Safety Mechanisms for Electro-Pneumatic Controls

Hazards and Protective Mechanisms

Safe operation of electro-pneumatic controls requires extensive safety mechanisms.

Hazards due to moving Machine and Plant Components

One major cause of danger is posed by moving machine and plant components such as cylinders, grippers, shafts, presses etc. In a pneumatic press, for example, it is necessary to ensure that no part of the operator's body (such as fingers) can become trapped in the machine. The following list summarises the relevant protective measures.

Protection via encapsulation or protective covering Protective cage Protective grilles   Protection via controls and indicators Warning and indicator lights Emergency shut-off switch Two-handed safety controls (requiring the operator to use both hands)   Protection internal to the signal processing procedure Protection against unauthorised starting Priming procedure   Hazards due to Electrical Power An important source of danger is posed by the elect4rical current flowing through components such as power supplies, sensors, directional control valves etc. The respective safety regulations are laid out in specifications for protection of high-voltage equipment (e.g. DIN VDE 0100) or electrical wiring and safety for machines (e.g. DIN/EN 60204). The following list summarises the most important protective measures.   Protection  for excess contact voltage Safety extra-low voltage Earthing Housings or covers Sufficient safety perimeter   Protection during maintenance and repair work Main switch (with separate locking mechanism)   Protection of electrical components against environmental influences Protection against water and damp Protection against dust and foreign matter