Modular PLC series to enhance safety

In recent years, compliance with international safety standards has become an essential requirement across global markets. In addition, quick recovery from control-system breakdowns has emerged as a common necessity. Many key production applications require full redundancy conforming to the IEC 61508 SIL 2 standard, so critical systems can still operate in case of a failure or accidental damage to the primary CPU unit.

The MELSEC iQ-R redundant pair of PLCs comply with the functionality requirement of this standard, which is certified by TÜV Rheinland to meet global needs. The guidelines within the redundancy standard necessitate a full duplicate PLC rack with all modules, which the primary set will switch-over to instantaneously.

The programming platform, GX Works3 engineering software integrates both process and safety control programming in one environment. This enables the execution of integrated process and safety control programs with a single CPU module, eliminating the time and cost associated with purchasing and installing a separate safety controller.

Process integrity and dependability are the main reasons for plant operators to install redundant automation controllers into their systems, which is why another layer of protection has been added to the basic redundancy architecture of the iQ-R.

The safety version includes a SIL2-process CPU module and a separate SIL2-function module as a set, sitting alongside the power supply module, basic base unit and network module. This ensures continuous operation by switching to standby operation if an error occurs in the control system.