diff --git a/src/spicelib/devices/asrc/asrcdefs.h b/src/spicelib/devices/asrc/asrcdefs.h
index 818eef775..ffc21ca03 100644
--- a/src/spicelib/devices/asrc/asrcdefs.h
+++ b/src/spicelib/devices/asrc/asrcdefs.h
@@ -23,8 +23,8 @@ typedef struct sASRCinstance {
                                              * current model */
     IFuid ASRCname;            /* pointer to character string naming this instance */
     int ASRCstates;            /* state info */
-    int ASRCposNode;           /* number of positive node of source */
-    int ASRCnegNode;           /* number of negative node of source */
+    const int ASRCposNode;     /* number of positive node of source */
+    const int ASRCnegNode;     /* number of negative node of source */
 
     int ASRCtype;              /* Whether source is voltage or current */
     int ASRCbranch;            /* number of branch equation added for v source */
diff --git a/src/spicelib/devices/bjt/bjtdefs.h b/src/spicelib/devices/bjt/bjtdefs.h
index 000919e3f..040a242c2 100644
--- a/src/spicelib/devices/bjt/bjtdefs.h
+++ b/src/spicelib/devices/bjt/bjtdefs.h
@@ -23,10 +23,10 @@ typedef struct sBJTinstance {
     IFuid BJTname;  /* pointer to character string naming this instance */
     int BJTstate; /* pointer to start of state vector for bjt */
 
-    int BJTcolNode; /* number of collector node of bjt */
-    int BJTbaseNode;    /* number of base node of bjt */
-    int BJTemitNode;    /* number of emitter node of bjt */
-    int BJTsubstNode;   /* number of substrate node of bjt */
+    const int BJTcolNode;   /* number of collector node of bjt */
+    const int BJTbaseNode;  /* number of base node of bjt */
+    const int BJTemitNode;  /* number of emitter node of bjt */
+    const int BJTsubstNode; /* number of substrate node of bjt */
     int BJTcolPrimeNode;    /* number of internal collector node of bjt */
     int BJTbasePrimeNode;   /* number of internal base node of bjt */
     int BJTemitPrimeNode;   /* number of internal emitter node of bjt */
diff --git a/src/spicelib/devices/bsim1/bsim1def.h b/src/spicelib/devices/bsim1/bsim1def.h
index 7e8188499..75540bbb3 100644
--- a/src/spicelib/devices/bsim1/bsim1def.h
+++ b/src/spicelib/devices/bsim1/bsim1def.h
@@ -26,10 +26,10 @@ typedef struct sBSIM1instance {
     IFuid B1name; /* pointer to character string naming this instance */
     int B1states;     /* index into state table for this device */
 
-    int B1dNode;  /* number of the gate node of the mosfet */
-    int B1gNode;  /* number of the gate node of the mosfet */
-    int B1sNode;  /* number of the source node of the mosfet */
-    int B1bNode;  /* number of the bulk node of the mosfet */
+    const int B1dNode;  /* number of the gate node of the mosfet */
+    const int B1gNode;  /* number of the gate node of the mosfet */
+    const int B1sNode;  /* number of the source node of the mosfet */
+    const int B1bNode;  /* number of the bulk node of the mosfet */
     int B1dNodePrime; /* number of the internal drain node of the mosfet */
     int B1sNodePrime; /* number of the internal source node of the mosfet */
 
diff --git a/src/spicelib/devices/bsim2/bsim2def.h b/src/spicelib/devices/bsim2/bsim2def.h
index d60d268c8..94ec28ce2 100644
--- a/src/spicelib/devices/bsim2/bsim2def.h
+++ b/src/spicelib/devices/bsim2/bsim2def.h
@@ -22,10 +22,10 @@ typedef struct sBSIM2instance {
     IFuid B2name; /* pointer to character string naming this instance */
     int B2states;     /* index into state table for this device */
 
-    int B2dNode;  /* number of the gate node of the mosfet */
-    int B2gNode;  /* number of the gate node of the mosfet */
-    int B2sNode;  /* number of the source node of the mosfet */
-    int B2bNode;  /* number of the bulk node of the mosfet */
+    const int B2dNode;  /* number of the gate node of the mosfet */
+    const int B2gNode;  /* number of the gate node of the mosfet */
+    const int B2sNode;  /* number of the source node of the mosfet */
+    const int B2bNode;  /* number of the bulk node of the mosfet */
     int B2dNodePrime; /* number of the internal drain node of the mosfet */
     int B2sNodePrime; /* number of the internal source node of the mosfet */
 
diff --git a/src/spicelib/devices/bsim3/bsim3def.h b/src/spicelib/devices/bsim3/bsim3def.h
index 1db57b357..c8fc235a1 100644
--- a/src/spicelib/devices/bsim3/bsim3def.h
+++ b/src/spicelib/devices/bsim3/bsim3def.h
@@ -22,10 +22,10 @@ typedef struct sBSIM3instance
     struct sBSIM3instance *BSIM3nextInstance;
     IFuid BSIM3name;
     int BSIM3states;     /* index into state table for this device */
-    int BSIM3dNode;
-    int BSIM3gNode;
-    int BSIM3sNode;
-    int BSIM3bNode;
+    const int BSIM3dNode;
+    const int BSIM3gNode;
+    const int BSIM3sNode;
+    const int BSIM3bNode;
     int BSIM3dNodePrime;
     int BSIM3sNodePrime;
     int BSIM3qNode; /* MCJ */
diff --git a/src/spicelib/devices/bsim3soi_dd/b3soidddef.h b/src/spicelib/devices/bsim3soi_dd/b3soidddef.h
index 35a981ab4..bc7a9cf7e 100644
--- a/src/spicelib/devices/bsim3soi_dd/b3soidddef.h
+++ b/src/spicelib/devices/bsim3soi_dd/b3soidddef.h
@@ -26,13 +26,13 @@ typedef struct sB3SOIDDinstance
     IFuid B3SOIDDname;
     int B3SOIDDstates;     /* index into state table for this device */
 
