In the 1970s, machine builders began to change the way they wired machines, replacing relays with automatic sequencers – known today as PLC (programmable logic controllers). However, regulators excluded PLCs from playing a role in machine safety. Little attention was paid to safety by end users. Machine builders addressed safety as an afterthought.
Today, however, machine builders and end users are enjoying the benefits of new machine guarding technologies endorsed by international safety standards. From the most sophisticated manufacturing operation, to the simplest relay based system, machine manufacturers and end users now have economical and effective choices to enhance machine safety.