Daisy-Chaining Devicemaster Eip-Mod Units With Two Ethernet Ports - Comtrol DeviceMaster EtherNet/IP-Modbus EIP-MOD User Manual

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12.3. Daisy-Chaining DeviceMaster EIP-MOD Units With Two

Ethernet Ports

DeviceMaster EIP-MOD models with two Ethernet ports follow the IEEE specifications for standard Ethernet

topologies.

When using the E1/E2 ports, the DeviceMaster EIP-MOD is classified as a switch. When using the UP port

only, it is a simple end node device.

The maximum number of daisy-chained DeviceMaster EIP-MOD units, and the maximum distance between

units is based on the Ethernet standards and will be determined by your own environment and the conformity

of your network to these standards.

Pepperl+Fuchs Comtrol, Inc. has tested with seven DeviceMaster EIP-MOD units daisy-chained together

using 10 foot CAT5 cables, but this is not the theoretical limit. You may experience a performance hit on the

devices at the end of the chain, so it is recommended that you overload and test for performance in your

environment. The OS and the application may also limit the total number of ports that may be installed.

Following are some quick guidelines and URLs of additional information. Please note that standards and

URLs do change.

•

Ethernet 10BASE-T Rules

The maximum number of repeater hops is four.

You can use Category 3 or 5 twisted-pair 10BASE-T cables.

The maximum length of each cable is 100m (328ft).

Note: Category 3 or 5 twisted pair cables look the same as telephone cables but they are not the same.

The network will not work if telephone cables are used to connect the equipment.

•

Fast Ethernet 100BASE-TX rules

The maximum number of repeater hops is two (for a Class II hub). A Class II hub can be connected

directly to one other Class II Fast Ethernet hub. A Class I hub cannot be connected directly to another

Fast Ethernet hub.

You must use Category 5 twisted-pair 100BASE-TX cables.

The maximum length of each twisted-pair cable is 100m (328ft).

The total length of twisted-pair cabling (across directly connected hubs) must not exceed 205m (672ft).

Note: Category 5 twisted pair cables look the same as telephone cables but they are not the same. The

network will not work if telephone cables are used to connect the equipment.

•

IEEE 802.3 specification: A network using repeaters between communicating stations (PCs) is subject to

the "5-4-3" rule of repeater placement on the network:

Five segments connected on the network.

Four repeaters.

Three segments of the 5 segments can have stations connected. The other two segments must be inter-

repeater link segments with no stations connected.

See

http://www.optronics.gr/Tutorials/ethernet.htm

Additional information may be found at

searching the web.

Chapter 12. Troubleshooting and Technical Support