-    int B3SOIDDdNode;
-    int B3SOIDDgNode;
-    int B3SOIDDsNode;
-    int B3SOIDDeNode;
-    int B3SOIDDbNodeExt;
-    int B3SOIDDtempNodeExt;
-    int B3SOIDDpNodeExt;
+    const int B3SOIDDdNode;
+    const int B3SOIDDgNode;
+    const int B3SOIDDsNode;
+    const int B3SOIDDeNode;
+    const int B3SOIDDbNodeExt;
+    const int B3SOIDDtempNodeExt;
+    const int B3SOIDDpNodeExt;
     int B3SOIDDbNode;
     int B3SOIDDtempNode;
     int B3SOIDDpNode;  
diff --git a/src/spicelib/devices/bsim3soi_fd/b3soifddef.h b/src/spicelib/devices/bsim3soi_fd/b3soifddef.h
index 4816ed689..6f1434e99 100644
--- a/src/spicelib/devices/bsim3soi_fd/b3soifddef.h
+++ b/src/spicelib/devices/bsim3soi_fd/b3soifddef.h
@@ -26,13 +26,13 @@ typedef struct sB3SOIFDinstance
     IFuid B3SOIFDname;
     int B3SOIFDstates;     /* index into state table for this device */
 
-    int B3SOIFDdNode;
-    int B3SOIFDgNode;
-    int B3SOIFDsNode;
-    int B3SOIFDeNode;
-    int B3SOIFDbNodeExt;
-    int B3SOIFDtempNodeExt;
-    int B3SOIFDpNodeExt;
+    const int B3SOIFDdNode;
+    const int B3SOIFDgNode;
+    const int B3SOIFDsNode;
+    const int B3SOIFDeNode;
+    const int B3SOIFDbNodeExt;
+    const int B3SOIFDtempNodeExt;
+    const int B3SOIFDpNodeExt;
     int B3SOIFDbNode;
     int B3SOIFDtempNode;
     int B3SOIFDpNode;  
diff --git a/src/spicelib/devices/bsim3soi_pd/b3soipddef.h b/src/spicelib/devices/bsim3soi_pd/b3soipddef.h
index c742f9ee8..d38c9ea78 100644
--- a/src/spicelib/devices/bsim3soi_pd/b3soipddef.h
+++ b/src/spicelib/devices/bsim3soi_pd/b3soipddef.h
@@ -30,13 +30,13 @@ typedef struct sB3SOIPDinstance
     IFuid B3SOIPDname;
     int B3SOIPDstates;     /* index into state table for this device */
 
-    int B3SOIPDdNode;
-    int B3SOIPDgNode;
-    int B3SOIPDsNode;
-    int B3SOIPDeNode;
-    int B3SOIPDbNodeExt;
-    int B3SOIPDtempNodeExt;
-    int B3SOIPDpNodeExt;
+    const int B3SOIPDdNode;
+    const int B3SOIPDgNode;
+    const int B3SOIPDsNode;
+    const int B3SOIPDeNode;
+    const int B3SOIPDbNodeExt;
+    const int B3SOIPDtempNodeExt;
+    const int B3SOIPDpNodeExt;
     int B3SOIPDpNode;
     int B3SOIPDbNode;
     int B3SOIPDtempNode;
diff --git a/src/spicelib/devices/bsim3v0/bsim3v0def.h b/src/spicelib/devices/bsim3v0/bsim3v0def.h
index a72931e73..2e14bed98 100644
--- a/src/spicelib/devices/bsim3v0/bsim3v0def.h
+++ b/src/spicelib/devices/bsim3v0/bsim3v0def.h
@@ -20,10 +20,10 @@ typedef struct sBSIM3v0instance
     IFuid BSIM3v0name;
     int BSIM3v0states;     /* index into state table for this device */
     
-    int BSIM3v0dNode;
-    int BSIM3v0gNode;
-    int BSIM3v0sNode;
-    int BSIM3v0bNode;
+    const int BSIM3v0dNode;
+    const int BSIM3v0gNode;
+    const int BSIM3v0sNode;
+    const int BSIM3v0bNode;
     int BSIM3v0dNodePrime;
     int BSIM3v0sNodePrime;
     int BSIM3v0qNode; /* MCJ */
diff --git a/src/spicelib/devices/bsim3v1/bsim3v1def.h b/src/spicelib/devices/bsim3v1/bsim3v1def.h
index 3424582f2..8aba22813 100644
--- a/src/spicelib/devices/bsim3v1/bsim3v1def.h
+++ b/src/spicelib/devices/bsim3v1/bsim3v1def.h
@@ -21,10 +21,10 @@ typedef struct sBSIM3v1instance
     IFuid BSIM3v1name;
     int BSIM3v1states;     /* index into state table for this device */
 
