EPA SM-Ethernet, Руководство пользователя

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SM-Ethernet User Guide
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4.2 Cabling considerations
To ensure long-term reliability it is recommended that any cables used to connect a
system together are tested using a suitable Ethernet cable tester, this is of particular
importance when cables are constructed on site.
4.3 Module grounding
SM-Ethernet is supplied with a grounding tag on the module that should be connected
to the closest possible grounding point using the minimum length of cable. This will
greatly improve the noise immunity of the module.
4.4 SM-Ethernet cable shield connections
Standard Ethernet UTP or STP cables do not require supplementary grounding.
4.5 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.
4.6 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.
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
Table 4.2 Ethernet maximum network lengths
Type Of Cable
Data rate
(bit/s)
Maximum trunk length
(m)
Copper - UTP/STP CAT 5 10M 100
Copper - UTP/STP CAT 5 100M 100
fiber Optic - Multi-mode 10M 2000
fiber Optic - Multi-mode 100M 3000
fiber Optic - Single-mode 10M no standard
fiber Optic - Single-mode 100M 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