems
  are less secure.
 In old manual method the sensed
  information about temperature,
  pressure, and humidity was
  manually recorded by a
  supervisor in charge. This often
  results in data entry errors.
 Advantages of Automation
 Makes human safety the
  primary objective

 Can provide a cost effective
  means of collecting
  meaningful process data

 Reduction of labour

 Flexibility to change the batch
  process control as the
  process changes.
 Increases the ability of a machine to be
  interfaced into a computer controlled process

 Makes it easier to comply with cGMP, GLP and
  FDA guidelines

 Laboratory scientists can focus on essential
  research and development

 Stable plant operation with reduced
  operational errors and rejected products

 Automated process control and data management
  allows easy expansion
 Greater efficiency and
  shorter time to market the

 A technician can monitor
  many reactors from one
  station, or respond to
  alarms remotely

 Instrument resources can be
  shared. e.g. one expensive
  gas analyzer can serve
  many reactors.
    Automation of Process

A process variable is the current status of
a process under control.

Measurement of process variables is
important in controlling a process.
At the heart of industrial
    process control is the
    measurement of process
    variables, such as:

     Temperature
     Pressure
     Humidity etc.

Measurements are made by
 sensors, meters, and sent
 by a transmitting device
 to an indicator or
 recorder for display.
 The transmitter also sends the measurements to
  a controller, where the data are compared to a
  pre-established set of parameters.

 The controller calculates the difference between
  the measured data and the programmed
  "setpoint" values.

 If necessary, the process variables are adjusted
  to conform to the desired parameters.

 This feedback-and-response cycle is called a
     Instruments Used To Measure
             Process Variables
Flow and Level Instruments
The most common flow meters are differential-
 pressure, turbine, mass-flow, magnetic, and
 positive-displacement meters.
Flow meters are used to measure the rates of flow
  of fluid chemicals, gases, liquids containing
  particulate matter (slurries), water.
Level instruments can be used to determine the
  amount of raw materials. They are typically
  installed in tanks, hoppers, or other storage
Pressure Instruments

o    Majority of industrial manufacturing processes
    use pressure to perform work.

o     Punch presses and boilers are typical
    pressure-based industrial process machines.

o    Pressure measuring instruments like gauges
    and pressure transmitters operate
    hydraulically or electronically to measure
    absolute pressure, vacuum pressure etc.
 Temperature Instruments

o More than half of all measured
  process variables undergo some
  form of temperature measurement
  during the manufacturing process.

o Accurate temperature
  measurements are critical in
  processes where slight temperature
  variances can destroy final product

o Some basic temperature-measuring
  instruments are thermocouples,
  resistance thermometers, thermal
  radiation meters, mercury-filled
  thermometers etc.
Gas and Liquid Analyzers

o    GL Analyzers allow molecular-level
    measurement of process materials without
    interruption of the process for sample

o    They are used to measure industrial effluents
    and waste products, viscosity of liquids used in
    mixing processes and food processing, the
    acidity or alkalinity of process materials.
Humidity Instruments
o     The humidity measurement equipment
    is highly used in pharmaceutical industry.

o Most drugs are sensitive to variations
in humidity and moisture levels.

o    Humidity should be controlled during all
    phases of drug development.

o     Hygrometers and psychrometers
    measure the humidity in such industrial
    applications as test chambers,
    pharmaceutical packaging, and industrial
Other Process Control

This category includes
  instruments for measuring
  such process variables as:
o Specific gravity
o Density
o Viscosity
o Weight
o Force
Digitalization of pharmaceutical Industry
Pharmaceutical and healthcare industries are highly
  regulated industries in each and every nation around
  the globe.

Every nation has a governing body that assures the
  medicines are manufactured under strict guidelines to
  ensure highest quality of manufactured products.

However assuring high quality products requires that the
  manufacturing facility is monitored and this monitoring
  requires the use of high end networking technology.

Currently pharmaceutical plants capture this information
  using a number of sensors that measure temperature,
  pressure, humidity etc.
Computer Assisted Manufacturing
 One of the most dramatic of
  these changes is the
  introduction of Computer
  Aided Manufacturing (CAM), a
  system of using computer
  technology to assist the
  manufacturing process.

 CAM is the use of computer
  software and hardware in the
  translation of computer-aided
  design models into
  manufacturing instructions.
Computer Aided Manufacturing is commonly
 linked to Computer Aided Design (CAD)
 systems. The resulting integrated CAD/CAM
 system then takes the computer-generated
 design, and feeds it directly into the
 manufacturing system.

Persons interested in manufacturing
  technology should possess:
 Mechanical aptitude
 Good basic math skills
 Ability to work well with others
 An interest in design and computer
   Benefits and Application of using
 It can be used to facilitate mass

 It enables manufacturers to reduce the costs
  of producing goods by minimizing the
  involvement of human operators.

 It enables manufactures to make quick
  alterations to the product design, feeding
  updated instructions to the machine.
Many CAM software
 packages have the ability
 to manage simple tasks
 such as the re-ordering of

CAM software represents
 a continuation of the trend
 to make manufacturing
 entirely automated.
 Can be applied from
  development of the basic
  design to the bill of materials
  necessary to manufacture
  the product

 Bridges the gap between the
  conceptual design and the
  manufacturing of the
  finished product.
Problems Related to CAM
 The setting up the infrastructure to begin
  with can be extremely expensive.
 Computer-aided manufacturing requires not
  only the numerical controlled machine tools
  themselves but also an extensive suite of
  software and hardware
 The field of computer-aided management is
  fraught with inconsistency.
 The lack of standardizations may become a
  problem when the time comes to convert 3D
  designs into G-code.

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