Lenze SimpleServo 94, User Manual

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4.2 Shielding and grounding
4.2.1 General guidelines
Lenze recommends the use of single-point grounding (SPG) for panel-mounted
controls. Serial grounding (a “daisy chain”) is not recommended. The SPG for all
enclosures must be tied to earth ground at the same point. The system ground and
equipment grounds for all panel-mounted enclosures must be individually connected
to the SPG for that panel using 14 AWG (2.5 mm
2
) or larger wire.
In order to minimize EMI, the chassis must be grounded to the mounting. Use 14
AWG (2.5 mm
2 ) or larger wire to join the enclosure to earth ground. A lock washer
must be installed between the enclosure and ground terminal. To ensure maximum
contact between the terminal and enclosure, remove paint in a minimum radius of 0.25
in (6 mm) around the screw hole of the enclosure.
Lenze recommends the use of the special SimpleServo cables provided by Lenze. If
you specify cables other than those provided by Lenze, please make sure all cables
are shielded and properly grounded.
It may be necessary to earth ground the shielded cable. Ground the shield at the
SimpleServo end and at the motor end.
If the SimpleServo continues to pick up noise after grounding the shield, it may be
necessary to add an AC line filtering device and/or an output filter (between drive and
servo motor).
4.2.2 EMI Protection
Electromagnetic interference (EMI) is an important concern for users of digital
servo control systems. EMI will cause control systems to behave in unexpected and
sometimes dangerous ways. Therefore, reducing EMI is of primary concern not only
for servo control manufacturers such as Lenze, but the user as well. Proper shielding,
grounding and installation practices are critical to EMI reduction.
4.2.3 Enclosure
The panel in which the SimpleServo is mounted must be made of metal, and must be
grounded using the SPG method outlined above.
Proper wire routing inside the panel is critical; power and logic leads must be routed in
different avenues inside the panel.
You must ensure that the panel contains sufficient clearance around the drive. Refer
to Section 3.2 suggested cooling air clearance.