A Series Transition Centre

Mitsubishi Electric is planning a transition from the MELSEC A-Series PLC product families (10" rack height) to the Q Series Automation Platform. This is planned to be completed by September 2006. IMPORTANT: The compact MELSEC AnSH and QnAS(H) PLC Series are not affected by this announcement.  Their full availability will continue for the foreseeable future (until at least 2010).

Q Series PLC from Mitsubishi Electric[Note: Throughout the ASTC and associated materials, "A Series" is used to mean all An, AnN, AnA, AnU, QnA CPUs and all associated racks, power supplies, I/O, special function and network modules, and related peripherals.]

The full-size (10" rack height) A Series was introduced in 1985. It has provided 20 years of service and will continue to serve reliably for many customers. However, the transition to the Q Series is being driven by environmental (RoHS Directive) and supply (obsolescence of parts) reasons as follows:


  • Mitsubishi Electric is committed globally to conducting its businesses in an environmentally responsible manner. Along with this, the European Union has enacted the Restriction of Hazardous Substances Directive ("RoHS"). This will take effect in July 2006, and has had global influence for all electrical and electronic equipment manufacturers. RoHS places strict limitations on the levels of toxic materials such as lead, cadmium and other substances that can be used in electronic devices.
  • Since many A Series products were introduced years before the RoHS Directive was even considered, it would require an extensive re-design of much of the product line to make it RoHS compliant. Since the A Series has been surpassed by the AnSH and Q Series lines, it does not make economic sense to embark on a development project of this nature at this point in the product lifecycle. Committing this level of resources to such a project would limit continuing product development on our current lines such as the Q Series, and hence potentially limit future development of current systems.

Parts supply

  • Many A Series products were designed with components that have long ceased to be available. Mitsubishi has continually mitigated this through periodic redesigns of specific products to accommodate newer parts. We have also stockpiled key components to extend the lifetime of the most popular A Series products. However, these measures cannot guarantee an indefinite lifespan, and we are now beginning to experience increasingly severe difficulties with component supply. Hence many products now face a short life expectancy.

Users of the A & QnA Series should begin to plan for this transition.  Mitsubishi will offer various options including continued short term A/QnA-Series use, integration of newer products to existing installations, and comprehensive conversion to newer products. 

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