Feig Electronic OBID i-scan ISC.LR200-A/B Installation and operating instructions

APPLICATION-NOTE
final
public
2003-12-03
N11200-0e-ID-B.doc
OBID i-scan
®
ID ISC.LR200-A/B
ID ISC.LRM200-A/B
Synchronizing RFID Long Range Readers
using the Digital In-/Outputs

OBID i-scan®Application-Note ID ISC.LR(M)200
FEIG ELECTRONIC GmbH Page 2 of 27 N11200-0e-ID-B.doc
Note
Copyright 2003 by
FEIG ELECTRONIC GmbH
Lange Strasse 4
D-35781 Weilburg-Waldhausen
Tel.: [phone]
http://www.feig.de
With the edition of this document, all previous editions become void. Indications made in this manual may be
changed without previous notice.
Copying of this document, and giving it to others and the use or communication of the contents thereof are
forbidden without express authority. Offenders are liable to the payment of damages. All rights are reserved
in the event of the grant of a patent or the registration of a utility model or design.
Composition of the information in this manual has been done to the best of our knowledge. FEIG
ELECTRONIC GmbH does not guarantee the correctness and completeness of the details given in this
manual and may not be held liable for damages ensuing from incorrect or incomplete information. Since,
despite all our efforts, errors may not be completely avoided, we are always grateful for your useful tips.
The installation instructions given in this manual are based on advantageous boundary conditions. FEIG
ELECTRONIC GmbH does not give any guarantee promise for perfect function in cross environments.
FEIG ELECTRONIC GmbH assumes no responsibility for the use of any information contained in this
manual and makes no representation that they free of patent infringement. FEIG ELECTRONIC GmbH does
not convey any license under its patent rights nor the rights of others.
OBID®and OBID i-scan®are registered trademarks of FEIG ELECTRONIC GmbH.
I-CODE®is a registered trademark of Philips Electronics N.V.
Tag-itTM is a registered trademark of Texas Instruments Incorporated.

OBID i-scan®Application-Note ID ISC.LR(M)200
FEIG ELECTRONIC GmbH Page 3 of 27 N11200-0e-ID-B.doc
Contents
1. Synchronizing Readers, Applications 4
1.1. Purpose of Reader-Antenna synchronizing ................................................................... 4
2. Synchronizing RFID Long Range Readers using the digital in-/outputs 5
2.1. Design notes..................................................................................................................... 6
2.1.1. Configuring the reader parameters for synchronizing................................................... 7
2.1.2. Determining the maximum speed of the transponder in the antenna.......................... 10
3. Required components 12
4. Possible disturbances caused by mutual interference of the RFID systems 13
4.1. Minimum separations between two RFID systems ...................................................... 14
5. System structure 16
5.1. Wiring the serial interface.............................................................................................. 16
5.2. Wiring the digital in- and outputs.................................................................................. 17
5.3. Configuring the readers for synchronizing .................................................................. 19
5.4. Requesting data from the reader................................................................................... 22
5.5. Setting up and running a test and demo program ....................................................... 23
Appendix A: Helpful tools for constructing and testing the antennas 25
Recommended equipment and possible sources: .............................................................. 26

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1. Synchronizing Readers, Applications
1.1. Purpose of Reader-Antenna synchronizing
Readers, antennas and transponders together form an RFID system. A single reader or RFID
system in a room, building or close area does not need to be synchronized.
The transmitting energy of the reader which is radiated through the antenna is not limited to the
particular read range. As a consequence, multiple RFID systems having the same transmission
frequency located in the same room or building will mutually interfere with each other. This reduces
the read range and reliability of the system.
This interference depends on various factors:
•Size, Q, form and orientation of the antennas with respect to each other
•Set transmitting power of the reader
•Distance between antennas
•Whether the antennas are shielded or not
When planning RFID systems, a minimum distance between antennas should always be
configured.
For example, two RFID systems consisting of one each ID ISC.ANT300/300-A (300 mm x 300 mm)
antenna and one Long Range Reader ID ISC.LR200 with 4 W output power must be separated by
at least 3 m.
Larger antennas require a minimum separation of up to 10 m to avoid mutual interference.
In summary, planning for RFID systems should always allow for a minimum separation between
the antennas. See section 4.1. Minimum separations between two RFID systems
If synchronizing the systems is not possible, interference can be prevented by proper shielding.

