Scalable solutions for the design of batch control systems

When the ISA (society for the systems of instrumentation and automation, by its initials in English) defined the standard ANSI/ISA-S88-01-1995 more than ten years ago, he created a language and a common models for the design and specification of systems of control for batch processing. For machinery manufacturers, already undergoing the usual pressures to provide more flexible machines, faster and with lower costs, the standard heralded an acknowledgement a remarkable reduction of the complexity in the design of systems.

Now known simply as S88, the standard ANSI/ISA-S88.01-1995, its counterpart in the International Electrotechnical Commission (IEC 61512-01) and the subsequent extensions of the standard have paved the way so that machinery manufacturers can make optimal use of modular systems in order to reduce costs. In addition, they have eliminated the need for coding customized for each application, thus reducing development times, and allowed the reuse of code written for a system in later systems, regardless of the scale and complexity.

Therefore, machinery manufacturers benefit from a reduction of deadlines for marketing thanks to standardized equipment, the effective reuses of the code, scalable controls and information platforms from front row grids.

Created in 1995, the standard charted the way forward in the development of systems of control batch (batch), defining models and terminology for the physical plant, procedures and formulas of a batch. The standard has evolved over the years: ANSI/ISA-88.00.02-2001, which deals with the structure of the data and guidelines for languages, was published in 2001 and in 2004 was ANSI/ISA-88.00.03-2004, which deals with models and representations of general formulae and plants.

In addition, the standard S88 derived the S95 for the integration of control systems business, which defined a common terminology for the description and understanding of the information on a company manufacturing. It also defines the exchange of information between the functions of control of manufacture and other functions of the enterprise, including data models and functions of Exchange.

Then, what exactly means for machinery manufacturers work to processing industries? Control equipment in batches to the processing industry aims to be able to manufacture many products with the same computer, or carry out various operations in the product, without the need for large manuals reconfigurations of the production team and without having to rewrite the control software batcha potentially expensive task and it takes time.

The S88 model of physical plant defines the team depending on process cells. Each of them contains the necessary equipment for the production of one or more lots. A cell of process is made up of all units: sets of process equipment, control equipment and the associated control logic that performs the activities of processing.

The basic capabilities of processing of the unit can be defined through «team modules» and these define what can be done a formula unit, usually actions as additions of material, transfer of material, heat or cool a container, pressurize a container and mix materials in a container. The S88 standard even more composed team modules control modules, which are a combination of the basic logic of control and the various sensors and actuators within the unit.

The effect of this is to define the hierarchical formulas and management frameworks of segmentation processes to materialize the goal of separating products in manufacture of the equipment to manufacture, and thus allow manufacturers to enjoy significant improvements in productivity.

You can use the same computer to produce multiple products or to perform different operations on a given product, with a development and easy deployment of the formula and without need for engineers specializing in control systems.

This effectively reduces the cost overall of the design, development and supply through less intervention from the project engineering (design, programming, cabling, testing, installation, technical assistance), a saving of energy scalable, modular and open system of control and information system of automation.

Obviously, one thing is to have a viable model to develop systems and modular equipment control batch, and other have the physical tools to convert that model in tangible systems. S88-based computer applications have been around almost as long as the own rule, but not always these functions have been available in automaton «turnkey».

However, the picture is changing thanks to a new family of controllers with integrated S88 functions that allow you to adopt a methodology of modular design. These teams are giving new impetus to the design of machines and devices compatible with S88.

These products are defined by the platform RSLogix 5000 of Rockwell Automation with PhaseManager. PhaseManager is a function that was incorporated into the programming RSLogix 5000 software and enter code S88 all controllers Logix family to offer a standardized framework for configuring and sequence State of phase logic directly in the controller or by Rockwell Automation's FactoryTalk Batch. This function executes phases based on data and S88 and PackML control structures. These predefined structures encapsulate code PLI (Phase Logic Interface) complex and, therefore, they save time of programming and money.

Phases is can quickly sequencing with FactoryTalk Batch or directly on the controller Logix using routines SFC (Sequential Function Chart), and can be viewed on a monitor built-in phase to help test and repair phases during the start up and maintenance.

As PhaseManager consists of series of Rockwell Automation controllers, the knowledge that may be acquired with a machine can be easily applied to the following. In addition, as software engineering is homogeneous across the family of controllers Logix, the code developed for an application can be reused easily in many other applications. In the same way as the S88 defines a modular concept that is scalable across different levels of complexity, Rockwell Automation hardware is scalable across different levels of complexity and different machine sizes.

The result is that machinery manufacturers can dramatically reduce the deadlines for systems design and provide solutions of greater capacity and flexibility to customers more quickly. By not having to rely on custom hardware and software, development costs are drastically reduced and the subsequent applications are easier and faster to implement.

In summary, the S88 redefined the way in which control systems could build batch enabling a modular approach to systems design. However, what really has made possible the realization of the objectives of the S88 is the arrival of standard computer tools combined with standard, scalable teams and «turnkey». Machinery manufacturers finally have the tools they need to build systems of control by lots of any size and level of complexity for any sector, fast and cost-effective way.