I am thinking about outfitting my HO locomotives with decoders. I have a question as to 2 function decoders versus 4 function. My question is, a function I assume would be a command to turn a set of ditch lights on or off or a strobe light on or off. I would thing also that a forward or reverse move of the locomotive would also be a function being used by the decoder. I guess what I am trying to ask is if you have a two function decoder can you only do two things ala direction and lights on and off or can you program the functions to cover more control of the items on a locomotive? Once again thanks for the info that anyone has out there.
Brad
A two function decoder will give you directional lighting which you can turn on or off. You can program the functions, like program the headlight to be a mars light. Or on a steamer, you can eliminate the backup light, put an LED in the firebox and set it to random flicker. You can also program things like rule 17 lighting. If you program for rule 17, when the engine is not moving the lights dim. The more functions you have, the more lights you can have. With a 4 function decoder, you could have directional lighting, ditch lights and a flashing beacon, or directional lighting and flashing ditch lights. making ditch lights flash alternately uses 2 functions on the decoder. I installed 4 functions in my amtrak loco, it has directional lighting, flashing ditch lights, and red lights on the front that come on in reverse. The red lights need not be another function, just wire them into the reverse lighting circuit. The possibilities are basically endless. One of the reasons I like TCS decoders is because you can set the motor circuit to button control to power smoke machines, cameras or whatever else you have in the loco. Of course then you need another decoder for motor control.
Decoder functions are in addition to the motor control, so a 2-function decoder can be used to turn two separate lights on or off; a 4-function can turn 4 lights on or off, etc. Flashing ditch lights would be a special programming feature of one of the functions, so you would need to read each decoder’s documentation to determine what it can perform. This is no problem, because you can download decoder specifications from each manufacturer’s web site in Acrobat format.
Check the decoder specs, some manufactures consider the headlights as 1 function, other call it 2, when calculating the total number of functions.
For alternating ditch lights, you need two functions, one for each bulb. Plus headlights. SO those that count the lights as 1 function, it would be a ‘3-function’ decoder - lights plus 2 others. For those that count the lights as 2, it would be a ‘4-function’ decoder. Plus any extras you want like a rooftop beacon or mars light.
–Randy