3 & 4 Aspect Signalling
MAS-SEQUENCER-4 AND IRDASC-4
The MAS-SEQUENCER-4 and IRDASC-4 have been designed to give easily installed 3 and 4 aspect signal control.
Although the units can operate a string of signals in a prototypical way they can also operate just one or two multi aspect signals on a small layout.
Both units have built in infra red train detection and can be supplied with options for 2, 3 or 4 aspect LED signals. Units are available for either common negative or common positive LED signals.
The MAS-SEQUENCER-4 operates 2, 3 or 4 aspect signals. It provides automatic multiple aspect signal operation on a small layout, even for just one signal. To have prototypical operation of a 4-aspect signal would require at least four block sections connected together. (i.e. if a signal is at red the previous signals will be yellow, double yellow and green.) Instead the MAS-SEQUENCER-4 works by a time sequence. The MAS-SEQUENCER-4 is positioned past the signal.
A feature of the MAS-SEQUENCER-4 is the simple wiring.
The MAS-SEQUENCER-4 operates a signal as follows. The signal is normally at green. As a train passes the signal it will be detected by the MAS-SEQUENCER-4, this causes the signal to change to red. Once the train is clear of the MAS-SEQUENCER-4's detector a timing sequence begins.
After the first timing interval the signal changes from red to yellow, after the next timing interval to double yellow then after the last timing interval it changes back to green.
The length of the timing is easily adjusted with a "pot" on the board.
To operate two or more signals an IRDASC4 is used for every additional signal. The IRDASC4s are also positioned to detect the train after it passes the signal.
For 4 aspect signalling, with all signals set initially at green the following sequence takes place
For 4-aspect signals the signals change as shown above as a train travels along the line passing the IRDASC-4s.
When the MAS-SEQUENCER-4 is passedits signal changes to red and the timing sequence begins. The other signals will continue in the correct sequence.
At the end of the timing sequence, provided no trains have travelled along the line, every signal will have returned through all aspects to green.
Wiring between units:
A single wire connects between each unit. The wire goes from the "S" (send) terminal to the "R" (receive) terminal. This wire sends information back about the signals aspect. Suppose the MAS-SEQUENCER-4 is at yellow then the wire will be read by the IRDASC-4 controlling the following signal which will make this signal display double yellow. This IRDASC-4 in turn will tell theleft-most IRDASC-4 that its aspect is double yellow causing the left-most signal to display green. As the MAS- Sequencer-4's timing sequence progresses each signal will eventually work its way to green.
The wiring diagram shows the single wire between the units (from "send" to "receive"). Also shown are the 2 wires from a power supply to power the units. The only other wires necessary are those to the signal. If more than 3 signals are used then more IRDASC-4s are added, wired in the same pattern.
For an oval long enough for at least 4 block sections then the MAS-Sequencer-4 may be omitted and a ring of IRDASC-4 units wired with each "SEND" terminal being wired back to the "RECEIVE" terminal of the previous unit.
Signals
LED signals are operated. The units can be supplied for signals with common negative or common positive wiring.
They can be supplied to work 2, 3 or 4 aspect signals, please state which when ordering.
The MAS-Sequencer-4 and IRDASC-4 can now be supplied to work signals with German aspect i.e. red, green and yellow, green.
RR terminal
Use of this terminal is optional. Its purpose is to cause the signal to stay at red whilst a connection is made to the terminal. Uses are for junctions (interlocking with points so that if the point is wrongly set the signal changes to red) or for manually setting the signal to red for station stops. It can also be used when a train is running in the opposite direction to the signals. It is activated whilst a connection is made to 0V (negative). This connection may be made with a switch or with the direction detector. One switch or direction detector may be connected to a line of RR terminals.
Isolation sections (IRDASC-5)
The IRDASC-5 works in the same way as the IRDASC-4 but has in addition an output to isolate a section of track in front of the signal to prevent trains passing signals at red. The track is isolated when the signal is at red otherwise it is live.
Junctions
If the "R" (receive) terminal is disconnected the IRDASC-4 will display a red signal. This makes correct signalling of converging junctions easy. The wire from the "S" terminal of the IRDASC-4 can be routed through a contact operated by the point so it only connects to the "R" terminal of the IRDASC-4 when the point is correctly set. When the point is not set for this signal the signal will be at red as the "R" terminal will not be connected.
