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Step 3: Plan Device Placement

Once you have divided your layout into functional zones and determined the resources you’ll need, its time to consider the interrelated issues of node and peripheral placement.

Small Layouts #

Continuing with the basic 4 x 8 HO Layout, let’s assume we’ve decided to use Tortoise switch machines. With that decision, we can determine what components are needed and where they should be placed. In this plan we can use a single LCOS Client node controlling a chain of 6 or more DNOU8 boards, with 2 channel relays to control the Tortoise switch machines. The remaining DNOU8 ports can be used for signals or other purposes.

What makes this plan work is the reach of a chain of DNOU8 boards. In this case, we need 27 ports for the signals and 8 ports (2 each) for the relays that run the turnouts. If we stack DNOU8’s in pairs, we will end up with 3 groups of 16 ports. Most of the wiring is contained in small areas — power plus a 3 wire connecting cable (running from the Client LCOS Node to one of the stacks, then from there to each additional stack forming a chain) are the only wiring outside of these areas. With 35 ports in use, 13 remain for other uses such as layout lighting.

Your Master (Node 00) will be mounted on your control panel and can be located anywhere adjacent to or within a dozen feet line-of-sight (no obstructions) from the Client. That gives lots of latitude in locating controls. With wireless communication, your control panel can be an independent object with just a power connection.

Larger Layouts #

Lets look at a mid-sized layout. This plan is HO scale, approximately 10 x 16′. Features include a large yard, a passenger station, two industrial spurs and a passing track, with a large open mainline area with varied terrain on one side. Many modelers would run a view blocks separating zones 01-02 from zones 03-04.

A Spacious, 16′ x 10′ HO Layout, divided into functional zones.

In this layout, the combination of physical size and track complexity calls for four Client nodes, with an optional 5th node in zone 05.

As before, turnouts tend to drive decisions. In this case, many modelers would choose servo motors over Tortoise or SwitchMaster motors for turnouts in the main yard (zones 01-02) for two good reasons: 1) the big cost difference when dealing with 15 turnouts: Tortoises cost $20+ each and SwitchMasters cost $30 ea.; SG90 servos about $2.00 – 3.00 each. Even with the cost of supporting hardware, you come out ahead with no functional compromise. Plus: 2) in a yard ladder, SG90 servos are more compact and easier to fit, especially in smaller scales.

The other turnouts can use different motors if you wish. For this demonstration layout, let’s assume the modeler has some Tortoise motors on hand and wishes to use them on the other turnouts.

With that in mind, the layout naturally divides into 5 functional zones. You’ll notice that four of the zones are a little smaller than 4 x 4; here the number of objects (for example, a Client can manage no more than 8 turnouts) is that factor driving zone size. On the other hand, the Eastern Mainline zone is rather large mainline aare, and placement of a Client Node there is optional. A Client Node in that zone could be tasked with block occupancy detection and could run signals if you desire.

This map reflects the devices a modeler would need in each zone.

  • Zone 1: The client will use a PC9685 board to control 7 turnout servo motors. There will be some signals so at least one DNOU8 Output duinoNode is required;
  • Zone 2: Same as zone 1.
  • Zone 3: The client will run a Tortoise motor using a relay, and will support signals and more substantial layout lighting, all using a DNOU8 stack. An optional DNIN8 board is included to read the accessory switches on the Tortoise to know its position.
  • Zone 4: Same as zone 3.
  • Zone 5: Optional. Here we’ve decided to include a Client with a DNOU8 stack to support signals.

You can implement block detection in any or all zones to support full ABS signalling based on block occupancy and turnout position.

Node Addresses >

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