ESU Accessory decoder and Traintronics

[The Black Hat]

Hello, 

 

I'm looking for advice. 

 

I have gone and hooked up a Bachmann/ESU accessory decoder to the layout electronics. The control from the ESU centre goes to the track entry wiring on the input on the decoder. Power comes from a Gaugemaster T1DC 12v DC transformer and goes to the power inputs. I wired the signal from the traintronics control board to the outputs on the exit of the accessory decoder controlling the accessory.

 

Outputs I thought would control the colour of the signal, with the return through the centre port marked, C. However the signal remains black and obviously no power getting to it. 

 

Any thoughts as to whether its possible to wire it up as it is, or am I needing a relay to help control the powerflow as shown in this later found Youtube video. 

 

 

Any help is most welcome...

[Phil S]

If you read the manual  (an online version is avaiable from the ESU site)  you will find that the outputs are COMMON POSITIVE  and not common negative as your signals may be assuming.

[The Black Hat]

That could be it - but would a relay be able to switch it from one to the other?

[Phil S]

You mention a 12V DC 'transformer' ! - did you mean a 12Vdc (switched mode for efficiciency) power supply ? - ideal souce for colour light signals...

The Bachmann/ESU SwitchPilot can be powered in any of 3 ways:  DC, AC or DCC

 

12Vdc MAY be insufficient for powering some SOLENOID point motors - not a problem with coulour light signals.

Using DCC to POWER the module is okay for (LED) colour light signals - not consuming much of the track power but best avoided if used for point control as you would be unable to change a (live frog) point which had been overrun causing a short circuit.

16Vac has the greatest power capability - and with an unregulated transformer output, nothing is wasted regulating the supply back at the source, before it is used in the SwitchPilot module where the input is rectified and switched (and regulated down to 5V for the logic circuitry) . It also has a special mode for the high current Peco Point Motors - best used with the 16Vac input.

 

The COMMON of each output is +ve, and the switched output(s) is(are) switched to 0 -  for colour light signals your 12Vdc should therefore be a suitable flicker free +ve supply.

Yes, of course you could add a SPDT relay on half of  each output which  swapped the +12V from the power supply to either the red or green lamp, with the signal's common -ve going back to the power supply -ve ..... a bulky and tedious addition for each of the outputs  (which could be supplied by the ESU Switchpilot Relay Add-on module, with 4 relays.)

 

However I would recommend the benefit of simplicity and appearance by using the DCC version of the signal - allowing each one to be connected individually with minimal wiring, and the lamps fade up and down instead of switching.

The switchpilot's 4 ouptuts and 2 servo outputs could then be used for something else.

[Suzie]

Since the signal should have external resistors you should be able to make it work with the addition of a couple of diodes rather than messing about with a relay.

 

When controlling signals it is best to use a dedicated signal decoder like the Signalist SC1 to give you maximum flexibility and simplify the wiring.

 

Anyway here is the ESU wiring for Common Cathode 2-aspect LED signals which is the missing bit from Fig5 on page 12 of the ESU Switchpilot manual:-

 

[The Black Hat]

Thanks for your advice.

 

The problem is that the signals have already been purchased (which are all TT102) and are running using what is essencially an analogue system. Its sees the 12Vdc gaugemaster transformer hooked up to the signals via a on-on switch which is mounted on the side of the boards, that switches the current between red and green aspects.

 

What Im looking to do is replace the switches and hook them up to the new accessory decoders Ive purchased to make the whole system DCC. Given that the system Im using is ESU, Im using Bachmann/ESU accessory decoders which Ive been told have a positive common output. (Im just saying this so that what I say is right). Im thinking it means that I cant connect analogue version of the signal (TT102) to the ESU accessory decoder, unless I do get a relay to switch things over so that the current can be accepted.

 

As a result, Im checking that I need the relay to alter the circuit so that both connect. Im looking to use a 12V DC 2A dpdt relay as shown in the link below;

 

http://www.maplin.co.uk/p/12v-dc-2a-dpdt-miniature-latching-relay-n38aw

 

Would that be right?

[Suzie]

The signals are not the problem, it is the unsuitable choice of the ESU accessory decoder which as it comes is not flexible enough to control your signals. The ESU recommended solution is to use the add-on switchpilot companion (which has the relays) to switch the signals. DCC is an inter-operable standard so you can use any accessory decoder that is suitable for your accessories - you do not have to just buy the limited signal functionality ESU offering.

 

The circuit I have shown you in the diagram above is quite simple just consisting of two resistors (1K for a start if you do not have any yet) and two diodes (1N4148 if you do not have any in stock). Just a few pennies worth of components that can be wired up very quickly to get you round the problem.

[two tone green]

They are doing something about the poor support for signals by introducing this http://www.esu.eu/en/products/signalpilot/

[The Black Hat]

I'll be honest. Wiring like this is probably one of my weaker areas when it comes to the layout. I know it should be simple, but I believe now that the fact that the signal needs a common negative and the ESU accessory decoder gives out a common positive is the reason why the signal is not working.

 

If I get the relay, will that be able to control current flow in such a way that it allows the signal to be activated? I'm thinking it should, if wired correctly, as per the video shown above. Would that be right?