Example of a ControlDraw P&ID for a BioFermenter

The diagram below (click for full size) is a 'typical' BioReactor as found in bio pharma plants. This diagram was produced in ControlDraw.

Pharmaceutical Fermenter Equipment Modules

I have recently been looking at ControlDraw models for  large scale Pharmaceutical Fermenter Units from 4 different companies. Process wise, all the fermenters are broadly similar, but each client has their own way!
I cannot publish them because because they are confidential, agreements signed!

However I have summarised them using some statistics from the models. 

Some differences are immediately apparent.

Why is the IO Count for Client 3 so low? This is because they do not use limit switches on their valves. This is something I have never understood as it seems to me that any cost savings would be obliterated by the downtime cause by the inablity to quickly diagnose valve failures.

Why do  Clients 1 and 3 have so many parameters? I think that this is in part because they do not distinguish between critical parameters (that can be changed to define the product or CIP ) and other parameters

Actually the differences are greater than they appear, mostly because of different ways of handling routing and cleaning.
What they all have in common is Equipement modules for:

Agitator Control
CIP / SIP
Dissolved Oxygen Control
Exhaust Filter
Gas Feed
Inoculation Transfer
Media Supply
pH Control
Pressure Control
Product Transfer
Sampling
Temperature Control

Some of the models are Unit Centric (the EM's are driven to states by a Unit Level phase) and some are EM Centric where the EM's run phases in parallel with each other. The former approach is my preference as it results in less complexity

Equipment Modules in Equipment Modules

As you all know S88 Part 1 supports Equipment Modules in Equipment Modules as indicated by this in the latest draft update.

I cannot at this moment think of one and nobody has ever shown me a real case that justifies it – if you know different Please Let Me Know. (You can comment here or email us.)

What I have seen is Equipment modules containing some sequential logic. But these are not phases that really perform Process Actions as phases should – I don’t rate sending a set point or prompting an operator as a Process Action by the way.

(I have also seen Common Resources implemented and Equipment modules and then containing equipment modules, but in those cases the Common resources were more like Units.)

Whenever I first review an S88 functional specification I look for this by the way. (If the functional specification is a ControlDraw model it takes about 10 seconds with Word it can take hours).

It is very rare, and always arguable.

Now, I think S88 would be greatly simplified and the implementations improved if the ability to have Equipment Modules in Equipment Modules was removed.

Of course you can do that yourselves when you do an S88 modularisation and without straying from the standard – and I highly recommend that you do.

Equipment Modules or Control Modules, which are cheaper?

I heard a good one today. I had emailed the State Based Control paper to a customer asking why parts of their plant model did not have Equipment Modules, perhaps on the lines of those in the SBC paper. I got a very good answer, part of which was that all the operational aspects in those areas are manual SOP guided. And that maybe some procedural control will be added when they understand better how to run the equipment.

But another aspect was that they get charged more for more equipment modules.

Now, I have been looking into the complexity of systems, and hence the time it should take to program them. And part of the point of using Em's is to reduce complexity.
So I suggested that as they do not have to run phases ( just like those in the SBC paper) call them Control Modules!