Estun E21 - Page 38

E21 Installation Manual
35
Coupling mode
Cause
Typical cases
Inductive
coupling
Changing current flows
through current loop.
Transformer;
Contactor and relay pull-in or disconnect;
High frequency signal cable, etc.
Radio frequency
coupling
Space electromagnetic field
makes guide line generate
induced voltage current.
-
Measures to ensure electromagnetic compatibility
 Low resistance grounding: make sure uncharged metal parts (such as enclosure,
shield layer) are ground well. Earth conductor connects to grounding bar inside
cabinet. Grounding bar shall connect the ground by low resistance, anti-corrosion
and make sure good electrical conductivity;
 Cabling in correct way
- Cables must be sorted: high-tension line, power line, encoder cable, and signal
line (such as input and output cable).
- Cables of different kinds shall lie separately and keep distance to the greatest
extent, high-tension line in particular. Do not lie together with power line,
encoder cable and signal line.
- Encoder cable shall be kept away from power line and signal line to the largest
extent.
 Connect to shield layer correctly
- Encoder cable shall have shield layer. Both ends of shield layer must connect
to protective ground.
- Connected area of shield layer and protective ground shall be as low as
possible. Do not twist the shield layer into a rope. Connect to protective
ground.
- The smaller resistance between shield layer and protective ground, the better.
 Other requirement
- Inductive load, frequency converter and servo driver inside the cabinet shall be
kept away from power line, encoder cable and signal line.
- Earth potential difference between different equipment is the smaller the better,
theoretically, zero is the best.