Atlas Adapter User Manual ¶

Overview¶

The SimpleSig Atlas Adapter is designed to allow users of the Atlas All Scales Signal System to bridge to standard Modular Signal System (MSS) modules, such as Iowa Scaled Engineering's SimpleSig line. This gives you the ability to extend your Atlas signals using a variety of vendors' MSS modules without needing to tear out and replace your existing investment in Atlas boards. It's not really intended for modular users, but rather focused at home layouts that already have an Atlas system in place.

MSS provides a number of advantages over the Atlas system:

As an open standard, interoperable modules are available from a variety of different vendors, or you can build your own to the specification
MSS only requires one cable and one set of modules to handle bi-directional signaling, rather than separate modules and separate wiring for each direction
MSS detects the whole train even without resistor-equipped axles by using a combination of optical and current detection

Features¶

Combines two directional Atlas All Scales Signal System buses into a single bidirectional MSS-compatible connection
Powered from 8V to 24V DC, AC, or DCC power.
Compatible with Modular Signaling System standards 1.x, 2.x, and (proposed) 3.x
Onboard diagnostic LEDs help debug problems between the two systems
Robust, protected bus interfaces assure reliable operation
Preserves your existing investment in the Atlas system

Typical Applications¶

Expand your existing Atlas signal system installation using using standard ISE SimpleSig or other Modular Signal System-compatible modules

Quick Start Guide¶

Turn The Power Off!

All wiring and setup of the board should be done with the power off. This significantly reduces the chances of accidentally slipping and causing a short circuit that damages the board, the block detectors, or the signals.

Please Note

Since the wiring nomenclature gets a bit confusing in terms of directions, looking at the wiring diagram below is highly recommended rather than just relying on the text.

Step 1 - Power¶

The Atlas Adapter needs 6V to 24V of DC, AC, or DCC power, and it must be the same power supply that is used to power the Atlas modules, since the Atlas signal bus does not carry a ground wire. Connect power to the terminals marked "POWER" on the PCB.

Step 2 - Atlas Upstream¶

Connect J1 on the Atlas Adapter board to J2 on the last Atlas Universal Signal Control Board (USCB) for signals headed away from the connection point, as shown in blue below. Connections should be made with standard 4 or 6 wire, "straight through" RJ11 cables, same as is used to connect the Atlas USCB modules.

Step 3 - Atlas Downstream¶

Connect J2 on the Atlas Adapter board to J2 to J1 on the last Atlas USCB for signals headed towards the connection point, as shown in blue below. Connections should be made with standard 4 or 6 wire, "straight through" RJ11 cables, same as is used to connect the Atlas USCB modules.

Step 4 - MSS¶

Using the provided short RJ45 cable, connect the adapter board's MSS port to the next MSS signal module as shown below in orange. (Note that this is a normally-wired network cable and not a crossover cable normally used with MSS.)

Simplified Wiring Diagram¶

Simplified Wiring Diagram for Atlas-MSS System

Block Detector Placement

Please note that the current-based block detector for the block between Atlas USCB board 3E and MSS signal board 4 on the diagram should be attached to Atlas USCB 3E, as shown in the full diagram above. The MSS board does not need a detector for that block, and will get that block's occupancy through the Atlas Adapter connection.

Diagnostic LEDs¶

For describing the purpose and meaning of the diagnostic LEDs on the board, we'll use the Simplified Wiring Diagram from above as a reference. Each of the Atlas and MSS boards is numbered. Atlas boards along the bottom will be described as "eastbound" and carry a #E designation, meaning a train moving from left to right (or east if this were a map) would be seeing those signals. Atlas boards along the top will be described as "westbound" and carry a #W designation, meaning a train moving right to left (or west if this were a map) would see signals controlled by those boards.

Direction	LED Name/Color	If Indicator is On
Atlas->MSS	ADV APRCH Blue (D11)	The Atlas USCB 3W on the diagram is sending an "advance approach" indication to MSS, indicating that it is currently displaying an approach indication and the Atlas USCB 2W is displaying a stop indication for westbound trains.
Atlas->MSS	APRCH Amber (D8)	The Atlas USCB 3W is sending an "approach" indication to MSS, indicating that it is currently displaying a stop indication for westbound trains.
Atlas->MSS	CURR BLOCK Red (D7)	The Atlas USCB 3E is sending occupancy for the block detector connected to it that covers the block between it and the first MSS signal.
MSS->Atlas	APRCH Amber (D8)	MSS Cascade module 4 is sending that it is displaying a stop indication, and that it expects the right-most bottom (eastbound) Atlas module to display an approach indication.
MSS->Atlas	ADV APRCH Amber (D8)	MSS Cascade module 4 is sending that it is displaying an approach indication, and that it expects the right-most bottom (eastbound) Atlas module to display an advance approach indication if 4-aspect signaling is enabled, or green if only 3-aspect signaling is enabled.

Specifications¶

Input Power: 5 to 24 volts DC, AC, or DCC
Input Supply Current: 30 milliamps @ 12V (typical)
MSS Standard Compatibility: 1.x, 2.x, and (proposed) 3.x
Size: 2.75"(L) x 2.5"(W) x 0.5"(H)

Open Source¶

Iowa Scaled Engineering is committed to creating open designs that users are free to build, modify, adapt, improve, and share with others.

The design of the MSS-ATLASADAPTER hardware is open source hardware, and is made available under the terms of the Creative Commons Attribution-Share Alike v3.0 license. Design files can be found in the mss-atlasadapter project on GitHub.