User Manual

ThingMagic Nano User Guide 62
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Raising the ESD Threshold
For applications where full ThingMagic Nano power is needed for maximum tag read range and ESD is
suspected, the following components are recommended additions to the installation to raise the level of
ESD the reader can tolerate:
• Select or change to an antenna with all radiating elements grounded for DC. The MTI MT-262031-
T(L,R)H-A is recommended. The Laird IF900-SF00 and CAF95956 are not recommended. The
grounding of the antenna elements dissipates static charge leakage, and provides a high pass
characteristic that attenuates discharge events. (This also makes the antenna compatible with the
ThingMagic Nano antenna detect methods.)
• Install a Minicircuit SHP600+ high pass filter in the cable run at the ThingMagic Nano end. This additional
component will reduce transmit power by 0.4 dB which may affect read range in some critical
applications. However the filter will significantly attenuate discharges and improve the ThingMagic Nano
ESD survival level.
• 90 V lightning arrestors, such as the Terrawave Solutions Model TW-LP-RPTNC-PBHJ have been
shown to be effective in suppressing ESD. This model contains a gas discharge tube which must be
replaced periodically.
• Install a Diode Clamp* circuit immediately outboard from the SHP600 filter. This will reduce transmit
power by an additional 0.4 dB, but in combination with the SHP600 will further improve the ThingMagic
Nano ESD survival level. Contact [e-mail] for details.
Further ESD Protection for Reduced RF Power Applications
In addition to the protective measures recommended above, for applications where reduced ThingMagic
Nano RF power is acceptable and ESD is suspected, the following protective measures can also be
applied:
• Install a half watt attenuator with a decibel value of +27 dBm minus the dBm value needed for tag power
up. Then run the reader at +27 dBm instead of reduced transmit power. This will attenuate inbound ESD
pulses by the installed decibel value while keeping the tag operation generally unchanged. Note that the
receive sensitivity will be reduced by this same amount. Position the attenuator as close to the
ThingMagic Nano as feasible.
• As described above, add the SHP600 filter immediately adjacent to the attenuator, on the antenna side.
• If required, add Diode Clamp adjacent to the SHP600, on the antenna side.
Variables Affecting Performance
Environmental
Reader performance may be affected by the following environmental conditions:
• Metal surfaces such as desks, filing cabinets, bookshelves, and wastebaskets may enhance or degrade
reader performance.
• Antennas should be mounted far away from metal surfaces that may adversely affect the system
performance.
• Devices that operate at 900 MHz, such as cordless phones and wireless LANs, can degrade reader
performance. The reader may also adversely affect the performance of these 900 MHz devices.
• Moving machinery can interfere with the reader performance. Test reader performance with moving
machinery turned off.