Innotech Omni C14, Installation Instructions Manual

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Page 57
Omni Installation Instructions
© Mass Electronics Pty Ltd 2017 Chapter 4 – Networking
4-3.3 Ethernet Considerations
Only Cat 6 or Cat 5e cables should be used. Cat 5 Ethernet cabling should NOT be used.
The signal degrades over distance more in lower quality cables, which causes the bandwidth to drop
due to frequent re-transmissions of data.
It is recommended that high quality branded Cat 6 / 5e Ethernet cable is used for your networking
requirements to achieve the best results from your Omni device.
4-3.4 Cable Specifications - RS-485
Innotech recommends the use of cables specifically designed for RS-485 networks. There are many
cables on the market that meet the specifications for RS-485 networks.
Best reliability is achieved through a cable consisting of two individually shielded twisted pairs of low
capacitance. Such cables also provide excellent mechanical strength and lowest electrical resistance,
which is beneficial for maximum length cable runs.
Some CAT6 cable types may also be suitable in certain applications. Care should be taken when using
CAT6 for Primary Networks as they frequently omit shielding. CAT6 cables should be shielded in order
to provide reliable communications.
Any cable that meets or exceeds all the stated specifications is suitable for use:
• 2 twisted pairs
• Minimum conductor cross section AWG24 (0.205 mm
2
)
• Stranded core type is recommended (7 strands of 0.193 mm)
• Conductor Foil screened cable with a wire drain
• Less than 50 pf capacitance per metre between conductors
• Less than 80 pf capacitance per metre between conductors and screen
• Impedance 100 – 120 Ohms
• Sheath thickness 0.8 mm 240 V rated
• Equivalent to the Belden Part #8102
CAT6 STP (Shielded Twisted Pairs), where each pair is individually shielded, are suited for use with multiple
RS-485 communications channels such as the Innotech Primary Comms network. Shielding is required because of
increased pair to pair capacitance, which is the primary culprit for Global/Net channel cross talk.