-    int BSIM3v1dNode;
-    int BSIM3v1gNode;
-    int BSIM3v1sNode;
-    int BSIM3v1bNode;
+    const int BSIM3v1dNode;
+    const int BSIM3v1gNode;
+    const int BSIM3v1sNode;
+    const int BSIM3v1bNode;
     int BSIM3v1dNodePrime;
     int BSIM3v1sNodePrime;
     int BSIM3v1qNode; /* MCJ */
diff --git a/src/spicelib/devices/bsim3v32/bsim3v32def.h b/src/spicelib/devices/bsim3v32/bsim3v32def.h
index 6bc0d27e8..1a65860e6 100644
--- a/src/spicelib/devices/bsim3v32/bsim3v32def.h
+++ b/src/spicelib/devices/bsim3v32/bsim3v32def.h
@@ -22,10 +22,10 @@ typedef struct sBSIM3v32instance
     struct sBSIM3v32instance *BSIM3v32nextInstance;
     IFuid BSIM3v32name;
     int BSIM3v32states;     /* index into state table for this device */
-    int BSIM3v32dNode;
-    int BSIM3v32gNode;
-    int BSIM3v32sNode;
-    int BSIM3v32bNode;
+    const int BSIM3v32dNode;
+    const int BSIM3v32gNode;
+    const int BSIM3v32sNode;
+    const int BSIM3v32bNode;
     int BSIM3v32dNodePrime;
     int BSIM3v32sNodePrime;
     int BSIM3v32qNode; /* MCJ */
diff --git a/src/spicelib/devices/bsim4/bsim4def.h b/src/spicelib/devices/bsim4/bsim4def.h
index c85683654..2a10ea10b 100644
--- a/src/spicelib/devices/bsim4/bsim4def.h
+++ b/src/spicelib/devices/bsim4/bsim4def.h
@@ -73,10 +73,10 @@ typedef struct sBSIM4instance
     struct sBSIM4instance *BSIM4nextInstance;
     IFuid BSIM4name;
     int BSIM4states;     /* index into state table for this device */
-    int BSIM4dNode;
-    int BSIM4gNodeExt;
-    int BSIM4sNode;
-    int BSIM4bNode;
+    const int BSIM4dNode;
+    const int BSIM4gNodeExt;
+    const int BSIM4sNode;
+    const int BSIM4bNode;
     int BSIM4dNodePrime;
     int BSIM4gNodePrime;
     int BSIM4gNodeMid;
diff --git a/src/spicelib/devices/bsim4v5/bsim4v5def.h b/src/spicelib/devices/bsim4v5/bsim4v5def.h
index c40d70ba2..300900695 100644
--- a/src/spicelib/devices/bsim4v5/bsim4v5def.h
+++ b/src/spicelib/devices/bsim4v5/bsim4v5def.h
@@ -24,10 +24,10 @@ typedef struct sBSIM4v5instance
     struct sBSIM4v5instance *BSIM4v5nextInstance;
     IFuid BSIM4v5name;
     int BSIM4v5states;     /* index into state table for this device */
-    int BSIM4v5dNode;
-    int BSIM4v5gNodeExt;
-    int BSIM4v5sNode;
-    int BSIM4v5bNode;
+    const int BSIM4v5dNode;
+    const int BSIM4v5gNodeExt;
+    const int BSIM4v5sNode;
+    const int BSIM4v5bNode;
     int BSIM4v5dNodePrime;
     int BSIM4v5gNodePrime;
     int BSIM4v5gNodeMid;
diff --git a/src/spicelib/devices/bsim4v6/bsim4v6def.h b/src/spicelib/devices/bsim4v6/bsim4v6def.h
index a3348f07a..5f2a94f28 100644
--- a/src/spicelib/devices/bsim4v6/bsim4v6def.h
+++ b/src/spicelib/devices/bsim4v6/bsim4v6def.h
@@ -33,10 +33,10 @@ typedef struct sBSIM4v6instance
     struct sBSIM4v6instance *BSIM4v6nextInstance;
     IFuid BSIM4v6name;
     int BSIM4v6states;     /* index into state table for this device */
-    int BSIM4v6dNode;
-    int BSIM4v6gNodeExt;
-    int BSIM4v6sNode;
-    int BSIM4v6bNode;
+    const int BSIM4v6dNode;
+    const int BSIM4v6gNodeExt;
+    const int BSIM4v6sNode;
+    const int BSIM4v6bNode;
     int BSIM4v6dNodePrime;
     int BSIM4v6gNodePrime;
     int BSIM4v6gNodeMid;
diff --git a/src/spicelib/devices/bsim4v7/bsim4v7def.h b/src/spicelib/devices/bsim4v7/bsim4v7def.h
index 469172445..1803e0c4e 100644
--- a/src/spicelib/devices/bsim4v7/bsim4v7def.h
+++ b/src/spicelib/devices/bsim4v7/bsim4v7def.h
@@ -34,10 +34,10 @@ typedef struct sBSIM4v7instance
     struct sBSIM4v7instance *BSIM4v7nextInstance;
     IFuid BSIM4v7name;
     int BSIM4v7states;     /* index into state table for this device */
-    int BSIM4v7dNode;
-    int BSIM4v7gNodeExt;
-    int BSIM4v7sNode;
-    int BSIM4v7bNode;
+    const int BSIM4v7dNode;
+    const int BSIM4v7gNodeExt;
+    const int BSIM4v7sNode;
+    const int BSIM4v7bNode;
     int BSIM4v7dNodePrime;
     int BSIM4v7gNodePrime;
     int BSIM4v7gNodeMid;
diff --git a/src/spicelib/devices/bsimsoi/b4soidef.h b/src/spicelib/devices/bsimsoi/b4soidef.h
index 726390bb0..ce858a1a7 100644
--- a/src/spicelib/devices/bsimsoi/b4soidef.h
+++ b/src/spicelib/devices/bsimsoi/b4soidef.h
@@ -31,13 +31,13 @@ typedef struct sB4SOIinstance
     IFuid B4SOIname;
     int B4SOIstates;     /* index into state table for this device */
 
-    int B4SOIdNode;
-    int B4SOIgNodeExt; /* v3.1 changed gNode to gNodeExt */
-    int B4SOIsNode;
-    int B4SOIeNode;
-    int B4SOIpNodeExt;
-    int B4SOIbNodeExt;
-    int B4SOItempNodeExt;
+    const int B4SOIdNode;
+    const int B4SOIgNodeExt; /* v3.1 changed gNode to gNodeExt */
+    const int B4SOIsNode;
+    const int B4SOIeNode;
+    const int B4SOIpNodeExt;
+    const int B4SOIbNodeExt;
+    const int B4SOItempNodeExt;
     int B4SOIpNode;
     int B4SOIbNode;
     int B4SOItempNode;
diff --git a/src/spicelib/devices/cap/capdefs.h b/src/spicelib/devices/cap/capdefs.h
index 4d61b5bf5..7a4e26307 100644
--- a/src/spicelib/devices/cap/capdefs.h
+++ b/src/spicelib/devices/cap/capdefs.h
@@ -24,8 +24,8 @@ typedef struct sCAPinstance {
                                              * current model*/
     IFuid CAPname;  /* pointer to character string naming this instance */
     int CAPstate;   /* pointer to start of capacitor state vector */
-    int CAPposNode; /* number of positive node of capacitor */
-    int CAPnegNode; /* number of negative node of capacitor */
+    const int CAPposNode; /* number of positive node of capacitor */
+    const int CAPnegNode; /* number of negative node of capacitor */
 
     double CAPtemp;     /* temperature at which this capacitor operates */
     double CAPdtemp;    /* delta-temperature of this instance */
diff --git a/src/spicelib/devices/cccs/cccsdefs.h b/src/spicelib/devices/cccs/cccsdefs.h
index 4515a6e1e..0a5875927 100644
--- a/src/spicelib/devices/cccs/cccsdefs.h
+++ b/src/spicelib/devices/cccs/cccsdefs.h
@@ -22,8 +22,8 @@ typedef struct sCCCSinstance {
     IFuid CCCSname; /* pointer to character string naming this instance */
     int CCCSstate; /* not used */
 
