I've got different slopes so I guess I need two amplifier circuits with different gains (16 and 24 plus a 2V offset). Even so how do I select one of the two? Using a third op amp used as a comparator? Is there a more obvious solution?
This does what you are asking with one dual op-amp. R1 and R3 give the gain of 16, and R2 increases the gain when the input voltage rises above 250mV. OA2 saturates to the positive supply for lower inputs. Since temperature is the variable, presumably speed is not of concern.