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2. Synchronizing RFID Long Range Readers using the digital in-/outputs
In this context synchronization means that the magnetic field of the RFID Reader antennas are
alternately turned on while all other antenna outputs on the readers are turned off.
This is implemented for readers with antennas using the digital in- and outputs by having the
reader firmware itself turning on only one antenna of several readers. During this time the other
readers turn off the HF field of the respective antennas.
Fig. 1: Sequence of communication between the readers
Communication takes place through the digital inputs IN1 and outputs OUT1. The Master starts by
sending a pulse to the next reader as soon as it has finished communicating with the transponder.
The latter passes the signal to the next reader after finishing its read cycle. The last reader then
passes the signal back to the Master.
MASTER SLAVE 1 SLAVE 2
IN 1 IN 1 IN 1OUT 1 OUT 1 OUT 1

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2.1. Design notes
Synchronizing using the digital in-/outputs is possible only in Scan- and Buffered Read Mode of the
ID ISC.LR200 Reader!
The system requirement is a Long Range Reader ID ISC.LR200 or ID ISC.LRM200 Software
Version V4.00 or higher and board Version FE 498/4.
In order to wire the digital in- and outputs of the readers together, a data line must be connected
between the readers. See section: 5.2. Wiring the digital in- and outputs An external power supply
is used to supply the digital in-/outputs.
To trigger the reader synchronization process and define the timing sequence of the reads, you
need to adapt the configuration in the reader. See section: 2.1.1.Configuring the reader parameters
for synchronizing.
The read speed is reduced by the alternate powering of the RFID systems. See section:
2.1.2.Determining the maximum speed of the transponder in the antenna.
Depending on the antenna shape, size and distance, various interference prevention measures
need to be taken. See section 4.1. Minimum separations between two RFID systems.
When the distances between antennas cannot be greater than 2 m, an additional shield must be
installed between them. See section: 4. Possible disturbances caused by mutual interference of
the RFID systems.

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2.1.1.Configuring the reader parameters for synchronizing
2.1.1.1. Transponder Response Time
For the reader to be able to read a transponder, the latter must remain within the magnetic field of
the antenna until the read cycle is completed. This time is called “Transponder Response Time”
and is set in the reader ( CFG2:COM-Interface –Transponder Response Time).
The Transponder Response Time is a function of the transponder model, the number of time slots,
the number of transponders to be read and the amount of data. The Transponder Response Time
(TRT) is calculated as follows.
TRT = Timing of Inventory + (Timing of read function * Number of transponders * 1,1) + 10ms.
If no data are read from the transponder, the formula is:
TRT = Timing of Inventory + 10ms.
Other conditions:
-A Transponder Response Time of less than 20ms is not allowed for synchronized systems.
-The calculated Transponder Response Time is always rounded up to the next 10 milliseconds.
-If ISO 15693 compatible transponders from different manufacturers are used, the timing of the
slowest transponder should always be used as the basis.
-If various transponder types are used which are not mutually compatible (e.g. I-Code 1 and I-
Code SLI or Tag-it HF and Tag-it HF-I), then you must calculate TRT for each type. The sum of
the individual values then gives the total TRT to be set.
The parameters „Timing of Inventory“ and „Timing of read function“ depend on the transponder
type and the number of time slots and can be referenced in the System Manual for the ID
ISC.LR200 Reader.
The calculated Transponder Response Time taking into account the above conditions must be set
in all readers (configuration block CFG2 Byte6+7).

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2.1.1.2. Synchronization-Timeout
The Synchronization-Timeout is another important parameter. It determines two things:
-The response time of the RFID system ! The maximum required time until a transponder is
read in a synchronized system.
-The time the reader waits after turning of the antenna for another synchronization pulse from
the previous reader. If the pulse does not arrive, it reports a “Synchronization Error” and turns
on the magnetic field of the antenna for Transponder Response Time (TRT).
When there are two synchronized RFID systems in an RFID complex, each reader requires one
Transducer Response Time, since the systems are alternately turned on and off.
When there are more than two synchronized RFID systems, the Transponder Response Time
must be multiplied by the number of systems. From this you can calculate the cycle time of the
RFID complex which is set as the Timeout time in the reader (CFG11: Buffered Read Mode -
Synchronisation-TIMEOUT).
Synchronization-Timeout = (TRT + 20 ms)* number of synchronized readers.
The calculated synchronization timeout is always rounded up to the next ten milliseconds.

