Gilbarco MRIR8 User Manual
Series 2000 Reader System
High Performance RFM RI-RFM-007B
Reference Guide
11-06-21-042 April 1999
1
High Performance RFM RI-RFM-007B April 1999
Second Edition - April 1999
This manual describes the
hereafter referred to as the RFM.
TIRIS High Performance RFM RI-RFM-007B
,
Important Notice
Texas Instruments reserves the right to change its products or services or to
discontinue any product or serv ice at an y time witho ut n otice. T I pr ovides c ustom er
assistance in various technical areas, but does not have full access to data
concerning the use and applications of customer's products.
Therefore, TI assum es no liability and is not resp onsible for cus tomer applications
or product or software design or perform ance relating to systems or applications
incorporating TI products . In additio n, TI ass um es no liab ilit y and is not respons ible
for infringement of patents and/or any other int ellectual or industrial propert y rights
of third parties, which may result from assistance provided by TI.
TI products are not designed, intend ed, authorized or warranted to be suitable for
life support applications or any other life critical applications which could involve
potential risk of death, personal injury or severe property or environmental damage.
The
TIRIS
Instruments Incorporated.
Copyright 1998 Texas Instruments Incorporated. All rights reserved.
logo and the word
TIRIS
are registered trademarks of Texas
2
April 1999 Contents
Table of Contents
Preface.................................................................................................................5
Chapter 1: Product Description ........................................................................7
1.1 General.......................................................................................................8
1.2 Transmitter ...............................................................................................10
1.3 Receiver ...................................................................................................11
1.4 RFM Connectors and Jumpers ................................................................11
Chapter 2: Specifications ................................................................................17
2.1 Recommended Operating Conditions ......................................................18
2.2 Dimensions...............................................................................................22
Chapter 3: Installation......................................................................................23
3.1 Power Supply Requirements....................................................................24
3.2 Power Supply Connection........................................................................25
Chapter 4: Associated Antenna Systems......................................................27
4.1 Antenna Requirements.............................................................................28
4.2 Antenna Resonance Tuning.....................................................................29
4.3 Tuning Procedure.....................................................................................30
Appendices
Appendix 1: Expanding Antenna Tuning Inductance Range..........................33
Appendix 2: Field Strength Adjustment..........................................................37
Appendix 3: Adjustment of Oscillator Signal Pulse Width..............................39
Appendix 4: Threshold Level Adjustment.......................................................41
Appendix 5: Transmitter Carrier Phase Synchronization (CPS) ....................43
Appendix 6: Noise Considerations .................................................................47
Appendix 7: Over Voltage Protection .............................................................49
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High Performance RFM RI-RFM-007B April 1999
Table Locations
Table 1: J1 Pin Functions ................................................................................................................................ 13
Table 2: J2 Pin Functions ................................................................................................................................ 14
Table 3: J4 Pin Functions ................................................................................................................................ 14
Table 4: J3 Pin Functions ................................................................................................................................ 15
Table 5: Antenna Connectors.......................................................................................................................... 15
Table 6: Operating Conditions......................................................................................................................... 18
Table 7: Electrical Characteristics ................................................................................................................... 20
Table 8: Timing Characteristics....................................................................................................................... 21
Table 9: Mechanical Parameters..................................................................................................................... 21
Table 10: Power Supply Ripple Specifications................................................................................................ 24
Table 11: Antenna Requirements.................................................................................................................... 28
Table 12: Capacitor Values for Expanding Antenna Tuning Range to Lower Values..................................... 34
Table 13: Capacitor Values Expanding Antenna Tuning Range to Higher Values ......................................... 35
Table 14: Oscillator Signal Pulse Width versus Resistor Value (estimated values)........................................ 40
Table 15: Maximum Distances between Antennas ......................................................................................... 44
Table 16: Characteristics of Radiated and Conducted Noise.......................................................................... 47
Figure Locations
Figure 1: RFM Block Schematic........................................................................................................................ 8
Figure 2: Pulse Width Examples ..................................................................................................................... 10
Figure 3: RFM Top View.................................................................................................................................. 12
Figure 4: RFM Bottom View............................................................................................................................. 13
Figure 5: Mechanical Dimensions ................................................................................................................... 22
Figure 6: External Ground Connection (GND to GNDP)................................................................................. 26
Figure 7: Tuning Example showing Increase of Total Tuning Capacity.......................................................... 31
Figure 8: Flow-chart for Tuning the Antenna to Resonance............................................................................ 32
Figure 9: Circuit for Expanding Antenna Tuning Range to Lower Values....................................................... 34
Figure 10: Circuit for Expanding Antenna Tuning Range to Higher Values.................................................... 35
Figure 11: Distance between Antennas (top view).......................................................................................... 44
Figure 12: Noise Testing Configuration........................................................................................................... 48
Figure 13: Circuit for Overvoltage Protection .................................................................................................. 50
4
FCC/PTT Regulations
The TIRIS RFM generates RF emissions at 134.2 kHz. The radiation of the
fundamental and harmonics will var y with the type of antenna and other devices or
functions connected to the RFM.
