diff --git a/atintegrators/BeamLoadingCavityPass.c b/atintegrators/BeamLoadingCavityPass.c
index c5029fc16..f3f7f30a9 100644
--- a/atintegrators/BeamLoadingCavityPass.c
+++ b/atintegrators/BeamLoadingCavityPass.c
@@ -234,11 +234,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         feedback_angle_offset=atGetOptionalDouble(ElemData,"feedback_angle_offset", 0.0); check_error();
 
         /* Check energy */
-        Energy = atEnergy(Param->energy, Energy);
-        if (Energy == 0) {
-            atError("Energy needs to be defined. Check lattice parameters or pass method options.\n");
-            check_error();
-        }
+        Energy = atEnergy(Param->energy, Energy); check_error();
 
         int dimsth[] = {Param->nbunch*nslice*nturns, 4};
         atCheckArrayDims(ElemData,"_turnhistory", 2, dimsth); check_error();
@@ -279,7 +275,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         Elem->ts = ts;
         Elem->system_harmonic = system_harmonic;
     }
-    energy = atEnergy(Param->energy, Elem->Energy);
+    energy = atEnergy(Param->energy, Elem->Energy); check_error();
 
     if(num_particles<Param->nbunch){
         atError("Number of particles has to be greater or equal to the number of bunches."); check_error();
diff --git a/atintegrators/BndMPoleSymplectic4E2RadPass.c b/atintegrators/BndMPoleSymplectic4E2RadPass.c
index d446a4330..ad5e1c161 100644
--- a/atintegrators/BndMPoleSymplectic4E2RadPass.c
+++ b/atintegrators/BndMPoleSymplectic4E2RadPass.c
@@ -233,11 +233,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         KickAngle=atGetOptionalDoubleArray(ElemData,"KickAngle"); check_error();
 
         /* Check energy */
-        Energy = atEnergy(Param->energy, Energy);
-        if (Energy == 0) {
-            atError("Energy needs to be defined. Check lattice parameters or pass method options.\n");
-            check_error();
-        }
+        Energy = atEnergy(Param->energy, Energy); check_error();
 
         Elem = (struct elem*)atMalloc(sizeof(struct elem));
         Elem->Length=Length;
@@ -265,7 +261,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         Elem->KickAngle=KickAngle;
     }
     irho = Elem->BendingAngle/Elem->Length;
-    energy = atEnergy(Param->energy, Elem->Energy);
+    energy = atEnergy(Param->energy, Elem->Energy); check_error();
 
     BndMPoleSymplectic4E2RadPass(r_in, Elem->Length, irho, Elem->PolynomA, Elem->PolynomB,
             Elem->MaxOrder, Elem->NumIntSteps, Elem->EntranceAngle, Elem->ExitAngle,
diff --git a/atintegrators/BndMPoleSymplectic4QuantPass.c b/atintegrators/BndMPoleSymplectic4QuantPass.c
index d94586046..059becdbe 100644
--- a/atintegrators/BndMPoleSymplectic4QuantPass.c
+++ b/atintegrators/BndMPoleSymplectic4QuantPass.c
@@ -216,11 +216,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         KickAngle=atGetOptionalDoubleArray(ElemData,"KickAngle"); check_error();
 
         /* Check energy */
-        Energy = atEnergy(Param->energy, Energy);
-        if (Energy == 0) {
-            atError("Energy needs to be defined. Check lattice parameters or pass method options.\n");
-            check_error();
-        }
+        Energy = atEnergy(Param->energy, Energy); check_error();
 
         Elem = (struct elem*)atMalloc(sizeof(struct elem));
         Elem->Length=Length;
@@ -252,7 +248,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         Elem->KickAngle=KickAngle;
     }
     irho = Elem->BendingAngle/Elem->Length;
-    energy = atEnergy(Param->energy, Elem->Energy);
+    energy = atEnergy(Param->energy, Elem->Energy); check_error();
 
     BndMPoleSymplectic4QuantPass(r_in, Elem->Length, irho, Elem->PolynomA, Elem->PolynomB,
             Elem->MaxOrder, Elem->NumIntSteps, Elem->EntranceAngle, Elem->ExitAngle,
diff --git a/atintegrators/BndMPoleSymplectic4RadPass.c b/atintegrators/BndMPoleSymplectic4RadPass.c
index 7d6042cbb..897906ff9 100644
--- a/atintegrators/BndMPoleSymplectic4RadPass.c
+++ b/atintegrators/BndMPoleSymplectic4RadPass.c
@@ -169,11 +169,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         KickAngle=atGetOptionalDoubleArray(ElemData,"KickAngle"); check_error();
 
