Developments In Marshalling Of Electrical Signals

Louise Smyth

Processing plants worldwide are under increased pressure to operate more efficiently and make cost savings. One area that is often overlooked is marshalling of electrical signals, but this is where huge improvements to operations and maintenance, and ultimately the bottom line, can be made.

What Is Marshalling?

Marshalling can be defined as the grouping of inputs and outputs (I/O). It enables diverse operating systems to interact, and it encompasses a wide range of requirements: including intrinsic safety (IS) isolation, signal conditioning, relay interfaces, surge protection and cable terminations, often including loop disconnects.

However, marshalling is also a neglected area of system design that has historically lacked an overall vision for future development. This is a challenge that Eaton, as an expert in reliability, efficiency and safety of electrical products, has been keen to address.

Marshalling Challenges & Complexities

It can be a real challenge for process engineers to know what their exact marshalling requirements may be in a few years’ time: because the site grows, projects evolve and customer priorities change. Marshalling system flexibility is therefore paramount to prevent delays from changes (and associated cost increases) in project specification.

Complex Wiring

Traditionally there may be up to five separate cabinets for the different marshalling functions, with complex wiring between the marshalling components: up to eight interconnections per channel. This creates a complex wiring structure and is a major source of faults and downtime.

Multiple Components From Multiple Suppliers

Another major source of complexity is multiple components from multiple suppliers. A traditional marshalling solution with IS typically involves 20 different component types. During later design stages the component type often needs to be amended, which results in changes to the Bill of Materials that are long and complex. Additionally, late changes make it difficult for end users to maintain the marshalling system and control lifetime costs.

Space Requirements

Space requirements are also a key challenge – particularly in oil & gas processing – and marshalling systems can become increasingly unwieldy as further cabinets are added in response to post-installation changes.

Clearly, it is time for a new solution that facilitates a standard design for all marshalling requirements, that is compact and space-saving, while at the same time is simple to install and maintain. Furthermore, any new marshalling solution should be easy to reconfigure and have minimal impact on project and whole life cost.

Introducing Smart Universal Marshalling

Eaton has applied its industry knowledge and technical expertise to develop a new solution that offers the simplification and standardisation that customers are seeking, with no compromise on functionality.

What Is Smart Universal Marshalling (SUM)?

Smart Universal Marshalling (SUM) is a modular approach that enables the five key marshalling requirements to be achieved using a single cabinet design. Eaton calls its solution MTL SUM5.

Everything In One Unit

Benefits for process engineers are considerable. Firstly, all the marshalling functions are in one unit, so there is no longer any requirement for complex, hard-wired interconnections – eliminating the risk, downtime and associated costs that arise from wiring faults. The configurable design accommodates late changes, reducing risk during project execution. It also ensures that the system is adaptable over time, without major rewiring or the need for cumbersome ‘bolt-on’ equipment.

Component Reduction

SUM typically reduces the number of marshalling components by 65% compared to a standard solution. For example, on a project with 4,500 I/O small changes in the number of each I/O type results in the Bill of Materials for the traditional solution required 4,651 changes. The Bill of Materials for the same project using MTL SUM5 would require only 115 changes.

Plug And Play

The modular ‘plug and play’ approach makes maintenance simpler. Fewer component types mean fewer spare parts need to be held in stock. With MTL SUM5, configuration information is held in the terminal, so a module can be changed out without the need for reprogramming.

Modular Design

The modular design approach eliminates some components altogether and makes others more compact, so there is typically a 30-50% saving in the number of marshalling cabinets required. This in turn means there is potential to reduce the overall size of control rooms – freeing more room for production.

Fit For Purpose Marshalling

SUM addresses concerns regarding the costs and complexities associated with traditional marshalling systems. It makes life easier for busy process engineers by significantly reducing the number of components required and totally eliminates the need for complex wiring.

This in turn delivers advantages that include a reduced Bill of Materials, simplified installation and maintenance, and the ability to adapt rapidly to change. In short, it makes marshalling fit for purpose in an automated, connected world.

Roger Highton is with Eaton