-    int CCCSposNode;    /* number of positive node of source */
-    int CCCSnegNode;    /* number of negative node of source */
+    const int CCCSposNode; /* number of positive node of source */
+    const int CCCSnegNode; /* number of negative node of source */
     int CCCScontBranch;    /* number of branch eq of controlling source */
 
     char *CCCScontName; /* pointer to name of controlling instance */
diff --git a/src/spicelib/devices/ccvs/ccvsdefs.h b/src/spicelib/devices/ccvs/ccvsdefs.h
index 9a80e5876..1c96890a6 100644
--- a/src/spicelib/devices/ccvs/ccvsdefs.h
+++ b/src/spicelib/devices/ccvs/ccvsdefs.h
@@ -22,8 +22,8 @@ typedef struct sCCVSinstance {
     IFuid CCVSname; /* pointer to character string naming this instance */
     int CCVSstate; /* not used */
 
-    int CCVSposNode;    /* number of positive node of source */
-    int CCVSnegNode;    /* number of negative node of source */
+    const int CCVSposNode;    /* number of positive node of source */
+    const int CCVSnegNode;    /* number of negative node of source */
 
     IFuid CCVScontName; /* pointer to name of controlling instance */
     int CCVSbranch; /* equation number of branch equation added for v source */
diff --git a/src/spicelib/devices/csw/cswdefs.h b/src/spicelib/devices/csw/cswdefs.h
index 6a52c37e2..59522dabb 100644
--- a/src/spicelib/devices/csw/cswdefs.h
+++ b/src/spicelib/devices/csw/cswdefs.h
@@ -25,8 +25,8 @@ typedef struct sCSWinstance {
     IFuid CSWname;  /* pointer to character string naming this instance */
     int CSWstate;   /* pointer to start of switch's section of state vector */
 
-    int CSWposNode; /* number of positive node of switch */
-    int CSWnegNode; /* number of negative node of switch */
+    const int CSWposNode; /* number of positive node of switch */
+    const int CSWnegNode; /* number of negative node of switch */
     int CSWcontBranch; /* number of branch of controlling current */
 
     IFuid CSWcontName; /* name of controlling source */
diff --git a/src/spicelib/devices/dio/diodefs.h b/src/spicelib/devices/dio/diodefs.h
index c80364862..65c0f869b 100644
--- a/src/spicelib/devices/dio/diodefs.h
+++ b/src/spicelib/devices/dio/diodefs.h
@@ -23,8 +23,8 @@ typedef struct sDIOinstance {
                                              * current model*/
     IFuid DIOname;      /* pointer to character string naming this instance */
     int DIOstate;   /* pointer to start of state vector for diode */
-    int DIOposNode;     /* number of positive node of diode */
-    int DIOnegNode;     /* number of negative node of diode */
+    const int DIOposNode;     /* number of positive node of diode */
+    const int DIOnegNode;     /* number of negative node of diode */
     int DIOposPrimeNode;    /* number of positive prime node of diode */
 
     double *DIOposPosPrimePtr;      /* pointer to sparse matrix at 
diff --git a/src/spicelib/devices/hfet1/hfetdefs.h b/src/spicelib/devices/hfet1/hfetdefs.h
index 9a324b4c6..61ed45403 100644
--- a/src/spicelib/devices/hfet1/hfetdefs.h
+++ b/src/spicelib/devices/hfet1/hfetdefs.h
@@ -20,9 +20,9 @@ typedef struct sHFETAinstance {
     IFuid HFETAname;
     int HFETAstate;   /* index into state table for this device */
     
-    int HFETAdrainNode;
-    int HFETAgateNode;
-    int HFETAsourceNode;
+    const int HFETAdrainNode;
+    const int HFETAgateNode;
+    const int HFETAsourceNode;
     int HFETAdrainPrimeNode;
     int HFETAgatePrimeNode;
     int HFETAsourcePrimeNode;
diff --git a/src/spicelib/devices/hisim2/hsm2def.h b/src/spicelib/devices/hisim2/hsm2def.h
index e37320f17..77e290735 100644
--- a/src/spicelib/devices/hisim2/hsm2def.h
+++ b/src/spicelib/devices/hisim2/hsm2def.h
@@ -143,10 +143,10 @@ typedef struct sHSM2instance {
   IFuid HSM2name; /* pointer to character string naming this instance */
   int HSM2states; /* index into state table for this device */
 
-  int HSM2dNode;      /* number of the drain node of the mosfet */
-  int HSM2gNode;      /* number of the gate node of the mosfet */
-  int HSM2sNode;      /* number of the source node of the mosfet */
-  int HSM2bNode;      /* number of the bulk node of the mosfet */
+  const int HSM2dNode;      /* number of the drain node of the mosfet */
+  const int HSM2gNode;      /* number of the gate node of the mosfet */
+  const int HSM2sNode;      /* number of the source node of the mosfet */
+  const int HSM2bNode;      /* number of the bulk node of the mosfet */
   int HSM2dNodePrime; /* number od the inner drain node */
   int HSM2gNodePrime; /* number of the inner gate node */
   int HSM2sNodePrime; /* number od the inner source node */
diff --git a/src/spicelib/devices/hisimhv1/hsmhvdef.h b/src/spicelib/devices/hisimhv1/hsmhvdef.h
index a60dcfb1b..91db73d52 100644
--- a/src/spicelib/devices/hisimhv1/hsmhvdef.h
+++ b/src/spicelib/devices/hisimhv1/hsmhvdef.h
@@ -219,12 +219,12 @@ typedef struct sHSMHVinstance {
   IFuid HSMHVname; /* pointer to character string naming this instance */
   int HSMHVstates; /* index into state table for this device */
 