         /* Check energy */
-        Energy = atEnergy(Param->energy, Energy);
-        if (Energy == 0) {
-            atError("Energy needs to be defined. Check lattice parameters or pass method options.\n");
-            check_error();
-        }
+        Energy = atEnergy(Param->energy, Energy); check_error();
 
         Elem = (struct elem*)atMalloc(sizeof(struct elem));
         Elem->Length=Length;
@@ -205,7 +201,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         Elem->KickAngle=KickAngle;
     }
     irho = Elem->BendingAngle/Elem->Length;
-    gamma = atGamma(Param->energy, Elem->Energy, Param->rest_energy);
+    gamma = atGamma(Param->energy, Elem->Energy, Param->rest_energy); check_error();
 
     BndMPoleSymplectic4RadPass(r_in, Elem->Length, irho, Elem->PolynomA, Elem->PolynomB,
             Elem->MaxOrder, Elem->NumIntSteps, Elem->EntranceAngle, Elem->ExitAngle,
diff --git a/atintegrators/CrabCavityPass.c b/atintegrators/CrabCavityPass.c
index d03686752..cde2c1fdc 100644
--- a/atintegrators/CrabCavityPass.c
+++ b/atintegrators/CrabCavityPass.c
@@ -102,11 +102,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
 		SigVV = atGetOptionalDouble(ElemData,"SigVV",0.0); check_error();
 
         /* Check energy */
-        Energy = atEnergy(Param->energy, Energy);
-        if (Energy == 0) {
-            atError("Energy needs to be defined. Check lattice parameters or pass method options.\n");
-            check_error();
-        }
+        Energy = atEnergy(Param->energy, Energy); check_error();
 
         Elem = (struct elem*)atMalloc(sizeof(struct elem));
         Elem->Length=Length;
@@ -125,7 +121,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         SigPhi=Elem->SigPhi;
         SigVV=Elem->SigVV;
     }
-    energy = atEnergy(Param->energy, Elem->Energy);
+    energy = atEnergy(Param->energy, Elem->Energy); check_error(); check_error();
     nvx = Elem->Vx;
     nvy = Elem->Vy;
 
diff --git a/atintegrators/ExactMultipoleRadPass.c b/atintegrators/ExactMultipoleRadPass.c
index 3beab66f4..e4a2f1a94 100644
--- a/atintegrators/ExactMultipoleRadPass.c
+++ b/atintegrators/ExactMultipoleRadPass.c
@@ -164,7 +164,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData, struct elem *Elem,
     Elem->RApertures = RApertures;
     Elem->KickAngle = KickAngle;
   }
-  gamma = atGamma(Param->energy, Elem->Energy, Param->rest_energy);
+  gamma = atGamma(Param->energy, Elem->Energy, Param->rest_energy); check_error();
 
   multipole_pass(r_in, Elem->Length, Elem->PolynomA, Elem->PolynomB,
                  Elem->MaxOrder, Elem->NumIntSteps,
diff --git a/atintegrators/ExactRectBendRadPass.c b/atintegrators/ExactRectBendRadPass.c
index 723e10047..203385f0d 100644
--- a/atintegrators/ExactRectBendRadPass.c
+++ b/atintegrators/ExactRectBendRadPass.c
@@ -174,11 +174,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         }
 
         /* Check energy */
-        Energy = atEnergy(Param->energy, Energy);
-        if (Energy == 0) {
-            atError("Energy needs to be defined. Check lattice parameters or pass method options.\n");
-            check_error();
-        }
+        Energy = atEnergy(Param->energy, Energy); check_error();
 
         Elem = (struct elem*)atMalloc(sizeof(struct elem));
         Elem->Length=Length;
@@ -207,7 +203,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         Elem->RApertures=RApertures;
         Elem->KickAngle=KickAngle;
     }
-    gamma = atGamma(Param->energy, Elem->Energy, Param->rest_energy);
+    gamma = atGamma(Param->energy, Elem->Energy, Param->rest_energy); check_error();
 
