The objective of this Standard is to specify product-specific requirements of AS61508.1-2011, AS61508.2-2011 and AS61508.3-2011 for functional safety programmable logic controllers (FS-PLC) and their associated peripherals. Some aspects do not have a direct correlation with the AS61508 series structure and are addressed somewhat differently. In part, this is due to addressing hardware, software, firmware, etc., in a single document.