These instructions describe how to install & configure an upgraded processor for a SIGM20 board. Please read carefully before proceeding!

This note describes how a SIGM20 board can be configured to signal an oval track with reversing loop, where the trains can be run in any direction. This example invokes most of the complexity available from the SIGM20 and gives a good example of its capabilities. The track configuration is shown below. (UK exhibition attendees may recognise it as Ted Smale’s Digitrax demonstration layout).

The SIGM20 is able to detect that a train has passed a signal set at red. It does this because a track sensor belonging to the track just beyond the signal mast can be programmed. The SIGM20 can't intervene on LocoNet to have the throttle speed demand reduced to zero: but it can control a relay to remove the power to the track immediately beyond.

The SIGM20 controls signals automatically on a LocoNet railway. It can drive eight, 3-aspect signals or six, 4-aspect signals: i.e. a total of 24 LED outputs. It is important to realise what is happening when 4 aspect signals are connected.

The "TrainController" software package is a very capable system for automatic control of model railways.

TrainController does not decode the LocoNet messages used by the SIGM20 to show signal aspects. However, if you have sensors (e.g. IRDOT or BD4) connected to the SIGM20, then TrainController can use them.

The green LED will be lit if all is well on the board and it is correctly decoding DCC packets from the LocoNet cable. In general if the track power is on, your green LED should always be on.

The SIGM20 drives most signals that have LEDs. Using an additional output adapter board, it can also drive signals using miniature incandescent light bulbs. We don't currently make that available as a product, but its schematic is available for anyone that wants to construct one themselves.

 

Paul Hamilton from Australia has included a video on the SIGM20 on his YouTube channel "Digitrax Dad" and has allowed us to post it here.

We would like to thank Paul for sharing this video while he works on his OO gauge "Hightor" layout based on the Peak District in Derbyshire.