ASP2-NS Infra-Red Model Railway Signal Controller - 2, 3 & 4 Aspect

About the Product

The BLOCKsignalling ASP2-NS is a compact infra-red model railway signal controller for 2-, 3- and 4-aspect common-anode LED signals. Its built-in infra-red train sensor automatically detects passing trains and changes the connected signal through realistic signalling sequences, with no separate detector, soldering or track isolation required.

The sensor projects invisible infra-red light upwards and detects reflections from passing rolling stock. Installation is straightforward: drill an 8mm hole between the sleepers and insert the sensor from beneath the baseboard. The sensor requires only around a 2mm gap between the sleepers, making it suitable for N gauge as well as larger scales.

During normal operation, the signal displays green. When a train passes over the sensor, the ASP2-NS automatically changes the signal to red. Once the complete train has cleared the detector, the signal progresses back towards green, passing through yellow and double yellow where appropriate for the selected signal type.

The ASP2-NS also provides realistic fading between signal aspects to simulate traditional filament lamps. Although the module operates automatically using its default settings, signal timings, detection release time, fade rates, LED brightness and other operating parameters can be adjusted if required.

Key Features

• Automatic model railway signal control using infra-red train detection.
• Built-in infra-red sensor for simple installation.
• Supports 2-, 3- and 4-aspect LED signals.
• Designed specifically for common-anode (common-positive) signals.
• Automatically changes the signal to red when a train is detected.
• Automatically returns through the appropriate aspects to green after the train has passed.
• Realistic fading between signal aspects to simulate filament lamps.
• Adjustable red, yellow and double-yellow timings.
• Adjustable detection release time to accommodate gaps between rolling stock.
• Adjustable LED brightness and aspect fade rates.
• No soldering required.
• No programming required for normal operation.
• Built-in LED resistors mean external resistors are normally not required.
• Suitable for N gauge and larger model railway scales.
• Requires a 12V DC power supply.
  

2-, 3- and 4-Aspect Signal Operation

The ASP2-NS can operate 2-, 3- or 4-aspect common-anode signals. The signal normally displays green and immediately changes to red when a train is detected. The subsequent sequence depends on the selected signal mode.

In 2-aspect mode, the signal remains red while the sensor is occupied. Once the train has cleared the detector and the programmed release and red times have expired, the signal returns to green.

In 3-aspect mode, the signal changes from green to red when a train is detected and subsequently progresses through yellow and back to green after the train has cleared.

In 4-aspect mode, the signal changes immediately to red when a train is detected. After the train has cleared, it progresses through yellow, double yellow and then green according to the programmed timings.

Built-In Infra-Red Train Detection

Unlike signal controllers that use a separate detector, the ASP2-NS has its infra-red sensor built directly into the module. The controller is mounted beneath the track with the sensor positioned through an 8mm hole in the baseboard between the sleepers.

Invisible infra-red light is projected upwards and passing trains trigger the controller automatically. The sensor requires only around a 2mm gap between the sleepers, allowing it to be installed on N gauge layouts as well as larger scales. Alternatively, the module can be positioned beside the track and concealed with scenery.

Signal Compatibility

The ASP2-NS is specifically designed for common-anode (common-positive) LED signals and must not be connected to common-cathode signals. It is not intended for signals using bulbs.

Connections are provided for red, yellow, green and second-yellow aspects. The Vin terminal also provides the connection for the signal's common-positive wire. LED resistors are built into the controller, so external resistors are normally unnecessary.

For common-cathode LED signals, use the BLOCKsignalling ASP1-NS instead.

Electrical Requirements

• Supply voltage: 12V DC
• Current consumption: Approximately 50mA (0.05A)
• Recommended power supply: 0.25A to 1A
• Signal type: Common-anode (common-positive) LED
• Signal aspects: 2, 3 or 4
• Detection method: Built-in reflective infra-red sensor
• Baseboard mounting hole: 8mm
• External LED resistors: Normally not required

The ASP2-NS should be powered from a suitable regulated 12V DC power supply, such as the BLOCKsignalling PSU2. Do not connect the module to the auxiliary terminals of a train controller, as these outputs may not be sufficiently smooth or stable and could cause unpredictable operation or damage.

Documentation & Support

For full installation instructions, signal wiring, programming options and troubleshooting, please refer to the product instruction manual:

User Instruction Manual