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Example 1: Synchronizing 4 personnel gates with ISO 15693 transponders:
In the example we will assume that there are a maximum of 3 transponders in one personnel gate.
In other words, the configuration in CFG8: General Transducer Parameters: ASK; 1 Timeslot can
be used in the reader. We further assume that 2 data blocks (block size 4 bytes) will be read from
the transponders.
From the graph in the System Manual for the ID ISC.LR200 Reader, section: Annex C „Time
Behavior of ISO 15693 Transponder“ paragraph: „Time Behavior for Inventory“ we see:
Time of Inventory for 3 transponders => approx. 60 ms (3 x 20 ms)
Read 2 data blocks (Philips SLI, Texas Instruments HF-I) = 12 ms
TRT = 60 ms + (12 ms * 3* 1.1) + 10 ms = 109.6 ms
Therefore the „Transponder Response Time“ should be set to 110ms !
The processing time or cycle time of the RFID complex and the Synchronization-Timeout to set
would therefore be 3 x (110 ms + 20 ms) = 330 ms !
Summary: Set a time of 330 ms in configuration block CFG8.

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2.1.2.Determining the maximum speed of the transponder in the antenna
As described above, alternately turning the antennas on for 2 to n readers results in a reduction of
the maximum read speed by 1/n.
When doing your planning, you should therefore check whether the possible read speed and
consequently the maximum traverse velocity of the transponders are compatible with the
requirements of the application.
The maximum traverse velocity of the transponders per system depends on the length of the read
zone in the direction of motion and on the cycle time of the RFID complex. The precise limit value
can only be determined when all these data are known.
To help you, here is the calculation for an ID ISC.ANT800/600-A antenna with a transponder
orientation parallel to the antenna:
vB=> traverse velocity
sL=> read zone length of the transponder in the antenna
tZ= cycle time of the RFID complex.
The read zone length of a transponder in the antenna depends on the transponder, the reader and
its transmission and reception parameters, on the distance to the antenna and the orientation of
the transponder. These data should be measured manually in a test configuration for each required
transponder orientation.
Near a single loop antenna and with the transponder oriented parallel to the antenna conductor,
the read zone length of the antenna corresponds to the spacing of the antenna conductors in the
loop. For an ID ISC.ANT800/600 antenna mounted horizontally, this is approx. 0.80 m.

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Fig. 2: Read zone length of the ID ISC.ANT800/600 antenna, transponder parallel to antenna
SL= 0.8 m
tZ= 0.33 s (from Example 1)
The maximum permissible traverse velocity is thus:
vB Max= sL/ tZ= 0.8 m / 0.33 s = 2.42 m/s (8.7 km/h)
sl

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3. Required components
To configure an application with „n“ RFID systems you will need:
•Qty. „n“ ID ISC.LR200 or ID ISC.LRM200 (Software Version 4.00 or higher and board Version
FE498/4)
•Qty. „n“ Complete antenna assemblies, incl. Power Splitter and Transformer
•Qty. 1 Interface converter RS232/RS485
•Qty. 1 Shielded, twisted-pair cable between the individual readers. Example: LiYCY (TP)
2x2x1.0 mm2
•Qty. 1 power supply DC 5V - 24V, 20 mA (see installation manual for ID ISC.LR200, section X7
Inputs and section X6 Outputs).
•Qty. „n“ resistor ¼ W (see installation manual for ID ISC.LR200 LR200, section X7 Inputs and
section X6 Outputs).
•Qty. „n“ terminal strips for connecting the cable between the readers.
Components needed for starting up:
•Qty. 1 ID ISC.SATC-A Automatic Tuning Controller
•Service software ISOStart Version 6.10 or higher on a PC running under Windows. The
ISCStart software can be found on the OBID®i-scan CD from FEIG ELECTRONIC GmbH.
•Service software BRMDemo Version 1.07 on a PC running under Windows. The BRMDemo
software can be found on the OBID®i-scan CD from FEIG ELECTRONIC GmbH.
•Qty. 1 SWR Meter with SMA sockets or SMA socket adapter
•Qty. 1 cable RG 58 C/U approx. 20 – 25 cm long with two SMA plugs
•Qty. 1 amber screwdriver
•Qty. 1 oscilloscope
•Qty. 2 measuring loops
More detailed information about the equipment can be found in section Fehler! Verweisquelle
konnte nicht gefunden werden. !

