In the past few years, we have seen changes to the scope and nature of our controls projects. What used to be a landscape of Greenfield projects has evolved into smaller process additions and the upgrading of legacy control systems. These systems are upgraded for many different reasons, and the solutions that are available for doing this work are just as varied. So, how can you determine what can or should be done? Let’s start with asking why.
Why does the system need to be upgraded? One reason control systems are upgraded is obsolescence of hardware. Some manufacturers are not able to get the components they need to build legacy modules, and hardware lines are being discontinued. This makes it increasingly difficult for plants to find the replacement components they need to keep their facilities functioning correctly. Another common situation is that the current hardware and/or software is failing and no longer reliable, causing downtime.
To determine the best path for upgrading a control system and its hardware, design teams and customers must address some specific questions:How much time is there to perform an upgrade?
- How much time is there to perform an upgrade?
- What is the overall scope of hardware?
For some types of hardware, there are conversion solutions available to speed the process of upgrading and minimize downtime; we refer to this as a hardware conversion. Conversions require additional hardware, as well as extra time and planning to design and procure the necessary components. Conversion hardware may or may not fit in an existing panel space and may not be available for every hardware type. In these instances, the project team needs to remove old hardware and replace it with the new hardware, or “rip and replace.” This method is more time consuming and likely to require longer downtime, but it does not require the additional conversion hardware. Knowing not only what needs to be done but also how will determine the time needed for the solution.
Design teams investigate the latest technologies and what changes need to be done to implement them when looking into hardware solutions. New technologies such as HART-enabled analog I/O modules can leverage increased capabilities in either existing or new instruments. Ethernet communications allow current technologies to be used but may require cabling installations, in addition to new networking hardware, to be implemented.
Once upgraded, either by conversion or “rip and replace”, one of the benefits a customer can realize is updated documentation for the control system. Documentation can be done on a basic level to support the upgrade or to an extended level where each motor and device that connects to the control system is documented with a drawing.
There are many options to consider when determining how best to upgrade a control system, and there is no one-size-fits-all answer. Ultimately, considering why the upgrade is needed, how much time you have, and the scope of your hardware will help you and your design team find the smartest solution.