User's Guide

ThingMagic M3e User Guide
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This appendix details environmental factors that should be considered relating to reader performance and
survivability.
ElectroStatic Discharge (ESD) Considerations
Warning: The ThingMagic M3e antenna port may be susceptible to damage from Electrostatic
Discharge (ESD). Equipment failure can result if the antenna or communication
ports are subjected to ESD. Standard ESD precautions should be taken during
installation to avoid static discharge when handling or making connections to the
ThingMagic M3e reader antenna or communication ports. Environmental analysis
should also be performed to ensure static is not building up on and around the
antennas, possibly causing discharges during operation.
ESD Damage Overview
In ThingMagic M3e-based reader installations where readers have failed without known cause, ESD has
been found to be the most common cause. Failures due to ESD tend to be in the ThingMagic M3e Power
Amplifier (PA) section. PA failures typically manifest themselves at the software interface in the following
ways:
• RF operations (read, write, etc.) respond with Assert - 7F01 - indicating a fatal error. This is typically due
to the module not being able to reach the target power level due to PA damage.
• RF operations (read, write, etc.) respond with No Antenna Connected/Detected even when a known
good antenna is attached.
• Unexpected Invalid Command errors, indicating command not supported, when that command had
worked previously. A command may become unsupported when the reader, during its self-protection
routines, has returned to the bootloader to prevent any further damage. This jump to boot loader caused
by power amp damage occurs at the start of any read tag commands.
Determining that ESD is the root cause of failures is difficult because confirmation is only possible if the
failed components are isolated, taken apart, and examined under high power microscopy. Often,
concluding that ESD was the cause of a failure is inferred if conditions that could produce ESD are present,
anti-ESD precautions have not been taken, and other possible causes are eliminated.
ESD discharges come with a range of values. For many installations, ThingMagic M3e has been
successfully deployed and operating. For a different installation with ThingMagic M3e, a failure problem
from ESD may result in some distribution of ESD intensities occurring. Without knowledge of a limit in the
statistics of those intensities, there may be the bigger charge in the future, For the bare ThingMagic M3e
equipped with the mitigation methods described below, there will be the rogue ESD discharge that exceeds
any given mitigation, and results in failure. Fortunately, many installations have some upper bound on the
value of ESD events given the geometry of that installation.
Several sequential steps are recommended to a) determining the ESD is the likely cause of a given group
of failures, and b) enhance the ThingMagic M3e’s environment to eliminate ESD failures. The steps vary
depending on the required ThingMagic M3e output power in any given application.
Appendix C: Environmental Considerations