-  int HSMHVdNode;      /* number of the drain node of the mosfet */
-  int HSMHVgNode;      /* number of the gate node of the mosfet */
-  int HSMHVsNode;      /* number of the source node of the mosfet */
-  int HSMHVbNode;      /* number of the bulk node of the mosfet */
-  int HSMHVsubNodeExt; /* number of the substrate node */
-  int HSMHVtempNodeExt;/* number of the temp node----------SHE--------*/
+  const int HSMHVdNode;      /* number of the drain node of the mosfet */
+  const int HSMHVgNode;      /* number of the gate node of the mosfet */
+  const int HSMHVsNode;      /* number of the source node of the mosfet */
+  const int HSMHVbNode;      /* number of the bulk node of the mosfet */
+  const int HSMHVsubNodeExt; /* number of the substrate node */
+  const int HSMHVtempNodeExt;/* number of the temp node----------SHE--------*/
   int HSMHVsubNode;    /* number of the substrate node */
   int HSMHVtempNode;   /* number of the temp node */
   int HSMHVdNodePrime; /* number od the inner drain node */
diff --git a/src/spicelib/devices/hisimhv2/hsmhv2def.h b/src/spicelib/devices/hisimhv2/hsmhv2def.h
index 8569a7d03..f13b4732c 100644
--- a/src/spicelib/devices/hisimhv2/hsmhv2def.h
+++ b/src/spicelib/devices/hisimhv2/hsmhv2def.h
@@ -267,12 +267,12 @@ typedef struct sHSMHV2instance {
   IFuid HSMHV2name; /* pointer to character string naming this instance */
   int HSMHV2states; /* index into state table for this device */
 
-  int HSMHV2dNode;      /* number of the drain node of the mosfet */
-  int HSMHV2gNode;      /* number of the gate node of the mosfet */
-  int HSMHV2sNode;      /* number of the source node of the mosfet */
-  int HSMHV2bNode;      /* number of the bulk node of the mosfet */
-  int HSMHV2subNodeExt; /* number of the substrate node */
-  int HSMHV2tempNodeExt;/* number of the temp node----------SHE--------*/
+  const int HSMHV2dNode;      /* number of the drain node of the mosfet */
+  const int HSMHV2gNode;      /* number of the gate node of the mosfet */
+  const int HSMHV2sNode;      /* number of the source node of the mosfet */
+  const int HSMHV2bNode;      /* number of the bulk node of the mosfet */
+  const int HSMHV2subNodeExt; /* number of the substrate node */
+  const int HSMHV2tempNodeExt;/* number of the temp node----------SHE--------*/
   int HSMHV2subNode;    /* number of the substrate node */
   int HSMHV2tempNode;   /* number of the temp node */
   int HSMHV2dNodePrime; /* number od the inner drain node */
diff --git a/src/spicelib/devices/ind/inddefs.h b/src/spicelib/devices/ind/inddefs.h
index cd3ada512..c21c75466 100644
--- a/src/spicelib/devices/ind/inddefs.h
+++ b/src/spicelib/devices/ind/inddefs.h
@@ -32,8 +32,8 @@ struct sINDinstance {
                                    * current model */
     IFuid INDname;  /* pointer to character string naming this instance */
     int INDstate;   /* pointer to beginning of state vector for inductor */
-    int INDposNode; /* number of positive node of inductor */
-    int INDnegNode; /* number of negative node of inductor */
+    const int INDposNode; /* number of positive node of inductor */
+    const int INDnegNode; /* number of negative node of inductor */
 
     int INDbrEq;    /* number of the branch equation added for current */
     double INDinduct;    /* inductance */
diff --git a/src/spicelib/devices/isrc/isrcdefs.h b/src/spicelib/devices/isrc/isrcdefs.h
index f06741eb7..1519168da 100644
--- a/src/spicelib/devices/isrc/isrcdefs.h
+++ b/src/spicelib/devices/isrc/isrcdefs.h
@@ -25,8 +25,8 @@ typedef struct sISRCinstance {
     IFuid ISRCname; /* pointer to character string naming this instance */
     int ISRCstate;  /* not used */
 
-    int ISRCnegNode;    /* number of negative node of source */
-    int ISRCposNode;    /* number of positive node of source */
+    const int ISRCnegNode;    /* number of negative node of source */
+    const int ISRCposNode;    /* number of positive node of source */
 
     int ISRCfunctionType;   /* code number of function type for source */
     int ISRCfunctionOrder;  /* order of the function for the source */
diff --git a/src/spicelib/devices/jfet/jfetdefs.h b/src/spicelib/devices/jfet/jfetdefs.h
index 929e43f7e..9ec278104 100644
--- a/src/spicelib/devices/jfet/jfetdefs.h
+++ b/src/spicelib/devices/jfet/jfetdefs.h
@@ -26,9 +26,9 @@ typedef struct sJFETinstance {
                                              * current model*/
     IFuid JFETname; /* pointer to character string naming this instance */
     int JFETstate; /* pointer to start of state vector for jfet */
-    int JFETdrainNode;  /* number of drain node of jfet */
-    int JFETgateNode;   /* number of gate node of jfet */
-    int JFETsourceNode; /* number of source node of jfet */
+    const int JFETdrainNode;  /* number of drain node of jfet */
+    const int JFETgateNode;   /* number of gate node of jfet */
+    const int JFETsourceNode; /* number of source node of jfet */
     int JFETdrainPrimeNode; /* number of internal drain node of jfet */
     int JFETsourcePrimeNode;    /* number of internal source node of jfet */
 
diff --git a/src/spicelib/devices/jfet2/jfet2defs.h b/src/spicelib/devices/jfet2/jfet2defs.h
index 572f34b20..86f1dd798 100644
--- a/src/spicelib/devices/jfet2/jfet2defs.h
+++ b/src/spicelib/devices/jfet2/jfet2defs.h
@@ -31,9 +31,9 @@ typedef struct sJFET2instance {
                                              * current model*/
     IFuid JFET2name; /* pointer to character string naming this instance */
     int JFET2state; /* pointer to start of state vector for jfet */
-    int JFET2drainNode;  /* number of drain node of jfet */
-    int JFET2gateNode;   /* number of gate node of jfet */
-    int JFET2sourceNode; /* number of source node of jfet */
+    const int JFET2drainNode;  /* number of drain node of jfet */
+    const int JFET2gateNode;   /* number of gate node of jfet */
+    const int JFET2sourceNode; /* number of source node of jfet */
     int JFET2drainPrimeNode; /* number of internal drain node of jfet */
     int JFET2sourcePrimeNode;    /* number of internal source node of jfet */
 
