Applying Automation to
Batch anufacturing
Using industry Standards
By Bruce Jensen & Marcus Tennant
Yokogawa Corporation ofAmerica
Sugarland, TX
Abstract
Batch processes in many industries, including grease
manufacturing, are built to achieve very flexible
manufacturing requirements. Often, when automating a
batch process, that flexibility is lost making it difficult for
operators to introduce new products and make process
modifications. Developed and refined over the past 20
years, the ISA Batch Standard (ISA 88) has become a
commonly understood approach to communicate batch
system requirements across R&D, process engineering
and control disciplines, and has enabled manufactures
to build flexible and highly automated batch systems.
This presentation will outline the basics of the ISA-88
standard and provide an overview of how it has helped
many different companies achieve agile and flexible
manufacturing in highly automated batch systems.
Overview ofBatch Processing
In the universe of manufacturing, there are two broad
ways to produce items for mass markets. On one end of
the spectrum, a discrete manufacturer produces things:
cars, electronics, appliances and tools. This is where
assembly lines with robots and high speed packaging are
very prevalent. At the other end, process manufactures
make material: gasoline, diesel fuel, paper, and bulk
chemicals. Both of these manufacturing worlds share
many common traits. They both strive for high levels
of automation to help them meet market demands by
producing efficiently and at a high rate of speed.
Some products for more specialized markets do not
have to be produced in quantities that justify major
manufacturing efforts. There are many opportunities
for more complex and customized production. For
products where the marketplace demands more limited
qualities such as pharmaceuticals, food, and many
specialty chemicals, including greases and lubricants,
manufacturers walk a fine line between producing
products that are considered commodities on one hand,
while still being very specialized to meet customers’
exacting standards.
Issues with Automation in Batch Production
Processes
For batch processing, the biggest advantage is often the
capability to customize each batch to meet a customer’s
requirements. With the advent of computer-based
control system technology, the continuous process world
quickly adopted the DCS (distributed control system)
to automate control functions, replacing pneumatic
and single loop analog control. On the discrete
manufacturing side, the PLC (programmable logic
controller) was developed to replace complicated relaybased machine controls used in many industries.
For batch manufacturers, the introduction of computerbased automation and control technology put them in
a quandary. There were certainly recognizable benefits
to automating a batch process: improved quality,
consistency and lower manufacturing costs, but there
were downsides as well. In batch manufacturing,
procedural control is a major requirement and
programming often became very complex to allow users
the ability to switch product manufacturing procedures.
Typically the systems were coded by very talented control
engineers who understood the embedded procedural
34
VOLUME 79, NUMBER 4
control and had to make changes requested by the plant chemist or process engineer.
Often the programing was very complex and if the control engineer who designed it
originally switched jobs or got promoted, it became difficult to make changes to the
batch system.
A BriefHistory of the ISA-88 Standard.
This kind of frustration was duplicated in many industries such as food and beverage,
pharmaceutical and specialty chemical manufacturing. In response, in 1988, the
International Society of Automation (ISA) formed standard and practices committee
SP88 to provide guidelines for the design and specifications of batch control systems,
drawing from existing standards and recommended practices in the industry with the
objectives of:
1. Define terminology specific to batch control systems that will encourage
understanding between users, equipment vendors and system integrators.
2. Provide a standard structure for data in a batch control language to simplify
programming, configuration tasks and communication between various components
of the system.
3. Provide a standard data structure for batch systems that will simplify data
communications within the system architecture.
4. Determine a standard batch control architecture.
After many years of intense work by the committee, the ISA 88 standard was approved
in 1995 and was approved by the IEC (International Electrotechnical commission) in
1997 as lEG 61512-1. The standard was reviewed and updated in 2010.
Advantages of the Standard
Since the approval and publication of the standard in 1995, many companies in many
different industries saw many benefits in ISA 88, including:
• A common terminology and set of models for owner operators to discuss system
requirements with automation vendors and system integrators.
• A conceptual basis for separating the recipe that instructs how the batch is to be
made from the equipment that is used to make the batch. This separation enables
process specialists, chemists, and formulation scientists to make changes in their
recipe procedures without having to make changes to equipment control code.
• A modular structural approach that promotes reusable code and procedures.
• Scalable models and concepts that are expandable if additional levels are needed
and collapsible if all the levels described are not needed.
• A structure that can apply to automated and manually-controlled batches.
• A methodology that applies to simple batch processes as easily as it does to
complex batch processes.
