Series Mode Track Circuit Application; Figure 2-2. Series Mode Track Circuit Application - Hitachi ATT-20 Installation, Operation, Troubleshooting

2.3. Series Mode Track Circuit Application

In this application, the transmitter and receiver are wired in sequence via a jumper on
the ATT-20 unit. This jumper connects transmitter output terminal 4 to the receiver input
terminal 6. The remaining transmitter output lead (terminal 3) and the remaining
receiver lead (terminal 5) are twisted as a pair and each is connected to its respective
rail (see Figure 2-2). The presence of a train axle across the rails completes the series
signal path, thus detecting the approach of a
The series mode of operation is a non-vital application.
"O"
OHM SHUNT
1
12V
BATTERY
2
CABLE COMPENSATING PCB
1

Figure 2-2. Series Mode Track Circuit Application

Copyright 2019
60 FEET
1 2
USSP-21
3 4
3
5 7
8
4 6
ATT-20
L1
C1 2
T2 T3
T1
CT
SM 6299 Rev. 3, March 2019
ATT-20 Audio Track Transceiver
train.
75 FEET
ADJUSTMENT
SHUNT
_
+
TWISTED PAIR
2-2