The signal controller is able to set points to red if a point is set "against" the track ahead. To do this, it needs to know point positions. It finds them out through decoding both LocoNet and DCC accessory messages on the LocoNet cable.

Yes, you can. You can program various conditions into the signal logic to make the signal go red. Conditions can include the settings for points, track sensors and other signals.

To make your signal go red if signal 103 is red: in the "Signal goes red when" section of the signal editor, add an entry "signal 103 is red". Remember that the number you need is the DCC accessory address of that signal.

The signal will not work correctly until LocoNet has been re-interrogated. Turn track power off then track power on to trigger the LocoNet "interrogate" process.

TrainController and the SIGM20 each work out the aspect that each signal should be shown at. For most users, leaving the SIGM20 to set the signals and ignoring the TrainController signalling works well. However, some users want to force the SIGM20 to display the same aspect as TrainController shows.

Traincontroller does not decode the message used by the SIGM20 signal controller to report each signal mast's aspect. So it is not possible for Traincontroller to display the aspect shown by a SIGM20 signal. Further, a SIGM20 only has limited manual control: it can be forced to red, but not to any other aspect.

The "TrainController" package is widely used for automatic control of model railways. TrainController does not use the LocoNet messages that the SIGM20 uses to indicate signal aspects, so it can't know the settings of those signals. Most users of both TrainController and the SIGM20 use them independently. In most cases the logic can be programmed so that the signals are correct.

As the SIGM20 is designed to operate low voltage LED’s, devices with higher power consumption – or reversible drive - such as the Tortoise™ point motor require a relay to switch the power from the 12v supply to/from the SIGM20.

 

Most "colour light" signals use light emitting diodes. These take tiny currents and the signal controllers can drive them directly. However some signals use incandescent lamps: these are miniature versions of lamps used for domestic lighting. These require a higher operating voltage and current.

In some respects the SIGM20 is like two units in one. It has the signal controller, which responds to sensor messages on LocoNet; and it has the sensor inputs that cause it generate sensor messages onto LocoNet. The LocoNet messages allow up to 256 modules or board to generate sensor messages, with up to 16 sensor inputs to each.

Sensor inputs, when they are programmed into signal logic, are referred to by the combination of the sensor module (board) number and the sensor input number. The sensor input number 13 on a board programmed to be board 137 would be referred to as “sensor 137,13”.

The SIGM20 Automatic Signal Controller needs to know where the trains are to be able to operate correctly. This can be provided using any LocoNet interfaced block detector. Using this approach, train positions are reported using sensor report messages on LocoNet, and these messages can be decoded to determine which track sections are occupied.

The SIGM20 has 8 sensor inputs that can be connected via SK7. These inputs can be connected to detectors from many sources. This note covers several kinds of sensor; a separate note covers connecting the BD-4 from Digitrax. 

The SIGM20 Automatic Signal Controller needs to know where the trains are to be able to operate correctly. This can be provided using any LocoNet interfaced block detector. Using this approach, train positions are reported using sensor report messages on LocoNet, and these messages can be decoded to determine which track sections are occupied. Sensor messages can be generated from, among others, the following combinations:

  • Digitrax BDL168 block detector units.
  • CML Electronics DAC10 accessory decoders, with block detectors attached to its inputs.
  • Digitrax DS64 accessory decoders, with block detectors attached to its inputs.
  • The SIGM20 itself, with block detectors attached to its inputs.

Sometimes it appears that signals aren't responding correctly. There can be some simple causes for this. This note helps to identify problems.