GMC-TLU DCC Operation

[am549]

Not sure whether this would come under DCC or Railmaster but here goes...

Now I (think) I'm finally happy with my layout I've been looking at the various uncoupling methods available.

The Hornby point motor activated ones seem to require some modification to get working and I'm not sure whether I want a piece of plastic sticking up which only works in one direction, which has lead me to the GMC-TLU.

Is this something which can be operated via DCC and the Hornby accessory decoder? I'm thinking an extended pulse (few seconds) in standard mode should suffice to uncouple? I have read something about insulation for interference as well due to the way it operates.

Is there anything else I've missed that can be easily operated via the accessory decoder?

[P-Henny]

The GMC-TLU instructions state an operating voltage of 15 to 25 volts AC or DC. The output of a Hornby DCC Accessory decoder will be less than 15 volts.

The design is based upon a Solenoid, thus the likelihood is that it will require a current of about 1 Amp to operate robustly & reliably. The instructions state not to use extended operation times which supports a high current required deduction. The Hornby R8247 IIRC is rated at about 200mA continuious current output which may not be enough.

If I was you, I would clarify directly with Gaugemaster as to whether they would recommend use with a normal DCC Accessory Decoder and also ask them what the operating current would be at 15 volts DC (which is the lowest voltage their instructions specify).

Alternatively, you used to be able to buy on ebay a DCC decoder that operated on-board relay contact outputs. But AFAIK that particular seller has stopped making them now. Such a decoder if you can find one should work fine with the TLU, as a separate dedicated external power supply more suited to the TLU could be switched via the decoder relay contacts.

EDIT: Not the seller I was previously thinking of, but these commercial German branded DCC relay output decoders I found in an ebay search do the same function. Two versions are available. One with 4 relays and the second with 8 relays - one relay used per TLU. They can be powered by DCC track voltage (or separate DC power). They are also 'self learning' so setting up DCC addresses should be a breeze. The outputs can be configured for different types of outputs i.e. continuous, pulse or timed (1 to 255 seconds). Click the 'See full description' hyperlink below the brief product description for full product details.

Quad Output:

https://www.ebay.co.uk/itm/165920983637

Octal Output:

https://www.ebay.co.uk/itm/165921816457

I'm sure that a more extensive search than the one I made could probably find other similar products in different price bands.

[Brew Man]

Uncouplers are the bane of my life! I think you are right to dismiss the Hornby one. They are fiddly to put together and you have to file off the ribs along the top to stop them coming into contact with the under carriage gears of some locos. Currently I have four GMC TLUs on my layout though not operating via DCC. I prefer all my accessories to be DC operated. So, I operate my TLUs via lever switched from a 19V DC supply. I find them OK but my gripe with them is the continuous current required to keep the operational. So if you coaches/wagons don't uncouple immediately you might find your finger on the button so to speak for some time. I'm currently experimenting with a servo motor solution using a bent wire with a rectangle of stiff plastic glued to the top. It's based on the Heathcote design but I didn't like the way their controller was programmed so I am using a Megapoints controller. It's working well up to now and doesn't draw nearly as much current, (can't off the top of my head remember how much). I am sure such an arrangement could be used with a DCC accessory decoder.

[am549]

Hmmmm I missed the voltage requirements on the tlu and don't really fancy needing to put another supply in on top of the lighting bus and dcc bus so perhaps back to the drawing board.

I'm perplexed by the ribs on the Hornby decoupler. Why knowingly put something on which most will need to file off. The areas where these will be used will be mostly shunters with said protuding gear so that's a faff (actually liked the one click operation from the motors). The heathcote one did look like a great idea, just a bit more effort than I was planning on with the wiring and control.

Nothings ever easy 😂

[Brew Man]

Yes they are a bit more work but they do work well. I'm planning servo motors for my remaining points too which can be done surface mount or under board.

[am549]

Yes they are a bit more work but they do work well. I'm planning servo motors for my remaining points too which can be done surface mount or under board.

 

 

The megapoints option does look good, and they have a dcc module available as well, though not a cheap option for a few motors (unless I decide to motorise the level crossing as well!) as I've already invested in the solenoid point motors across the layout so don't fancy replacing those yet.

Might just have to stick to the bent paperclip for the time being