Diverging junctions can also be signalled using a contact operated by the points. This allows the IRDASC-4 controlling the route to be followed by the point setting to be linked to the IRDASC-4 before the junction. If the train travels onto a line without IRDASC-4s, the last signal it passed will be left at red. The signal can be reset by shorting the connection of the send/receive wire to 0 volts. A push button switch or terminal 2 of an IRDOT-1 will do this.
Route Indicator (IRDASC-4RI and IRDASC-5RI)
The signal controlling diverging junctions often has a route indicator or feather. This indicates to the engine driver when the points are set to leave the mainline. If the signal is at red the feather does not light. The IRDASC-4RI and IRDASC-5RI provides for operation in this way. Relay contacts are provided for operating the feather. The relay closes when a connection (from a contact operated by the point) is applied to terminal "I2" provided the signal is not at green. 3 and 4 aspect versions are available which otherwise operate in the same way as the IRDASC-4 and 5. Versions are available which only allow yellow and red or double yellow, yellow and red to be indicated when the points are set for the branch line. This is to tell the engine driver to reduce speed for the curve of the junction.
Operation with DCC and computer interface
The IRDASC-4 or 5 may be used with DCC. The IRDASC-5s isolation section may be positioned in front of the signal or it may be used as an emergency system by placing the isolation system after the signal. The train will then be stopped if the driver passes a red signal.
A similar system has been supplied for use on a large Digitrax DCC, two relays being used on this board, one for isolation and the second to give track occupation information to a computer which controls some of the trains. Interlocking of double junctions has been undertaken so that the isolation sections in conjunction with a red signal prevent collisions. Please contact us for more information about combining our products with DCC control.
Operation with SA units
We can supply modified SA units, for example SA8-S station stop so that the SA8-S signal control can be linked into the RR terminal to give 3 or 4 aspect station stops.
Block sections, IRDASC-4, IRDASC-5 and MAS-SEQUENCER-4 can be supplied with a "D" output which allows the unit to replace the "start slowing" IRDOT-1
Power
The MAS-Sequencer-4 IRDASC-4, IRDASC-5 and route indicator versions are powered from either an AC or DC supply of 12 to 16volts.
IRDASC-4 with reed or micro switch operation
IRDASC-4 units have been supplied to a passenger carrying MiniatureRailway with 2 and 3 aspect signals. The IRDASC-4s have been modified to operate from a treadle worked micro switch instead of by infrared detection.To operate 24 volt bulb signals instead of LEDs the IRDASC-4s have been connected to relay boards. Please email us if you require more information.
WIRING DIAGRAM
A single wire connects between each unit. This wire sends information back about the signals aspect. Suppose the MAS-Sequencer-4 is at yellow then the wire will be read by the middle IRDASC4 which will make its signal display double yellow. The Middle IRDASC 4 in turn will tell the last IRDASC4 that its aspect is double yellow causing the last IRDASC4 to display green. As the MAS- Sequencer-4's timing sequence progresses each signal will eventually work its way to green.
As a train travels along the line signal 1 will change to red as it is passed then to yellow as signal 2 is passed and to double yellow as MAS-Sequencer-4 is passed after which the timing sequence begins.
The diagram shows the single wire between the units (from "send" to "receive"). Also shown are the 2 wires from a power supply to power the units. The only other wires necessary are those to the signal. If more than 3 signals are used then more IRDASC-4s are added, wired in the same way.
For an oval long enough for at least 4 block sections then the MAS-Sequencer-4 may be omitted and a ring of IRDASC 4 units wired with each "SEND" terminal being wired back to the "RECEIVE" terminal of the previous unit.
The MAS-Sequencer4 and IRDASC4s may be powered from either an AC or DC a supply of 12 to 16volts
Internal wiring of the signal
Signals
LED signals are operated. The IRDASC 4 can be supplied for signals with common negative or common positive wiring.
C=common
R=red
Y=yellow
DY=double yellow
G=green
The diagram shows a 4 aspect common negative signal (all the short legs (cathodes) of the LEDs connect to "C" common).
A common positive signal has all the long legs (anodes) of the LEDs connected together. Current limiting resistors are fitted on the board.
| SPECIFICATION | ||
| Voltage | 12 to 16 volts, AC or DC | |
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SIZE |
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| Inches | Millimetres | |
| Length x Width | 6 x 1.25 | 150 x 32 |
| Height of infrared components | 0.9 | 22 |