How to setup DS1820 One Wire for redundancy

Hello everyone,

I have built a device which takes the temperature input of a DS1820 One Wire sensor and controls a heat source accordingly.

This is a critical process. Thats why I want to get a second sensor for redundancy.

This is what should happen:

-Both Sensors are hooked up to the Arduino
-Both Sensors are working, temperature should be read from the first sensor
-One sensor fails, temperature should now be read from the other sensor
-Both Sensors fail, shut off heating.

How could I accomplish this?

Thanks!

If sensor1 = 127, read sensor 2.