Data Declaration System

Transcription

1 The Axes DDS Data Declaration System Page: 1

2 Content How are Axes used? Virtual Axes Declaration Objectives: After completing this unit you will: know how axes are used be able to declare different kinds of axes Page: 2

3 Axes Reference to Online - Approximation A measurement can have many different values. e.g. A 2-byte integer type online, for instance, can have 65,536 values. So these input values must all mapped 1:1 to an output value. Gain Map (Look-up Table) => reduction of values by approximation. divide an axis into segments all values in a segment are mapped to a single axis point online mapping 0 N Input (int: 65,535 possible values) 6 Axis values 6 Map values Page: 3

4 Axes Reference to Online - Interpolation The approximation can be done in two ways: No interpolation: The input value is rounded to the nearest axis value. The output is exactly the map value. online Input Value: 115 Noninterpolated output value: Map(200)= With interpolation: The output value is calculated by linear interpolation, using the two axis points on either side of the input value and their associated map values. online Input Value: 115 Interpolated output value: Map(0, 200)= Interpolate(1, 0.98)= Page: 4

5 Virtual Axis A virtual axis is an axis that is not actually created in memory. axis values are calculated for every measure value This costs performance, but saves ECU memory space. Virtual axes cannot have a memory region, and are not tunable. Online input variable Perceived path Input Value Actual path Calculation Algorithm in ECU SW Virtual axis Map Page: 5

6 Shared Axis standalone C instance, it can be shared by several maps. embedded in an instance it can only be assigned to this one map. (DDS) Map 1 (DDS) Map Standalone or embedded axis depend on the selected representation model. online output 1 (DDS) Map 2 (DDS) Axis-x online output 2 online input online output 3 (DDS) Map 3 (DDS) Axis-x (common) set of shift characteristics Page: 6

7 CHARACTERISTIC with embedded Axis ASAM View Example: /begin CHARACTERISTIC BRABEVI_KL acceleration with a ramp" CURVE 0x814E00 RAMP_LAYOUT 0 nmot_lin EXTENDED_LIMITS /begin AXIS_DESCR STD_AXIS vfzg_w AxisConversion /begin ANNOTATION ANNOTATION_LABEL First Test ANNOTATION_ORIGIN Mkh /begin ANNOTATION_TEXT This Text is for demo only /end ANNOTATION_TEXT /end ANNOTATOION DEPOSIT ABSOLUT /end AXIS_DESCR /end CHARACTERISTIC The group of keys named ANNOTATION is used to add minutes or hints to an ASAM Element. ANNOTATION_LABEL is a short description ANNOTATION_ORIGIN is used for a sign of the responsible of the annotation ANNOTATION_TEXT holds the complete Text The axis points are stored as absolute values ( not in differences ) Page: 7

8 CHARACTERISTIC with external Axis ASAM View External Axis Prototype: Description: /begin CHARACTERISTIC... /begin AXIS_DESCR... AXIS_PTS_REF identifier /end AXIS_DESCR /begin AXIS_DESCR... AXIS_PTS_REF identifier /end AXIS_DESCR /end CHARACTERISTIC definition of x axis ( first axis ) reference to an external axis definition of y axis ( second axis ) reference to an external axis /begin AXIS_PTS identifier string address input quantity Layout max Diff conversion max axis points limit limit /end AXIS_PTS name of the calibration value description of the calibration value access address in the ECU for the calibration value reference to a measurement to define the current operating point representation of the calibration value in the ECU reference to the conversion formula maximum difference between two proximate values lower physical limit upper physical limit Page: 8

9 CHARACTERISTIC with external Axis ASAM View Example: /begin CHARACTERISTIC... MAP... Map_LAyout /begin AXIS_DESCR COM_AXIS... AXIS_PTS_REF XAXIS_REFERENCE /end AXIS_DESCR /begin AXIS_DESCR COM_AXIS... AXIS_PTS_REF YAXIS_REFERENCE /end AXIS_DESCR /end CHARACTERISTIC /begin AXIS_PTS XAXIS_REFERENCE definition of xaxis points" 0x OperatingPointXAxis LayoutForXAxis 0 ConversionFormulaOfXAxis /end AXIS_PTS Both axis are completely independent /begin AXIS_PTS XYXIS_REFERENCE definition of yaxis points" 0x OperatingPointyAxis LayoutForyAxis 0 ConversionFormulaOfyAxis /end AXIS_PTS Page: 9

10 Definition Tab Data type of entire axis = type. If no type is used, this field is blank. For axes, memory region will typically be ROM. The address is shown here after locator (IEEE or ELF) import. Data type of element(s) (in this example blue, meaning from type definition) Onlines, parameters, axes, and map do not necessarily have the same representation models. Entity Name Representation Model, needed and important because this is an object to be exported as source code Page: 10

11 Calib Tab Number of axis points Display attribute Make this axis virtual Inserts a threshold causing the working point to displayed across two values only if it deviates from the axis point by more than this value. Limits can be set to disable drastic changes during calibration. Page: 11

12 Init Tab The values in the init tab table are used to initialize the values in the ECU The Equidistant feature can save you typing; if you specify start and shift values the rest is filled in automatically. Page: 12

13 Ref Tab Axes reference an online to obtain an input value. Page: 13

14 Summary Page: 14