Lyngsoe Systems PT40A PT40A Postal tag User Manual
Lyngsoe Systems Ltd. PT40A Postal tag
User Manual
PT40A Postal Tag RFID-LSCAN
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PT40A Postal Tag
User Manual
Version 2 – Feb 2012
PT40A Postal Tag RFID-LSCAN
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TABLE OF CONTENTS
1 INTRODUCTION 3
1.1 Purpose 3
1.2 Definitions 3
2 BLOCK DIAGRAM 3
3 PT40A OPERATION DESCRIPTION 3
3.1 Modes of operation 4
3.2 Valid Excitation Fields 4
3.3 Commands and Parameters 4
3.4 PT23 / PT40A vs. PT21 4
3.4.1 ExId range 4
3.4.2 Black-out 4
4 REGULATORY COMPLIANCE 5
4.1.1 Maximum Transmission Time 5
4.1.2 Maximum Duty Cycle 6
PT40A Postal Tag RFID-LSCAN
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1 INTRODUCTION
1.1 Purpose
The purpose of this document is to describe the functionality and operation of the PT40A tag intended for use in a RFID system
custom designed for International Post Corporation. The tag features reflect the application requirements. You can find more
details into “PT40A Functional Specifications”.
1.2 Definitions
Valid LF Field – A 125 kHz carrier signal modulated OOK with a signal carrying the exciting device identification number
(ExID).
Excitation Mode – tag transmits its ID together with the exciter ID when it is woken up by a valid LF field.
Transmission – When is excited by a valid LF field, the tag transmits its ID over a 433.92 MHz FSK modulated carrier.
2 BLOCK DIAGRAM
Block diagram for Postag PT40A is presented in Figure 2-1 below:
3 PT40A OPERATION DESCRIPTION
Postag PT40A is a transponder (RF Tag) that receives an excitation signal and responds by transmitting back a message. It is
custom designed for low cost and reliability in the postal environment. It is a direct replacement of previous models PT21 and
PT23 tags and can be used with any of the Lyngsoe RFID systems – S96, S21 S23, and S30. PT40A operates exactly the same
as PT30 only in a smaller form factor that can be placed in a foam carrier.
Postag PT40A provides the following main functions:
- Identifies a valid excitation field and reads the excitation identifier (ExId);
- Following a valid excitation, it transmits on 433.92MHz several identical messages that include (among others) the tag user
data, the ExId and a battery flag.
- Its user data and operating parameters are programmed wirelessly using a special programming device
LF_RX
uCtrl
UHF_TX
3V
Battery
UHF Antenna
LF
Ant
13.56MHz
crystal
Figure 2-1
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3.1 Modes of operation
Postag PT40A has several main modes of operation: sleep, LF excitation recognition, UHF transmission and programming. The
sleep mode is the normal mode of operation.
In the sleep mode, only the LF receiver is powered up and the total current consumption is less than 5uA. When a LF signal is
detected by the LF receiver, it wakes-up the microcontroller to check if this signal has a valid modulation pattern. The LF field
validation is done by the microcontroller using an RC internal 90 kHz clock at a low current consumption. If a valid excitation
field is recognized, then the microcontroller wakes-up its UHF Transmitter and transmits on the UHF the pre-programmed
messages. When PT40A recognizes a valid S21 / S23 excitation it transmits on UHF messages using S21 format. The PT40A
operation and the message content can be programmed using dedicated devices.
The tag transmits a number of messages each time it enters a valid S21 or S23 fields. First transmission is delayed a few ms
depending of the parameter WID that programmed randomly for each tag within the 10 -30 range during the manufacturing
process. Subsequent transmissions are each randomly delayed compared with the preceding one based on a calculation that
involves several random numbers generated internally function of another parameter WSD. This WSD parameter is also
programmed randomly for each tag within the 10 -30 range during the manufacturing process. Repeating the same message a
number of times ensures that, even if multiple tags are excited in the same time, many messages will not collide and at least one
from each tag will be successfully received.
3.2 Valid Excitation Fields
For a field to be valid, it has to have a special pattern called exciter ID. If fields with different exciter ID overlap and a tag moves
from one to another it will transmit WEP number of messages each time it “sees” a new exciter ID.
3.3 Commands and Parameters
The commands and parameters accepted by Postag PT40A are the same as for the Postag PT21 / PT23 and are listed in the RFID
System S21 – Reference Guide, document 950061 rev. 1.
The most used programmable parameters for PT40A are WIP, WRC and WUD. Examples of default parameters’ values that will
fit most applications are:
WUD = “xxxxx” 5 characters of user data
WIP, WRC= their sum represents the number of identical messages to transmit following an excitation. WIP
parameter range is 1 to 20, WRC parameter range is 0 to 10, and default values for each are 10.
WID = randomly assigned initial delay after excitation, multiples of 4 ms, range 1-200, default 1. This
ensures a randomization of the first transmissions following an (almost) simultaneously excitation of multiple tags.
