Monday, April 9, 2001
Chicago—Today's Ethernet promises big benefits across all
levels of industrial control. But one major question remains for automation and
control engineers. Can standard RJ45 connectors and CAT5 cables, designed for
the front office, survive out back on the factory floor?
Fact is, at least three companies don't think so. At least, not
when it comes to taking Ethernet components out of the protective confines of
the enclosure (IP20 or less), and putting them in the harsh (IP67 or greater),
dirt-filled reality of shock, vibration, moisture, and extreme temperature.
That's why in a joint press briefing at National Manufacturing
Week last month, Lumberg, Commscope, and Interlink BT announced a ruggedized
Industrial Ethernet field-interface solution that's really ready for the plant
The system supports legacy RJ45 connectors within protected
environments. However, etherMATE™ RJ45-M12 bulkhead receptacles from Lumberg (www.lumbergusa.com) seamlessly convert the
RJ45 connectors inside the enclosure to the tried and proven threaded M12 form
factor outside of the cabinet.
Connector cordsets and patch cords tie everything together with
shielded and braided ICAT5e cable. The new industrial-grade cable was
specifically developed by Commscope (www.commscope.com) to handle different
combinations of noise and flex that are found in the heavy industrial
To complete the new industrial Ethernet solution, Interlink BT (www.interlinkbt.com) talked about its
industrially hardened Ethernet switches, routers, and hubs, and how they will
provide completely enclosure-less Ethernet connectivity to reduce cabinet real
estate on the machine, decrease maintenance, and simplify installation.
Given Ethernet's momentum today, about the only thing that could
stop it dead in its tracks is the sour taste of factory-floor failures in the
mouths of automation and control engineers. Radiographic inspections indicate
that the RJ45 connector just isn't up to the task of implementing Ethernet on
physical field devices, according to Sundar Balu, product manager industrial
automation products at Lumberg.
"I have absolutely no faith in the reliability of RJ45 connectors
outside of the electrical enclosure," he explains. "The snap-fit design gives no
control over the insertion and pullout forces, and its thin contact area is
susceptible shock and vibration." In contrast, the M12's threaded housing
provides a secure fit, and contact size and material can be easily altered for
"M12 offers excellent protection against moisture buildup, dust,
corrosion, EMI/RFI, vibrations, and shock," says Balu. "And it doesn't create
any new implications for the existing environment where people are already using
RJ45 inside of a cabinet."