September 2007

Great expectations and nothing less 

By Michael Whitt

Whether project execution is internal by plant forces or external by a systems integrator, deliverables need to come about and support the project. 

Here are some we should expect:

I/O list: Given an instrument list and a set of P&IDs, the systems integrator should produce an I/O list that has the computer addresses (both the hardware address and the software address) of each I/O point in the system.  

PLC program: The PLC program should be well organized and modular in design. Documentation should be clear with embedded comments and pertinent symbol names. Everyone should be in agreement as to the naming conventions early in the process.

Network single line: There should be a single-line diagram of the data communications scheme. Addressing information should be at each drop.

HMI: Before beginning work on the HMI, produce a sample screen and operations personnel should review it. Specify naming conventions, symbols, and color schemes early on in the process. On completion of the project, as a part of the documentation process, producing optional HMI screen diagrams is a good idea.

Logic diagram: Before beginning the PLC programming activity, detail the process logic. This can be as a process narrative, or as a set of Scientific Apparatus Maker's Association (SAMA) logic diagrams.

Factory Acceptance Test (FAT): A FAT is an important feature of a properly executed integration project. Prior to shipment, the systems integrator should write a procedure. This procedure should demonstrate compliance with the scope of work and be approved by the customer before its execution. The customer should observe the execution of the procedure and should accept the procedure prior to shipment to the site.

Site Acceptance Test (SAT): Normally, the constructor does electrical continuity checks as the construction process evolves. At some point in this process, after the continuity checks but before the process is wetted, the integration team installs the software on the process computers and begins the checkout phase. An SAT checkout procedure should govern this phase. 

The SAT formalizes the "bump and stroke" process. It is, in fact, the FAT revised to include the expected responses from the field devices. For example, where the FAT might describe a voltage level present at a terminal, the SAT describes the expected effect on the field device. A qualified customer representative should observe and approve each test.

Startup (Commissioning) procedure: Write the startup procedure around process sequences. After the process is wetted and temperatures and pressures are reading properly, systematically "exercise" the facility to demonstrate proper operation through each operating mode, with special attention to emergency modes of operation. Again, the approval of this procedure prior to the commissioning process is important. 

Operations and maintenance (O&M) manual: An O&M manual, or set of manuals, should be produced as a corroborative effort. Often the systems integrator is in the best position to head this effort, as he will have the most information available about the inner workings of the system. Operating procedures may need to come out of the operations department, and the maintenance department may need to provide certain types of maintenance information.

Training manual: Training is a major consideration for the customer. The systems integrator should perform operator and maintenance training prior to commissioning. A training manual, or lesson plan, should be in the hands of the customer for prior approval. The training should at a minimum go over the contents of the O&M manual(s).  




Michael Whitt ( is an ISA Senior Member and the I&C (instrumentation and controls) manager at Mesa Associates. His book is Successful instrumentation and control systems design, ISA Press, 2004.