In relation to getting a machine compliant, a machine builder should look to the experience of the standards. Although not necessarily legally binding, these standards are created from a wealth of experience and technical knowledge. An example of this is considered when looking at:
• Safety Related Control System Design for machines
• General requirements for electrical systems of machines
These 2 principles are considered separately; the easier to comply with is the General Requirements for Electrical systems. For machine builders the key standard here is ANSI NFPA 79 or EN IEC 60204-1. Pilz assesses the machine and the associated electrical panels with the intent of obtaining compliance with this standard. ANSI NFPA 79 or EN IEC 60204-1 looks at the general electrical systems and covers general requirements such as disconnects, cable sizing, over-current protection, colors of wires, colors of pushbuttons and panel lamps, bonding and protection against electric shock.
The 2nd principle of Safety Related Control System Design looks more at the safety control philosophy (rather than the general electrical system design) such as "control reliable” per ANSI and CSA standards, or fault tolerance as described by Categories B,1,2,3 & 4 to EN954-1. As part of this service Pilz analyzes the control architecture and philosophy used by the machine builder to determine its acceptability. This includes an appraisal of the components used in the electrical design to ensure that they have been selected and applied correctly, e.g. compliance with the emergency stop devices to ISO 13850 / EN418 and light curtains to ANSI B11.19, CSA Z432, ISO 13855 / EN999 would be checked.
Using Automation to achieve safety is the most practical and lean way of designing machinery. Safety must now be integrated directly into the machinery design process, meaning that automation products can almost be decided by the process, rather than an individual's preference. Using lean AND safe processes will help add value as the safety system becomes complimentary to production rather than being contradictory. There is a large amount of safety automation now; however the basis for compliance should always be the standards. Integrating these safety automation principles with lean manufacturing concepts is the next challenge facing machinery designers.