True2scale
True2scaleTrain modeling components
The detector circuit is used to detect the presence of a train on a section of track. It is installed into one of the leads that feed power to the rails. It can be installed in either the left or right rail feed, but it needs to be consistent around the layout. It makes no difference in which direction the current will flow, thus it is suitable for either digital or analog use. It determines the presence of a train by detecting the flow of electric current through the locomotive or any lighted car. It is capable of detecting a train with as little as 1 milliamp of current. (Approximately half of the amount it takes to light an LED headlight.) When a train is present, the detector responds by shorting a signal terminal to ground, thus providing a logic zero indication of train presence.
The first 1.4 Volts sent to the track is used by the detector to do it's work. A train will not start to move until at least this 1.4 Volts is applied to the track. If a train were to move from a block which has a Detector to one which does not, the voltage seen by the train would immediately jump by 1.4 volts causing a noticeable increase in speed. For this reason, it is necessary to put a detector into every block of your layout even those which will not affect signals. Minimal cost "Dummy Detectors" are available for this purpose.
The two screw terminals (green) to the left in the photo are for connection to the
track leads which feed electric to the rails. A lead which currently feeds
your track should be disconnected and connected to either of the left screw
terminals on this detector. A short jumper can then be installed from the
other terminal to the point where your track lead was connected. The
detector is now ready to detect the presence of a train.
The two screw terminals to the right are for connecting the wires which feed signal controllers.
The connection marked "G" is the ground connection. It must be connected either to the Negative lead of the 5V power supply that powers a signal controller board(s), or to one of the ground connections of the controller board(s).
The connection marked "+" or "S" is the signal output to a signal controller board(s). One or more Green, Yellow, or Red wires can be connected here from a signal controller board(s). When the detector detects a train, this signal lead will be shorted to the ground connection described above.
Detectors are available in Two or Four amp variations. The two amp detectors
will be adequate for nearly all analog or digital layouts. For digital layouts
with blocks that could have more than four trains operating concurrently in the
single block, there is also a Four amp variation. The two and four amp
variations can be used interchangeably around a layout
Because it is also necessary to install the detector to obtain the same voltage drop in all blocks of a layout, there is also a "Dummy" detector. These are meant to minimize the cost of installing detectors when they will not control signals. These will have the track lead connections, but will not have the connectors or circuitry to drive a signal controller.