For a project I have going on, I would like to know what the upper limits are as far as voltage and current for the smoke heater power input to the SC2. I'm thinking the amps are somewhere around 200 mili-amps similar to the other inputs/outputs on the board?
This is a non TMCC project.
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The input is just a signal, so it's just milliamps to drive an opto-coupler. It's rated to accept 18 VAC, if you want to put more voltage on it, add a series resistor to keep the current to around 10 milliamps.
The function output I want to use to drive the smoke heater is about 16.5 volts and all six of the outputs have 400 milliamps to use. If I use a 100 ohm resistor for the smoke heater that would be about 165 milliamps so doesn't sound like that would work either. Using the decoder to turn the smoke on and off directly is the simplest wiring, no heater power supply needed so was hoping I could do that. Seems I will have to use a power switch and separate power supply for the heater, then no need to switch resistors in the smoke unit, but really adds to the complexity.
You're missing the point of the Super-Chuffer sensing. I'm just seeing if there is voltage on the smoke resistor to enable fan control. The input only needs a milliamp or two to be sufficient for the opto-coupler to sense the heater voltage.
Your problem appears to be you may not have enough power to create smoke, depending on what the other outputs are doing.
I might not be thinking clearly, right in the middle of my 8 day, 12 hour night shift :-)
I don't think I can use the decoder outputs and get good smoke, they are intended for lights to begin with. If I use a 5v power supply, the stock resistor would get me 625 milliamps and about 3 watts of power. I would then use a mosfet power switch to turn the smoke on or off using one of the decoder outputs. I will only be using 2 other outputs for the headlight and mars light. If I use the decoder output I would have 16.5v across a 100 ohm resistor for 165 milliamps and 2.7 watts of power and no extra circuit needed to turn smoke on or off. If I use a 2k ohm resistor on the sense line that would put it under the 10 milliamps you quoted me, but my mind can't seem to figure out how that would effect the amps through the smoke resistor - I keep thinking I'm adding parallel resistor circuit which would change the calculations. Now my head hurts and I have to get ready for work, LOL!
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