This document provides information on the G.G.Tronics SSDAC axle counting system. It can be configured as a 2DP1S, 3DP1S, 3DP2S, or AS system. The 2DP1S configuration is described for a straight line or block section with start and end fed units communicating over a single pair of quad cable. Diagrams show the typical installation and positions of cards in the evaluator cabinet. The wheel detection principle based on phase detection is explained. Different configurations and their operation are also summarized.

2. G.G.Tronics SSDAC
It is an Versatile Axle counting system configurable as
2DP1S, 3DP1S, 3DP2S (IBS), AS
This is a fail-safe microcontroller based system with 2 out of
2 architecture suited for proving Block Section and
Entry/Exit of station.

3. G.G.Tronics SSDAC
Salient features of SSDAC-G36, 2DP-1S:
 The system consists of a Start Fed Unit (SF), an End Fed Unit
(EF) housed in location boxes adjacent to the track with
associated axle detectors web mounted on the track. The
distance between the unit & the detectors being 15m max.
 The block section to be monitored can be up to 25Kms.
 This is a rugged system & dispatched as a full package of
assembled & tested equipment, to make installation &
maintenance easier & quicker.
 The SF & EF units communicate with each other in FSK mode
at 1200bauds over a single pair of quad cable..

4. G.G.Tronics SSDAC
Salient features of SSDAC-G36, 2DP-1S:
 A diagnostic routine will be running continuously in both the
units & will be exchanging information through communication
over quad cable.
 The axle detectors are fed with 21 KHz & 25 KHz in both SF &
EF units.
 VR & PR relays are provided in the relay box along with the
system in the location box.
 The system is based on phase reversal technology wherein
the Tx & Rx signals will be in phase under no train condition &
will be out of phase during detection of a wheel/axle.

5. G.G.Tronics SSDAC
Salient features of SSDAC-G36, 2DP-1S:
 The system is designed to work with 90-R, 52Kg, 60Kg rails.
 The system is suitable for axle detection for train speed from 0
to 250KMPH with recognition of direction of movement of
train..
 The system can tolerate a vertical limit of worn out rail
specified by RDSO as indicated below
Sl. No. Rail Section Vertical wear in mm
1 60 Kg / meter 13.00
2 52 Kg / meter 8.00
3 90 R 5.00

6. G.G.Tronics SSDAC
Salient features of SSDAC-G36, 2DP-1S:
 Very much suitable for last vehicle detection.
 Can work in RE/Non RE areas satisfactorily
 The system senses wheels above 550mm dia, by which only
train wheels are detected & trolley wheels are ignored.
 Motor trolley wheels are not counted & also will not lead to
error condition.
 Two consecutive motor trolleys entering the same section
within a time gap of more than 6 seconds are allowed & will
not cause the system to go to error.
 One motor trolley following a train is allowed.

7. G.G.Tronics SSDAC
Salient features of SSDAC-G36, 2DP-1S:
 LED s are provided on individual modules for indication of
different stages of the working of the system.
 Seven segment displays are provided on CPU module for
bold display of status & error codes.
 LCD display modules of the unit & reset box provide plain
English messages of status & error codes making the system
highly user friendly during installation, commissioning &
maintenance.
 For resetting the system under different conditions, interactive
& intelligent reset box is provided in the station.

8. G.G.Tronics SSDAC
Salient features of SSDAC-G36, 2DP-1S:
 The system accepts co-operative reset with piloting of a train
or direct reset with/without line verification depending upon
the field conditions.
 If one field unit is reset & the second one is not reset within 5
minutes the reset initiation automatically gets cancelled.
 A 48V potential (from the 24V supply) is developed within the
reset box for effecting the reset of the system.
 A voltage window circuit ensures that the reset potential is
maintained within the limits of 36 to 52V.
 Foolproof working is ensured in hardware with polarization for
avoiding mix up of positioning of modules in SF/EF units.

9. G.G.Tronics SSDAC
Salient features of SSDAC-G36, 2DP-1S:
 Co-existence of multiple units without interference is achieved
by having 255 unique addresses through software.
 Amply protected with fuses & surge arrestors.
 Water clogging/flooding of track does not affect the working of
the system.
 Anti theft fixing bolts are provided for the coils on the track.
 Deflectors are also provided for avoiding damage to the
detector coils.
 The system works OFF 24V DC with a range of 20%, the
average current drain being <1.5Amps
 The system can work between -10 to +70 C.

10. Installation Details – Cable requirement
Station A Station B
2 Core ½ quad 2 Core
Al to 6 Core 1.5sqmm 6 Core 1.5sqmm ½ quad Al
Power Reset Copper for Copper for to Power
cable box Repeater relays Repeater relays Reset cable
and Reset and Reset box
START Maximum 25 Kms END
FED Modem Communication ½ Quad Cable FED
Evaluator Evaluator
21 KHz 25 KHz 21KHz 25 KHz
Tx-1 Tx-2 Tx-1 Tx-2
Rx-1 Rx-2 Rx-1 Rx-2
21 KHz 25 KHz 21 KHz 25 KHz

