AnsaldoSTS MicroLok II User manual
To order, call 1-800-652-7276
www.ansaldo-sts.com
p. 1
Wayside Signaling
Systems
Ansaldo STS USA
(Formerly known as Union Switch & Signal)
Rev. 4-11
MicroLok II Track Circuit PCBs
MicroLok II Track Circuit PCBs permit the system to perform the
critical function of train detection in railroad applications, both
along the mainline and interlocking locations. The MicroTrax
Coded Track Circuit PCB is part of a total track circuit system that
enables very long track circuits, accurate train detection
regardless of ballast conditions, and data-intensive through-the-
rails communications. The ECode Track Circuit PCB allows
MicroLok II systems to interface with most versions of the
Electrocode Track Circuit, thus expanding applications to more
territories and simplifying the transition to all-MicroTrax
operations. For railroad interlocking (e.g. end of siding), the OS
Track Circuit board provides a simple and reliable means of
detecting trains within the interlocking tracks (no track occupany
relays required).
Descriptions
“MicroTrax” Coded Track Circuit PCBs (N451910-0701, -7601, -7602, -
7603)
The MicroTrax Coded Track Circuit PCB provides an interface between
the CPU PCB vital microprocessor and MicroTrax style DC coded track
circuits. The MicroLok II CPU PCB monitors incoming coded track
circuit communications through this PCB, and interprets a loss of
communications (due to shunting of the signal by an approaching train)
as a track occupancy condition (train detection). Each Coded Track
Board monitors two adjacent track circuits simultaneously. The CPU
processes the occupancy inputs in the context of the entire interlocking
control scheme.
The generation track code signal is connected to the
rails through a Track Interface Panel consisting of a
transformer and a low impedance inductor (see RSE-
1D3). Eight front-panel LEDs on the board monitor a
variety of signals such as Master and Slave track
signal pulse transmissions and receptions (+/-) and
valid message confirmation.
ECode Track Circuit PCB (N17063901)
The ECode Track Circuit PCB enables MicroLok II
systems to be installed in territory equipped with
current and past generations of Electrocode track
circuits. This board interfaces with the MicroLok II
CPU PCB, where the actual processing of track
messaging and train detection indications are
performed. Both this PCB and its associated Track
Interface Panel (see RSE-1D3) are dual-capacity units
capable of handling two independent dc coded track
circuits.
The front panel of this board contains LEDs and
switches that permit on-site observation of track
signals, calibration and maintenance checks. By using
a pushbutton on the ECode Track Circuit PCB’s front
panel, users can view the transmitted/received codes,
receive current, transmit voltage and transmit current.
Rotary switches on the panel permit manual
adjustment of track code transmit levels for the two
controlled track circuits.
OS Track Circuit PCB (N451810-6701)
The On Switch (OS) Track Circuit PCB interfaces the
MicroLok II system to the OS track circuit at
interlocking applications requiring one OS transmitter
and two OS receivers (end-of-siding). An OS track
circuit is used to indicate the track occupancy status of
both the crossover track and the short section of
mainline track near the switch. Detection of the
presence of a train in either of these areas is used to
prohibit activation of the switch machine. Train
, p. 2
(Formerly known as Union Switch & Signal)
Rev. 4-11
MicroLok®II Track Circuit PCBs
OS Track Circuit PCB
Descriptions (cont’d)
OS Track Circuit PCB (cont’d)
detection indications are typically fed to a channel of
the Vital Input PCB in the same MicroLok II cardfile. It
is not necessary to connect both receivers if it is not
required by the application. In many cases the
transmitter is connected at the heel block and the two
receivers provide independent train detection on the
interlocking through and turnout tracks.
The OS Track Circuit PCB is not equipped with a front
panel and operates independently from the MicroLok II
cardfile bus. Four jumper locations on the board are
used to set the OS track shunting voltage.
Advantages
MicroTrax and ECode PCBs provide highly flexible
interface between the rails and the MicroLok CPU.