diff --git a/src/spicelib/devices/ltra/ltradefs.h b/src/spicelib/devices/ltra/ltradefs.h
index 71833ba33..33e9eb43d 100644
--- a/src/spicelib/devices/ltra/ltradefs.h
+++ b/src/spicelib/devices/ltra/ltradefs.h
@@ -23,10 +23,10 @@ typedef struct sLTRAinstance {
                                              * current model*/
     IFuid LTRAname;      /* pointer to character string naming this instance */
     int LTRAstate;	 /* not used */
-    int LTRAposNode1;    /* number of positive node of end 1 of t. line */
-    int LTRAnegNode1;    /* number of negative node of end 1 of t. line */
-    int LTRAposNode2;    /* number of positive node of end 2 of t. line */
-    int LTRAnegNode2;    /* number of negative node of end 2 of t. line */
+    const int LTRAposNode1;    /* number of positive node of end 1 of t. line */
+    const int LTRAnegNode1;    /* number of negative node of end 1 of t. line */
+    const int LTRAposNode2;    /* number of positive node of end 2 of t. line */
+    const int LTRAnegNode2;    /* number of negative node of end 2 of t. line */
 
     int LTRAbrEq1;       /* number of branch equation for end 1 of t. line */
     int LTRAbrEq2;       /* number of branch equation for end 2 of t. line */
diff --git a/src/spicelib/devices/mes/mesdefs.h b/src/spicelib/devices/mes/mesdefs.h
index 316f14b8c..71ae13565 100644
--- a/src/spicelib/devices/mes/mesdefs.h
+++ b/src/spicelib/devices/mes/mesdefs.h
@@ -25,9 +25,9 @@ typedef struct sMESinstance {
                                              * current model*/
     IFuid MESname; /* pointer to character string naming this instance */
     int MESstate; /* pointer to start of state vector for mesfet */
-    int MESdrainNode;  /* number of drain node of mesfet */
-    int MESgateNode;   /* number of gate node of mesfet */
-    int MESsourceNode; /* number of source node of mesfet */
+    const int MESdrainNode;  /* number of drain node of mesfet */
+    const int MESgateNode;   /* number of gate node of mesfet */
+    const int MESsourceNode; /* number of source node of mesfet */
     int MESdrainPrimeNode; /* number of internal drain node of mesfet */
     int MESsourcePrimeNode;    /* number of internal source node of mesfet */
 
diff --git a/src/spicelib/devices/mesa/mesadefs.h b/src/spicelib/devices/mesa/mesadefs.h
index 37fffc4a4..13e8a046d 100644
--- a/src/spicelib/devices/mesa/mesadefs.h
+++ b/src/spicelib/devices/mesa/mesadefs.h
@@ -24,9 +24,9 @@ typedef struct sMESAinstance {
     IFuid MESAname; /* pointer to character string naming this instance */
     int MESAstate; /* pointer to start of state vector for MESAfet */
     
-    int MESAdrainNode;  /* number of drain node of MESAfet */
-    int MESAgateNode;   /* number of gate node of MESAfet */
-    int MESAsourceNode; /* number of source node of MESAfet */
+    const int MESAdrainNode;  /* number of drain node of MESAfet */
+    const int MESAgateNode;   /* number of gate node of MESAfet */
+    const int MESAsourceNode; /* number of source node of MESAfet */
     int MESAdrainPrimeNode; /* number of internal drain node of MESAfet */
     int MESAgatePrimeNode; /* number of internal gate node of MESAfet */
     int MESAsourcePrimeNode;    /* number of internal source node of MESAfet */
diff --git a/src/spicelib/devices/mos1/mos1defs.h b/src/spicelib/devices/mos1/mos1defs.h
index c51cc2eb9..6d99af876 100644
--- a/src/spicelib/devices/mos1/mos1defs.h
+++ b/src/spicelib/devices/mos1/mos1defs.h
@@ -24,10 +24,10 @@ typedef struct sMOS1instance {
     IFuid MOS1name; /* pointer to character string naming this instance */
     int MOS1states;     /* index into state table for this device */
 
-    int MOS1dNode;  /* number of the gate node of the mosfet */
-    int MOS1gNode;  /* number of the gate node of the mosfet */
-    int MOS1sNode;  /* number of the source node of the mosfet */
-    int MOS1bNode;  /* number of the bulk node of the mosfet */
+    const int MOS1dNode;  /* number of the gate node of the mosfet */
+    const int MOS1gNode;  /* number of the gate node of the mosfet */
+    const int MOS1sNode;  /* number of the source node of the mosfet */
+    const int MOS1bNode;  /* number of the bulk node of the mosfet */
     int MOS1dNodePrime; /* number of the internal drain node of the mosfet */
     int MOS1sNodePrime; /* number of the internal source node of the mosfet */
     
diff --git a/src/spicelib/devices/mos2/mos2defs.h b/src/spicelib/devices/mos2/mos2defs.h
index 6d42d8eee..8e2b38f37 100644
--- a/src/spicelib/devices/mos2/mos2defs.h
+++ b/src/spicelib/devices/mos2/mos2defs.h
@@ -23,10 +23,10 @@ typedef struct sMOS2instance {
                                               *current model*/
     IFuid MOS2name; /* pointer to character string naming this instance */
     int MOS2states;     /* index into state table for this device */
-    int MOS2dNode;  /* number of the gate node of the mosfet */
-    int MOS2gNode;  /* number of the gate node of the mosfet */
-    int MOS2sNode;  /* number of the source node of the mosfet */
-    int MOS2bNode;  /* number of the bulk node of the mosfet */
+    const int MOS2dNode;  /* number of the gate node of the mosfet */
+    const int MOS2gNode;  /* number of the gate node of the mosfet */
+    const int MOS2sNode;  /* number of the source node of the mosfet */
+    const int MOS2bNode;  /* number of the bulk node of the mosfet */
     int MOS2dNodePrime; /* number of the internal drain node of the mosfet */
     int MOS2sNodePrime; /* number of the internal source node of the mosfet */
 
diff --git a/src/spicelib/devices/mos3/mos3defs.h b/src/spicelib/devices/mos3/mos3defs.h
index 51fe799a7..0089ef378 100644
--- a/src/spicelib/devices/mos3/mos3defs.h
+++ b/src/spicelib/devices/mos3/mos3defs.h
@@ -23,10 +23,10 @@ typedef struct sMOS3instance {
                                               *current model*/
     IFuid MOS3name; /* pointer to character string naming this instance */
     int MOS3states;     /* index into state table for this device */
-    int MOS3dNode;  /* number of the gate node of the mosfet */
-    int MOS3gNode;  /* number of the gate node of the mosfet */
-    int MOS3sNode;  /* number of the source node of the mosfet */
-    int MOS3bNode;  /* number of the bulk node of the mosfet */
+    const int MOS3dNode;  /* number of the gate node of the mosfet */
+    const int MOS3gNode;  /* number of the gate node of the mosfet */
+    const int MOS3sNode;  /* number of the source node of the mosfet */
+    const int MOS3bNode;  /* number of the bulk node of the mosfet */
     int MOS3dNodePrime; /* number of the internal drain node of the mosfet */
     int MOS3sNodePrime; /* number of the internal source node of the mosfet */
 