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4. Possible disturbances caused by mutual interference of the RFID systems
There are three main causes of mutual interference between the RFID systems:
•Direct affects on the systems caused by strong coupling between the antennas
•Carrier signal effects caused by mutual interference
•Artifacts in the receiver caused by the modulation pulses of the adjacent system.
Which disturbances are measurable in the systems depends on the distance between the
antennas, the antenna geometry, the output power and the orientation of the antennas with respect
to each other.
Synchronizing the antennas only minimizes the last two effects. At a distance of 2 m or less
between the systems, additional shielding (e.g. a metal plate) should be installed between the
systems. See 4.1.
Taking into consideration the power-up and power-down times, all readers must be turned off for a
brief time (approx. 2-10 ms).
If the systems are spaced between 5 m and 10 m apart, it may be sufficient to synchronize only the
transmission protocols instead of turning the transmitter on and off. This speeds up the process
somewhat, since the pauses between the systems are eliminated.
The physical configuration, wiring, connection to the host and the settings in the reader are all
identical except for the setting in configuration block CFG11 Byte 7. Here the “RF switched off” bit
is not set.

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4.1. Minimum separations between two RFID systems
If multiple antennas are installed in a room or building, they can interfere with each other. This
reduces the read range and reliability of the systems. A minimum separation of 8 – 10 m between
the antennas should be allowed for.
If lesser distances are necessary, mutual interference can be minimized by means of
synchronizing and shielding. Synchronizing is performed several times a second, so that the user
of a personnel gate is scarcely aware of it.
When synchronizing the HF field the reader only enables the RF when a protocol is sent and a
reply from the transponder is pending. In other words, the gates are not continuously on but rather
are cycled on and off.
When synchronizing the transmission protocol the RF is always on, but the readers send and
receive the protocols in alternation. This ensures that the second reader is not sending while the
first reader is exchanging protocols with the transponder.
For separations of 1 m - 2 m you must install additional shielding. This metal shield should be
located in the middle between the gates, parallel to the antennas, and should be at least as large
as the antennas excluding the housing.
Table 1 Minimum separations between the gates resp. systems
Minimum separations between the
antennas or systems
Antenna / gate / system
configuration
Setting in the Reader
CFG11 field:
Synchronization RW 50-60 cm RW 80-100 cm
Two systems with no
synchronization
OFF 8 m 10 m
Synchronizing of the
transmission protocols
Cascaded, RF stays
on, Master/Slave
5 m 6 m
Synchronizing of the HF field Cascaded, RF
switched off,
Master/Slave
2 m 2.8 m
Synchronizing of the HF field,
shield between the systems
Cascaded, RF
switched off,
Master/Slave
1 m 1.30 m
RW : Read range for the antenna

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Fig. 3: Position and size of the shield, configuration using two ID ISC.ANT800/600 antennas
The shield should be installed in the middle between the two systems/antenna assemblies
Fig. 4: Position and size of the shield. Configuration: Two gates with ID ISC.ANT1400/700 antenna
2 x ID ISC.ANT800/600-A
Shield