WSD = inter-message random delay, range 7 – 15, default 10 (no direct physical interpretation of this value)
3.4 PT40A vs. PT21
The main functional differences between tags model PT40A and PT21 are related to the ExId range of identifiers and the black-
out time. PT40A behaves the same as PT30.
3.4.1 ExId range
Postags PT21 recognize and report received ExId with S21 format in the range 0 to 31.
PT40A recognize and report received ExId with S21 format in the range 0 to 31, and with S23 format in the range 0 to 127.
3.4.2 Black-out
Black-out is the minimum time interval between two consecutive excitations which the tag can recognize. Postag PT21 has a
black-out time 10.0 s. For PT40A this blackout time was reduced to less than 2.0 s. In situations where we want to re-register a
tag that leaves and re-enters a field with the same exciter ID, the tag has to be out of the field for more than the black out time
duration. This happens for example when you try to excite a tag multiple times using the same exciter, like a Universal
PT40A Postal Tag RFID-LSCAN
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Programmer UP23 box. The tag will not transmit if it enters an LF field but the excitation pattern cannot be recognized (i.e.
overlapping fields or interference).
4 REGULATORY COMPLIANCE
This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may
not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause
undesired operation.
This equipment has been tested and found to comply with the limits for Class B digital devices, pursuant to Part 15 of the FCC
Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This
equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the
instruction manual, may cause harmful interference to radio communications. However, there is no guarantee that interference
will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which
can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one of more of
the following measures:
• Reorient or relocate the receiving antenna
• Increase the separation between the equipment and receiver
• Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
• Consult the dealer or an experienced radio/TV technician for help.
This device complies with Industry Canada licence-exempt RSS standard(s). Operation is subject to the following two
conditions: (1) this device may not cause interference, and (2) this device must accept any interference, including interference
that may cause undesired operation of the device.
Le présent appareil est conforme aux CNR d'Industrie Canada applicables aux appareils radio exempts de licence. L'exploitation
est autorisée aux deux conditions suivantes : (1) l'appareil ne doit pas produire de brouillage, et (2) l'utilisateur de l'appareil doit
accepter tout brouillage radioélectrique subi, même si le brouillage est susceptible d'en compromettre le fonctionnement.
Warning: Changes or modifications not expressly approved by the party responsible for compliance could void the user’s
authority to operate the equipment.
4.1.1 Maximum Transmission Time
To comply with 15.231(a) of FCC regulations, the maximum transmission time of PT40A in Excitation mode must not exceed 5
seconds.
To minimize collisions in an application, PT40A tags are programmed with random values for the WSD parameter, which
ensures that inter-message durations are randomized differently for individual tags. To ensure sufficient transmission redundancy
in an application a certain optimum number of transmitted messages is selected and programmed into the WIP+WRC parameters.
The sum of both parameters represents the number of messages transmitted in a burst and this affects the overall transmission
duration.
In our typical application WIP + WRC = 20 and WSD = 7 and the resulting average transmission time is around 2s. If we set
maximum values for these parameters WIP + WRC = 30 and WSD = 30 the resulting transmission time is 4.3s so PT40A still
complies with the FCC requirements for maximum transmission time.
PT40A Postal Tag RFID-LSCAN
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4.1.2 Maximum Duty Cycle
To comply with 15.231(a) of FCC regulations from average transmitted power point of view, the maximum transmission Duty
Cycle for PT40A must not exceed 24% in any 100ms time window.
The maximum value of duty cycle in PT40A is achieved when 100ms window falls on the Excitation transmission bursts. The
table below shows the best estimate of the duty cycle in 100ms for different combinations of WEP = WIP+WRC and WSD. As
we can see as long as WEP = WIP+WRC > 3 and WSD ≥ 7 the duty cycle in any 100ms window varies between 8% and 16% so
there is margin compared with the maximum value of 24%.
Max Duty Cycle: 20 %Annex 3
WSD
WEP 12345678910 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
14444444444444444444444444444444444444444
28888888888888888888888888888888888888888
312 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
416 16 16 16 16 16 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
520 20 20 20 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
624 24 24 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
729 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
833 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
933 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
10 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
11 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
12 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
13 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
14 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
15 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
16 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
17 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
18 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
19 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
20 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
21 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
22 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
23 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
24 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
25 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
26 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
27 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
28 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
29 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
30 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
31 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
32 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
33 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
34 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
35 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
36 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
37 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
38 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
39 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
40 33 29 29 24 20 20 16 16 16 16 12 12 12 12 12 12 12 12 12 12 12 12 888888888888888888
Maximum possible Duty Cycle in any 100ms time window during a transmission of one packet of MsgNo messages
(set by WBP, WEP, WEB tag parameters).
This graph also depends on values of CC and EN parameters set in TagParms form.