diff --git a/cscripts/csbkgmodel.par b/cscripts/csbkgmodel.par
index c5814d3..1d7eb8a 100755
--- a/cscripts/csbkgmodel.par
+++ b/cscripts/csbkgmodel.par
@@ -27,8 +27,8 @@ spatial,    s, a, GAUSS,IRF|AEFF|GAUSS,, "Spatial model component"
 gradient,   b, a, yes,,, "Allow for spatial gradient?"
 spectral,   s, a, NODES,PLAW|NODES,, "Spectral model component"
 ebinalg,    s, a, LOG,FILE|LIN|LOG,, "Algorithm for defining energy nodes"
-emin,       r, a, 0.1,,, "First node energy (TeV)"
-emax,       r, a, 100.0,,, "Last node energy (TeV)"
+emin,       r, a, 0.1,,, "Lower energy limit (TeV)"
+emax,       r, a, 100.0,,, "Upper energy limit (TeV)"
 enumbins,   i, a, 10,1,200, "Number of energy nodes"
 ebinfile,   f, a, NONE,,, "Name of the file containing the energy node definition"
 runwise,    b, a, yes,,, "Generate runwise background model?"
diff --git a/cscripts/csbkgmodel.py b/cscripts/csbkgmodel.py
index 4b1efaa..678a540 100755
--- a/cscripts/csbkgmodel.py
+++ b/cscripts/csbkgmodel.py
@@ -68,6 +68,8 @@ class csbkgmodel(ctools.csobservation):
         if self['spatial'].string() == 'NODES':
             self._create_energies()
         self['runwise'].boolean()
+        self['emin'].real()
+        self['emax'].real()
         self['rad'].real()
 
         # Query ahead output model filename
@@ -176,8 +178,8 @@ class csbkgmodel(ctools.csobservation):
         select['rad']      = self['rad'].real()
         select['tmin']     = 'UNDEF'
         select['tmax']     = 'UNDEF'
-        select['emin']     = 'UNDEF'
-        select['emax']     = 'UNDEF'
+        select['emin']     = self['emin'].real()
+        select['emax']     = self['emax'].real()
         select['usethres'] = 'DEFAULT'
 
         # Select events