Reading PT100 probe

Other Hardware Sensors
2

The code looks quite organized. I would replace the long if-else construct by a for loop with arrays:

#define NUMVALS 11
int16_t ohmcheck[NUMVALS] = { 60, 100, 139, 176, 214, 248, 281, 315, 346, 376, 32767 };
int16_t outvalues[NUMVALS] = { -200, -100, 0, 100, 200, 300, 400, 500, 600, 700, 800 };

uint8_t i;
for (i = 0; i < NUMVALS; i++) {
  if (ohms < ohmcheck[i]) {
    temptest1 = outvalues[i];
    break;
  }
}