Industrial Automation Wiring and Grounding Guidelines
E115P
8
Some products have no visible groundable chassis and
no ground lug or ground terminal, but mount on a DIN rail.
The chassis of these products are grounded only through
the DIN rail. For these products, connect an equipment-
grounding conductor directly from the mounting bolt on
the DIN rail to an individual bolt on the ground bus.
Grounding-Electrode Conductor —
Connect the ground
bus to the grounding-electrode system through a
grounding-electrode conductor. The grounding-electrode
system is at earth-ground potential and is the central
ground for all electrical equipment and AC power within
any facility. Use 8 AWG copper wire minimum for the
grounding-electrode conductor to help guard against EMI.
The National Electrical Code specifies safety requirements
for the grounding-electrode conductor.
Shielded Cables —
Certain I/O connections require
shielded cables to help reduce the effects of electrical
noise coupling. Ground each shield at one end only. A
shield grounded at both ends forms a ground loop which
can cause a processor to fault.
Ground each shield at the end specified in the appropriate
publication for the product. Never connect a shield to the
common side of a logic circuit (this would introduce noise
into the logic circuit). Connect each shield directly to a
chassis ground.
For some communication network cables, the shield
connections are unique to the particular cabling system.
In some such cases, a DC short to ground is not needed
because a low-impedance AC path to ground and a high-
impedance DC path to ground are provided internally at
each node. Follow the specific instructions in the
publication provided for the specific communication
network cabling system.
Avoid breaking shields at junction boxes. Many types of
connectors for shielded conductors are available from
various manufacturers. If you do break a shield at a
junction box, do the following:
• Connect only category-2 conductors in the junction box.
• Do not strip the shield back any further than necessary
to make a connection.
• Connect the shields of the two cable segments to
ensure continuity along the entire length of the cable.
Summary of Contents for H Series
Page 135: ...DeviceNet Media Design and Installation Guide...
Page 144: ...Publication DNET UM072C EN P July 2004 Table of Contents iv...
Page 170: ...Publication DNET UM072C EN P July 2004 1 26 Get Started Notes...
Page 194: ...Publication DNET UM072C EN P July 2004 2 24 Identify Cable System Components Notes...
Page 212: ...Publication DNET UM072C EN P July 2004 3 18 Make Cable Connections Notes...
Page 238: ...Publication DNET UM072C EN P July 2004 4 26 Determine Power Requirements Notes...
Page 248: ...Publication DNET UM072C EN P July 2004 5 10 Correct and Prevent Network Problems Notes...
Page 250: ...Publication DNET UM072C EN P July 2004 A 2 Understand Select NEC Topics Notes...
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Page 267: ...Isysnet Serial Bus System Selection Guide Pneumatic...
Page 287: ...H Series Fieldbus DeviceNet Adapters PSSCDM12A PSSCDM18PA User Manual...