User guide

10 MDX-ETHERNET User Guide
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4.3 MDX-ETHERNET cable shield connections
Standard Ethernet UTP or STP cables do not require supplementary grounding.
4.4 Cable
It is recommended that a minimum specification of CAT5e is installed on new
installations, as this gives a good cost/performance ratio. If you are using existing
cabling this may limit the maximum data rate depending on the cable ratings. In noisy
environments the use of STP or fiber optic cable will offer additional noise immunity.
4.5 Maximum network length
The main restriction imposed on Ethernet cabling is the length of a single segment of
cable as detailed in Table 4.2. If distances greater than this are required it may be
possible to extend the network with additional switches or by using a fiber optic
converter.
Table 4.2 Ethernet maximum network lengths
4.6 Minimum node to node cable length
There is no minimum length of cable recommended in the Ethernet standards for UTP
or STP. For consistency across fieldbus modules, LEROY-SOMER recommends a
minimum network device to device distance of 1 metre of cable. This minimum length
helps to ensure good bend radii on cables and avoids unnecessary strain on
connectors.
Cabling issues are the single biggest cause of network down-time. Ensure cabling is
correctly routed, wiring is correct, connectors are correctly installed and any switches or
routers used are rated for industrial use. Office grade Ethernet equipment does not
generally offer the same degree of noise immunity as equipment intended for industrial
use.
NOTE
Type of cable
Data rate
(bit/s)
Maximum trunk length
(m)
Copper - UTP/STP CAT 5 10 M 100
Cooper - UTP/STP CAT 5 100 M 100
Fiber optic - Multi mode 10 M 2000
Fiber optic - Multi mode 100 M 3000
Fiber optic - Single mode 10 M No standard
Fiber optic - Single mode 100 M Up to 100000
The distances specified are absolute recommended maximums for reliable
transmission of data. The distances for the fiber optic sections will be dependent on the
equipment used on the network. The use of wireless networking products is not
recommended for control systems, as performance may be affected by many external
influences.
NOTE