ETAS Hardware Description
ES930.1 - User Guide 25
3.7 Signal Acquisition and Signal Output
3.7.1 Signal Acquisition and Signal Conversion
3.7.1.1 Measure Variables
In the automotive sector, it is frequently necessary to measure non-electrical
variables, such as temperature, torque, force, pressure, filling level, path (dis
-
tance) and flow rate. These non-electrical physical variables are converted into
electrical signals with transducers and sensors and subsequently processed
further. The capture of these signals is the basis for determining information.
The following table contains a few examples:
3.7.1.2 Configuration of the Signals
The captured signals can be configured in the application software, e.g. accord-
ing to the following criteria:
• by name
• by unit
• by acquisition rate
3.7.1.3 Adaptation of the Signals
It is possible to adapt or correct the determined values in the application soft-
ware using mathematical algorithms.
The following methods are available:
• Offset: Addition of a constant to the measured values
• Factor: Multiplication of the measured values with a fixed factor
– Conversion to physical variables
Example: Conversion from scan ratio to electrical power
– Compensation of scaling factors of the measuring hardware
Example: Predivider in turbocharger measuring sensors
Example: Measurement in wheel wells with driven axles
• Linearization of the measurement curves or all measurement results
– Correction of measurement errors
– Compensation of nonlinearity of sensors
Example: Flow sensor, axle speed is not proportional to flow rate
The measured signals and their adaptation allows a representation of the phys-
ical, technical and derived variables as well as the measure variables in the
desired physical unit.
Measuring function Determinable information
Frequency measurement Revolutions per minute
Speed
Counter measurement Flow rate
Position
PWM measurement Activation time of positioning motors
Control of heating elements
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