diff --git a/applications/NXcanSAS.nxdl.xml b/applications/NXcanSAS.nxdl.xml
index 4e87a4384b..692782960e 100644
--- a/applications/NXcanSAS.nxdl.xml
+++ b/applications/NXcanSAS.nxdl.xml
@@ -247,6 +247,19 @@
``Q`` data is time-dependent: :math:`\vec{Q}(t)`.
+
+
+ Name of the data mask field.
+
+ .. see: https://github.com/nexusformat/definitions/issues/533
+
+ The data *mask* must have the same shape as the *data* field.
+ Positions in the mask correspond to positions in the *data* field.
+ The value of the mask field may be either a boolean array
+ where ``false`` means *no mask* and ``true`` means *mask*
+ or a more descriptive array as as defined in :ref:`NXdetector`.
+
+
Integer or integer array that describes which indices
@@ -289,6 +302,23 @@
:math:`|\vec{Q}|`
or :math:`\vec{Q}`, depending on the context.
+
+
+ Engineering units to use when expressing
+ :math:`Q` and related terms.
+
+ Data expressed in other units will generate
+ a warning from validation software and may not
+ be processed by some analysis software packages.
+
+
+
+ -
+ preferred
+
+
+
+
(optional: for numerical arrays)
@@ -439,6 +469,29 @@
data may be presented in other units and still be consistent with NeXus.
See the :ref:`design-units` section.
+
+
+ Engineering units to use when expressing
+ :math:`I` and intensity-related terms.
+
+ Data expressed in other units (or missing a ``@units`` attribute)
+ will be treated as ``arbitrary`` by some software packages.
+
+ For software using the UDUNITS-2 library, ``arbitrary`` will be
+ changed to ``unknown`` for handling with that library.
+
+
+ -
+ includes m2/m3 and 1/m/sr
+
+ -
+ includes cm2/cm3 and 1/cm/sr
+
+
+
+
+
+
(optional: for numerical arrays)
@@ -500,6 +553,30 @@
I/@uncertainties="Idev"
+
+
+ Engineering units to use when expressing
+ :math:`I` and intensity-related terms.
+
+ Data expressed in other units (or missing a ``@units`` attribute)
+ will generate a warning from any validation process
+ and will be treated as ``arbitrary`` by some analysis software packages.
+
+ For software using the UDUNITS-2 library, ``arbitrary`` will be
+ changed to ``unknown`` for handling with that library.
+
+
+ -
+ includes m2/m3 and 1/m/sr
+
+ -
+ includes cm2/cm3 and 1/cm/sr
+
+
+
+
+
+
@@ -520,6 +597,22 @@
Q/@resolutions="dQw", "dQl"
+
+
+ Engineering units to use when expressing
+ :math:`Q` and related terms.
+
+ Data expressed in other units may not be processed by some
+ software packages.
+
+
+
+ -
+ preferred
+
+
+
+
@@ -539,6 +632,22 @@
Q/@resolutions="dQw", "dQl"
+
+
+ Engineering units to use when expressing
+ :math:`Q` and related terms.
+
+ Data expressed in other units may not be processed by some
+ software packages.
+
+
+
+ -
+ preferred
+
+
+
+
@@ -558,6 +667,22 @@
Q/@resolutions="dQw", "dQl"
+
+
+ Engineering units to use when expressing
+ :math:`Q` and related terms.
+
+ Data expressed in other units may not be processed by some
+ software packages.
+
+
+
+ -
+ preferred
+
+
+
+
@@ -569,6 +694,22 @@
It is expected that ``Q`` is provided
and that both ``Q`` and ``Qmean`` will have the same units.
+
+
+ Engineering units to use when expressing
+ :math:`Q` and related terms.
+
+ Data expressed in other units may not be processed by some
+ software packages.
+
+
+
+ -
+ preferred
+
+
+
+