Prior to operating the RFM together with antenna(s), power supply and a control
module or other dev ices, the required FCC, PTT or relevant government agency
approvals must be obtained.
Preface
CE Conformity
Sale, lease or operation in some countries may be subject to prior approval by
governmental and other organizations or agencies.
A CE Declaration of Conformity is available for this module in a typical
configuration. An y device or s ystem incor porating th is m odule in a n y other tha n the
original CE configuration needs to be verified against the European EMC directive.
A separate Declarat ion of Conformity must be is sued by the system integrator or
user of such a system prior to marketing it and operating it in the European
Community.
5
High Performance RFM RI-RFM-007B April 1999
Conventions
Certain conventions are used in order to display important information in this
manual, these conventions are:
WARNING: A warning is used where care must be
taken, or a certain procedure must be followed, in
order to prevent injury or harm to your health.
CAUTION: This indicates information on conditions which
must be met, or a procedure which must be followed,
which if not heeded could cause permanent damage to the
RFM.
Note: Indicates conditions which must be met, or procedures which
must be followed, to ensure proper functioning of the RFM.
6
Chapter 1
Product Description
This chapter introduces the RFM component assemblies, s howing the transmitter
and receiver sections and placement of key user-accessible components.
Topic Page
1.1 General.......................................................................................................8
1.2 Transmitter ...............................................................................................10
1.3 Receiver ...................................................................................................11
1.4 RFM Connections and Jumpers...............................................................11
7
High Performance RFM RI-RFM-007B April 1999
1.1 General
WARNING: Care must be taken when handling the
RFM. High voltage across the antenna terminals, all
antenna components and some parts of the printed
circuit board (PCB) could be harmful to your health. If
the antenna insulation is damaged, the antenna
should not be connected to the RFM.
CAUTION: This product may be subject to damage by
electrostatic discharge (ESD). It should be handled by ESD
protected personnel at ESD secured workplaces only. The
transmitter power output stage can only operate with a
limited duty cycle. Please pay attention to this whilst
performing antenna tuning procedures. Ground pins GND
and GNDP must be connected externally to avoid damage
to the unit.
TXCT-
RXDT
RXCK
ATI
Interface
RXSS-
The RFM is an integra l part of the TIRIS system. Coupled with a Control Mod ule
and an antenna, it is use d for wir eles s identif icat ion of T IRIS transpo nder s. A block
schematic is shown in Figur e 1.
TX
Osc illator
RX
Demodulator
demodulator
6
ATI
Int
.
RXSS
Threshold
threshold
CPS
PWM Control Input
PW M
RX
Amplif ier
Overvoltage Protection
TX Powe r
Stage
Antenna
Circuit
TX/RX
Antenna
Figure 1: RFM Block Schematic
8
April 1999 Product Description
The RFM contains all the analogue functions of a TIRIS reading unit needed to
send an energizing signal via the antenna to initialize a TIRIS transponder, to
demodulate the received identification signal and to send the received data
together with clock signals to a Control Module.
The RFM also sends the necessary programming and addressing signals to
Read/Write and Multipage transponders.
The data input and output lines, which are connected to a data pr ocess ing u nit, are
low-power Schottky TTL and HCMOS logic compatible.
The functions of the RFM are described in the following section.
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High Performance RFM RI-RFM-007B April 1999
1.2 Transmitter
The transmitter power s tage is supplied with power via two separate supply lines
VSP and GNDP. Because of the high current requirements for the transmitter
power stage, these supply lines are separated from the logic secti on supply lines
and have two pins per line.
