Integrated staging is the process of checking to see if the control
system works as you want. As the system is staged, problems are uncovered in design
philosophy, in documentation, in equipment operation and in many other areas. You can use
the process itself to do this, or you can use a simulation of it. MEL's simulation tools
allow you to see how you process will operate real time in a dynamic environment before
you go to the field. Once there, you'll know with confidence that any problems that
surface are related to the equipment in the facility ( i.e. cables) and not with the
MEL's simulation models are typically built from completed PFDs, P&ID's and device specifications and other documents. The same equipment names, numbers, and P&ID numbers are used for identification to make it easy to go back and forth from model to documentation.
The initial model is built using simulated controls (from the MEL controls library) to tune and verify the model operation against specifications. Once the model operation is validated they will be replaced with control system communication objects. These will be tagged based on the plant tagging convention, and cross references are automatically provided. This cross-reference tag list will then be used to fill in the tagged communication objects with the specific control system I/O dialog items. This allows the simulation to be built before the control system configuration has been completed, thus allowing testing to begin as soon as configuration is done.
The documentation to be verified is the I/O list, the P&ID's, control system graphics, and logic diagrams. The control system configuration and operation is checked against each of these documents. As each point and control loop is verified it is checked off in the control system documentation. Configuration problems are corrected as checkout progresses and the documentation/design is changed as needed.
By using MELs dynamic simulator for staging the problems are found in the test area, not in the field on the process itself. This saves time, money and is less dangerous and potentially harmful than testing on a live system.