SIGM20: Control from TrainController

 

However, the SIGM20 doesn't "know" about planned train movements, and can't hold a signal red if (for example) the track ahead is reserved for another train. A SIGM20 signal can't be forced to any aspect; but it can be forced to red. This is usually sufficient to allow the SIGM20 signals to reflect a planned train movement that needs a train not to proceed. This can be done in two ways:

  1. by setting its DCC address to THROWN;
  2. or by programming conditions into its logic to "go red when" an accessory address has been operated.

There are two kinds of signals in TrainController:

  • The BLOCK SIGNALS, shown on each end of a block in the switchboard. TrainController sets the aspects of these signals automatically.
  • ACCESSORY SIGNALS, which can be 2,3 or 4 aspect and whose aspect can be controlled by logic. They can drive an externally attached DCC accessory device.

By using a little ingenuity in TrainController, you can control your SIGM20 signals to some extent by TrainController. The way to do this is to control your SIGM20 signal by an ACCESSORY SIGNAL, which has a DCC accessory address that sets one or two accessory addresses to closed or thrown according to its aspect. There are two ways to do this:

  1. If you have a two aspect signal in TrainController, it can operate a single DCC accessory address to CLOSED or THROWN. This can be used to control the signal's DCC address directly.
  2. If you have a three or four aspect signal in TrainController, it can operate two consecutive DCC addresses. You can't use the signal's DCC address, because the second address operated by TrainController will operate a second signal. Use "phantom" addresses that are not attached to any real device on your railway; then use conditions on the SIGM20 to make it go red if the TrainController signal is red.

You can then use programming on the accessory signal itself in TrainController to set its aspect. for example, you could set it to be red if the block signal is red. We can't support the TrainController side of this - but it can be made to work!