Multiplexer Module (TX2A/TX4A)
18 November 1996
MUX-10
Notes:
If you are not using the TIRIS Add-on Module ‘Dynamic Auto Tuning’ remember that
the antennas are not individually tuned to resonance when used together with the
Multiplexer. So either tune the RF Module to the best resonance condition for all the
antennas being used, or include a ‘Dynamic Auto Tuning’ Module in your system.
Enabling a TX/RX channel enables both the transmit and receive function. However
disabling a TX/RX channel only disables the Transmit function (charge-up of a
transponder). The transmit function of a disabled channel is never completely switched
off, as there is still some coupling of the antenna resonance voltage from the active
channel to the disabled channels via the parasitic capacitance of the MOSFET switch.
This means that a transponder could still be charged-up at a distance of a few
centimetres from a disabled TX/RX antenna.
The receive function at a switched off antenna is never completely switched off, because
there is still reasonable coupling via the parasitic capacitance of the MOSFET switch.
As the TIRIS receiver is very sensitive, the small voltage which is coupled via this
capacitance, can still be enough to receive a transponder signal. Basically the receive
performance at a switched off TX/RX antenna is reduced by about 50% compared to an
enabled TX/RX antenna.
CAUTION: The RF Module must not be operated in continuous transmit mode.
WARNING
Care must be taken when handling the RF Module. HIGH
VOLTAGE across the antenna terminals and all antenna resonator
parts could be harmful to your health. If the antenna insulation is
damaged it should not be connected to the RF Module.
2
1
4
3
2
1
ANTENNAS
14 - 24 VDC
GND
4 WAY MUX
1 2 3 4
CHANNEL SELECT SIGNAL B
CHANNEL SELECT SIGNAL A
1 2 3
1 2 3 4 5 6 7 8 9
1 2 3 4 5 6
1 2 3
1 2 3 4 5 6
1 2
1 2 3 4
5 6
7 8
9 1 0 11 12 13 14 15
1 2
1 2 3
4 5 6
1 2 3
4 5 6
1 2 3
4 5
6
1 2 3 4 5
6
1 2 3
4 5 6
1 2
CPS
O.K.
O.K.
MAX
PWM
EMI
ACTIVE
DAT
CTL
RFM
RS422
CTL
O.C. - I/O
OFF / ON
RS232
RXSS- (EMI)
GND
GEN. I/O
S2510
MIN
SYNC
RX-ANT
ANT1 ANT2
4 A SLOW BLOW
+ - DC IN
J5 out
+
====
−
Figure 6: Connection of Multiplexer to S25x0 Reader
