Step 3 - Define Potential Failure Modes in terms of out of tolerance conditions
In Step 3, you identify all potential failure modes and how those failures modes are characterized in the data log. You will identify what data is in the log file relative to the annunciation of the fault.
To define potential failure modes in terms of out of tolerance conditions:
- Starting at the rightmost column, select a measurement from the list. Click on the rightmost box. A down-arrow will be displayed. Click on the down-arrow to display the contents of the drop-down list box. This list reflects the measurements defined in the Diagnostic Knowledge Base. Select a measurement. The measurement includes the syntax required for the Diagnostician, in run-time, to identify that that measurement has failed (Test Name.Measurement Name=Fail;).
- Next, in the leftmost column, identify which field, in the logged data file, the parameter will be stored in. Click on the leftmost box. A down-arrow will be displayed. Click on the down-arrow to display the contents of the drop-down list box. This list reflects the fields defined in Step 1. Select which field the potential failure mode will be stored in.
- Define the value associated with what declares the contents of that field as a fault.
Range - If a fail is indicated when a measured parameters falls outside a certain range, then enter the high and low values of that range in the High Value and Low Value columns of that row. The data type for ranges is Doubles.
Discrete Value - If a fail is indicated by a discrete value, then enter that value in the Value (if exact match) column of that row. Leading zeroes (0) will be truncated, as they are treated as numerical values.
Text - If a fail is indicated by a character or text tag, then enter that tag in the Text (if exact text match) column of that row. This text field is case sensitive. Size limit is 255 characters.
- When you are done, press Save, and then press Next. If you press Next without pressing Save, you will be prompted to save your entries.
Some examples of data entered in Step 4 are presented below. The following Figure may be helpful
in following these examples.
The first seven rows represent Fault Codes that are logged in the fault code field. These fault codes were previously defined in the Diagnostic Profiler project as measurements. In the Diagnostic Profiler, a test called MSP Codes was created which reflected all potential fault codes as a measurement. The measurement name provided was the same designation as the MSP code (for example, MSP Code 718 has a test name of MSP Codes and a measurement name of 718). The value is an exact match of the MSP Code entered in the fault code field (e.g., 718). At run-time, when 718 is found in the fault code frame, the message MSP Codes.718=Fail; will be sent to the Diagnostician by Operator Debrief.
In the row labeled Left Engine EGT is the definition of the characterization of the potential failure mode for left engine exhaust gas temperature (EGT). Left Engine EGT is a field that was previously defined in Frame 2 (in Step 1). The value 770 has been entered into the column Low Value. The way this is handled is as follows: if at any time in the log file, the field location designated as Left Engine EGT has an entry that exceeds 770, then it will be identified as a potential failure to Operator Debrief.
In the row labeled Left Engine Oil Pressure, the value 133 has been entered in the column High Value. The way that this is handled is as follows: if at any time in the log file, the field location designated as Left Engine Oil Pressure has an entry that is below 133, then it will be identified as a potential failure.
In the row labeled Right Engine Fuel Flow, the values in the High Value and Low Value columns are, respectively, 150 and 1700. The way that this is handled is as follows: if at any time in the log file, the field location designated as Right Engine Fuel Flow has an entry that is lower than 150 or higher than 1700, then it will be identified as a potential failure.
In the row labeled AutoPilot Status, the value in the Text (if exact match) column is On. The way that this is handled is as follows: if at any time in the log file, the field location designated as AutoPilot Status has an entry that matches the text On, then it will be identified as a potential failure.
Note: The consequence of not having a Profiler Project Pass/Fail flag in the rightmost column is that it is considered a potential failure, "Incident", but is not used by the Diagnostician and is probably used for filtering or is grouped with another incident that has a Diagnostician measurement.