The ground pins for the logic section and the transmitter are not connected
internally in order to a void possible problem s with a high resistivit y of GNDP pins
and in order to increase flexibility when using long supply lines. Pins GND and
GNDP must be connected to each other externally. For more details, refer to
Section 3.1, Power Supply Connection.
The regulated transm itter power stage supply may var y between +7V and +24V.
The supply lines VSP and VSL should be connected together when the supply
voltage is +7 V or more. For details refer to Section 2, Specifications.
Note: The RFM has an in-built temperature protection circuit which
sharply limits the transmitter power stage output if an over-current
situation or an over-tem perature environment c auses the tem perature
to exceed the allowed limits. After the devic e is switched off and has
time to recover (when the tem peratur e drops again or the o ver-c urrent
situation is otherwise rectified) the unit reverts to normal operation
when it is switched o n again. Such an occ urrence is an in dicatio n th at
the RFM is not being operated within specification.
The transmit frequency (134.2 kHz) from the oscillator is fed to the pulse width
modulator (PWM). By changing the value of a resistor, the PWM can s et the pulse
width ratio between 0% and 50%. For an example of two different oscill ator signal
pulse widths see Figur e 2. Decreasing the 134.2 k Hz frequency pulse width ratio
decreases the generated transmit (charge-up) field strength.
It is therefore possible to adjust th e generated field strength by selecting different
pulse width ratios. For more information about setting the field strength, refer to
Appendix 2, Field Strength Adjustment.
Pulse width of 50% Pulse width of 12.5%
Figure 2: Pulse Width Examples
10
April 1999 Product Description
CAUTION: The RFM must not be operated in continuous
transmit mode when operated at full power output. For
details please refer to Section 2, Specifications. When
using pulse widths smaller than 50%, the RFM transmitter
power stage works in a less efficient way. This leads to an
increased power dissipation and thus to higher
temperature increase of the transmitter power stage, so
ensure that more cooling is provided.
Note: If the RFM is going to be ph ysically located within the ante nna
field, it may be necessary to shield the module.
1.3 Receiver
The signal receive d from the transponder is a frequency s hift keying ( FSK) signal
with typical low and h igh bit frequenc ies of 134.2 k Hz and 123 .2 kHz r espectively.
The signal is received from the ante nna resonat or, whic h is capac itivel y coupled to
the receiver.
The signal RXCK is the ref erence clock signal to decode t he RXDT data stream.
The RXCK signal changes from low to high level during each data bit and the
RXDT signal is valid before and after this pos itive slope for a certain tim e window.
For more details refer to Table 8, Timing Characteristics.
The receiver also has a built-in RF receive signal strength detector. T he receive
signal strength is indicat ed b y the digit al out put RX SS- .
RXSS- becomes active ( logic low level) when the received RF signal strength
exceeds a defined l evel. This thr eshold level c an be adjus ted with a potentiom eter
(R409) on the RFM. The potentiometer is located near SW1 on the board. See
Figure 3, RFM Top View.
The RXSS- output is used for detect ion of other tr ansm itting re ading un its an d thus
can be used for wireless read cycle synchronization of several reading units.
1.4 RFM Connectors and Jumpers
There are a number of connectors, jumpers and other components on the RFM
available for use.
These are:
J1 Connector for supply voltages and interface signal lines to and from the
RFM
J2 Connector for the (optional) Anten na Tuning Indicator (ATI), which c an be
used for easy antenna tuning during installation.
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High Performance RFM RI-RFM-007B April 1999
J3 Connector for antenna resonance tuning, used to connect the required
tuning capacitors.
J4 Connector for field strength adjustment resistor and also direct access to
receiver input.
JP3 Additional antenna damping connector.
JP4 Common-mode noise choke bypass.
R409 RXSS noise level adjustment potentiometer.
SW1 Default all on. (Pos. 1 CPS setting see Appendix 5.)
ANT1/ANT2 (two M3 screw connectors) connect the transmit/receive (TX/RX)
antenna to the RFM.
The RFM is normally mounted from the und er side utilizing ap propr i ate sp ac er s and
M3 mounting bolts.
The top view of the RF M ( witho ut th e n or mally fitted heatsink ) is shown in Figur e 3.
Connectors J2, J3, J4, J P3, JP4, R 409 , switch SW 1 and the antenn a ter m inals ar e
accessible from the top.
