Safety Instrumented Systems (SIS) is not a new concept. It has long been the practice to fit protective systems to industrial process plants wherever there is a potential threat to life or the environment if something should go wrong. What is new is that IEC61508 now provides guidelines for achieving an adequate Safety Integrity Level (SIL) for systems, sub-systems and components.
The new MTL4000-SR, MTL5000-SR and MTL4840 HART®-SR products come with certified reliability data, giving the safety system designer a known quantity around which to design. The SR-Series Isolators cover Digital Input (DI), Digital Output (DO) and Analogue Input (AI) functions. These SR labelled products are supplied with the knowledge that their integrity will be maintained during the life of the product. Any changes to standard versions will not compromise the certified characteristics of these products as they will be maintained as individual products.
In addition to the certified products, MTL have all other products in the MTL4000 and MTL5000 ranges assessed to the IEC61508 standard. These have been third-party assessed by Exida and the reports can be viewed, along with the SR certification.