Methods and systems for testing electro optic sensors
Methods and systems for in-fluid testing of electro optic liquid sensors are provided. The electro optic sensor has a light source and a light detector such that a first power state is applied to the light source to generate a first light for determining whether liquid is present within the electro optic sensor. Based on a determination that liquid is present within the electro optic sensor, a second power state is applied to the light source for generating a second light. The second power state having higher power over a shorter period of time than the first power state. The second light generated from the light source is reflected and the reflected second light is received at the light detector. The reflected second light is compared to a pulse current threshold value to determine whether the electro optic sensor is functioning properly.
1 . An electro optic sensor system comprising:
an electro optic sensor comprising:
a light source;
a light detector;
a prism; and
a reflective optical member;
a power source coupled to the electro optic sensor and comprising a normal excitation driver in parallel with a multiplexed test driver; and
an electronic control unit including a light timer control and configured to:
apply a first power state to the light source via the normal excitation driver to generate a first light for and determine whether liquid is present within the electro optic sensor, wherein the first power state corresponds to a constant current level of the light source;
based on a determination that liquid is present, apply a second power state to the light source via the multiplexed test driver to generate a second light, wherein the second power state corresponds to a peak current level of the light source and a duration of the second power state is controlled by the light timer control;
reflect, by the reflective optical member, the second light generated from the light source;
receive the reflected second light at the light detector; and
compare the reflected second light to a pulse current threshold to determine whether the electro optic sensor is functioning properly.
2 . An electro optic sensor system comprising:
an electro optic sensor comprising:
a light source;
a light detector;
a prism; and
a reflective optical member;
a power source coupled to the electro optic sensor and comprising a normal excitation driver in parallel with a multiplexed test driver;
a light timer control; and
an electronic control unit configured to operate in at least a liquid determination mode and a test mode,
wherein the liquid determination mode determines whether liquid is present within the electro optic sensor based on a first power state applied to the light source via the normal excitation driver to generate a first light, wherein the first power state corresponds to a constant current level of the light source, and
wherein the test mode determines whether the electro optic sensor is functioning properly, the test mode including an in-fluid control circuit that applies a second power state to the light source via the multiplexed test driver for generating a second light when liquid is determined to be present within the electro optic sensor, wherein the second power state corresponds to a peak current level of the light source and a duration of the second power state is controlled by the light timer control.
3 . The electro optic sensor system of claim 2 , wherein the light detector is configured to receive reflected light and detection parameters of the light detector for the liquid determination mode and the test mode are different.
4 . The electro optic sensor system of claim 2 , wherein the power source is configured to change an applied driver of the normal excitation driver or the multiplexed test driver to define the applied power state.
5 . The electro optic sensor system of claim 2 , wherein the liquid determination mode operates at a greater frequency than the test mode.
6 . The electro optic sensor system of claim 2 , wherein the liquid determination mode occurs prior to the test mode.
7 . The electro optic sensor system of claim 2 , wherein in the liquid determination mode, the determination of whether liquid is present in the electro optic sensor is based on a comparison of a reflected first light, reflected by one of the prism and the reflective optical member, with a constant current threshold value, and in the test mode, the determination of whether the electro optic sensor is functioning properly is based on a comparison of a reflected second light, reflected by the reflective optical member, with a pulse current threshold value.
8 . The electro optic sensor system of claim 2 , wherein the test mode further includes an in-air control circuit that applies a third power state to the light source via an in-air light source driver of the multiplexed test driver when liquid is determined not to be present within the electro optic sensor.
9 . The electro optic sensor system of claim 8 , wherein the liquid determination mode is connected in parallel with the test mode.