Key Concepts ofISA-88
To introduce the working concepts of ISA-88 we need to examine the primary models
and definitions that are the most important components of the standard.
Physical model (for equipment)
The physical model describes the hierarchy of equipment used in batching operations.
35
NLGI SPOKESMAN, SEPTEMBER/OCTOBER 2015
The model describes seven
levels shown in Figure 1.
The first three levels
.
.
..
(enterprise, site and
area) primarily provide a
connection into the business
systems of a company and
are not used in detail when
implementing a batch
automation process.
The enterprise is the
company that owns the plant.
It may include multiple
production sites. The site
is typically the plant where
the manufacturing takes
place. It may be identified
by physical, geographical
or a logical segmentation.
An area defines a specific
location within a site such as
Some of the other possible relationships
a building or other physical
Figure 1 From ANSI/ISA-88.OO.O1-2010 Batch Control Part 1: Models and Terminology Page 34
layout.
The process cell is the
Procedural model (for recipes)
highest level of ISA-88 where batch control boundaries
The procedural model (figure 2) defines the equipment
are defined when implementing the standard. The
actions that occur in a sequence. Like the physical model
process cell contains all of the equipment required to
it is hierarchical in nature and also contains equipment
manufacture a batch. A process cell may contain more
requirements and formulation information.
than one pathway or process train to complete a batch.
A procedure is an ordered set of unit procedures and
A unit is where batch processing occurs, and is typically
encompasses the overall strategy for manufacturing
a vessel such as a reactor or mixing tank that performs
a batch. It orchestrates the complete control of all the
some sort of value-added activity such as blending or
equipment in the process cell.
reaction that adds value to the product being processed.
The next level is the unit procedure, which is an ordered
A unit can only contain one batch at a time.
sequence of operations carried out in a single unit. Only
An equipment module is a group of items that
one unit procedure can be active in one unit at a time,
works together to perform a processing activity Some
although two or more unit procedures can be active as
equipment modules might be fixed in place and therefore
long as they are in separate units.
associated with only on unit. Other items may be more
An operation is an ordered sequence of phases carried
portable and shared among multiple units. Something
out in a single unit. Operations typically involve taking
like a CIP (clean in place) system might be allocated
the batch being processed from one type of physical
temporarily from one unit to another during processing.
change to another, such as a reaction, mixing or heating.
Control modules form the lowest level of the model
The phase is the final element of the procedural
which includes basic sensors, actuators and other
model and performs actions on the process. They are
process equipment that can operate as a single entity and
the elements of the procedural model that actually
typically interfaces with the plant’s control system.
perform processing actions on the batch. The higher
– 36 VOLUME 79, NUMBER 4
Model
Procedulal
Co~d
Modd
(S~Fçt~2)
(S~F~.~)
Model
order
order
order
Figure 3 From ANSI/ISA-88.OO.O1-2010 Batch Control Part 1:
Models and Terminology Page 50
Figure 2 From ANSI/ISA-88.OO.O1-2010 Batch
Control Part 1: Models and Terminology Page 47
level procedure, unit procedure, and operations are used
primarily to group, organize and direct phases
Linkingprocedures to physical equipment
At some point, a procedure to manufacture a batch
must connect the procedural model and physical model
to achieve process functionality~ The capabilities of the
physical model equipment are used to accomplish the
desired processing tasks of the procedural control model.
Figure 3 from 1SA88 shows an example of the mapping
between the procedural control model, physical model,
and process model. Note that a one-to-one relationship
is not required. In the example shown, unit procedures,
operations and phases of the procedural control model
can be supported by the units of the physical model.
States and commands
ISA-88 emphasizes the importance of process states
and commands. The state specifies the current condition
of a procedural element. A command is one method
for moving the procedural element from one state
to another. The standard gives an example of a state
diagram, but it is not necessary to follow the example. In
the example shown in figure 4, the procedural element
in a routine execution would start in an idle state.
When issued a run command, the procedural element
transitions to a running state performing its normal
processing task. Once the procedural element completes
its processing task, it transitions from a running state to
a complete state and waits for a reset command to cause
a transition to an idle state. The commands pause, hold,
stop and abort and the corresponding process states
paused, held, stopped and aborted represent different
levels of exception handling of the procedural element to
get it in a condition that is appropriate for efficient and
safe operation of the plant.
Example in grease manufacturing
Figure 5 gives an example of how processing
equipment may be categorized utilizing the ISA-88
Physical model. In this simple example the Process
Cell contains only one Unit, the dispersion vessel.
