diff --git a/python/converters/vasp/python/plotools.py b/python/converters/vasp/python/plotools.py
index 44fa053f..0bd14a16 100644
--- a/python/converters/vasp/python/plotools.py
+++ b/python/converters/vasp/python/plotools.py
@@ -76,7 +76,10 @@ def check_data_consistency(pars, el_struct):
     """
     Check the consistency of the VASP data.
     """
-    pass
+# Check that ions inside each shell are of the same sort
+    for sh in pars.shells:
+        sorts = set(el_struct.poscar.type_of_ion[sh['ion_list']])
+        assert len(sorts) == 1, "Each projected shell must contain only ions of the same sort"
 
 ################################################################################
 # select_bands()
diff --git a/python/converters/vasp/test/_plotools/POSCAR.complex b/python/converters/vasp/test/_plotools/POSCAR.complex
new file mode 100644
index 00000000..c7693ced
--- /dev/null
+++ b/python/converters/vasp/test/_plotools/POSCAR.complex
@@ -0,0 +1,28 @@
+NdNiO3
+1.0
+        5.3871197701         0.0000000000         0.0000000000
+        0.0000000000         5.3826699257         0.0000000000
+        0.0000000000         0.0000000000         7.6093997955
+   Nd   Ni    O
+    4    4   12
+Direct
+     0.995800018         0.035000000         0.250000000
+     0.004199982         0.964999974         0.750000000
+     0.495800018         0.465000004         0.750000000
+     0.504199982         0.535000026         0.250000000
+     0.500000000         0.000000000         0.000000000
+     0.000000000         0.500000000         0.000000000
+     0.500000000         0.000000000         0.500000000
+     0.000000000         0.500000000         0.500000000
+     0.069300003         0.489699990         0.250000000
+     0.930700004         0.510300040         0.750000000
+     0.569299996         0.010300010         0.750000000
+     0.430700004         0.989699960         0.250000000
+     0.716600001         0.287099987         0.039500002
+     0.283399999         0.712900043         0.960500002
+     0.216600001         0.212900013         0.960500002
+     0.783399999         0.787099957         0.039500002
+     0.283399999         0.712900043         0.539499998
+     0.716600001         0.287099987         0.460500002
+     0.783399999         0.787099957         0.460500002
+     0.216600001         0.212900013         0.539499998
diff --git a/python/converters/vasp/test/_plotools/test_consistency.py b/python/converters/vasp/test/_plotools/test_consistency.py
index eeac9961..bf0a7c0a 100644
--- a/python/converters/vasp/test/_plotools/test_consistency.py
+++ b/python/converters/vasp/test/_plotools/test_consistency.py
@@ -1,6 +1,8 @@
 
 import vaspio
 from inpconf import ConfigParameters
+from plotools import check_data_consistency
+from elstruct import ElectronicStructure
 import mytest
 
 ################################################################################
@@ -12,23 +14,26 @@ class TestDataConsistency(mytest.MyTestCase):
     """
     Function:
 
-    def read_plocar(filename)
+    def check_data_consistency(pars, el_struct)
 
     Scenarios:
 
-    - **if** file PLOCAR does not exist **raise** IOError
-    - **if** PLOCAR is truncated **raise** IOError
-    - **if** the precision flag is not 4 or 8 **raise** ValueError
-    - **if** PLOCAR with prec=8 is read **compare** the output
-    - **if** PLOCAR with prec=4 is read **compare** the output
+    - **if** a shell contains ions of different types **raise** AssertionError
     """
 # Scenario 1
-    def test_example(self):
-        conf_file = 'example.cfg'
-        pars = ConfigParameters(conf_file)
-        pars.parse_input()
-        vasp_data = vaspio.VaspData('./')
-
-        print pars.shells
-        print pars.groups
+    def test_shell_ion_types(self):
+        pass
+#        conf_file = 'wrong_shell.cfg'
+#        pars = ConfigParameters(conf_file)
+#        pars.parse_input()
+#        vasp_data = vaspio.VaspData('./', read_all=False)
+#        vasp_data.poscar.from_file('./', poscar_filename='POSCAR.complex')
+#        el_strct = ElectronicStructure(vasp_data)
+#
+#        print pars.shells
+#        print vasp_data.poscar.type_of_ion
+#
+#        err_mess = "Each projected shell must"
+#        with self.assertRaisesRegexp(Exception, err_mess):
+#            check_data_consistency(pars, el_struct)
 
diff --git a/python/converters/vasp/test/_plotools/wrong_shell.cfg b/python/converters/vasp/test/_plotools/wrong_shell.cfg
new file mode 100644
index 00000000..13435387
--- /dev/null
+++ b/python/converters/vasp/test/_plotools/wrong_shell.cfg
@@ -0,0 +1,8 @@
+
+[Shell 1]
+LSHELL = 2
+IONS = 4 5 6 7
+EMIN = -15.0
+EMAX = 5.0
+
+