     ExactRectangularBendRad(r_in, Elem->Length, Elem->BendingAngle,
             Elem->PolynomA, Elem->PolynomB,
diff --git a/atintegrators/ExactRectangularBendRadPass.c b/atintegrators/ExactRectangularBendRadPass.c
index dff706fb9..66f2d9d61 100644
--- a/atintegrators/ExactRectangularBendRadPass.c
+++ b/atintegrators/ExactRectangularBendRadPass.c
@@ -176,11 +176,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         }
 
         /* Check energy */
-        Energy = atEnergy(Param->energy, Energy);
-        if (Energy == 0) {
-            atError("Energy needs to be defined. Check lattice parameters or pass method options.\n");
-            check_error();
-        }
+        Energy = atEnergy(Param->energy, Energy); check_error();
 
         Elem = (struct elem*)atMalloc(sizeof(struct elem));
         Elem->Length=Length;
@@ -209,7 +205,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         Elem->RApertures=RApertures;
         Elem->KickAngle=KickAngle;
     }
-    gamma = atGamma(Param->energy, Elem->Energy, Param->rest_energy);
+    gamma = atGamma(Param->energy, Elem->Energy, Param->rest_energy); check_error();
 
     ExactRectangularBendRad(r_in, Elem->Length, Elem->BendingAngle, Elem->PolynomA, Elem->PolynomB,
             Elem->MaxOrder, Elem->NumIntSteps, Elem->EntranceAngle, Elem->ExitAngle,
diff --git a/atintegrators/ExactSectorBendRadPass.c b/atintegrators/ExactSectorBendRadPass.c
index e194b9438..d4ed0b06b 100644
--- a/atintegrators/ExactSectorBendRadPass.c
+++ b/atintegrators/ExactSectorBendRadPass.c
@@ -161,11 +161,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         }
 
         /* Check energy */
-        Energy = atEnergy(Param->energy, Energy);
-        if (Energy == 0) {
-            atError("Energy needs to be defined. Check lattice parameters or pass method options.\n");
-            check_error();
-        }
+        Energy = atEnergy(Param->energy, Energy); check_error();
 
         Elem = (struct elem*)atMalloc(sizeof(struct elem));
         Elem->Length=Length;
@@ -193,7 +189,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         Elem->KickAngle=KickAngle;
     }
     irho = Elem->BendingAngle/Elem->Length;
-    gamma = atGamma(Param->energy, Elem->Energy, Param->rest_energy);
+    gamma = atGamma(Param->energy, Elem->Energy, Param->rest_energy); check_error();
 
     ExactSectorBendRad(r_in, Elem->Length, irho,
             Elem->PolynomA, Elem->PolynomB,
diff --git a/atintegrators/GWigSymplecticPass.c b/atintegrators/GWigSymplecticPass.c
index dcc40b619..d8501bdb4 100644
--- a/atintegrators/GWigSymplecticPass.c
+++ b/atintegrators/GWigSymplecticPass.c
@@ -145,11 +145,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         T2 = atGetOptionalDoubleArray(ElemData, "T2"); check_error();
 
         /* Check energy */
-        Energy = atEnergy(Param->energy, Energy);
-        if (Energy == 0) {
-            atError("Energy needs to be defined. Check lattice parameters or pass method options.\n");
-            check_error();
-        }
+        Energy = atEnergy(Param->energy, Energy); check_error();
 
         Elem = (struct elem*)atMalloc(sizeof(struct elem));
         Elem->Energy=Energy;
@@ -168,7 +164,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         Elem->T1=T1;
         Elem->T2=T2;
     }
-    gamma = atGamma(Param->energy, Elem->Energy, Param->rest_energy);
+    gamma = atGamma(Param->energy, Elem->Energy, Param->rest_energy); check_error();
 
     GWigSymplecticPass(r_in, gamma, Elem->Length, Elem->Lw, Elem->Bmax,
             Elem->Nstep, Elem->Nmeth, Elem->NHharm, Elem->NVharm,
diff --git a/atintegrators/GWigSymplecticRadPass.c b/atintegrators/GWigSymplecticRadPass.c
index 577389640..8df2d7c03 100644
--- a/atintegrators/GWigSymplecticRadPass.c
+++ b/atintegrators/GWigSymplecticRadPass.c
@@ -271,11 +271,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         T2 = atGetOptionalDoubleArray(ElemData, "T2"); check_error();
 