11. G.G.Tronics SSDAC
Installation Details – Typical Installation- 2DP

12. G.G.Tronics SSDAC
Evaluator Cabinet And Its Cards Positions

13. G.G.Tronics SSDAC
Positions of the Cards
Phase Detector Card-1
Phase Detector Card-2
DC-DC Converter
Event Logger
SM CPU/
CPU-1
CPU-2
Common for all Configurations like EF, SF and CF

14. Phase Detector Card-1
Positions of the Cards
Phase Detector Card-2
CPU-1 COM-2
CPU-2 Relay
Driver-2
Start Fed
Dummy
Dummy
SM CPU/
Event Logger
G.G.Tronics SSDAC
DC-DC Converter

15. Phase Detector Card-1
Positions of the Cards
Phase Detector Card-2
CPU-1 Dummy
CPU-2
Dummy
End Fed
COM-1
Relay
SM CPU/
Driver-1
Event Logger
G.G.Tronics SSDAC
DC-DC Converter

16. Phase Detector Card-1
Positions of the Cards
Phase Detector Card-2
CPU-1 COM-2
CPU-2 Relay
Driver-2
Center Fed
COM-1
Relay
SM CPU/
Driver-1
Event Logger
G.G.Tronics SSDAC
DC-DC Converter

17. G.G.Tronics SSDAC
Polarization of the Cards
Polarization of the Cards prevents wrong insertion of the cards

18. Wheel Detection Principle

19. G.G.Tronics SSDAC
Wheel Detection Principles
 Phase detection employed
 Signals fed at 21Khz and 25Khz to Tx coils – at 60V
 Phase of signal output of Rx compared with Tx
 AT PD Module/Card :
 Under No wheel Tx and Rx signals will be 180° OUT-OF-PHASE >10V
 Under wheel condition Tx and Rx will be IN-PHASE <1V
 These are fed to CPU at 5V and 0V
 Wheels above 550mm diameter only are detected
 For a train at 250Kmph, pulse width is about 2.2ms
 Frequency of Scanning by processor for PD signal is 300µs – 7 times for
every wheel

20. G.G.Tronics SSDAC
Wheel Detection Principle
Transmitter coil
Input and
Reference Signal
Receiver Coil Output
(Normally 180⁰ out of
phase under No wheel)
Wheel between
Tx and Rx coil
Receiver Coil Output
Under Wheel
Between t1 and t2
Once again Phase
shifted and now IN Phase shifted by 180⁰ and
PHASE with Decreased Amplitude
Tx / Reference Signal t0 Time t1 t2

21. G.G.Tronics SSDAC
Wheel Detection Principle Wheel between
Tx and Rx coil
Receiver Coil Output
Under Wheel
10V
Rectified
Voltage
Schmitt trigger
corresponding Threshold
to the Phase
1V
Shift 0V
5V
PD Card Output
0V
Equivalent Digital 1 1 1 1 0 0 1 1 1 1
data
t0 Time t1 t2

22. G.G.Tronics SSDAC
Wheel Detection Principle (Trolley Wheel)
Receiver Coil Output
Under Trolley Wheel
Trolley Wheel between
Tx and Rx coil
Rectified 10V
Voltage
corresponding Schmitt trigger
to the Phase threshold
Shift 1V
0V
PD Card Output 5V
Equivalent Digital 1 1 1 1 1 1 1 1 1 1
data 0V
t0 Time t1 t2

23. G.G.Tronics SSDAC
Differentiation of wheels
Train Trolley Wheel - Count
The wheel with Diameter
more than 550mm
1 1 1 0 0 1 1 1 PD-1
1 1 1 1 0 0 1 1 PD2
Overlap
Motor Trolley Wheel - No Count
The wheel with Diameter
less than 550mm
1 1 1 0 0 1 1 1 PD-1
1 1 1 1 1 1 0 0 PD-2
No Overlap

24. G.G.Tronics SSDAC
Differentiation of wheels
Wheel Detection - Dip Lorry - No Count
The Dip Lorry wheel with Diameter less
than 550mm and lesser wheel flange
1 1 1 1 1 1 1 1 PD-1
1 1 1 1 1 1 1 1 PD-2
No Pulse and No Detection

25. G.G.Tronics SSDAC
DIFFERENT CONFIGURATIONS OF THE SYSTEM

26. G.G.Tronics SSDAC
2DP1S Configuration:
Operation on Straight Lines Station or Block Section.
Communication using Single pair quad cable.
Preparatory reset configurable either with or without Piloting.
PR and VR contacts available at each detection points.

27. G.G.Tronics SSDAC
System Configuration - 2DP1S Version
Start Fed Legend : End Fed
RD1, RD2  Relay Drive Card
Com1, Com2  Communication Card
VR RD2 VR RD1
SF  Start Fed
EF  End Fed
PR DAC-1 VR  Vital Relay PR DAC-2
PR  Preparatory Relay
Com2 Com1
DAC-1 DAC-2
Relay Drv-2
Relay Drv-1
Com-2
DC-DC Converter(+24V)
DC-DC Converter(+24V)
Phase Detector Card-1
Phase Detector Card-2
Phase Detector Card-1
Phase Detector Card-2
Event Logger
Event Logger
SM-CPU
SM-CPU
Com-1
CPU-1
CPU-2
CPU-1
CPU-2
2DP Card Configuration in SSDAC G36

28. G.G.Tronics SSDAC
3DP1S Configuration:
Operation on Point Zones/ Set of Points.
Communication using Single pair quad cable.
Detection at any points and clearing at any points.
Preparatory reset with Line Verification.

