Omron SYSMAC CJ1W-EIP21, Operation Manuals

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2 Installing Ethernet Networks
CJ-series EtherNet/IP Units Operation Manual for NJ-series CPU Unit (W495)
2-4 Ne
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2-4-3 Preca
utions
• Do not lay the twisted-pair cable in locations subject to excessive dirt and dust or to oil mist or other
contaminants.
• Do not ground the Ethernet switch in the same location as a drive-system component, such as an
inverter.
• Always use a dedicated power supply for the Ethernet switch’s power supply. Do not use the same
power supply for other equipment, such as an I/O power supply, motor power supply, or control power
supply.
• Before installation, check the Ethernet switch’s environmental resistance specifications, and use an
Ethernet switch that is appropriate for the ambient conditions. Contact the Ethernet switch manufac-
turer for details on Ethernet switch’s environmental resistance specifications.
• Connect two Ethernet switches to each other as follows:
Connect an MDI port to an MDI-X port with a straight cable.
Connect two MDI ports or two MDI-X ports with a cross cable.
Note It is very difficult to distinguish cross cables and straight cables by appearance. Incorrect cables will cause
communications to fail. We recommend cascade connections with straight cables whenever possible.
• Some Ethernet switches can automatically distinguish between MDI and MDI-X. When this kind of
Ethernet switch is used, straight cable can be used between Ethernet switches.
Precautions for Correct Use Precautions for Correct Use
Adjust the EtherNet/IP Unit’s link settings to match the communications settings of the con-
nected Ethernet switch. If the settings do not match, the link will be unstable and prevent normal
communications. The following table shows the allowed settings for each Ethernet switch com-
munications mode. (Auto-Nego: Auto negotiation, Full: Full duplex, Half: Half duplex)
Best = Recommended; OK = Allowed; --- = Not allowed.
Ethernet Switch Installation Environment Precautions
Ethernet Switch Connection Methods
Ethernet switch
EtherNet/IP Unit
Auto-
Nego
10 Mbps (fixed) 100 Mbps (fixed)
Full Half Full Half
Auto-Nego Best --- OK --- OK
10 Mbps (fixed) Full --- OK --- --- ---
Half OK --- OK --- ---
100 Mbps (fixed) Full --- --- --- Best ---
Half OK --- --- --- OK
Cross cable
Straight cable
Ethernet
switch
Ethernet switch
MDI port
MDI-X port (cross)
Ethernet
switch
Ethernet
switch