         /* Check energy */
-        Energy = atEnergy(Param->energy, Energy);
-        if (Energy == 0) {
-            atError("Energy needs to be defined. Check lattice parameters or pass method options.\n");
-            check_error();
-        }
+        Energy = atEnergy(Param->energy, Energy); check_error();
 
         Elem = (struct elem*)atMalloc(sizeof(struct elem));
         Elem->Energy=Energy;
@@ -294,7 +290,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         Elem->T1=T1;
         Elem->T2=T2;
     }
-    gamma = atGamma(Param->energy, Elem->Energy, Param->rest_energy);
+    gamma = atGamma(Param->energy, Elem->Energy, Param->rest_energy); check_error();
 
     GWigSymplecticRadPass(r_in, gamma, Elem->Length, Elem->Lw, Elem->Bmax,
             Elem->Nstep, Elem->Nmeth, Elem->NHharm, Elem->NVharm,
diff --git a/atintegrators/RFCavityPass.c b/atintegrators/RFCavityPass.c
index f12e9fe7e..8a365432b 100755
--- a/atintegrators/RFCavityPass.c
+++ b/atintegrators/RFCavityPass.c
@@ -49,11 +49,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         PhaseLag=atGetOptionalDouble(ElemData,"PhaseLag",0); check_error();
 
         /* Check energy */
-        Energy = atEnergy(Param->energy, Energy);
-        if (Energy == 0) {
-            atError("Energy needs to be defined. Check lattice parameters or pass method options.\n");
-            check_error();
-        }
+        Energy = atEnergy(Param->energy, Energy); check_error();
 
         Elem = (struct elem*)atMalloc(sizeof(struct elem));
         Elem->Length=Length;
@@ -64,7 +60,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         Elem->TimeLag=TimeLag;
         Elem->PhaseLag=PhaseLag;
     }
-    energy = atEnergy(energy, Elem->Energy);
+    energy = atEnergy(energy, Elem->Energy); check_error();
 
     RFCavityPass(r_in, Elem->Length, Elem->Voltage/energy, Elem->Frequency, Elem->HarmNumber, Elem->TimeLag,
                  Elem->PhaseLag, nturn, T0, num_particles);
diff --git a/atintegrators/StrMPoleSymplectic4QuantPass.c b/atintegrators/StrMPoleSymplectic4QuantPass.c
index 00b1eab6c..d2bcbe79b 100644
--- a/atintegrators/StrMPoleSymplectic4QuantPass.c
+++ b/atintegrators/StrMPoleSymplectic4QuantPass.c
@@ -185,11 +185,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         KickAngle=atGetOptionalDoubleArray(ElemData,"KickAngle"); check_error();
 
         /* Check energy */
-        Energy = atEnergy(Param->energy, Energy);
-        if (Energy == 0) {
-            atError("Energy needs to be defined. Check lattice parameters or pass method options.\n");
-            check_error();
-        }
+        Energy = atEnergy(Param->energy, Energy); check_error();
 
         Elem = (struct elem*)atMalloc(sizeof(struct elem));
         Elem->Length=Length;
@@ -212,7 +208,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         Elem->RApertures=RApertures;
         Elem->KickAngle=KickAngle;
     }
-    energy = atEnergy(Param->energy, Elem->Energy);
+    energy = atEnergy(Param->energy, Elem->Energy); check_error();
 
     StrMPoleSymplectic4QuantPass(r_in, Elem->Length, Elem->PolynomA, Elem->PolynomB,
             Elem->MaxOrder, Elem->NumIntSteps,
diff --git a/atintegrators/StrMPoleSymplectic4RadPass.c b/atintegrators/StrMPoleSymplectic4RadPass.c
index c292829d4..546ad8b78 100644
--- a/atintegrators/StrMPoleSymplectic4RadPass.c
+++ b/atintegrators/StrMPoleSymplectic4RadPass.c
@@ -145,11 +145,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         KickAngle=atGetOptionalDoubleArray(ElemData,"KickAngle"); check_error();
 
         /* Check energy */
-        Energy = atEnergy(Param->energy, Energy);
-        if (Energy == 0) {
-            atError("Energy needs to be defined. Check lattice parameters or pass method options.\n");
-            check_error();
-        }
+        Energy = atEnergy(Param->energy, Energy); check_error();
 