29. VR
Phase Detector Card-1
Phase Detector Card-2
RD2
CPU-1 Com-2
Unit A
DAC-1
CPU-2
Relay Drv-2
Com1 Com2
DAC-1
Com-1
SM-CPU
Event Logger
VR
DC-DC Converter(+24V)
RD2
Phase Detector Card-1
Unit B
DAC-2
Phase Detector Card-2
Com1 Com2
System Configuration - 3DP-1S
CPU-1 Com-2
CPU-2
Relay Drv-2
VR
DAC-2
Com-1
SM-CPU
Event Logger
RD2
DC-DC Converter(+24V)
Unit C
DAC-3
Com1 Com2
3DP Card Configuration in SSDAC G36
Phase Detector Card-1
VR
Phase Detector Card-2
G.G.Tronics SSDAC
CPU-1 Com-2
Legend :
RD1, RD2
CPU-2
Relay Drv-2
DAC-3
Com-1
SM-CPU
Event Logger
 Vital Relay
DC-DC Converter(+24V)
 Relay Drive Card
Com1, Com2  Communication Card

30. G.G.Tronics SSDAC
3DP2S (IBS) Configuration:
Operation on two consecutive sections on a straight Line
(IBS Configuration.
Communication using Single pair quad cable.
Preparatory reset configurable either with or without Piloting.
PR and VR contacts available at all detection points.

31. Phase Detector Card-1
PR A
SFVR-A
Phase Detector Card-2
CPU-1 Com-2
Reset-SF
RD2
Section-A
CPU-2
Relay Drv-2
SF
DAC-SF
Com2
Station-A
SM-CPU
Event Logger
Reset-CF
Section-B
DC-DC Converter(+24V)
System Configuration - 3DP-2S
Phase Detector Card-1
PR A
PR B
CFVR-A
CFVR-B
Phase Detector Card-2
CPU-1 Com-2
CPU-2
RD2
Relay Drv-2
CF
Com-1
DAC-CF
RD1
SM-CPU Relay Drv-1
Com1 Com2
Event Logger
DC-DC Converter(+24V)
Phase Detector Card-1
3DP-2S Card Configuration in SSDAC G36
PR B
Phase Detector Card-2
EFVR-B
G.G.Tronics SSDAC
CPU-1
Reset-CF
Section-A
EF
CPU-2
RD1
Com1
Com-1
Station-B
DAC-EF
SM-CPU Relay Drv-1
Event Logger
Reset-EF
Section-B
DC-DC Converter(+24V)

32. G.G.Tronics SSDAC
AS or Auto Signalling
Section A Section B Section C Section n+1
Block 1 Block 2 Block n+1
 Operation on continuous sections in suburban areas or on a long track
 Up to 128 SSDAC’s can be daisy chained in series
 Communication using single pair / half quad cable or OFC voice channel
 Option of Preparatory Reset with or without piloting

33. G.G.Tronics SSDAC
FIXING OF TRANSDUCERS:
60 Kg 60 Kg
52 Kg 52 Kg
90 Lb 90 Lb

34. G.G.Tronics SSDAC
FIXING OF TRANSDUCERS:
 Tx & Rx coils to be fixed on the rails by drilling 14mm dia
holes with the help of the jig provided for fixing the
distance of the holes from bottom on different rails
 These coils are fixed to the rails through tamper proof
bolts.
 Tx & Rx coils are supplied with 15m cables. Each pair
has to be taken up to the system independently through
HDPE pipes.

35. G.G.Tronics SSDAC
FIXING OF TRANSDUCERS:
Axle detector coils web mounted on to a track

36. G.G.Tronics SSDAC
Typical SSDAC-G36 Unit
Relay Drive Card
PD Cards
CPU Cards Event Logger Card
Communication 24VDC Power Supply
Card

37. G.G.Tronics SSDAC
Configuration of CPU:
For setting the configuration & address, berg sticks
are provided with links. These links have to be set
as per the requirement.

38. G.G.Tronics SSDAC
Start Fed Configuration:

39. G.G.Tronics SSDAC
End Fed Configuration:

40. G.G.Tronics SSDAC
CPU Address Setting of SF:
Jumper Settings
LK10 LK11 LK12 LK13 LK14 LK15 LK16 LK17 Address
Assigned
LSB MSB
1 0 0 0 0 0 0 0 1
0 1 0 0 0 0 0 0 2
▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼
0 0 1 1 1 1 1 1 252

41. G.G.Tronics SSDAC
CPU Address Setting of EF:
Jumper Settings
LK10 LK11 LK12 LK13 LK14 LK15 LK16 LK17 Address
Assigned
LSB MSB
1 1 0 0 0 0 0 0 3
0 0 1 0 0 0 0 0 4
▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ▼
0 1 1 1 1 1 1 1 254

