ThingMagic Mercury xPRESS, Руководство по платформе, Страница: 16 / 146

A D I V I S I O N O F T R I M B L E
16
Regulatory and Safety Compliance
Common Installation Best Practices
The following are common installation best practices which will ensure the readers isn’t
being unnecessarily exposed to ESD in even low risk environments. These should be
applied to all installations, full power or partial power, ESD or not:
Š
Select an antenna with all radiating elements grounded for DC. The MTI MT-
262031-T(L,R)H-A is such an antenna. The Laird IF900-SF00 and CAF95956 are not
such antennas. The grounding of the antenna elements dissipates static charge
leakage, and provides a high pass characteristic that attenuates discharge events.
Š
V erify R-TNC knurled threaded nuts are tight and stay tight. Don’t use a thread
locking compound that would compromise the grounding connection of the thread to
thread mate. If there is any indication that field vibration might cause the R-TNC to
loosen, apply RTV or other adhesive externally.
Š
Use antenna cables with double shield outer conductors, or even full metallic
shield semirigid cables. ThingMagic specified cables are double shielded and
adequate for most applications. ESD discharge currents flowing ostensibly on the
outer surface of a single shield coaxial cable have been seen to couple to the inside
of coaxial cables, causing ESD failure. Avoid RG-58. Prefer RG-223.
Š
Minimize ground loops in coaxial cable runs to antennas. Having the M6e/Micro
and antenna both tied to ground leads to the possibility of ground currents flowing
along antenna cables. The tendency of these currents to flow is related to the area of
the conceptual surface marked out by the antenna cable and the nearest continuous
ground surface. When this conceptual surface has minimum area, these ground loop
currents are minimized. Routing antenna cables against grounded metallic chassis
parts helps minimize ground loop currents.
Š
Keep the antenna radome (non-metallic cover) in place. It provides significant
ESD protection for the metallic parts of the antenna, and protects the antenna from
performance changes due to environmental accumulation.
Š
Keep careful track of serial numbers, operating life times, and numbers of units
operating. You need this information to know what your mean operating life-time is.
Only with this number will you be able to know if you have a systemic failure problem,
ESD or otherwise. After any given change, you will be able to determine whether
things have improved and whether the failures are confined to one area, or
distributed across your population.