User's Manual
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PN02509 REV01
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PN02509 REV01
A762 People/Event Correlation Process
The A762 Proximity Locator works in conjunction with A750 Room Locators and R142 Proximity Badge tags.
A750 Room Locators are positioned to cover specic areas, such as rooms, closets or entire oors. The IR-enabled
R142 tags can report specic location data when it transmits its RF location payload to an RF Code reader. As a per-
son moves from one room to another, their badge tag will transmit the location code it detected from the last seen
A750. Each A750 Room Locator is assigned a unique ID for distinct room locations. A762 Proximity Locators are
also assigned ID’s which allow for people and event tracking with sub-room level accuracy. For example, if an LTX
soap dispenser is equipped with the A762 embedded module, soap dispense events can be correlated with a wearer
of an R142 Proximity Badge. The communication between the solution components is as follows:
1. A762 draws parasitic power from the LTX dispenser and detects soap dispense events.
2. A762 unit and badge tag communicate (send/receive) via low power 915 MHz broadcasts. A762 unit deter-
mines closest badge tag if multiple badge tags are within close proximity.
3. Badge tag transmits via 433 MHz RF, broadcasting its unique tag ID, room location, and event payload to the
RF Code reader infrastructure.
4. The A762 unit also has a unique ID and signals events via 433 MHz RF to the existing RF Code reader infra-
structure.
5. Time stamps, payloads and IDs from the A762 unit and badge tag transmissions are correlated via software
to accurately report who did what, when, and where. Because the software system is informed of all nearby
badges, it is capable of compiling an inventory of badges that were present for the Proximity Event and not
just the badge that was closest.
Figure 1: A762 People/Event Correlation Process
Proximity Logic Details
The antenna pattern of the A762 determines the RF eld strength at various points near the A762. Generally, the
eld strength decreases as you move farther away from the A762 but the rate at which it decreases is relative to the
orientation of the A762.
The diagram below (Figure 2) shows an approximation of the A762 antenna pattern. It is designed in such a way that
the signal strength will be highest for a person standing directly in front of the A762 (as opposed to a person stand-
ing beside or behind the A762).
1. Zone 1 represents the physical area in which the signal strength from the A762 is above a user-congurable
“immediate” threshold. This area is close to the A762 such that, under normal operating conditions, only one
person, and therefore only one badge, can be within Zone 1 at any given time. Following a Proximity Event
Activation, if a badge’s signal strength indicates it is within this zone, then the badge is immediately given
credit for the Proximity Event (no additional polling cycles).
2. Zone 2 represents the physical area in which the signal strength from the A762 is below the “immediate”
threshold but above a user-congurable “compete” threshold. Following a Proximity Event Activation, if
a badge’s signal strength indicates it is within this zone, then the badge is considered a candidate to receive
credit for the Proximity Event. Multiple polling cycles will be used to collect responses from badges in Zone
2 to ensure that all badges respond and the badge with the strongest response to any of the polling cycles will
receive credit for the Proximity Event.
3. Zone 3 represents the physical area in which the signal strength from the A762 is below the “compete”
threshold but still high enough to allow communication between the A762 and a badge. Badges within this
zone, although detectable, are not considered candidates to receive credit for a Proximity Event. Badges in
this zone can still report the event to zonal readers even though they do not get credit for the event.
4. Zone 4 represents the physical area in which communication with badges is possible, but the signal strength
from the A762 is below a user-congurable “ignore” threshold such that the badges in this zone ignore (do
not respond to) the A762 polling cycles and they do not report the event to the zonal readers.
5. Beyond Zone 4 the signal strength from the A762 is too weak to allow communication between the A762
and a badge. Badges in this area are unable to detect the A762.
Following a Proximity Event Activation, the A762 begins a series of polling cycles to collect badge responses from
all badges in Zone 1 and Zone 2. If a badge in Zone 1 responds to any polling cycle, it is immediately given credit
for the Proximity Activation and no further polling cycles are used. Otherwise, the A762 continues polling. After a
certain number of polling cycles with at least one badge responding from Zone 2, the A762 gives credit to the badge
with the strongest RSSI (received signal strength indication). The strongest RSSI is the maximum RSSI that a given
badge reported in any one of the polling cycles. If no badge responds within a certain number of polling cycles, the
A762 does not give any credit for the Proximity Event.
These are some of the advantages of this 4-zone method of proximity determination:
1. Badges within Zone 1 are given credit for the Proximity Event very quickly. A quick determination is often
needed when the dwell time of the badge is short.
2. Badges within Zone 2 are given multiple polling cycles to respond. This ensures the most accurate RSSI is
determined so that the correct badge is given credit for the Proximity Event.
3. A badge that starts in Zone 1 or Zone 2 and then moves into Zone 3 or Zone 4 can still communicate with
the A762 and therefore still receive credit for the Proximity Event even if it is in Zone 3 or 4 at the time when
the winner is decided and communicated to the system.
4. Because the “immediate”, “compete”, and “ignore” thresholds as well as the polling cycle requirements are
user-adjustable, the A762 can be adapted to monitor a variety of different Proximity Events depending on the
range and dwell time requirements of each situation.
Proximity Logic Details