42. G.G.Tronics SSDAC
Address Scheme for 2DP1S:
Group Group
SF EF
SSDAC Unit Local Local
Stat Fed End Fed
Address Address
SSDAC CPU-1 001 CPU-1 003
1-2 CPU-2 002 CPU-2 004
SSDAC CPU-1 005 CPU-1 007
3-4 CPU-2 006 CPU-2 008
SSDAC CPU-1 009 CPU-1 011
5-6 CPU-2 010 CPU-2 012
▼ ▼ ▼ ▼ ▼
▼ ▼ ▼ ▼ ▼
▼ ▼ ▼ ▼ ▼
SSDAC CPU-1 251 CPU-1 253
‘n’ CPU-2 252 CPU-2 254

43. G.G.Tronics SSDAC
HARDWARE MODULES AND CARDS
Functions of Each Card and their
settings

44. G.G.Tronics SSDAC
PHASE DETECTOR CARD (PD-1)
 It generates 21 Khz Signal and feeds to Tx1 Coil.
 It Receives 21 Khz Signal from Rx1 Coil.
 It detects the Amplitude and phase of the
Received signal.
 It generates a pulse depending on the
amplitude and phase reversal of the signal.

45. G.G.Tronics SSDAC
PHASE DETECTOR CARD (PD-2)
 It generates 25 Khz Signal and feeds to Tx2 Coil.
 It Receives 25 Khz Signal from Rx2 Coil.
 It detects the Amplitude and phase of the
Received signal.
 It generates a pulse depending on the
amplitude and phase reversal of the signal.

46. G.G.Tronics SSDAC
Monitoring Points of PD cards
As soon as power on Tx ON and SUP OK
indications should glow
Wheel Main and Wheel Sec Indications
should be OFF.
That Indicates the Tx and Rx coil
connections are correct.
And the Transmitted signal and Received
signals are in phase

47. G.G.Tronics SSDAC
Monitoring Points of PD Cards
On other hand along with Tx ON and Sup
OK green indications if Wheel Main and
Wheel Sec Red indications are also glowing.
That Indicates the Transmitted and
Received signals are 180˚ out of phase
without wheel over the coils
Then change the polarity of receiver coils
cable at termination. Then Wheel Main
and Wheel Sec Red indications
disappears.

48. G.G.Tronics SSDAC
PHASE DETECTOR CARD (PD-1 & PD-2)
Module Monitoring Point Name Expected values With wheel
Without wheel
RX-SIG and GND (Rx Adj) 900 mV to 1.2 V AC < 350mV AC
PHASE SUP-OUT and GND 4V to 5V DC 3V to 3.9V DC
DETECTOR
Wheel Main and GND 4.5v to 5V DC < 100mV
(PD1 & PD2 )
Wheel Sec and GND 4.5v to 5V DC < 100mV
RX Phase Sig and GND 10V to 12V DC <1V
(Phase Adj)
Sup Level and GND (Sup Adj) 4V to 5V DC 3V to 3.9V DC

49. G.G.Tronics SSDAC
CPU-1
It receives the pulses from PD1 and PD2 and
 Establishes the direction
 Counts the number of wheels.
 Adds the counts to IN or OUT Count register.
with the help of software installed in it.
It compares the counts of CPU-2 and the counts
of Remote end counts and gives the
clear/occupied decision of the section.
It continuously monitors the health of the
evaluator and its accessories.
It displays the error code through two seven
segment displays.

50. G.G.Tronics SSDAC
CPU-1
Here both the CPUs are of similar hard ware
and similar software.
Both the CPUs process the same data
separately and gives the decision separately.
 Failsafe 2 out of 2 architecture for controlling
and monitoring the SSDAC for reliable
operation
 Houses the system software that schedules the
overall operation as per configuration

51. G.G.Tronics SSDAC
Monitoring Points of CPU-1 & 2
Module Monitoring Point Name Measured Values
range
CPU-1 EN1B O/P and GND 11.5V to 12.5v DC
(for SF, CF, 3DP1S units
EN1A O/P and GND 11.5V to 12.5v DC
(for EF, CF)
CPU-2 EN2B O/P and GND 11.5V to 12.5v DC
(for SF, CF, 3DP1S units
EN2A O/P and GND 11.5V to 12.5v DC
(for EF, CF)

52. G.G.Tronics SSDAC
Relay Drive Card
Relay Driver card receives instructions from CPU for
actuating Vital relay for blocking a section as soon as
the first axle is detected. It is cleared after both IN
and OUT counts of the section match.
Expected
Module Monitoring point
values
RELAY DRIVE 1 VITAL RLY A O/P (+)
> 20V DC
(for EF, CF) VITAL RLY A O/P (-)
RELAY DRIVE 2 VITAL RLY B O/P (+)
> 20V DC
(for SF, CF, 3D units) VITAL RLY B O/P (-)

53. G.G.Tronics SSDAC
COMMUNICATION CARDS (COM1 & COM2)
 Communication between two SSDAC systems is through FSK
communication at 1200bps V.23 standard along with CRC check
 Vital data like axle counts and system status are
transmitted/received between the SSDAC system units
 The digital data packet (consisting of count information, Direction
information, Health of the equipment, Any error messages)
generated by CPU is converted into analog form and sends to
remote end evaluator through FSK communication.
 On other hand the information received in analog form from remote
end evaluator is converted into digital and gives to CPUs.

