The Mitsubishi MELSEC-QS safety programmable controller offers a modern approach to safety by combining a distributed I/O network with the flexibility of a modular controller. It covers an entire production line, bringing the benefits of reduced wiring, rapid diagnostics and easy program modification and maintenance. The MELSEC-QS is compliant with the international safety standards: EN954-1 Category 4, ISO13849-1 PL e, and IEC61508 (JIS C 0508) SIL 3.

The Mitsubishi Electric MELSEC-QS safety programmable controller is an International Safety Standard certified PLC for safety control. When connected with a safety device, such as an emergency stop switch or light curtain, the controller executes safety control by turning the safety output OFF with a user-created sequence program to stop movement toward a source of hazard, such as a robot.

Machine control of robots, conveyors and other equipment is executed with a general-purpose programmable controller in the conventional manner. The difference between the safety programmable controller and general-purpose programmable controller is if the safety programmable controller itself fails, it performs a self-diagnosis to detect the failure and turn the safety output OFF forcibly. This prevents the safety functions from being disabled because of a fault.

Create a distributed safety control system using the CC-Link Safety network or the CC-Link IE Field Network with Safety Communication Functions for large scale systems requiring many safety I/O points.

CC-Link Safety networks

Mitsubishi uses the CC-Link Safety open network that is available both in a fieldbus version and as an Industrial Ethernet field network. CC-Link Safety is an international standard for the safety field network, and has been enacted as the safety communication standard IEC61784-3-8.

CC-Link IE Field Network is an industrial Ethernet field network enabling intelligent manufacturing systems to perform high speed I/O control and distributed control simultaneously. Wiring is over standard Ethernet cables and flexible cabling. Safety information can be shared between two or more safety programmable controllers using “Safety Communication Functions”.

Communications between standard programmable controllers may be performed concurrently with communications between safety programmable controllers.
CC-Link IE Field Network with Safety Communication Functions meets international safety standards IEC61508 SIL3 and IEC61784-3(2010).

GX Developer safety compliant programming software

Programming the MELSEC-QS uses the same GX Developer programming tools already familiar to users of Mitsubishi systems as there are no new techniques to learn or software to buy.

However, a safety system should prevent malfunctions due to user-specified parameter settings or accidental program changes, and GX Developer prevents this with the following additional functions:

– Prevents unauthorized access to safety control programs.

– Login authentication prevents unauthorized users from accessing project files.Prevents unauthorized access to the Safety CPU.

– CPU access password prevents project files from being incorrectly written to the Safety CPU.

Safety Programmable Controller Application example

An application example of the Safety Programmable Controller at a manufacturing facility is introduced in this video movie, and contains an audio explanation in English (8 minutes)