Avery Dennison RFID - Manual (Page 17)

HowToRFID
Revision: 13 Date: 31 August 2009
Page 17 of 53
Limitations of this test
The built-in hotspot-/profile test was designed to be a customer self-care instrument. It can not completely replace
the advanced and more detailed tests made during the inlay qualification process done by Avery Dennison. If
published printer settings are available for a specific inlay, it’s highly recommend to use that settings before making
several trials with self determined settings. During the inlay qualification process a lot more inlays are tested to
intercept possible performance decreases from placement and sensitivity tolerances. A test with a single RFID
label can never provide that level of reliability…
The following limitations apply:
1) The test can not determine write zones (sensitive zones) located before or after the label itself. For very short
labels where the inlay is located near top of label and / or near the end of the label (for example pure paper
faced inlays), the sensitive zones might be located in before or after the inlay.
2) The test can not determine whether crosstalk effects have an influence. Crosstalk effects: while trying to write
to the inlay nearest the printer’s antenna, the radio energy is reflected or otherwise forwarded to the adjacent
inlays (on the web) and those inlays respond to the write attempt to. For details about cross talk/adjacency
problems see section 4.2.
3) The material length must be adjusted to meet the real material length (+/-10%), otherwise the printout fails. If
the inlay is located near TOL in a (very) long label, it’s required to run the test for the whole label even if it’s
expectable to have a large “dead” zone at the end.
2.4.7 Processing failures (errors) – Invalidating labels
For HF technology the RFID command execution starts with selecting the tag under the antenna. When tag
selection fails, it is retried like every RFID command that can fail. After a defined number of retries (compare RFID
parameter „Number of CMD retries“) it is concluded that there is no transponder under the antenna or the
transponder is defective. This is documented by
invalidating the label with printing a characteristic pattern
(diagonal bars) on the label.
Afterwards no more printing is done for this label and the next label is tried. This is repeated until a valid
transponder is found or a defined limit of invalid transponder in sequence is reached (defined in parameter „Max
tags to stop“).
When this maximum number of invalid labels in sequence is detected, job processing is stopped. It is assumed that
a certain number of invalid transponder is an indicator for a severe problem that has to be solved first. Afterwards
job processing can be continued.