54. G.G.Tronics SSDAC
COMMUNICATION CARDS (COM1 & COM2)
Tx Green indication should flash indicating
that it is transmitting data.
Rx Green indication should flash
indicating that it is Receiving data.
CD Green indication should flash
indicating that carrier is available
between the two evaluators.
Clear to Send Indication.
It should be flashing.
Request to Send Indication.
It should be flashing.
No measuring points were given on Communication card.

55. G.G.Tronics SSDAC
DC-DC Converter card
 Generates required multiple power outputs
from 24VDC input

56. G.G.Tronics SSDAC
Monitoring Points DC-DC Converter
Module Monitoring point Expected values
+5VDC and GND 4.75 to 5.25V DC
+18VDC and GND 17.75 to 18.25V DC
DC-DC Converter
+12VDC and GND 11.75 to 12.25V DC
-12VDC and GND 11.75 to 12.25V DC
+24VDC and GND 22V to 26V DC

57. G.G.Tronics SSDAC
SM CPU and Event Logger Card
 SM-CPU or Event Logger Card
 Monitors the SSDAC system and logs vital events during
normal and error operation with date and time stamp
 As many as 95 different events are recorded
 Optional display connected to Event Logger Card displays the
communication errors happening in Real-time which aids in
assessing the health of communication channel
 Event logged during normal operation
 Communication status ok
 Vital and Preparatory Relay pickup / drop
 Reset operations
 Event logged during error operation
 Communication link fail
 System down due to failure of any card
 Vital and Preparatory Relay error status
 +5 VDC variations
 Errors

58. G.G.Tronics SSDAC
Precautions to be taken for trouble free operation
Power Supply-24DC:
 Use Axle Counter type , ripple free Charger
 Use 120 AH battery with adequate life
 Use 25 sq mm AL cable for feeding power to the system
 Provide class ‘B’ Surge Protector at source of 24 V DC in station
 Avoid tapping of different loads to the power source of Axle
Counter

59. G.G.Tronics SSDAC
Precautions to be taken for trouble free operation
Quad Cable:
 Loss should be less than 30 db between SF and EF(1.2 db/km)
 Every joint adds loss to the cable, minimize joints and take care
for making good permanent joints .
 Insulation resistance to be more than 10 M ohms at 100 V DC
between conductors ,between pairs and between wire and armor
 Loop resistance to be within 56 ohms/km
 Maintain continuity of armor between SF and EF & earth at both
ends .

60. G.G.Tronics SSDAC
Precautions to be taken for trouble free operation
Parallel Circuits:
 It has come to notice that usage, termination and wiring of quad cable is far from
satisfactory for trouble-free working of digital axle counters. Basic issue pertains
to electromagnetic interference from parallel circuits in the cable and location.
Following guidelines are recommended to enhance performance of DAC
systems.
 Long parallel circuits shall be avoided in the same quad. Requirement is that
parallel circuit shall be as far spaced as possible. So, one long and one short
circuit can be accommodated in same quad but not both long circuits.
 DAC circuits in BPAC of up and down lines in double line sections shall be in
separate quads and kept one/two quads away from each other as far as possible
to avoid mutual interference due to long parallel circuits.
 DAC circuits in location shall not bunched along with parallel relay/power circuits.
Relay circuits are known to generate switching transients that can couple enough
energy in parallel circuits nearby and interference with low power circuits data
circuits.
 Any other parallel wiring (relay circuits/power circuits/earthling wires etc) shall
cross DAC circuits at perpendicular and any parallel portion shall be kept at
minimum 150mm lateral distance away from the wiring for DAC circuits.
 Relay circuits shall preferably be not taken in the same cable as DAC circuits. In
unavoidable circumstances relay circuits shall be in furthest quad (spatially) from
the one containing DAC circuits.

61. G.G.Tronics SSDAC
Precautions to be taken for trouble free operation
Twisting of Cable Pairs:
 Twisted pairs are required to avoid mutual interference between low
level ac signals. Even short lengths of non-twisting (few inches) can
couple enough differential mode electromagnetic signals to interfere
with low voltage DAC communication signals.
 Quad cable twisting shall be ensured during termination so that
minimum one twist per inch is maintained till the last inch into
terminations.
 Any wiring from quad cable terminations to equipment shall be done by
using twisted singles of indoor signaling cable (1mm square) or any
other approved indoor twisted pair cable.
 Signaling cable or any other untwisted pair cable shall never be used
in DAC communication circuits to avoid intermittent type of failure.

62. G.G.Tronics SSDAC
Precautions to be taken for trouble free operation
Continuity and Earthing of cable armor & screen at intermediate
terminations/Joints:
 Screening of quad cable of effective when induced current can flow in the
screen thereby canceling/reducing the induction for the cable conductors.
For adequate induced current to flow in screen, it is necessary that good
earth connections are provided for screen & armor at all the cable
terminations and joints.
 Quad cable screen & armor shall be made continuous at the intermediate
terminations/joints by soldering and connecting both ends of cable
screens & amours at the locations.
 Connections to screen shall preferably be made by metallic clamps
soldered to screen to ensure good surface connection for electrical
continuity.
 Combined earthing for both ends of armor and screen at intermediate
locations shall be ensured to be in good condition and having values as
low as possible but never more than 5Ω.
 Earthing connection shall be kept short and as straight as possible
because any loop or turns can create inductive elements that impede
quick discharge of transients and surges to ground.

