*
* If the relay is closed, then sense will be 0
* If no igniter is present, then sense will be v_pyro * 27k/227k = pyro * 127 / 227 ~= pyro/2
*
* If the relay is closed, then sense will be 0
* If no igniter is present, then sense will be v_pyro * 27k/227k = pyro * 127 / 227 ~= pyro/2