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MAS Sequencer RI


multi aspect signal with feather controlled by trains position

For an overview of all the different boards to control 3 and 4 aspect signalling see the 3_and_4 aspect_signalling page.

After passing the signal the train reaches the MAS Sequencer-RI (located under the baseboard). As the MAS Sequencer-RI's built in infra red detects the train it changes the signal to red. Once the train has cleared the detector the MAS Sequencer-RI starts timing.

There is a first timing interval at red followed by yellow then double yellow after which the signal returns to green. The timing is adjustable between 7 and 80 seconds.

If the signal is at yellow or double yellow when the train passes it still changes to red. There is information about how full size signals work in the signalling section of the web site. From this you will see that the MAS Sequencer-RI is an easy way to get the same effect as a real signal.

Terminal arrangement to control a model colour light signal with route indicator

As well as 4 aspect signals the MAS Sequencer-RI gives easily installed automatic operation of 2 and 3 aspect signals.

The wiring is very simple. The wires from the power supply connect to terminals + and 0V and the wires from the signal connect to the terminals shown in the diagram.

There is no connection to the track so the MAS Sequencer-RI works equally well with DC or DCC.

There are additional components to allow the MAS Sequencer-RI to also operate the feather (route indicator) on a signal at a junction.

Power supply

The MAS Sequencer-RI can be powered from AC or DC, any Voltage between 12 and 16 Volts.

Wiring Signals to the MAS Sequencer-RI

The MAS Sequencer works with LED signals. UK manufacturers (CR signals, Eckon, Bercko, Traintronics etc) wire their signals common negative. This means that the common wire (usually black) from the signal connects to all the cathode (negative) legs of the LEDs within the signal. European and American signals are usually common positive. Please specify which type of signal when ordering so that we can supply a compatible MAS Sequencer-RI. We also need to know how many aspects (number of lights) your signals have.

The signal terminals have built in resistors. This means that LED signals can be connected directly to them. If the signals already have resistors attached then they will still work but will be dimmer. If they are not bright enough the resistors supplied with the signal can be safely removed.

Adjusting the timing

The device labelled pot on the diagram is a potentiometer. This is rotated with a small screwdriver to adjust the length of the timing sequence.

Override to red

If there is a junction or station then the signal may sometimes need to be set to red to stop a train. The RR terminal is provided for this. A switch or a contact operated by a points movement is used to connect the RR terminal to the 0V terminal. Whilst these terminals are connected the signal will be at red.

Another use for the RR terminal is on bidirectional lines. When trains run in the opposite direction to that signaled the signal should be at red. If the control system is DC then the train direction detector can be wired into the RR terminal. For DCC a switch can be used. A single switch may be connected to more than one MAS Sequencer-RI or IRDASC-4. If a SPDT switch (single pole double throw) is used a single switch will work for both directions.

Infra red detection

The MAS Sequencer-RIs have built in infra red train detection. This consists of an infra red emitter and infra red detector which are located in a hole in the baseboard and reflect an infra red beam off the underside of rolling stock. Advantages to infra red detection are that no modifications to the rolling stock are required and that it works equally well in the dark. The infra red emitter and detector are 22mm (3/4inch long). If the base boards are thicker than this or support beams are in the way the MAS Sequencer-RI-EW has the infra red emitter and detector at the ends of 18 inch wires.

To aid testing on installation there is a train detected LED mounted on the board. This lights when a train is detected by the infra red.

More than one signal on a line

wiring for route indicator signal and second multi aspect signal in sequence

When there is more than one signal along a line each signal could be controlled by its own MAS Sequencer. However this could result in the model signals showing combinations of lights that are not accurate. A more realistic method is to control the second signal from an IRDASC-4 board. When the train is detected by the IRDASC-4 the signal it controls changes to red. This signal stays at red until the train has cleared the MAS Sequencer-RI then it will change to yellow. The correct sequence of signals as described in the signalling section will occur. Instead of controlling its signal with a timer the IRDASC-4 sets its signal according to the colour of the next signal up the line (MAS Sequencer-RI). The purple wire between the S (send) terminal of the MAS Sequencer-RI and the R (receive) terminal of the IRDASC-4 carries the information about what aspect (colour) the MAS Sequencer-RI is at. Both boards share the same power supply. If there are more signals along the line extra IRDASC-4s can be used linking the S and R terminals between each. There is a web page with more information about IRDASC-4s.

Route Indicator (feather)

Colour light signals use a line of five white lights set at an angle to indicate to the driver a diverging route is set. These lights are called Route Indicators or feathers. The MAS Sequencer RI is intended for operating signals with route indicators (feathers) automatically.

The feather is operated by a screw connection terminal on the board labelled OI. When no connection is made to this terminal the MAS Sequencer RI operates exactly as the standard MAS Sequencer. Connecting the OI terminal to the 0V terminal by a contact operated by the point or a switch tells the MAS Sequencer RI that the diverging route is set. Many point motors have contacts built into them. One of these contacts is very suitable for operating the OI terminal. When the OI terminal is connected to the 0V terminal the MAS-Sequencer RI switches a contact (accessed by the Y and Z terminals) to light the route indicator provided the signal is not at red. If the signal is at red the contact to light the route indicator does not switch until the signals aspect changes from red. This is the way full size signals operate. As well as switching the feather operating OI can have the option of changing the signal setting for the branch line. For example when the point is set for the branchline the signal can just display either red or single yellow but display red, yellow, double yellow or green when the point is set to the mainline. This is to warn the engine driver to reduce speed for the curve on the branchline.

Contact for operating the Route Indicator (feather)

Connections to make a point operated contact light a feather when the signal is not at red and the train is travelling down the branchline

Terminals Y and Z switch the feather on and off. These terminals are controlled by the OI terminal. When the OI terminal is connected to the OV terminal Y and Z will be connected together provided the signal is not at red.

The diagram shows the connections to one of CR signals signals. The white wire is drawn grey so that it shows up. The resistor needs to be left in place on this wire. Other makes of signals can be easily connected whether the route indicator shares a common like the CR signals model or has a separate return.

The signal returns to red when the train reaches the infra red detector on the MAS Sequencer-RI board. If the signal is located a short distance before the junction then the detector can be positioned just before the point. If the signal is very close to the point then this is not very practicable. In this case we can supply the MAS Sequencer-RI with 2 sets of extended leads so that a set can be located on each line.

Otherwise the MAS Sequencer-RI has the same terminals and operation as the MAS Sequencer.

Extended wires

Normally the MAS-Sequencer-RI is located under the track where the signal is to change to red, however this may be difficult if there are baseboard supports in the way or the base board thickness is greater than 22mm. In this case the MAS-Sequencer-RI-EW can be used. This has the infra red emitter and detector on the ends of 18 inch leads.


Two sets of detectors for the 2 diverging routes after a route indicator signal

If the signal is close to the point it may be impractical to position the MAS-Sequencer-RI before the point. However if it is positioned after the point then detectors are required on both lines so that the signal will change to red regardless of the route taken. The MAS-Sequencer-RI-2EW provides two sets of detectors to overcome this difficulty. Both sets of detectors are on 18 inch long extended wires.

Dimensions of MAS Sequencer RI

Length 135 mm 5.3 inches

Width 32 mm 1.25 inches