Process Height Sensor Signal/Voltage

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Process Height Sensor Signal/Voltage

The height sensor signal represents the mechanical suspension/vehicle height position and is one of the most critical signals of the system. Based on the value of the signal, the system should make height corrections by raising or lowering vehicle until ride height is met.

REQ_1

1. Height sensor signal should be sampled and filtered 10 msec intervals.

REQ_2

1. Height sensor signal should be filtered according to vehicle status (static/dynamic) as short term and long term filtering. If vehicle stay in static mode signal, filtering should be short term methodology. If vehicle in dynamic mode, signal filtering should be long term methodology.
2. Short term filtering should be used for height corrections that occur due to load changes, trim height changes, air supply etc.
3. Long term sensor signal filtering is intended to reject correction due to road disturbance and vehicle dynamic motion.

REQ_3

1. Height sensor signal should be (0-5V) and sensor signal should stay out of diagnostic range (From HEIGHT_SENSOR_UPPER_LIMIT to HEIGHT_SENSOR_LOWER_LIMIT).
2. According to this rule, the sensor diagnostic status must determine (Fault/No_Fault).
3. Knorr-Bremse sensor datasheet contains diagnostic ranges and all behaviors.

REQ_4

In order to indicate Sensor Signal Healthiness, coding will be used as below:

Unit	Coding
0	HGTK_NO_FAILURE
1	HGTK_NOT_AVAILABLE
2	HGTK_SUPPLY_FAILURE
3	HGTK_DAIGRANGE_FAILURE

1. If Sensor Power Command is enabled and Sensor Supply Fault is enabled then Height Sensor Status should be HGTK_SUPPLY_FAILURE.
2. If Sensor Power Command is disabled and Sensor Supply Fault is enabled, Height Sensor Status should be HGTK_SUPPLY_FAILURE.
3. If Sensor Power Command and Sensor Supply Fault are both disabled, Height Sensor Status should be HGTK_NOT_AVAILABLE.
4. If Sensor Power Command is enabled and Sensor Supply Fault is disabled then Height Sensor Status should be HGTK_DAIGRANGE_FAILURE if Height Sensor Signal is out of diagnostic range for 500 msec; otherwise HGTK_NO_FAILURE

Parameters
HEIGHT_SENSOR_UPPER_LIMIT	4.5 V
HEIGHT_SENSOR_LOWER_LIMIT	0.5 V
HEIGHT_SENSOR_ERROR_TIME	0.5 sec