63. G.G.Tronics SSDAC
Precautions to be taken for trouble free operation
Earthing :
 Earth resistance to be less than 2 ohms
 If not archived by single earth provide multiple earth and parallel then

64. G.G.Tronics SSDAC
Reset Box with LCD Display – Clear condition of track

65. G.G.Tronics SSDAC
Reset Philosophy
 Types of Reset
 Co-operative Preparatory Reset with piloting for  2D and 3D-2S
configurations
 Direct Reset with line verification for  3D configuration
 Reset Procedure
 2D : System powered onReset ModePrep
ModePilotingClear Mode
 3D-2S: System powered onReset ModePrep
ModePilotingClear Mode
 3D : System powered on Reset ModeLVClear Mode

66. G.G.Tronics SSDAC
Reset Philosophy
 For Single line working one reset box is provided at the station
associated with SF or EF unit of that track
 In double line section each station will have two reset boxes
corresponding to the two units of the SF/EF for UP/Down lines.
 Normally co-operative reset with the running of the pilot train is
accepted.
 When direct reset is required, line verification for the clear condition is
necessary.
 Under special field conditions direct reset can be applied without line
verification.
 The reset potential has to be within the range of 36 to 52V.

67. G.G.Tronics SSDAC
Reset Philosophy
The system accepts reset under the following conditions:
 Initial power ON.
 When power fails & restores back when I/P voltage to
the system fluctuates beyond limits.
 The reset is applied to both the field units.
 When there is an in count at the entry & at least one
out count at the exit indicating the train has touched the
end of block section.

68. G.G.Tronics SSDAC
Reset Philosophy
 The system will not accept reset under the following conditions:
 When the section is clear.
 When the system is waiting for pilot train.
 When there is an in count but no out count is registered.
(Occupied state)
 When reset is given only from one station (not co-operative)
 When the system is in permanent error status.
 When reset is applied at one end & the other end does not
reset within 5 minutes.
 Removal of any of the PCB modules or fuses.
 Disconnection / damage of axle detector of coils

69. G.G.Tronics SSDAC
Reset Philosophy

70. G.G.Tronics SSDAC
Installation Procedure
 The installation can be taken up with the following parallel activities
 Laying foundation as per Railway standards for fixing the location box
 Trenching for running the required length of cable
 Drilling of track for fixing TX/RX coils with the template
 Fixing of TX/RX coils on the track
 Laying of power cables, signalling cables and cables from TX/RX coils
 Painting and fixing of required planks and fuse the terminal block
 Digging Earth pit and getting ready the earthing arrangement
 Checking for the compliance of pre commissioning check list
 Placing the unit along with related PCB modules/cards and Display module
 Connecting earth terminal of the unit chassis to the main chassis and on to the
main earth through copper cables

71. G.G.Tronics SSDAC
Installation Procedure Contd…
 Placing Relay box adjacent to the unit
 Fixing of the MS Coupler cable assemblies on to the designated mating
Couplers on the rear panel of the system
 Checking continuity and insulation resistance between cable pairs and also
between the chassis and the cables
 Connecting all the shields and the screen wires to the earth
 Fixing of the reset box in a convenient location in the station
 Connecting the wires coming from the system to the reset box
 Connecting 24V DC to power supply
 Connecting the power cables coming from the system to the source of power
supply of 24V DC at the station, keeping the FTB connector open

72. G.G.Tronics SSDAC
Maintenance:
Periodicity Maintenance
Check for the proper voltage at the battery
Weekly
source for the unit
Check and record the readings of
Fortnightly 1. Power supply module
2. PD module
3. Check the coil Voltages
Half yearly / Yearly Replace defective parts if any
Power Supply/DC-DC Converter modules
Every 5 Years
must be replaced

73. G.G.Tronics SSDAC
Back Up Spares Required
Sl.No SSDAC Spares Quantity
1 Phase Detector modules1&2 (PD1 and PD2) 2
2 CPU1 and CPU2 Modules 2
3 Communication Modules 2
4 Relay drive Module 1
5 Event Logger/SM-CPU Module 1
6 DC-DC converter Module 1
7 Axle detectors 21 KHz/25KHz (TX coil) 2
8 Axle detectors 21 KHz/ 25 KHz (RX coil) 2
9 Hardware for mounting axle detectors 1
10 MS circular connectors (6 No.) 1
11 Reset box RB 1
12 SSDAC unit (housing with mother board, without modules) 1
13 Relay Box 1

74. G.G.Tronics SSDAC
Recommended Tools
Sl.No Tools Quantity
PC/Laptop for downloading event logger data for
1 1
analysis and report generation
Pure sine wave Digital Multimeter (Fluke make 187
2 1
or Rishab make 28S or similar
3 Train simulator 1
4 Extender module 1
5 Dummy wheel 1
6 Ring spanner 17-19,24-26 1
7 Open end spanner 17-19, 24-26 1
8 Socket spanner with handle 1
9 Torque wrench 1
10 Screw Driver No. 902 1
11 Screw Driver No. 935 1
12 Marking jig for drilling 1

