October 2007

Keeping it all between the lines

By Michael Whitt

Many times, the customer has knowledgeable control system professionals on staff. 

These personnel make process adjustments, conduct training, perform maintenance corrections, provide trouble- shooting services, and so on. 

Sometimes, however, this staff is not capable of handling the large capital projects in addition to their day-to-day duties. This is where the systems integrator steps in. 

Systems integrators are, largely, external contractors who are hired to provide programming and integration services. Sometimes they are individuals hired on an hourly basis to perform on-site changes under close supervision. Other times, a team of systems integrators works off-site to execute a turnkey project. 

How should a manufacturer handle a systems integrator? What services should a systems integrator be able to offer, and what controls should be in place to ensure a successful project?

Beating the bushes

Finding the right integrator is key. The first step is to determine the type of service one needs. There are three primary categories for integration services. 

Staff augmentation service: This service is to fill a short-term labor problem. The staff augmenter usually works closely with a member of the customer's organization who provides close supervision in the performance of maintenance upgrades, production modifications, minor process revisions, and the like. 

Turnkey service: This integration team is off-site and largely unknown to the customer's organization. The execution of the project takes place offsite, and the integration team sends one or more representatives to assist in start-up and training. An integration team usually wins the job contract because of its familiarity with the equipment, its low bid, or some combination of the two. Of minimal importance to the customer is the anticipation of a long-term relationship. 

General integration service: This integrator needs to be in close proximity to the site and needs to demonstrate a desire to maintain a long-term relationship. This integrator must be in a position to provide rapid support on call and needs to have the capability of learning the entire plant operation. 

Developing scope and flow

A systems integration project follows a predictable pattern as follows: 

Like any discipline, the systems integration team must develop a scope of work, a budget, and a schedule. Then a control system specification is developed and issued. 

Many times, the first deliverable is a control network single-line diagram. This shows all the major control system components and how they are interconnected. 

PLC programming and operator interface programming happen in parallel most of the time. Deliverables, other than the software, include SAMA (Scientific Apparatus Manufacturers Association) logic diagrams, screen diagrams, and an operations and maintenance manual.

A factory acceptance test (FAT) is good practice if the programming is taking place offsite. This gives the customer an opportunity to have input and the integrator a clinical environment in which to demonstrate scope compliance. A formal FAT procedure should be ready and acceptable to both parties ahead of time.

A site acceptance test (SAT) should be performed on-site. This is sometimes called the checkout or the "bump and stroke." Whatever the nomenclature, a procedure or checklist should be a part of the process to make sure everything is proper and verifiable before "wetting," or commissioning, the process. The customer should have someone observe this process and sign off confirming each item in progression. During this period, training of the operators and maintenance team should be ongoing.

Commissioning should occur only after a successful comprehensive SAT. Upon completion of a commissioning process, the plant should be on-line, up to temperature and pressure, and producing material.



Michael Whitt (mwhitt@mesainc.com) 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.