| CPC G05B 9/02 (2013.01) | 18 Claims |

|
1. A fault tolerant interface, comprising:
a sensor configured to provide a signal corresponding to an environmental parameter, wherein the sensor operates in one of a normal state, or an alarm or fault state, wherein the signal corresponds to one of the normal state, or the alarm state or the fault state, wherein a value associated with the signal is predetermined; and
a safety control coupled to the sensor via a single wire, the safety control configured to transmit serial data to the sensor and receive serial data from the sensor via the single wire in the normal state, wherein the safety control is further configured to detect the alarm state or the fault state based on the signal prior to decoding the serial data;
wherein the safety control is configured to determine a data bit associated with a time interval between changes in a voltage level detected on the single wire, the time interval constituting an interval between a rising edge and a falling edge of the voltage level; and
wherein the safety control and sensor each transmits training bits to define the time interval associated with the data bit.
|