Add getStartingPositionnersGroup function

src/PyMca5/PyMcaCore/NexusTools.py

@@ -510,6 +510,28 @@ def getPositionersGroup(h5file, path):
                 positioners = group
     return positioners
 
+def getStartingPositionersGroup(h5file, path):
+    """
+    Retrieve the start positioners group associated to a path
+    retrieving them from the same entry.
+
+    It assumes they are either in:
+
+    - NXentry/NXinstrument/positioners_start or
+
+    """
+    entry_path = getEntryName(path, h5file=h5file)
+    instrument = getNXClassGroups(h5file, entry_path, ["NXinstrument", b"NXinstrument"], single=True)
+    positioners = None
+    if len(instrument):
+        instrument = instrument[0]
+        for key in instrument.keys():
+            if key in ["positioners_start", b"positioners_start"]:
+                positioners = instrument[key]
+                if not isGroup(positioners):
+                    positioners = None
+    return positioners
+
 def getMeasurementGroup(h5file, path):
     """
     Retrieve the measurement group associated to a path

src/PyMca5/PyMcaGui/io/hdf5/NexusInfo.py

@@ -1,6 +1,8 @@
 import h5py
 
 from PyMca5.PyMcaGui import PyMcaQt as qt
+from PyMca5.PyMcaCore.NexusTools import getStartingPositionersGroup
+
 from . import HDF5Info
 
 
@@ -94,7 +96,7 @@ def get_motor_positions(hdf5File, node):
     if not isinstance(nxentry, h5py.Group):
         return dict()
 
-    nxpositioners = nxentry.get("instrument/positioners_start", None)
+    nxpositioners = getStartingPositionersGroup(hdf5File, nxentry_name)
     if nxpositioners is None or not isinstance(nxpositioners, h5py.Group):
         return dict()