Both PCBs highly adaptable to various interlocking
and mainline applications.
Both PCBs equipped with detailed LED indications
for routine monitoring and diagnostics.
ECode front panel permits on-unit track circuit
adjustments.
OS Track Circuit PCB ideal for intra-interlocking
train detection, without vital relays.
MicroTrax TC PCB
ECode TC PCB
, p. 3
MicroLok®II Track Circuit PCBs
(Formerly known as Union Switch & Signal)
Rev. 4-11
Specifications
MicroTrax Track Circuit PCB
Cab Signal Compatibility: 40, 50, 50 and 100 Hz (see ordering tab.)
T.C. Length Adjustment: 0 to 36,000 ft. (10,973 m) in 1000 ft. (305 m)
increments
Standard Codes: 23 total (3 reserved for link-up, sleep mode and
quick tumble down)
20 (12 sec. acceptance time)
Fast Codes: 2 (6 sec. acceptance time)
Code Format: AC
Code Message Length: 2 sec.
Code Start/End: 167 msec guard pulse
Code Pulse Durations: 167 or 333 msec.
Code Amplitude: 2V p-p
ECode Track Circuit PCB
Track Circuit Lengths: ECode-to-ECode: Up to 24,000 ft. (7315 m) @ 3
ohms/1000 ft. (305 m) ballast
ECode to EC4: Up to 15,000 ft. (4572 m) @ 3
ohms/1000 ft. (305 m) ballast
ECode-to-EC5: Up to 24,000 ft. (7315 m) @ 3
ohms/1000 ft. (305 m) ballast
Shunt Det. Response: Standard: 3.7 to 6.3 sec.
Shunt clear: 11.2 to 12.6 sec.
Quick shunt option: 100 msec (approx.)
Transmitter: Output to 2.5 Ohms: 1.0 to 2.5 Vdc
Output Impedance: 0.15 Ohms
Current measurement range: 0 to 6.0A
Receiver: Input impedance: 0.15 Ohms
Current measurement range: 0 to 3.6A
Sys. P.S. Current Draw: +5V: 110 Ma
+12V: 43 Ma
-12V: 52 mA
Battery: 180 Ma (nom.), 1.1A (max.)
OS Track Circuit PCB
Operating Power: B12/N12 and +5Vdc
Transmit/Receive Freq.: 400 Hz
Receiver Output Voltage: 12 Vdc to 20 Vdc (15 Vdc nom.)
Track Circuit Length: 1000 ft. (305 m)
Track Lead Resistance: 0.5 ohms (max.)
Shunting Voltage Adjust: Via jumpers
Ordering and Additional
Information
Refer to tabulation for track
circuit PCBs’ part numbers.
Refer to RSE-1A2 for
additional information on
ECode Track Circuit
applications.
Contact your ASTS USA
Account Executive for
MicroTrax and ECode
applications and MicroLok
II applications possibilities
in general.
Request ASTS USA
Service Manual SM-6800E
for detailed information on
ECode Track Circuit
installation and calibration.
Request ASTS USA
Service Manual SM-6800B
for detailed information on
MicroTrax Track Circuit and
OS Track Circuit installation
and calibration.
, p. 4
(Formerly known as Union Switch & Signal)
Rev. 4-11
MicroLok®II Track Circuit PCBs
Ordering Information
Order No. Coded Track Circuit and OS Track Circuit PCBs
N451910-0701 Coded Track Circuit PCB for general non-cab & 100 Hz cab sig.-compatible applications.
N451910-7601 Coded Track Circuit PCB for 40 Hz cab signal-compatible applications.
N451910-7602 Coded Track Circuit PCB for 50 Hz cab signal-compatible applications.
N451910-7603 Coded Track Circuit PCB for 60 Hz cab signal-compatible applications.
N17063901 E-Code Coded Track Circuit PCB for Electrocode applications
N451810-6701 OS Track Circuit PCB
MicroLok® and MicroTrax® are registered trademarks of Ansaldo STS USA, Inc.
