Reliability, Safety 2.6.4 Protection against External Electrical Influ- ences Connect the control system to the protective earth con- ductor to eliminate electromagnetic interference. Ensure practical wiring and laying of cables. 2.6.5 Cable Routing and Wiring Lay power supply circuits separately, never together with control current loops: ѕ DC voltage 60 V... 400 V ѕ AC voltages 25 V ... 400 V Joint laying of control current loops is allowed for:
ѕ shielded data signals ѕ shielded analogue signals ѕ unshielded digital I/O lines ѕ unshielded DC voltages ѕ unshielded AC voltages 2.6.6 Location of Installation Make sure that there are no impediments due to tem- peratures, dirt, impact, vibration and electromagnetic in- terference. 2.6.6.1 Temperature Consider heat sources such as general heating of rooms, sunlight, heat accumulation in assembly rooms or control cabinets. 2.6.6.2 Dirt Use suitable casings to avoid possible negative influences due to humidity, corrosive gas, liquid or conducting dust. E 327 GB 21 10.06.2003