diff --git a/src/spicelib/devices/mos6/mos6defs.h b/src/spicelib/devices/mos6/mos6defs.h
index af1ad82ac..b9f9438ea 100644
--- a/src/spicelib/devices/mos6/mos6defs.h
+++ b/src/spicelib/devices/mos6/mos6defs.h
@@ -21,10 +21,10 @@ typedef struct sMOS6instance {
                                               *current model*/
     IFuid MOS6name; /* pointer to character string naming this instance */
     int MOS6states;     /* index into state table for this device */
-    int MOS6dNode;  /* number of the gate node of the mosfet */
-    int MOS6gNode;  /* number of the gate node of the mosfet */
-    int MOS6sNode;  /* number of the source node of the mosfet */
-    int MOS6bNode;  /* number of the bulk node of the mosfet */
+    const int MOS6dNode;  /* number of the gate node of the mosfet */
+    const int MOS6gNode;  /* number of the gate node of the mosfet */
+    const int MOS6sNode;  /* number of the source node of the mosfet */
+    const int MOS6bNode;  /* number of the bulk node of the mosfet */
     int MOS6dNodePrime; /* number of the internal drain node of the mosfet */
     int MOS6sNodePrime; /* number of the internal source node of the mosfet */
 
diff --git a/src/spicelib/devices/mos9/mos9defs.h b/src/spicelib/devices/mos9/mos9defs.h
index 2a863c25d..e40588b33 100644
--- a/src/spicelib/devices/mos9/mos9defs.h
+++ b/src/spicelib/devices/mos9/mos9defs.h
@@ -23,10 +23,10 @@ typedef struct sMOS9instance {
                                               *current model*/
     IFuid MOS9name; /* pointer to character string naming this instance */
     int MOS9states;     /* index into state table for this device */
-    int MOS9dNode;  /* number of the gate node of the mosfet */
-    int MOS9gNode;  /* number of the gate node of the mosfet */
-    int MOS9sNode;  /* number of the source node of the mosfet */
-    int MOS9bNode;  /* number of the bulk node of the mosfet */
+    const int MOS9dNode;  /* number of the gate node of the mosfet */
+    const int MOS9gNode;  /* number of the gate node of the mosfet */
+    const int MOS9sNode;  /* number of the source node of the mosfet */
+    const int MOS9bNode;  /* number of the bulk node of the mosfet */
     int MOS9dNodePrime; /* number of the internal drain node of the mosfet */
     int MOS9sNodePrime; /* number of the internal source node of the mosfet */
 
diff --git a/src/spicelib/devices/nbjt/nbjtdefs.h b/src/spicelib/devices/nbjt/nbjtdefs.h
index 911dac696..6567b177d 100644
--- a/src/spicelib/devices/nbjt/nbjtdefs.h
+++ b/src/spicelib/devices/nbjt/nbjtdefs.h
@@ -40,9 +40,9 @@ typedef struct sNBJTinstance {
 #define NBJTdIcDVbe NBJTstate+7
 #define NBJTnumStates 8
 
-  int NBJTcolNode;		/* number of collector node of bjt */
-  int NBJTbaseNode;		/* number of base node of bjt */
-  int NBJTemitNode;		/* number of emitter node of bjt */
+  const int NBJTcolNode;		/* number of collector node of bjt */
+  const int NBJTbaseNode;		/* number of base node of bjt */
+  const int NBJTemitNode;		/* number of emitter node of bjt */
   ONEdevice *NBJTpDevice;
   GLOBvalues NBJTglobals;	/* Temp.-Dep. Global Parameters */
   int NBJTtype;
diff --git a/src/spicelib/devices/nbjt2/nbjt2def.h b/src/spicelib/devices/nbjt2/nbjt2def.h
index c66ac191a..fcd58f839 100644
--- a/src/spicelib/devices/nbjt2/nbjt2def.h
+++ b/src/spicelib/devices/nbjt2/nbjt2def.h
@@ -40,9 +40,9 @@ typedef struct sNBJT2instance {
 #define NBJT2dIcDVbe NBJT2state+7
 #define NBJT2numStates 8
 
-  int NBJT2colNode;		/* number of collector node of bjt */
-  int NBJT2baseNode;		/* number of base node of bjt */
-  int NBJT2emitNode;		/* number of emitter node of bjt */
+  const int NBJT2colNode;		/* number of collector node of bjt */
+  const int NBJT2baseNode;		/* number of base node of bjt */
+  const int NBJT2emitNode;		/* number of emitter node of bjt */
   double NBJT2width;		/* width factor for the bjt */
   double NBJT2area;		/* area factor for the bjt */
   TWOdevice *NBJT2pDevice;
diff --git a/src/spicelib/devices/ndev/ndevdefs.h b/src/spicelib/devices/ndev/ndevdefs.h
index 60e29d29b..2415cb9c0 100644
--- a/src/spicelib/devices/ndev/ndevdefs.h
+++ b/src/spicelib/devices/ndev/ndevdefs.h
@@ -30,7 +30,7 @@ typedef struct sNDEVinstance {
   IFuid NDEVname;		/* pointer to character string naming this
 				 * instance */
   int NDEVstate;		/* pointer to start of state vector for diode */
-  int pin[7];                   /* max 7 terminals are allowed */
+  const int pin[7];                   /* max 7 terminals are allowed */
   int  term;                    /* the real number of terminals */
   CKTnode *node[7];		/* the array of CKT node's node pointer */
   char *bname[7];               /* the electrode boundary label for numerical solver */
diff --git a/src/spicelib/devices/numd/numddefs.h b/src/spicelib/devices/numd/numddefs.h
index c24dd358d..080d49aaf 100644
--- a/src/spicelib/devices/numd/numddefs.h
+++ b/src/spicelib/devices/numd/numddefs.h
@@ -34,8 +34,8 @@ typedef struct sNUMDinstance {
 #define NUMDconduct NUMDstate+2
 #define NUMDnumStates 3
 
