23 Sep 2011

Bachmann suburbans - part 7: Programming the TCS FL2

This little project keeps throwing up problems that seem to cost a lot of time - firstly the locolamps not working, then the pull up circuitry to get the FL2 to work with the FF2 and now I hope a final problem - programming the FL2.

I don't want to do anything very sophisticated on the FL2 side but I did find that I couldn't use button 2 on the throttle to control the tail light (this is because on the digitrax throttle button 2 is not latching). Now there are various ways of programming DCC decoders - normally I only program on the programming track but on this occasion I used "ops mode programming" - in this the device does not need to be connected directly to the programming track instead the programming instructions are "sent" to its address and it can be on the main track.

Since my circuit was on my desk on the other side of the room from the programming track where i only had a connection to the main DCC rail supply I used ops mode programming. This worked fine to change the button for controlling the purple wire / locolamp - by loading CV 36 with value 16 I was able to change it to use button 3.

I was then stupid and went through the process of changing the FL2 to 4 digit DCC addressing, this is a multistage process and you first have to set CV 29 to 38 then load CVs 17 and 18 with some calculated values. The problem is that once you set CV 29 to 38 the "ops mode programming" ceases to work - as presumably the decoder is now at 4 digit address 0000 - only that isn't really a legal address and not one that you can use the digitrax to send stuff to. The decoder is now lost in (address) space. So now the only way of controlling the decoder until you have sorted this out is to put it on the programming track.

The problem I then found (and reading various internet boards I am not alone) is that I was unable to get the FL2 to respond on the programming track - argh!

I contacted TCS support who suggest a few things - but eventually I found the following - programming on the programming track only works if I disconnect the FL2 from the FF2s - The circuit I used was maybe over the top - but I put a resistor and LED on one funciont wire - the LED will then flash when programming happens giving you some visual feedback - I also connected a 47ohm resistor across one of the function wires and the blue return wire on the FL2. There was conflicting info from TCS if this was necessary or not - the instructions said yes but the support people said no.

Because the FL2 comes with a separate harness at least you can make up a harness for programming on the programming track to set four digit addresses and then do all other programming in "ops mode" on the main.

Circuit I used for programming the FL2 on the programming track using a digitrax DCC system...

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