Omron SYSMAC CJ1W-EIP21 - Manual (Page 68)

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Network Installation Section 3-4
• Press the cable connector in firmly until it locks into place at both the
switching hub and the EtherNet/IP Unit.
• Do not lay the twisted-pair cable together with high-voltage lines.
• Do not lay the twisted-pair cable near devices that generate noise.
• Do not lay the twisted-pair cable in locations subject to high temperatures
or high humidity.
• Do not lay the twisted-pair cable in locations subject to excessive dirt and
dust or to oil mist or other contaminants.
Switching Hub Installation Environment Precautions
• Do not ground the switching hub in the same location as a drive-system
component such as an inverter.
• Always use a dedicated power supply for the switching hub’s power sup-
ply. Do not use the same power supply used for other equipment, such as
an I/O power supply, motor power supply, or control power supply.
• Before installation, check the switching hub’s environment-resistance
specifications, and use a switching hub appropriate for the ambient condi-
tions. Contact the switching hub manufacturer for details on switching
hub’s environment-resistance specifications.
Switching Hub Connection Methods
Connect two hubs to each other as follows: Connect an MDI port to an MDI-X
port with a straight cable; connect two MDI ports with a cross cable; and
connect two MDI-X ports with a cross cable.
Note It is very difficult to distinguish cross cables and straight cables by appear-
ance. Incorrect cables will cause communications to fail. We recommend
using cascade connections with straight cables whenever possible.
Some switching hubs can automatically distinguish between MDI and MDI-X.
When this kind of switching hub is being used, straight cable can be used
between switching hubs.
Note Adjust the link settings of the EtherNet/IP Unit or built-in EtherNet/IP port to
match the communications settings of the connected switching hub. If the set-
tings do not match, the link will become unstable and prevent normal commu-
nications. The following table shows the allowed settings for each switching
hub communications mode.
MDI-X port
(cross)
Switching
Hub
Switching
Hub
Switching
Hub
Straight cable
Cross cable
Switching
Hub
MDI ports
Switching hub setting EtherNet/IP Unit setting
Auto-
negotiation
10 Mbps (fixed) 100 Mbps (fixed)
Full
duplex
Half
duplex
Full
duplex
Half
duplex
Auto-negotiation Best --- OK --- OK
10 Mbps
(fixed) Full duplex --- OK --- --- ---
Half duplex OK --- OK --- ---