S88 Modelling Guidelines
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See a diagram showing S88.01 Modelling with ControlDraw

This shows one example of how pages and symbols can be arranged to match the S88 phsysical and procedural models.


Operations may belong to units or they may only exist in the Batch manager.

This is a typical design decision. Most batch manager support either approach. In ControlDraw you can choose for yourself whether to instantiate the operations in the Units or in the Recipes.

Phases nearly always belong to Units or Equipment Modules

Most batch managers assume the phase logic is in the Controller, be it PLC or DCS.

And so Phases should be instantiated in the Units or Equipment Modules, not in the Unit Procedures. The Units should have Parent links whereas the Unit Procedures should have Jump Links (IE referenced by rather than owned by.)

Note however that you may have phases in the batch manager that are not in the Controller, these are generally called soft phases.

Observations from commercial procucts

From DeltaV Batch Control Software Spec

"Delta-V's Batch control software provides full analog, discrete and sequencing control within a single Delta-V controller. In addition, Phase Logic Modules make creation of multi-state phases integrated with recipe management and execution a breeze.

... The Phase Logic Module, included with the Batch controller, manages multiple states of a batch phase.

The Batch Executive handles phase co-ordination and communication with basic control functions processed in the M3 or M5 controller."

IE the Phase control is part of the Controller, Not the Batch Manager

This is why I put the phases in the Units, specifically under the units in the Physical model. The Unit procedure is part of the Recipe. Phases do not care what recipe they are working with.

From Wonderware InBatch spec

"Equipment Processing Capabilities:

Units that have the same processing capabilities are in the same Process Class. Each Process Class, and therefore each unit in the Process Class, has processing capabilities that are defined by Phases.

Each Process Phase defines a process action, such as: mix, heat, cool, cook and agitate."

IE the Phase capabilities of the Unit determine the Unit Class, And so instantiating the phases in the Unit diagrams ensures that you can easily identify the Unit Classes.

Furthermore the method means that recipes are generic. You can even make a matrix to define specific recipes