8 Pin TXS decoder and loco directional lights

[Bugsy1957]

Hello Everyone. I'm trying to work out if it is possible to drive (both logically and electrically) loco directional lights (such as for a class 47) from one of the TXS decoders 

Looking at the function map I believe this should be possible and if it is how do you wire these into the decoder? Do you need resistors? 

If anyone has done this I would appreciate learning from your experiences!

 

Thanks

 

Dave

[96RAF]

2 hours ago, Bugsy1957 said:

Hello Everyone. I'm trying to work out if it is possible to drive (both logically and electrically) loco directional lights (such as for a class 47) from one of the TXS decoders 

Looking at the function map I believe this should be possible and if it is how do you wire these into the decoder? Do you need resistors? 

If anyone has done this I would appreciate learning from your experiences!

 

Thanks

 

Dave

Hardware function outputs are standard 8 - pin. Blue is common positive, all other function wires are switched negatives - white is forward directional lights (white fwd, red rear), yellow is reverse directional lights (red fwd, white rear), and green is aux 1, say cab lights if separately wired in the loco, purple flying lead is aux 2 for another function if required.

F0 operates directional lighting, F1 operates aux 1 and F2 operates aux 2. TXS decoders with sound move F1 and F2 outputs to F21 and F22 as the other keys are used for sounds.

[Bugsy1957]

41 minutes ago, 96RAF said:

Hardware function outputs are standard 8 - pin. Blue is common positive, all other function wires are switched negatives - white is forward directional lights (white fwd, red rear), yellow is reverse directional lights (red fwd, white rear), and green is aux 1, say cab lights if separately wired in the loco, purple flying lead is aux 2 for another function if required.

F0 operates directional lighting, F1 operates aux 1 and F2 operates aux 2. TXS decoders with sound move F1 and F2 outputs to F21 and F22 as the other keys are used for sounds.

Very useful thanks. I may come back with more questions but work is getting in the way.

[Bugsy1957]

Further question: When driving LEDS via the TXS decoder do I need a current limiting resistor?

 

Thanks

[Bugsy1957]

17 minutes ago, Bugsy1957 said:

Further question: When driving LEDS via the TXS decoder do I need a current limiting resistor?

 

Thanks

I think I've found part of the answer....I've found the rating of the outputs to be Analogue 14VDC so can calculate the resistor value.

[96RAF]

1 hour ago, Bugsy1957 said:

Further question: When driving LEDS via the TXS decoder do I need a current limiting resistor?

 

Thanks

That depends upon if the lights are factory installed or you are using a kit or they are diy. Factory fit will have the correct resistors fitted and they should work out of the box when F0 is selected. A kit will come with all the bits you need and instructions, normally the resistors are pre-assembled to a small pcb that is the wired to the 8-pin socket inner four connections. DIY you need to provide and instal your own resistors, usually 1K ohm is a good starting point. I fit them in both the blue positive feed and each negative feed, although strictly you only need the correct resistor value in each led cathode side.

Appendix 3 of the famous decoder manual tells you everything you need to know about Leds and these decoders.