75. G.G.Tronics SSDAC
DOs :
Sl.No DO’s
The interconnection drawings are to be followed for connecting the Transmitter and Receiver
1
Coils. Tx1 is 21 KHz, Tx2 is 25 KHz & Rx1 and RX2 coils are 21 KHz & 25 KHz, respectively
2 Ensure that Receiver and Transmitter coil cables are laid in different pipes.
3 Ensure that both the TX coils & RX coils are having proper alignment on Rail.
4 Ensure that packing of sleepers with ballast on both sides of Axle detector is proper
5 Check that metal sheaths of the outdoor cable are connected to earth at both ends
6 The recommended cables for wiring of the system at site should be used
7 The steady battery voltage 24 V should be maintained.
8 The cable connections should not be loose
9 The M.S Coupler connectors of SSDAC are checked and maintained firmly.
10 Preparatory Reset should be done only after ensuring that there is no train
It is recommended that heat resisting paint to be used on the apparatus case so that the
11
temperature inside apparatus case is maintained lower in comparison to other normal paints

76. G.G.Tronics SSDAC
DONTs:
Sl.No DON’Ts
Don’t cut or join the Transmitter/Receiver cables supplied along with the coil.
1
It would result in change of levels of signals.
Don’t remove the modules from SSDAC Units under POWER ON condition of system.
2
Remove module if necessary after switching OFF the power to the Unit.
Local Address of the CPU-1 and CPU – 2 and configuration settings of the system
3
should not be changed at the field as far as possible.
The hardware of Communication module and Relay Drive module are similar for all
systems. However their positions of mounting is different in different unit types.
4
These modules have to be equipped correctly after verifying the drawings as mentioned
in the installation manual (DRG-1 to DRG-4) which indicates their positions
Caution Board has to be placed near the SSDAC Axle detectors to avoid damage to the
5
Coils from packing machines

77. G.G.Tronics SSDAC
Trouble Shooting:
 For ease of maintenance in the field messages are provided in the Display
Module both during healthy and Error conditions
 About 61 possible conditions have been identified which drives the system
into Error mode.
 The errors are displayed in plain English on the Display Module
 Further slides indicate the messages, their analysis and the corrective action
to be taken

78. G.G.Tronics SSDAC
Trouble Shooting:
Error Code on
Errors Analysis Corrective measure
display of CPU
Error occurred due to missing of the Phase detector 1 Place the PD1 module in the
1 PD1_BOARD_MISSING module (PD1- 21KHz) during run time and boot slot and reset the
time diagnosis. system
Error occurred due to missing of the Phase detector 2 Place the PD1 module in the
2 PD2_BOARD_MISSING module (PD2- 25KHz) during run time and boot slot and reset the
time diagnosis. system
Place the SM-CPU module in
Error occurred due to missing of the SM-CPU module
3 SM_CPU_MISSING the slot and reset the
during run time and boot time diagnosis.
system
Error occurred due to missing of the Communication A Place the Communication A
4 MODEM_MODULE_A_MISSING module during run time and boot time module in the slot and
diagnosis. reset the system
Place the Communication B
Error occurred due to missing of the Communication B
5 MODEM_MODULE_B_MISSING module in the slot and
module during run time and boot time diagnosis
reset the system
Place the Relay Drive A
Error occurred due to missing of the Relay Drive A
6 RELAY_DRIVE_A_MISSING module in the slot and
module during run time and boot time diagnosis
reset the system
Place the Relay Drive B
Error occurred due to missing of the Relay Drive B
7 RELAY_DRIVE_B_MISSING module in the slot and
module during run time and boot time diagnosis
reset the system

79. G.G.Tronics SSDAC
Trouble Shooting:
Error occurred due to missing of the any one of
Place the CPU module missing in
8 PEER_CPU_MISSING the CPU module during run time and
the slot and reset the system
boot time diagnosis
Check the communication links (MS
When EF CPU1 could not transmit to remote
9 COMM_LU1_TO_US1_FAILURE Coupler) and Reset the
unit (CF or SF) CPU1
system
Check the communication links (MS
When EF CPU1 could not transmit to remote
10 COMM_LU1_TO_US2_FAILURE Coupler) and Reset the
unit (SF or CF) CPU2
system
Check the communication links (MS
When SF CPU1 could not transmit to remote
11 COMM_LU1_TO_DS1_FAILURE Coupler) and Reset the
unit (CF or EF) CPU1
system
Check the communication links (MS
When SF CPU1 could not transmit to remote
12 COMM_LU1_TO_DS2_FAILURE Coupler) and Reset the
unit (CF or EF) CPU2
system
Check the communication links (MS
When EF CPU1 could not receive any response
13 COMM_US1_TO_LU1_FAILURE Coupler) and Reset the
from the remote unit (SF or CF) CPU1
system
Check the communication links (MS
When EF CPU2 could not receive any response
14 COMM_US2_TO_LU1_FAILURE Coupler) and Reset the
from the remote unit (SF or CF) CPU1
system
Check the communication links (MS
When SF CPU1 could not receive any response
15 COMM_DS1_TO_LU1_FAILURE Coupler) and Reset the
from the remote unit (CF or EF) CPU1
system

