Help with digital points

[Alan-380065]

Hi. If I want to use point motors with a digital controller is there any wiring involved? How does the controller connect to the point? Thanks.

[Brew Man]

You'd be better posting this in the DCC forum. You'll get better responses.

[P-Henny]

Firstly this is a DCC question, so if you lose sight of this thread then a mod has probably moved it to the DCC forum.

The answer to your question is 'it depends'.

• It depends upon which point motor is being used to operate the point.
• It depends upon whether the point motor that is chosen has an integrated decoder or not (integrated decoder point motors are not made or sold by Hornby).
• It depends upon which Accessory decoder is being used.

All point motors will require some wiring to power and control them.

In this reply I will consider only two of the many options available to you. Nearly all branded point motor solutions are in essence variations of these two schemes.

Scheme 1 - Solenoid 3 wire point motors.

In this scheme the point motor consists of two solenoid coils. The centre tap wire connection of the two coils is called the 'common' and the other two wires when energised pull the solenoid one way or the other to switch the point.

These three wires route to and connect to a 3 wire Accessory Decoder port output. The Accessory Decoder 2 wire input is connected to the DCC 2 wire Track output of the DCC Controller (in parallel to the actual layout track).

The Accessory Decoder can have multiple ports (one port per point motor). The Hornby ones have 4 ports but other brands can typically have 4 or 8 ports. Each port has to be given a DCC Address.

The DCC Controller sends a turn left or turn right DCC command via the track output to the Accessory Decoder input addressed to the DCC Address of the port that needs to switch the connected point. This command tells the Accessory Decoder to energise the appropriate 2 of the 3 wires on the target port DCC Address to move the solenoid and change the point.

Scheme 2 - Integrated Decoder point motors.

In this scheme each point motor only has a DCC 2 wire input. All the point motors are connected by the 2 wires in parallel to the DCC Controller 2 wire DCC track output that is also in parallel with the track itself. This is where the installation of a 2 wire DCC BUS power wiring scheme comes into its own.

Each DCC Integrated Decoder point motor is given its own DCC Address. The DCC Controller sends the turn left or turn right DCC Command via the DCC Track connections to the appropriate point motor DCC Address and the point motor responds accordingly to move the point left or right.

Integrated DCC Decoder point motors are available (non Hornby brands) using both solenoid or electric motors to actually move the point.

Additional external Accessory Decoders are not needed in this scheme because each point motor has an integrated decoder that performs the Accessory Decoder function.

In conclusion.

Nearly all the different point motors and Accessory Decoders available on the market fall broadly into either scheme 1 or scheme 2 in terms of wiring installation. There are however a very small number of point motors (not Hornby) that use 2 and not 3 wires. These fall into the 'Slow Motion Stall Motor' category and are less common these days and when used, more likely to be Analogue rather than Digitally controlled, so not covered further in my reply.

In my opinion, I find the scheme 2 solutions to function and operate more reliably, plus they are 'self learning' and can be easier to set up and configure.

IMPORTANT: My reply is very long. Please do not use the 'Quoted Reply' option to reply. Scroll to the bottom of the page and write any reply you want to make in the 'Reply Text Box' located there.

[Flashbang]

Hi. If I want to use point motors with a digital controller is there any wiring involved? How does the controller connect to the point? Thanks.

 

 

Hi

Yes, wiring is needed from the solenoid point motor to the pulse output of an Accessory decoder (see below).

You need a DCC system that is able to operate Accessory decoders (most are) and then an Accessory decoder to interface between the DCC and the actual solenoid motor. Hornby produce a four-output accessory decoder R8247 https://uk.hornby.com/products/digital-accessory-and-point-decoder-r8247 Or you can use other makes too some have less outputs while other have more than four!

 

[Bulleidboy]

I use DCC Concepts Cobalt Digital iP point motors and they are wired for both DCC and toggle switch operation. In my case the point motors take their power from the track (two droppers from track to the point motor) for DCC operation - and then two additional wires from the point motor to the toggle switch (On-Off-On sprung to centre). The point motor also allows for frog switching. It is quicker to use toggle switches for operation. The Cobalts have an in-built decoder so no additional accessory decoder is required and they are programmed rather like a loco. They have eight or nine terminals for attaching the various wires. Set-up is fairly straightforward. I use a Hornby Elite for DCC control so when operating a point, the signal is sent via the track.