01 December 2004
A batch of rules and regulations
Batch manufacturing—a technique for manufacturing parts or finished goods in groups, lots, or batches in which each part or finished product in the batch is identical.
Batch process—a process that leads to the production of finite quantities of material by subjecting quantities of input materials to an ordered set of processing activities over a finite time using one or more pieces of equipment.
Recipe—the complete set of data and procedures that define the control requirements of a particular product manufactured by a batch process. A recipe consists of a header, equipment requirements, procedure, and formula.
Process manufacturers must adhere to strict regulations and requirements, especially in batch-processing environments.
Impeccable record keeping is imperative to satisfy government regulations and continuously improve quality.
Internationally defined standards such as ANSI/ISA-88.01-1995–Batch Control Part 1: Models and Terminology; Namur NE33 Batch; IEC 61131-3; ISO 9000; and the Food and Drug Administration's (FDA's) 21 CFR specify the requirements for good manufacturing practices (GMP) in the design of batch systems.
Digital automation systems that follow these five standards have an advantage over both legacy systems and loosely developed batch processes in the following ways:
- The standards have defined a physical and functional batch control architecture that creates logical coherence throughout the system.
- A digital automation batch system that conforms to the accepted industry standards ensures an integrated batch control environment.
- A digital automation system in a batch environment seamlessly integrates the applications of the process with each other and with information systems, beginning with recipe management (configuration) through to batch execution and production planning and scheduling, and ending with batch history and analysis and reporting.
Once again, the giant leap in processing power has made it possible to create a powerful batch-processing environment. Only automation systems built with all-digital communications can achieve this level of integration.
A single, global database, not previously possible, enables seamless interaction be-tween recipe management, batch execution, production planning and scheduling, and batch history, analysis, and reporting.
Controller memory capacity, recipe size, and phase logic all have an impact on batch performance. However, the advanced, efficient communications of a digital automation system greatly increase the power of a batch system.
The digital automation system ensures the transparent, continuous flow of batch information between the PCs, servers, and controllers, including configuring and processing recipes, allocating equipment, implementing phase-to-phase communications, collecting and reporting history, and communicating with third-party software.
The result is diminished process variability and increased plant performance. The importance of following the ANSI/ISA-88.01-1995 and IEC 61131.3 batch design standards cannot be overstated.
By implementing these batch environment standards, digital automation system manufacturers and users are sure to leverage a common protocol in recipe management, batch execution, and historical collection.
A typical recipe operation
Nicholas Sheble (firstname.lastname@example.org) edits the Control Fundamentals department. One source for this installment is Fundamentals of Industrial Control, ISA Press 2005, D.A. Coggan, editor.
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