80. G.G.Tronics SSDAC
Trouble Shooting:
When SF CPU2 could not receive any Check the communication links
16 COMM_DS2_TO_LU1_FAILURE response from the remote unit (CF or (MS Coupler) and Reset
EF) CPU1 the system
Check the communication links
When EF CPU2 could not transmit to remote
17 COMM_LU2_TO_US1_FAILURE (MS Coupler) and Reset
unit (SF or CF) CPU1
the system
Check the communication links
When EF CPU2 could not transmit to remote
18 COMM_LU2_TO_US2_FAILURE (MS Coupler) and Reset
unit (SF or CF) CPU2
the system
Check the communication links
When SF CPU2 could not transmit to remote
19 COMM_LU2_TO_DS1_FAILURE (MS Coupler) and Reset
unit (CF or EF) CPU1
the system
Check the communication links
When SF CPU2 could not transmit to remote
20 COMM_LU2_TO_DS2_FAILURE (MS Coupler) and Reset
unit (CF or EF) CPU2
the system
When EF CPU1 could not receive any Check the communication links
21 COMM_US1_TO_LU2_FAILURE response from the remote unit (SF or (MS Coupler) and Reset
CF) CPU2 the system
When EF CPU2 could not receive any Check the communication links
22 COMM_US2_TO_LU2_FAILURE response from the remote unit (SF or (MS Coupler) and Reset
CF) CPU2 the system
When SF CPU1 could not receive any Check the communication links
23 COMM_DS1_TO_LU2_FAILURE response from the remote unit (CF or (MS Coupler) and Reset
EF) CPU2 the system

81. G.G.Tronics SSDAC
Trouble Shooting:
When SF CPU2 does not receive any
Check the communication links (MS
24 COMM_DS2_TO_LU2_FAILURE response from the remote unit
Coupler) and Reset the system
(CF or EF) CPU2
Carrier signal is being blocked by
25 MODEM_ERROR_NO_CARRIER Replace the faulty module
modem
Error occurred due to missing or error Check for the error or presence of SM-
in CPU/ SM-CPU module during CPU/CPU module in the system,
26 PEER_CPU_LINK_FAILURE
run time and boot time rectify the error and reset the
diagnosis system
Check the error at remote unit, rectify
27 FAILURE_AT_DS Error at Down stream unit
the error and reset the system
Check the error at remote unit, rectify
28 FAILURE_AT_US Error at Up stream unit
the error and reset the system
PD1 module supervisory is low for 3
Check the PD1 module, coils and reset
33 PD1_SUP_LOW seconds and TX and RX coils is
the system
not connected properly
PD2 module supervisory is low for 3
Check the PD2 module, coils and reset
34 PD2_SUP_LOW seconds and TX and RX coils
the system
not connected properly
Error occurs when any one sensor is
35 PD1_PULSING Reset the system
influenced two or more times.
Error occurs when any one sensor is
36 PD2_PULSING Reset the system
influenced two or more times.
Error occurs when double sensor is
37 PD_STATE_MISSING Reset the system
influence in the sequence

82. G.G.Tronics SSDAC
Trouble Shooting:
If supervisory signals pulsates more than
38 PD_SUP_PULSATING Reset the system
4 times
Error occurs when any state sequence is
39 PD_STATE_FAIL Reset the system
missing
Error occurs when both the PD modules
40 PD_NOT_SENSING doesn’t sense the wheel for more Reset the system
than 3 times
Check the connections of Preparatory
No/Improper feedback from Preparatory A
41 PREPARATORY_RELAY_A_FAILURE relay A (PRA) and reset the
relay
system
Check the connections of Preparatory
No/Improper feedback from Preparatory B
42 PREPARATORY_RELAY_B_FAILURE relay B (PRB) and reset the
relay
system
No/Improper feedback from Vital Relay A Check the connections of Vital relay A
43 VITAL_RELAY_A_FAILURE
relay (VRA) and reset the system
No/Improper feedback from Vital Relay B Check the connections of Vital relay B
44 VITAL_RELAY_B_FAILURE
relay (VRB) and reset the system
Without IN COUNT, OUT COUNT
45 DIRECT_OUT_COUNT Reset the system
registered
49 TRANSIENT_POWER_FAILURE_DS1 Power failure at Down stream CPU1 Reset the system
50 TRANSIENT_POWER_FAILURE_DS2 Power failure at Down stream CPU2 Reset the system
51 TRANSIENT_POWER_FAILURE_US1 Power failure at Up stream CPU1 Reset the system
52 TRANSIENT_POWER_FAILURE_US2 Power failure at Up stream CPU2 Reset the system

83. G.G.Tronics SSDAC
Trouble Shooting:
Change the address settings by using
57 INVALID_NETWORK_ADDRESS When CPU address range wrong LK10 to LK17 links and reset
the system
This is a Boot Up error. When CRC of
Re-program the processor and code
58 INCORRECT_CODE_CRC the code mismatches with the
memory checksum
stored CRC
Change the address and configuration
When unit type and address of CPU is
59 INVALID_CONFIGURATION settings as per the requirement
wrong
and reset the system
60 INVALID_COUNTS Train with 10,000 wheels Reset the system
This is an Boot up error when RAM
61 RAM_TEST_FAILED (In- built memory of Replace the Micro Controller
Microcontroller) is failed

84. G.G.Tronics SSDAC