Rockwell Automation 1398-DDM-xxx USE MNL/ULTRA 200 DIG.SERVO.DR - Manual (Page 281)

Publication 1398-5.0 – October 1998
Appendix E
Electromagnetic Compatibility
Guidelines for Machine Design
Appendix E
This appendix provides background information about
Electromagnetic Interference (EMI) and machine design guidelines
for Electromagnetic Compatibility (EMC). The ULTRA 200 Series
installation requirements for compliance to the European
Electromagnetic Compatibility Directive are specified in “European
Union Requirements” on page 2-7. AC Line Filters necessary for
European EMC compliance are listed in Chapter 5, “Installation”.
Perhaps no other subject related to the installation of industrial
electronic equipment is so misunderstood as electrical noise. The
subject is complex and the theory easily fills a book. This section
provides guidelines that can minimize noise problems.
The majority of installations do not exhibit noise problems. However,
the filtering and shielding guidelines are provided as counter
measures. The grounding guidelines provided below are simply good
grounding practices. They should be followed in all installations.
Electrical noise has two characteristics: the generation or emission of
electromagnetic interference (EMI), and response or immunity to
EMI. The degree to which a device does not emit EMI, and is immune
to EMI is called the device’s Electromagnetic Compatibility (EMC).
Figure E.1 shows the commonly used EMI model. The model consists
of an EMI source, a coupling mechanism and an EMI victim. Devices
such as servo drives and computers, which contain switching power
supplies and microprocessors, are EMI sources. The mechanisms for
the coupling of energy between the source and victim are conduction
and radiation. Victim equipment can be any electromagnetic device
that is adversely affected by the EMI coupled to it.
Immunity to EMI is primarily determined by equipment design, but
how you wire and ground the device is also critical to achieving EMI
immunity. Therefore, it is important to select equipment that has been
designed and tested for industrial environments. The EMI standards
for industrial equipment include the EN61000-4 series (IEC 1000-4
and IEC801), EN55011 (LISDR11), ANSI C62 and C63 and MIL-
STD-461. Also, in industrial environments, you should use encoders
with differential driver outputs rather than single ended outputs, and
digital inputs/outputs with electrical isolation, such as those provided
with optocouplers.