Fagor DDS Series Hardware Manual page 269

8.2 Inductive components
Installing the DDS system requires certain precautions regarding the
connection of the inductive components such as contactors, relays,
electrovalves, motor brakes or, in general, any type of coil.
Hence:
 All inductive circuits or components must have their own interference
suppressor that must be installed as close as possible to the inductive
component.
 The mentioned interference suppressors will be RC circuits, varystors or
suppressor diodes.
MANDATORY. Do not use fly diodes as interference suppression elements
for inductive components. These diodes can only serve as interference
suppressor of the inductance due to the cabling itself.
 The excitation cables of the inductive components and the signal cables
must not run in the same channel especially when not using shielded
cables for these signals. A typical scenario is when using inductive
proximity switches or similar usually connected with an unshielded
cable.
 In extreme situations and if the sensors used on the machine are very
sensitive to the interference conducted through the supply cables (24 V
DC), it may be necessary to isolate or decouple them from that of the
supply of the system elements (inductive components, drives, etc.).
   Installation
8.
DDS
HARDWARE
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