Figure 3: RFM Top View
12
April 1999 Product Description
The bottom view of the RFM is shown in F igure 4. The connector s J1, J2, J3 and
J4 are accessible from the underside. J1 is the 16-pin module connector, this
carries the supply voltage lines, the data, and the control lines.
J2
• •
• •
• •
J4
• •
• •
• •
• •
• •
• •
• •
• •
• •
• •
6
4
2
4
2
2
4
6
8
10
12
14
16
13
11
9
7
5
3
1
J3
• •
• •
• •
• •
• •
• •
• •
14
12
10
8
6
4
2
ANT 1
5
3
1
3
1
1
3
5
7
9
11
13
15
J1
ANT 2
Figure 4: RFM Bottom View
Table 1 lists the p in functi ons f or connec tor J1. T he conn ector t ype is 16 pin, 2 r ow
with 2.54 mm pin spacing.
Table 1: J1 Pin Functions
Pin# Signal Direction Description
1 GND IN Logic ground
2 TXCT- IN Tr ansmitter control input for activation of transmitter (active low, internal
pull-up resistor)
3 VSL IN Supply voltage for logic and receiver
4 RXDT OUT Logic level compatible receiver data signal output
5 RXSA IN/OUT Receiver signal strength adjust for RXSS- threshold level
6 RXCK OUT Logic level compatible receiver clock output
7 GNDP IN Transmitter power stage ground
8 No connection
9 GNDP IN Transmitter power stage ground
10 RSTP OUT Analog receiver signal strength test pin
11 VSP IN Supply voltage for transmitter power stage
12 CPS_OUT OUT Carrier Phase Synchronization os cil lat or signal output
13 VSP IN Supply voltage for transmitter power stage
14 RXSS- OUT Receiver signal strength output (active low)
15 No connection
16 CPS_IN IN Carrier Phase Synchronization os c illat or signal in put
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High Performance RFM RI-RFM-007B April 1999
CAUTION: The transmitter ground pins GNDP and logic
ground pin GND must be connected together externally.
The RFM may be otherwise permanently damaged.
Table 2 lists the pin functions for the ATI connector J2: The connect or type is a
6 pin, 2 row connector with 2.54 mm pin spacing.
Table 2: J2 Pin Functions
Pin# Signal Direction Description
1 TXCT-R IN Transmitter control signal via resistor (active low)
2 GND OUT Logic ground
3 VD OUT Internal regulated logic supply voltage output
4 F_OSC-R IN/OUT Pulse width modulated transmitter oscillator signal via resistor
5 RXSS- OUT Receiver signal strength output (active low)
6 F_ANT OUT Antenna resonance frequency output signal (open collector)
Table 3 lists the pin functions for the J4 pulse width adjustment connector. The
connector type is 4 pin, 2 row with 2.54 mm pin spacing.
Table 3: J4 Pin Functions
Pin# Signal Description
1 RX Analog transponder signal
2 GNDA Ground antenna circuit
3 Pulse width adjusting resistor
connecting pin
4 GND Logic ground
14
April 1999 Product Description
Table 4 lists the functions f or connector J3. This is a 14 pin, 2 ro w connector with
2.54 mm pin spacing.
Table 4: J3 Pin Functions
Pin# Signal Description
1 ATC1 Antenna tuning capacitor 1 (weighted value 1)
2 GNDA Ground antenna circuit
3 ATC2 Antenna tuning capacitor 2 (weighted value 2)
4 GNDA Ground antenna circuit
5 ATC3 Antenna tuning capacitor 3 (weighted value 4)
6 GNDA Ground antenna circuit
7 ATC4 Antenna tuning capacitor 4 (weighted value 8)
8 GNDA Ground antenna circuit
9 ATC5 Antenna tuning capacitor 5 (weighted value 16)
10 GNDA Ground antenna circuit
11 ATC6 Antenna tuning capacitor 6 (weighted value 32)
12 GNDA Ground antenna circuit
13 AMTP Antenna circuit test point
14 No connection
Table 5 lists the pin f unctions for the antenna term inal connectors: Metric scre ws
size M3 are used for connection.
Table 5: Antenna Connectors
Signal Description
ANT1 Antenna resonator (capacitor side)
ANT2 Antenna resonator (transformer side)
Jumper JP4 allows enabling and disabling of common noise filtering for EMI
purposes. The default setting, with common noise filtering active, jum pers pins 2
and 3. A jumper between pins 1 and 2 bypasses common noise filtering.
15
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