The equipment associated with the dispersion vessel
contains two equipment modules material charging and
recirculation. There are four control modules defined two
37 NLGI SPOKESMAN, SEPTEMBERJOCTOBER 2015
of them are organized under
the equipment modules
pump and material selection.
The other two Dispersion
and Temperature control are
directly associated with the
unit- the dispersion vessel.
Figure 6 shows how the
procedural model may be
applied to a basic grease
manufacturing procedure.
The overall procedure Make
Grease A contains the unit
procedure component
Make Suspension. The unit
procedure contains the
operation AlP suspension
with one of the phases add
oil. Typically it is the phases
that would be associated with
the control modules in the
physical model.
L’’1~ ~‘
__________
________
__________
________
Sc
~ ~i_’.i~::ri
~ii’
~•‘~ ~
Seep
li~E~I
Notes
I SC = Stale Change as a result of state actions completed.
2 Actions of an equipment procedural element are generally defined by Its Acting States.
3 The light. llght+medlum, and llght+medlum+dad~ grey boxes represent coflections of
states that can be preempted using the Hold. Stop, and Abort commands, respectively.
Figure 4 From ANSI/ISA-88.OO.O1-2010 Batch Control Part 1: Models and Terminology Page 83
Applying the principles ofISA 88 to other plant applications
Packaging and other discrete manufacturing
ISA-S88 Part 5 (Make2Pack) embraces some of the basic concepts developed for
the batch manufacturing industries with the intent of providing the same benefits
to the machine control industry,
________________________
specifically packaging machines.
An implementation example of
Process
ISA-88 became the basis of the
Cell
Matenal Selechon
Matenal
packaging standard known as
Charghig
PackML. The OMAC PackML
Implementation Guide can be
found at the OMAC website.
Temperature TT
Control
http://www.omac.org/contentl
packml
Equipment
___________
Disper~on
D
Dispersion
Vessel I
Discharge
Module
and
Recwculatlon
Continuous process
applications
Since ISA 88 was adopted,
many engineers have informally
applied the concepts of ISA 88
to continuous processing control
applications such as physical
Control
Module
Pum
FT
Figure 5- Example of how processing equipement may be catagorized
– 38 VOLUME 79, NUMBER 4
Procedure Model Applied
<II]
Procedure:
Manufacture
Grease A
Unit Procedure:
Make Suspension
Add
Oil
Phase:
H.at.STATUS COMPLETE
Operation:
AlP Suspension
Figure 6 Applied Prcedure Model
model, modularization and state operation model. In any
continuous process operation there are many procedures
that are executed to assure the safe and efficient running
of the process such as startup, shutdown, and product
grade transition. In 2010 the standards committee was
formed (ISA- 106) to focus on the procedural operations
in continuous process applications. In August of 2013 the
committee issued their first technical report, “Procedure
Automation for Continuous Process Operations
Models and Terminology” which is available from the
ISA http://www.isa.org/Template.cfm?Section=Standar
ds2&template /ContentManagement/ContentDisplay.
cfm&ContentlD 94066
—
ISA in different applications and industries.
Applying S88: Batch Control from a User’s
Perspective by Jim Parshall and Larry Lamb.
Published by the ISA(International Society for
Automation) 1999.
5. http://www.isa.org/Temp1ate.
cfm?Section=Books3&Template /Ecommerce/
ProductDisplay.cfm&ProductlD 2967
6. This book is a case history on applying ISA 88
at Ben & Jerry’s St. Albans ice cream plant. The
book is informative and entertaining for covering a
technical subject.
4.
Bibliography
Recommended reading
1.
2.
3.
•
The WBF Book Series: Volume 1 ISA-88
Implementation Experiences. Momentum Press
2010 Edited by Wffliam Hawkins, Dennis Brandi,
and Walt Boyes.
http://www.momentumpress.net/books/wbf-series
isa-88-implementation-experiences
This volume is a collection of papers that were
presented at the World Batch Forum (Now part of
MESA http://www~mesa.org/en/index.asp about
several companies experiences in implementing
•
ANSI/ISA-88.00.01-2010 Batch Control Part 1:
Models and Terminology. Research Triangle Park,
NC ISA, 2010
Ishchuck, Yu. L. Lubricating Grease Manufacturing
Technology. New Delhi, India, New Age
International Publishers 2005
39
NLGI SPOKESMAN, SEPTEMBER/OCTOBER 2015