$SSHQGL[
S7-300 Automation System, Hardware and Installation: CPU 31xC and CPU 31x
12-12
A5E00105492-03
6KLHOGLQJRI&DEOHV
3XUSRVHRIWKHVKLHOGLQJ
A cable is shielded to attenuate the effects of magnetic, electrical and
electromagnetic interference on the cable.
2SHUDWLQJSULQFLSOH
Interference currents on cable shielding is diverted to ground conductive
interconnection between the shielding and the cabinet. To avoid interference as a
result of these currents, it is imperative to provide a low-impedance connection to
the protective conductor.
6XLWDEOHFDEOHV
Whenever possible, use cables equipped with a shielding braid. Shielding density
should be at least 80%. Avoid cables with film shielding, because the film can be
easily damaged by tensile or pressure stress, thus reducing its shielding effect.
+DQGOLQJRIWKHVKLHOGLQJ
Note the following points on handling the shielding:
•
Always use metal clamps to mount shielding braid. The clamps must contact a
large area of the shielding and provide appropriate contact force.
•
Directly behind the cabinet's cable entry, terminate the shielding on a shielding
bus. Then, route the cable to the module; however, do not connect the shielding
once again to ground in this place.
•
In installations outside of cabinets (e.g. for wall-mounting) you can also
terminate the shielding on a cable duct.
Содержание CPU 312
Страница 10: ... RQWHQWV S7 300 Automation System Hardware and Installation CPU 31xC and CPU 31x x A5E00105492 03 ...
Страница 76: ... RQILJXULQJ S7 300 Automation System Hardware and Installation CPU 31xC and CPU 31x 5 50 A5E00105492 03 ...
Страница 146: ... RPPLVVLRQLQJ S7 300 Automation System Hardware and Installation CPU 31xC and CPU 31x 9 34 A5E00105492 03 ...
Страница 232: ... ORVVDU S7 300 Automation System Hardware and Installation CPU 31xC and CPU 31x 13 16 A5E00105492 03 ...