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<reference id="GUID-4DBE9AD9-2942-450B-B43C-3F2B47777357" xml:lang="en"><title>Scaling
Channel Data Values</title><shortdesc>The value of a channel data item can represent the actual or relative
value of the measured quantity. The relative value is a scaled value that
lies within the maximum and minimum values of the measured quantity.</shortdesc><prolog><metadata><keywords/></metadata></prolog><refbody>
<section id="GUID-D46EE015-C2B6-44AA-B021-F6AC1BB76F02">       <p>The <codeph>KSensrvPropIdChannelDataFormat</codeph> property
defines if channel data items are in a scaled format. For scaled data items,
the <codeph>KSensrvPropIdScaledRange</codeph> property defines range of the
data item value and the <codeph>KSensrvPropIdMeasureRange</codeph> property
defines range of the measured quantity.</p>     </section>
<example><p>The following example explains how the sensor data can be scaled
by reading the maximum value of measure range for data items (<codeph>KSensrvPropIdScaledRange</codeph>)
and the maximum value of the measured quantity (<codeph>KSensrvPropIdMeasureRange</codeph>).
The example considers that the <codeph>KSensrvPropIdMeasureRange</codeph> property
is defined as an array property. </p><codeblock xml:space="preserve">TSensrvProperty property;
    TInt  channelDataFormat( ESensrvFormatAbsolute );
    TInt  channelDataScaledRange( 1 );
    TReal channelDataMeasureRangeMaxValue( 1 );

    //Read channel data format
    iSensorChannel-&gt;GetPropertyL( KSensrvPropIdChannelDataFormat, KSensrvItemIndexNone, property );
    property.GetValue( channelDataFormat );

    if( ESensrvFormatScaled == channelDataFormat )
        {
        //Read data item scaled range
        iSensorChannel-&gt;GetPropertyL( KSensrvPropIdScaledRange, KSensrvItemIndexNone, property );
        property.GetMaxValue( channelDataScaledRange );

        //Read data item measure range
        iSensorChannel-&gt;GetPropertyL( KSensrvPropIdMeasureRange, KSensrvItemIndexNone, property );

        if( ESensrvArrayPropertyInfo == property.GetArrayIndex() )
            {
            TInt arrayIndex( 0 );
            property.GetValue( arrayIndex );//Value points to array index currently in use
            iSensorChannel-&gt;GetPropertyL( KSensrvPropIdMeasureRange,
                                          KSensrvItemIndexNone,
                                          arrayIndex,
                                          property );
            }
        else
            {
            //Single property
            }
        property.GetMaxValue( channelDataMeasureRangeMaxValue );
        }
    else
        {
        //No scaling needed.
        //Value of the data item represents actual value of the measured quantity.
        }</codeblock><p>You can convert the scaled channel data item value
to the absolute value by dividing the channel data item value with the maximum
value of scaled range of the channel and multiplying it with the maximum value
of the measured quantity. </p><p>For example, if the accelerometer channel
provides the following properties: </p><ul>
<li><p><codeph>KSensrvPropIdChannelDataFormat</codeph> with value <codeph>ESensrvFormatScaled</codeph></p></li>
<li><p><codeph>KSensrvPropIdScaledRange</codeph> with maximum value of 127</p></li>
<li><p><codeph>KSensrvPropIdMeasureRange</codeph> with maximum value of 2
g</p></li>
<li><p><codeph>KSensrvPropIdChannelUnit</codeph> with value <codeph>ESensrvUnitGravityConstant</codeph></p></li>
</ul><p>then the accelerometer channel data item value of 64 is equal to an
absolute value of 1.01g (that is, 64 / 127 * 2g = 1.01g).</p></example>
</refbody></reference>