         Elem = (struct elem*)atMalloc(sizeof(struct elem));
         Elem->Length=Length;
@@ -172,7 +168,7 @@ ExportMode struct elem *trackFunction(const atElem *ElemData,struct elem *Elem,
         Elem->RApertures=RApertures;
         Elem->KickAngle=KickAngle;
     }
-    gamma = atGamma(Param->energy, Elem->Energy, Param->rest_energy);
+    gamma = atGamma(Param->energy, Elem->Energy, Param->rest_energy); check_error();
 
     StrMPoleSymplectic4RadPass(r_in, Elem->Length, Elem->PolynomA, Elem->PolynomB,
             Elem->MaxOrder, Elem->NumIntSteps,
diff --git a/atintegrators/atelem.c b/atintegrators/atelem.c
index 8b597af37..71d323898 100755
--- a/atintegrators/atelem.c
+++ b/atintegrators/atelem.c
@@ -76,26 +76,17 @@ typedef mxArray atElem;
 
 double atEnergy(double ringenergy, double elemenergy)
 {
-    if (ringenergy!=0.0)
+    if (ringenergy > 0.0)
         return ringenergy;
     else
-        if (elemenergy!=0.0)
+        if (elemenergy > 0.0)
             return elemenergy;
         else {
-            atError("Energy not defined.");
+            atError("Energy must be positive. Check lattice or passmethod parameters.");
             return 0.0;   /* Never reached but makes the compiler happy */
         }
 }
 
-double atGamma(double ringenergy, double elemenergy, double rest_energy)
-{
-    double energy = atEnergy(ringenergy, elemenergy);
-    if (rest_energy == 0.0)
-        return 1.0E-9 * energy / __E0;
-    else
-        return energy / rest_energy;
-}
-
 static mxArray *get_field(const mxArray *pm, const char *fieldname)
 {
    mxArray *field;
@@ -206,11 +197,19 @@ typedef PyObject atElem;
 #define atError(...) PyErr_Format(PyExc_ValueError, __VA_ARGS__)
 #define atWarning(...) PyErr_WarnFormat(PyExc_RuntimeWarning, 0, __VA_ARGS__)
 #define atPrintf(...) PySys_WriteStdout(__VA_ARGS__)
-#define atEnergy(ringenergy,elemenergy) (ringenergy)
-#define atGamma(ringenergy,elemenergy,rest_energy) ((rest_energy) == 0.0 ? 1.0E-9*(ringenergy)/__E0 : (ringenergy)/(rest_energy))
 
 static int array_imported = 0;
 
+double atEnergy(double ringenergy, double elemenergy)
+{
+    if (ringenergy > 0.0)
+        return ringenergy;
+    else {
+        atError("Energy must be positive. Check lattice or set the track() keyword argument.");
+        return 0.0;   /* Never reached but makes the compiler happy */
+    }       
+}
+
 static NUMPY_IMPORT_ARRAY_TYPE init_numpy(void)
 {
     import_array();
@@ -362,6 +361,15 @@ static double *atGetOptionalDoubleArray(const PyObject *element, char *name)
 #define C_LINK
 #endif
 
+double atGamma(double ringenergy, double elemenergy, double rest_energy)
+{
+    double energy = atEnergy(ringenergy, elemenergy);
+    if (rest_energy == 0.0)
+        return 1.0E-9 * energy / __E0;
+    else
+        return energy / rest_energy;
+}
+
 C_LINK ExportMode struct elem *trackFunction(const atElem *ElemData, struct elem *Elem, double *r_in,
                                       int num_particles, struct parameters *Param);
 
diff --git a/atintegrators/ringproperties.c b/atintegrators/ringproperties.c
index baabef3db..47a1aec84 100644
--- a/atintegrators/ringproperties.c
+++ b/atintegrators/ringproperties.c
@@ -28,7 +28,11 @@ static void atProperties(const mxArray *opts, double *energy, double *rest_energ
     field = mxGetField(opts, 0, "Energy");
     if (field) {
         double ener = mxGetScalar(field);
-        if (ener != 0.0) *energy = ener;
+        if (ener > 0.0) {
+            *energy = ener;
+        }else{
+            mexErrMsgIdAndTxt("Atpass:WrongParameter", "Energy must be positive. Check lattice or passmethod parameters.");
+        }
         atParticle(opts, rest_energy, charge);
     }
 }