How do I convert a +10v to -10v single input to dual 0-5v outputs?
You can attenuate the input to +/-2 volts with a resistor voltage divider then add an offset of 2.5 volts (via an op-amp or a more sophisticated voltage divider) to get a range from 0.5 volts to 4.5 volts. Feed this into your analogue input and now you have -10 volts remapped to 0.5 volts and +10 volts remapped to 4.5 volts (leaving a bit of headroom either side).