Reliability/Safety 2.5.5 Protection against external electrical influences Connect the control system to the protective earth conduc- tor to eliminate electromagnetic interference. Ensure practi- cal wiring and laying of cables. 2.5.6 Cable routing and wiring Separate laying of power supply circuits, never together with control current loops: Ш DC voltage 60 V ... 400 V Ш AC voltage 25 V ... 400 V Joint laying of control current loops is allowed for:
Ш shielded data signals Ш shielded analogue signals Ш unshielded digital I/O lines Ш unshielded DC voltages Ш unshielded AC voltage 2.5.7 Location of installation Make sure that there are no impediments due to temperatu- res, dirt, impact, vibration and electromagnetic interfe- rence. Temperature Consider heat sources such as general heating of rooms, sunlight, heat accumulation in assembly rooms or control cabinets. 19