User's Manual
User Guide
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User Guide, WherePort IV D1300 REV A
© Copyright WhereNet, Corp. 2008 WhereNet Confidential
In mode 2 the tag must both leave the WherePort IV field and the specified interval elapse before a
WherePort IV blink will occur. If the tag enters a new WherePort IV field it will immediately transmit a
blink (Figure 2).
Figure 7 Retrigger Mode 2 and a New Capture Area
In mode 3, the set interval must elapse and the tag leave the field, and then the tag will transmit a blink to
indicate that it has left the field. If the tag enters a new field, the tag transmits a blink when it enters the
field. If the re-trigger time out is reached before a new field is entered a blink is transmitted which
indicates the tag is out of the field.
Figure 8 Retrigger Mode 3 and a New Capture Area
6.2. Using the WherePort IV ID
The tag response can also be changed by the WherePort IV. Ports with ids from 0 to 255 are used only
when the alternate blink mode is required. These reserved ids are split evenly between IDs (128 – 255) to
mark the entrance of tag into the field and ids (0 - 127) to mark the exit of a tag from the field. The
significance of other tag IDs is shown in Table 2.
WherePort IVs can turn tags on and off as they enter and leave a site. As an example, WhereTags can be
permanently mounted to trailers. These trailers need to be tracked while they are on the site, but not after
they leave. There is no need for the tag to continue to blink while it is off site. WherePort IVs positioned
at entry and exit gates can turn the tags on when the trailers enter the yard, and off when they leave.