DCC converted R410 turntable

[Nick-376669]

I have a R410 turntable that is now DCC enabled. To connect it to my track layout do I achieve this using a point decoder R8247 or not?

[Simon-372339]

How have you actually DCC enabled it? Motor added, rewired?

[P-Henny]

No ... use a locomotive decoder R8249. Firstly a loco decoder allows you to drive a TT in both directions. Secondly, a loco decoder allows you to control the rotation speed. Neither of these desirable features are available to you if using a R8247.

I suggest you read the FAQ 3 TT DCC Conversion instructions in the 'DCC FAQ Index' pinned sticky thread. Although written for a R070 TT, the same principles will apply to the R410 TT. Which describes in detail, the best method for connecting a Hornby TT to a DCC Powered layout track.

[96RAF]

The R8247 is not really suitable to control the rotation of a Hornby TT as each port output is only around 150mA and driving a TT motor both ways would likely require diodes fitted in the circuit.

The HM6010 module however has a dedicated 500mA output port, but the output is a set speed and in one direction only, so not that versatile.

My R070 TT is converted to DCC use per the guide linked to earlier and a simple basic decoder allows the table to be driven in either direction at a variable speed of choice. Such a set up is ideal for use with train operating software such as RM or TGG, etc.

[RDS]

I also used an R8249 Loco Decoder on the TT that I modified

[P-Henny]

........and driving a TT motor both ways would likely require diodes fitted in the circuit.

 

 

I did wonder myself it that was feasible, and before posting my earlier reply sketched out a number of different diode connection configurations, using just diodes on their own. In every case, the diode circuits resulted in one of the diodes creating a path between the common C and one or other of the switched negative outputs .... result ... a 'short circuit'.

However add a couple of transistors and bias resistors to the diode circuit to control switching and a feasible motor polarity reversing circuit can be built to work with a 3 wire Accessory Decoder.

See circuit schematic link below:

Datei:Motorweichenadapter.png - Digital Modellbahn

But this should be treated as just an academic exercise because it is just simpler, cheaper and more effective & efficient to use a loco decoder.

The circuit above is actually sold as a ready made product by 'DCC Concepts' to convert 3 wire Solenoid point motors to 2 wire reversing motors.

DCC Decoder Converter 3 Wire to 2 Wire (3 Pack)

EDIT: The R8247 Accessory Decoder would also have to be configured with a defined pulse length as using 'Always On' would be continuously driving the TT in one direction or the other and never stop. The need for a pulse length configuration then gives the issue of how long do you make it. Again a loco decoder overcomes this issue, as it is a simple matter to stop and start the TT motor at any time that is necessary for the number of track inputs that have to be traversed.