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5. System structure
In this application we assume that all readers are connected to the computer/host through an
RS485 bus. It is also possible to connect the reader to the network or directly to the computer
through the RS232 port.
5.1. Wiring the serial interface
If the readers are synchronized, a bus connection over the serial interface is generally
recommended. The reader includes an RS485 port for this purpose. If the host computer does not
have an RS485 port, various RS232-RS485 converters are commonly available (see Appendix A:
Recommended equipment and possible sources:.
Fig. 5: Wiring the serial interface
The serial port on the Long Range Reader ID ISC.LR200 is converted from RS232 to RS485 by
moving Jumpers J400 and J401. The cable length should not exceed 500 m.
For longer cable runs (100 m or greater), the bus terminal must also be set using Jumper J403 on
the last reader on the bus.
X9
1 2 3 4
ID ISC.LR200
5 6n.c.
n.c. n.c. RS485 - GND RS485 - (A-) RS485 - (B+)
X9
1 2 3 4
ID ISC.LR200
5 6n.c.
n.c. n.c. RS485 - GND RS485 - (A-) RS485 - (B+)
Reader 1 Reader 2
J401
J400
2
3
4
RS-232 TO RS-485
MODEL 485SD9R
Converter
RS - 485 RS - 232
B&B Electronics

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5.2. Wiring the digital in- and outputs
To synchronize the readers using the digital in- and outputs, the digital outputs must be wired as
shown in the diagram below. The supply voltage should be provided by an external power supply.
Fig. 6: Wiring the digital in- and outputs
To avoid noise on the data lines, the resistors should be installed as close to Terminal X7 on the
reader as possible. The data line should be a shielded, twisted-pair cable. Example: LiYCY (TP)
2x2x1.0 mm2.
U
1
=24 V DC
GND
X6
X7
X7
X6
500 Ω
Reader 2
Reader 3
500 Ω
500 Ω
500 Ω
R1
500 Ω
X6
X7
Reader 1
500 Ω
R1
R1

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The resistor values depend on the supply voltage. See installation guide for the ID ISC.LR200 and
Table 2.
Table 2 Resistor values
Voltage Resistor value
5 to 10 none
11 to 15 270 Ωx 0.25 W
16 to 20 560 Ωx 0.25 W
21 to 24 820 Ωx 0.25W

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5.3. Configuring the readers for synchronizing
Before setting the readers for synchronizing, the antennas must be tuned. This is described in the
installation guide for the antennas or in the application notes for special antenna configurations. Be
sure that all other readers are turned off when the antennas on the first reader are tuned. Proceed
analogously when tuning the other antennas.
Since the readers are operated on an RS485 bus, each reader must be given a unique address.
This is set as follows:
1. Configure COM port
Step Description Note
1Install the ISCStart software
tool or ISOStart
On the OBID i-scan®CD-ROM
2Connect the first reader ID
ISC.LR200 to the PC on the
RS232 or RS485 interface.
Disconnect all other readers
from the RS485 bus.
See Installation Manual ID ISC.LR200
3Start the ISOStart program and
load the configuration from the
EEPROM on the reader
4Click on the Configuration
button
5Select CFG2: COM-Interface
6IN the BUS-ADR field enter the
desired reader address
(0...254).
7Verify that the EEPROM is
selected as the destination
memory.
Save new parameters in the
reader by clicking on the Write
button.
The PC attempts to open the
connection to the reader using
the new address and various
baud rates.

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8Repeat steps 2-7 for each
additional reader on the bus.
Synchronizing is only possible in Scan- and Buffered Read Mode ! See System Manual Reader ID
ISC.LR200.
“Buffered Read Mode“ is the optimum operating mode of the reader for fast read operations. The
reader reads the transponder data at maximum speed and saves the data in a ring buffer on the
reader. These can then be queried by the host.
The parameters for synchronizing are set in configuration block CFG11 for „Buffered Read Mode“
in the „Synchronization“ field. In addition to turning on synchronization (cascaded), the parameters
“Master” or “Slave” and “RF stays on” or “RF switched off” must be configured. The master can be
any reader in the chain of synchronized devices. Since the Master is always the first to
communicate with the transponder after a reset, there can be only one Master. All other readers
are Slaves.
The readers are configured correspondingly (CFG11) using the ISOStart software. Synchronizing
is however only possible in Scan- and Buffered Read Mode !
2. Configuring synchronization
Step Description Note
1Menu: Click on Configuration
2Select CFG10: General .
3Set reader to
Buffered Read Mode.
(also set Anticollision Select Mode)
4Verify that the EEPROM is selected as the
destination memory.
Save the settings by clicking on the Write
button.
5Select CFG11: Buffered Read Mode.