Physical nodes

This webpage is about the properties of physical nodes used for designing, testing, selecting materials to build the controls for my model railway. It consists of the topics:

Command panel
Control unit
Command and control wiring
Signal wiring

Command panel

This is about the physical aspects of the SpDrL60 mosaic command panel like the construction, making the tiles and PCB for the tiles.

Control unit

This is about the physical aspects of the 19 inch and other sub racks including the PCB's with control circuitry, power PCB, and other PCB's.

Electronic components of the system controller shall be located on PCBs in Eurocard shelves, due to the lack of space behind the SpDrL panel. Common connections will run on the back plane and individual connections with plugs on the front of the Eurocards.

Command and control wiring

This is about wiring from the PCB's with control circuitry to the mosaic tiles, and DB 25 connectors behind the mosaic panel for rail and point motor connections.

The wire colours and their designation are:

SL	railT	The traction voltage for a traction rail section
GN	railD	The return voltage for a train detection rail section
WT	pointT	The control voltage for a point motor the set the points in the through direction
YW	pointD	The control voltage for a point motor the set the points in the diverge direction

The soldered wires to for example DB-25 D-subminature connectors are solid core to avoid breakage. All other wires connected to the Dupont connectors of the PCB's in sub racks are stranded. This ensures a reliable connection to the Dupont crimp pins especially with low-currents. The wires have enough over length to remove the connections and trace the wires.

ID	Component	Qty
0.50railT	Single solid core wire 0.50 mm². Outer diameter 1.4 mm Slate	100m
0.50railD	Single solid core wire 0.50 mm². Outer diameter 1.4 mm Green	200m
0.25pointT	Single solid core wire 0.20 mm². Outer diameter 0.7 mm White	100m
0.25pointD	Single solid core wire 0.20 mm². Outer diameter 0.7 mm Yellow	100m

Signal wiring

This is about the physical aspects of the communication of I2C for line side signals.