Sunday, 22 June 2008

Equipment Procedural Entity

There have been discussions in the S88.01 Update meetings about Equipment Procedural Entiies (EPE's)

This is how I view EPE's -

They are objects such as Phases that can be executed under the command of a Recipe - for example an SOP, or a Production batch, a Batch manager Control or MES Recipe - but which are contained in - and controlled by - the equipment controllers.

The Equipment Controller might be an Operator who runs the equipment manually or if the equipment is automated, the Process Controller - PLC/DCS, Relays or whatever - that is connected to the physical equipment. (Most times it is a mix of the two)

EPE's are part of equipment control.

In Object oriented terms they are like the Methods of Objects
The Equipment that contains the EPE is a Unit or an Equipment module depending whether the Recipe-Equipment Interface is at the Unit or EM level.
Note, the S88 standard says that Control modules cannot have EPE's. But this is no problem - if you must control one CM from the recipe, create an EM to contain it. There is no law against it.

The EPE's can be Phases, Operations or Unit Procedures.

Now, the standard does not say this, but what follows is I think consistent with the models. It is also a configurable aspect of ControlDraw.
Equipment that contains EPE's must also be Acquirable, which mean that the Control Recipe takes control of the Equipment when it needs to carry out some processing in it. And to take control of it means preventing others from controlling it. Which to me implies Acquiring the equipment.

There is a direct correlation between the Equipment Requirements of the Master Recipe and the Equipment that contains EPE's .

That means that the Recipe Equipment Requirement maps to the physical equipment.

This can be one for one in cases where the recipe must use specific equipment or one to many in cases where the Recipe can use different (but similar) equipment.
For example a Recipes' Equipment Requirements might have a Reactor and a Filter but the plant has several Reactors and Filters. The Acquire process involves reserving the equipment for the current batch.

The last draft has a diagram, "Figure 18 – Referencing equipment entities at different levels within a control recipe procedure."

See also
Think of batch standard as design philosophy
Much more to come !

1 comment:

Anonymous said...

Sounds reasonable. A good explanation of what (acquiring equipment prior to running phases/operations/UPs) has been incorporated into existing ControlDraw models - which have been used as a basis (nearly 1 to 1 of the sw to design) to configure automated batch plant.

Is anyone arguing against this methodology?