Loop and Logic Diagrams and P&ID’s

This has recently been discussed at length on LinkedIn  on the ISA – International Society of Automation group under the title "Does control logic belong on P&IDs?"

Among the comments are
....Adding logic functions to a P&ID clutters it, is prone to add further unnecessary revisions to the P&ID every time a logic is changed ...
...agree that the complexity that we can configure into the DCS, PLc, and SIS cannot be represented adequately on the P&IDs...
...No, detail logic does not belong to PIDs. A PID is a construction document, as such it must show:
1-Hardwired input to logic interlock, complex loop or DCS/SIS
2-Hardwired output from logic interlock, complex loop or DCS/SIS to Final Control Element FCE
3-Identification of logic interlock, complex loop or DCS/SIS. Separate documents are generated for interlocks and complex loops...

So, how much can reasonably be shown on the P&ID depends on the type of process and previous practise but at the end of the day there are nearly always extra diagrams, typically with a cross reference on the P&ID. This blog post provides an explanation of how you can use ControlDraw to draw all those extra diagrams and relate them to the P&ID's
Top level diagram contains an object for each P&ID and child pages then provide a graphical list of the relevant loop and logic diagrams which are then diagrams under each object.
Here is a diagram that explains this (click to see full size)

This can even be extended to cover such things as State based control Matrices and Cause and Effect Matrices
Note - if you have a list of the P&ID's (which is normal) you can copy the list to create the P&ID Overview diagrams using Paste Special as Rows. And you can create all the P&ID Overview diagrams with a couple of clicks from the Group Menu >Create/Link Child diagrams.

ControlDraw Model to Web Site
ControlDraw now provides the ability to generate a web site from the model.
This means that people will be able to view a model without the need to install any software or work from PDF output from the Reviewer.
The web version is of course much simpler than the original model and does not support such functions as running diagrams in simulation mode. However it is still useful.
Example is available to view here.
You can click on the objects that have numbers by them to go to the detailed diagram for the object,much like you can in ControlDraw itself

Each web page is a diagram page in the ControlDraw model.
Each ControlDraw diagram page is saved as a png file including automatic generation of the hot spots as an HTML ImageMap
The page description HTML was generated from the page RTF text

A more advanced version will soon be available that supports navigation view with a Hierarchical menu

New Start option - Larger Windows and Fonts

ControlDraw has been going for a long time, since before Windows XP in fact.
As Windows has developed and computers have arrived with large High Resolution displays, the standard size of the various ControlDraw windows has remained the same. This has had the effect of making them too small for some users and furthermore the latest versions of Windows 7 have a larger default font size. As a result some users were finding that the text in the labels and button etc in the ControlDraw windows did not fit the available space.
The latest version of ControlDraw now provides a solution by providing a selection at the Login screen.
As you change the option you can immediately see the effect.



So, if you find the screens too small, or have the Window 7 problem we hope this helps you.

Class Hierarchy and Field Inherits Map

The latest version, 1218 of ControlDraw provides new ways to look at the structure of a model.
The Field Inherits Map

This shows each field name where it's Special Default is !Inherit and the classes that the field value will pass through.
A drop down box lists all the inherited fields so you can pick one.
The Model Class Hierarchy

Note that these are automatically available - you do not have to draw them, they are built from the data in the model

How Process Engineers could use ControlDraw in early project stages

ControlDraw may never be suitable for large P&ID's, but I think it is already more than capable of producing PFD's and much more, including simple P&ID’s that could be used as a starting point for the CAD versions.

The diagram below is intended to show how Process Engineers could use ControlDraw in early project stages.

ControlDraw version 3.6.1210 - Faster and Smarter

This new release provides some great improvements, especially for those of you who have large models and who want to use the Recipe Modelling capabilities to define master recipes.

The Recipe Modelling  developments are mainly intended to support recipes that can have a large number of parameters. For example the Descended Objects view can be used to create parameters in a Recipe Procedure by scanning all the child hierarchy of a recipe type diagram and finding all the lower level parameters (typically in Phases or Operation) and making copies of them.

The improved Diagram List view - this now shows the link page and link type and allows you to change them and to change object classes.
In addition it is now possible to view and hide/unhide diagram objects from the List View.
Hidden objects do not appear on diagrams but still generate data.
If a diagram has hidden objects a count of them automatically appears on the diagram. There is also a new special symbol, 'Hidden Symbols' that you can put on a diagram to show a list of them

When using the Descended Objects to create recipe parameters you are now asked whether to make them hidden. This is mainly intended to support things like recipes that can have a large number of parameters that you still want in the data tables.

The improvements with handling large models are mostly speed, large diagrams load much faster and the data build process has been accelerated. Where ControlDraw used to read the records and rebuild all objects when a diagram was opened and then save all the records when the diagram was closed, it now (optionally) only reads and updates on a symbol basis. For large diagrams the improvement is large, a complex diagram with about 200 objects including a large state matrix now loads in under 2 seconds compared with 8 seconds on a 3 yr old PC that is not state of the art.

Pharmaceutical Fermenters

I have recently been looking at ControlDraw models for  large scale Pharmaceutical Fermenter Units from 4 different companies. All are broadly similar
I cannot publish them because because they are confidential, agreements signed!

However I have summarised them using some statistics from the models. (Click to enlarge)

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

ControlDraw verison 3.6.1208 improves Recipe Parameter Handling

This version has greatly improved the Descended Object Linking.

You can use this to establish links between objects, typically Recipe parameters.

For example you can create a link between a Master Recipe parameter on a Cell Level Recipe procedure and the corresponding parameter on the phase that actually deploys the parameter. Then you can using the new Parameter Map show the link and the Unit Procedures and Operations that the parameter has to pass through to get to the phase.

The Parameter Map below show 4 Master Recipe Parameters that are linked via Recipe Procedures and Operations down to phases. (In this example the Uit Procedure level is not used)

You can also use this to create Master Recipe Parameters by looking down the hierarchy and to find all the parameters that the Entire Recipe Procedure uses and then selecting some of them to be Masters.

Improved Hyperlinks to documents and web pages

When you are specifying or designing a system it is generally necessary to keep a collection of documents, such as the P&ID's, Process descriptions and so on. Often these documents can become superseded by a model, but it is always useful to be able to refer back to them, to ensure traceability and to be able to check back. Keeping track of these can be tedious.ControlDraw has long supported simple hyperlinks, provided you had a web or file address on the first line of an object's text. This has been greatly improved recently.
You can now set a Linked Documents Path that is a top level folder that contains all the documents that you want to be able to open from a model.
You can also copy File Names in Explorer and then paste them as hyperlinks.

The Transfer Route Queries

You may not know about this although it has been possible for a long time
If you draw a diagram that shows connections between units via common resources there are standard queries that can show a table of the routes, including those that go from unit to unit (single level) , those that go from onne unit to via another unit to the last unit (2 levels) and those that go from a unit to another via two units (3 levels).
The diagram below show a simple example.
For convenience the single level and two level queries are also shown on this diagram using FAV: UserQuery special objects.