On the revo is there anything you have to do to get the function buttons to work? I know about the latching and momentary settings but other than that is there anything I need to do?
I am using F5 for a simple on/off switch for a single light in the loco. I hit F5 and nothing happens. Lamp is good I even put a meter to the connector on the revo board and nothing. Wondering what I may be doing wrong?
Terry
Just a basic question, you know that the function “output” switches to ground, right? So that the other side of the lamp must be connected to the common (positive).
Also be very careful on current, they are really only rated for 10ma, although people often push them to 100 ma.
Regards, Greg
I have it wired from F5 (#5, red wire) to the common ground (#7, black wire)
All the trigger wires are grounds.
As Greg mentioned you have to provide a small amount of power to one side of the lamp and use a trigger wire (#5 red) to ground it.
A lot of the light bulbs in our large scale trains draw about 60 milliamps. You might want to consider using an LED. They only draw 20 milliamps.
Be aware that the Revolution receiver’s common power wire HD COM draws power directly from the power source (battery or track) to power the lights. You will need a dropping resistor or LED driver, depending on what you are using, to limit current to the bulb or LED.
And to answer the question, no I didn’t realize that they were all ground wires. i’ll have to reread the info but I didn’t see that anywhere.
So, resistors inline, can you use straight battery power to the LED (or lamp w/o resistor) or can the revo not handle that?
Terry
Terry
This page will give you a little more info about the aux outputs.
http://www.trainelectronics.com/artcles/Relay_Revolution/
Tom
I wouldn’t use the Aux outputs to power an incandescent bulb, as that has the potential to draw too much current. If you’re going to go that route, use the smoke unit control board to power the lights. LEDs with dropping resistors or current limiting thingies (technical term) will pose no problem. According to Dave’s article, the output transistors are rated at 100mA each, and each transistor drives two outputs.
I’ve been using 1000-ohm resistors with LEDs hooked directly to the function outputs for a number of years on my locos. I can drive two LEDs in parallel with one output. I use them for class lamps and the headlight.
Later,
K
According to Dave:
QUOTE:
The devices on the receiver are dual chip transistors, similar to part # SUR521H. According to the data sheet each of the transistors is rated at 100 ma. I would not, however, connect a device that would draw anything near that level. It is best to keep the current draw to 20 or 30 ma, maximum.
Kevin, there are TWO transistors in each package (not one driving 2 outputs), each one has the 100 ma max current
If you follow the link, you will find that the power dissipation of the package is 150 milliwatt at 25 degrees C, and remember this is for TWO outputs, so you should budget 75 milliwatt each.
So, it’s just not the current.
Therefore, I would closely follow Dave’s recommendation for max current of 20 to 30.
Greg
Thanks, Greg. I read it backwards. Even “better” if each output is rated at 100mA, not 100mA split between two outputs as I wrote it. Having said that, I wholeheartedly agree–it’s best not to redline things full time and would generally echo Dave’s recommendation. I don’t think the LEDs I use draw quite 20 mA each, so the two in parallel are probably in the 30 - 35mA range.
Later,
K
Yes, there is a difference between absolute maximum ratings, and what can work continuously and over a long time.
The power dissipation specification and the obvious fact that there is no heatsinking on the transistors is probably what fueled Dave’s recommendation.
There are also other factors, like surge current on certain components… most people don’t know that about incandescent bulbs.
Regards, Greg