SSDAC-G36

 An Insight Insight Into Single Section Digital Axle Counter (SSDAC-G36)  Approved by RDSO To SPEC No. RDSO/SPN/177/2005 Ver 2.0 with Amendment 1

By

G.G.Tronics India Private Limited SB 168, 3rd Cross, Peenya 1 st Stage, Peenya Industrial Estate, Bangalore-560 058 Ph 080-28372449/50/51

Fax 080

28372387

Web:www.ggtronics.com Web:www.ggtronics.com

Overview 

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SSDAC-G36 is a fail-safe microcontroller based system with 2 out of 2 architecture suited for for proving proving Block Section and Entry/Exit of station. Supports the following configurations with fool proof  arrangement of communication path and addressing scheme. 

2 DP-SS : in Straight Line (2D)

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3 DP-SS : in Point Zone / Set Points (3D)

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3 DP-2S : for two consecutive consecutive sections in Straight Line

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 AS

: auto signaling

Third party Verification and Validation of software completed for all configurations complying to CENELEC En50128 with SIL-4 level

 Application of SSDAC-G36 SSDAC-G36 

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2DP version is intended for providing clear/occupied status of a single section block or entry/exit of a station.

3DP-1S version used for proving point zone/set points working

3DP-2S version employed for proving two consecutive sections in a straight line treating each independent of the other

Functional Aspects 

Detection and counting of wheels / axles

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Detection of direction of axle movement

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Declaring a block section as occupied on the very first count of an axle

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Transmission/Reception of counts, system status and many vital information to other SSDAC unit via FSK communication employing quad cable Carrying out count comparison between local and remote units Declaring the track section clear after both the local and remote counts match after clearance of the last vehicle Displaying axle counts, unit status and error messages locally in each

unit and also remotely in the Reset box connected to the unit 

Logging vital information in event logger, for downloading on PC with GUI package through RS232C

Functional Aspects (Contd…) 

Shunting operation taken care of  

Train Shunting 

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No restrictions

Wheel Shunting 

Single sensor sensed once - allowed

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Single sensor sensed twice -Error mode

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Dual sensor - allowed up to 3 times

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Dual Sensor - 4 times - Error mode

Communication scheme  

Fail-safe feature incorporated to avoid wrong addressing Communication takes place only in fixed pairs Com1Com2 : Normal Com1Com1 : Error mode Com2Com2 : Error mode   

Functional Aspects (Contd…) 

Data Logger report retrieval (Through PC using GUI based S/W) 

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Local – RS232 (Serial port)

Portable Data Logger (Optional) 

For downloads all the events from SSDAC event logger card

Main Requirements of Specification - Complied 

To meet CENELEC SIL-4 Safety level

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Employ phase reversal technique

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Use of 2 out of 2 voting

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Data logging for 14000 events

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To work with 90-R, 52 Kg, 60 Kg rails

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Use of industrial grade components

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Stable operation in RE areas.

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To work between –10° C to +70° C

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MTBF more than 70000 hours ( As per QM115 method )

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To work between train speeds of 5Kmph to 250Kmph

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Not to need trolley suppression circuit

Salient Features 

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Common hardware/software for all configurations  Actuates Vital and Preparatory Relays

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Preparatory Reset after line verification possible

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Cooperative Reset from the station master cabin

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Reliable inter-communication of data between the units at distances up to 25 km or -30dB loss through quad cables at 1200bps using  V.23 protocol Works with 24V DC power supply

Salient Features (Contd…) 

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Wide input voltage operation from 16.8 VDC to 32.0 VDC Wrong operations totally avoided with unique addressing of  units up to 255 combinations

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Upgradation to higher configuration possible

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Integrated with lightening surge protectors

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Water logging on track does not affect the functioning of the system

Installation Details – Cable requirement STATION B

STATION A

1/2 quad cable (optional) station master communica tion

2 core cable 25 Sq mm power

6 core cable 1.5 Sq mm Reset and Repeat Relay Signal

2 core cable 25 Sq mm power

6 core cable 1.5 Sq mm Reset and Repeat Relay Signal

MODEM COMMUNICATION 1/2 quad cable

1/2 quad cable (optional) station master communica tion

END FED

START FED

APPROACH DETECTORS UP DIRECTION

21KHZ

21KHZ

25KHZ

TX1

TX2

RX1

RX2

25KHZ

MAXIMUM 25 KM's

21KHZ

21KHZ

25KHZ

TX1

TX2

RX1

RX2

APPROACH DETECTORS DOWN DIRECTION

25KHZ

Installation Details – Typical Installation- 2DP Railway Track 

21 KHz

25KHz

21 KHz RX

25 KHz

RX

TX

TX Axle Detectors

Axle Detectors

Filter Unit

Display Un it Relay Box Vital Relay B Prep Relay B P D1 P D2

 C  O M 2 

CP U 1

R D 2 

CP U 2

 S  P  A R E 

D  C -D  C  C  S   o P  SM n A R CPU /  v  e  E  Event r   t    e  Logger r 

SSDAC SF To SSDAC SF Unit

Display Unit

FSK  Communication

 S  P  A R E 

P D1 P D2

CP U 1

2  4   V D  C

 S  P  A R E 

R D 1 

 C  O M 1 

CP U 2

D  C -D  C  C  o SM n CPU /  v  e  r  Event  t    e  Logger r 

Relay Box Vital Relay A Prep Relay A

SSDAC EF Filter Unit

RS 232/ FSK  Communication

Reset Box

To SSDAC RS 232/ FSK  Communication EF Unit

Reset Box Power supply

Station A

Power supply

21 KHz RX 21 KHz TX

25 KHz RX 25 KHz TX

Station B

2  4   V D  C

Wheel Detection Principles 

Phase detection employed

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Signals fed at 21Khz and 25Khz to Tx coils – at 60V

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Phase of signal output of Rx compared with Tx

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 AT PD Module/Card : 

Under No wheel Tx and Rx signals will be 180° OUT-OF-PHASE >10V 

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Under wheel condition Tx and Rx will be IN-PHASE