DOC #512 add example with macros

Author: prjemian

XML_schema/example_attributes.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" standalone="no" ?>
+<!-- Attributes -->
+<Attributes
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:noNamespaceSchemaLocation="https://github.com/areaDetector/ADCore/blob/master/iocBoot/NDAttributes.xsd"
+    >
+    <Attribute name="AcquireTime"         type="EPICS_PV" source="13SIM1:cam1:AcquireTime"      dbrtype="DBR_NATIVE"  description="Camera acquire time"/>
+    <Attribute name="ImageCounter"        type="PARAM"    source="ARRAY_COUNTER"                datatype="INT"        description="Image counter"/>
+    <Attribute name="calc1_val"           type="EPICS_PV" source="$(P)userCalc1.VAL"            dbrtype="DBR_NATIVE" description="some calculation result"/>
+    <Attribute name="calc2_val"           type="EPICS_PV" source="$(P)userCalc2.VAL"            dbrtype="DBR_NATIVE" description="another calculation result"/>
+    <Attribute name="MaxSizeX"            type="PARAM"    source="MAX_SIZE_X"                   datatype="INT"        description="Detector X size"/>
+    <Attribute name="MaxSizeY"            type="PARAM"    source="MAX_SIZE_Y"                   datatype="INT"        description="Detector Y size"/>
+    <Attribute name="CameraModel"         type="PARAM"    source="MODEL"                        datatype="STRING"     description="Camera model"/>
+    <Attribute name="CameraManufacturer"  type="PARAM"    source="MANUFACTURER"                 datatype="STRING"     description="Camera manufacturer"/>
+</Attributes>