-  int NUMDposNode;		/* number of positive node of diode */
-  int NUMDnegNode;		/* number of negative node of diode */
+  const int NUMDposNode;	/* number of positive node of diode */
+  const int NUMDnegNode;	/* number of negative node of diode */
   ONEdevice *NUMDpDevice;
   GLOBvalues NUMDglobals;	/* Temp.-Dep. Global Parameters */
   int NUMDtype;			/* device type pn or np */
diff --git a/src/spicelib/devices/numd2/numd2def.h b/src/spicelib/devices/numd2/numd2def.h
index 46017446f..3aeffa568 100644
--- a/src/spicelib/devices/numd2/numd2def.h
+++ b/src/spicelib/devices/numd2/numd2def.h
@@ -34,8 +34,8 @@ typedef struct sNUMD2instance {
 #define NUMD2conduct NUMD2state+2
 #define NUMD2numStates 3
 
-  int NUMD2posNode;		/* number of positive node of diode */
-  int NUMD2negNode;		/* number of negative node of diode */
+  const int NUMD2posNode;	/* number of positive node of diode */
+  const int NUMD2negNode;	/* number of negative node of diode */
   TWOdevice *NUMD2pDevice;
   GLOBvalues NUMD2globals;	/* Temp.-Dep. Global Parameters */
   int NUMD2type;		/* device type pn or np */
diff --git a/src/spicelib/devices/numos/numosdef.h b/src/spicelib/devices/numos/numosdef.h
index 6bcad9fc8..18de61139 100644
--- a/src/spicelib/devices/numos/numosdef.h
+++ b/src/spicelib/devices/numos/numosdef.h
@@ -48,10 +48,10 @@ typedef struct sNUMOSinstance {
 #define NUMOSdIgDVgb NUMOSstate+14
 #define NUMOSnumStates 15
 
-  int NUMOSdrainNode;		/* number of drain node of MOSFET */
-  int NUMOSgateNode;		/* number of gate node of MOSFET */
-  int NUMOSsourceNode;		/* number of source node of MOSFET */
-  int NUMOSbulkNode;		/* number of bulk node of MOSFET */
+  const int NUMOSdrainNode;	/* number of drain node of MOSFET */
+  const int NUMOSgateNode;	/* number of gate node of MOSFET */
+  const int NUMOSsourceNode;	/* number of source node of MOSFET */
+  const int NUMOSbulkNode;	/* number of bulk node of MOSFET */
   double NUMOSarea;		/* area factor for the mosfet */
   double NUMOSwidth;		/* width factor for the mosfet */
   double NUMOSlength;		/* length factor for the mosfet */
diff --git a/src/spicelib/devices/res/resdefs.h b/src/spicelib/devices/res/resdefs.h
index 24d2c590c..b024f6a61 100644
--- a/src/spicelib/devices/res/resdefs.h
+++ b/src/spicelib/devices/res/resdefs.h
@@ -25,8 +25,8 @@ typedef struct sRESinstance {
 
     IFuid RESname;      /* pointer to character string naming this instance */
     int RESstate;       /* not used but needed for sructure consistency */
-    int RESposNode;     /* number of positive node of resistor */
-    int RESnegNode;     /* number of negative node of resistor */
+    const int RESposNode;     /* number of positive node of resistor */
+    const int RESnegNode;     /* number of negative node of resistor */
 
     double REStemp;     /* temperature at which this resistor operates */
     double RESdtemp;    /* delta-temperature of a particular instance  */
diff --git a/src/spicelib/devices/soi3/soi3defs.h b/src/spicelib/devices/soi3/soi3defs.h
index 4d7dba923..24cf30fb6 100644
--- a/src/spicelib/devices/soi3/soi3defs.h
+++ b/src/spicelib/devices/soi3/soi3defs.h
@@ -44,12 +44,12 @@ typedef struct sSOI3instance {
     int SOI3states;     /* index into state table for this device */
 
 
-    int SOI3dNode;  /* number of the drain node of the mosfet */
-    int SOI3gfNode;  /* number of the front gate node of the mosfet */
-    int SOI3sNode;  /* number of the source node of the mosfet */
-    int SOI3gbNode;   /* number of the back gate node of the mosfet */
-    int SOI3bNode;  /* number of the bulk node of the mosfet */
-    int SOI3toutNode;  /* number of thermal output node (tout) */
+    const int SOI3dNode;  /* number of the drain node of the mosfet */
+    const int SOI3gfNode;  /* number of the front gate node of the mosfet */
+    const int SOI3sNode;  /* number of the source node of the mosfet */
+    const int SOI3gbNode;   /* number of the back gate node of the mosfet */
+    const int SOI3bNode;  /* number of the bulk node of the mosfet */
+    const int SOI3toutNode;  /* number of thermal output node (tout) */
 
     int SOI3branch; /* branch number for zero voltage source if no thermal */
 
diff --git a/src/spicelib/devices/sw/swdefs.h b/src/spicelib/devices/sw/swdefs.h
index 6daf0ffe2..ff6c995af 100644
--- a/src/spicelib/devices/sw/swdefs.h
+++ b/src/spicelib/devices/sw/swdefs.h
@@ -25,10 +25,10 @@ typedef struct sSWinstance {
     IFuid SWname;  /* pointer to character string naming this instance */
     int SWstate;   /* pointer to start of switch's section of state vector */
 
-    int SWposNode; /* number of positive node of switch */
-    int SWnegNode; /* number of negative node of switch */
-    int SWposCntrlNode; /* number of positive controlling node of switch */
-    int SWnegCntrlNode; /* number of negative controlling node of switch */
+    const int SWposNode; /* number of positive node of switch */
+    const int SWnegNode; /* number of negative node of switch */
+    const int SWposCntrlNode; /* number of positive controlling node of switch */
+    const int SWnegCntrlNode; /* number of negative controlling node of switch */
 
     double *SWposPosPtr;  /* pointer to sparse matrix diagonal at
                                 (positive,positive) for switch conductance */
diff --git a/src/spicelib/devices/tra/tradefs.h b/src/spicelib/devices/tra/tradefs.h
index 17b158c1e..817f289a6 100644
--- a/src/spicelib/devices/tra/tradefs.h
+++ b/src/spicelib/devices/tra/tradefs.h
@@ -23,10 +23,10 @@ typedef struct sTRAinstance {
                                              * current model*/
     IFuid TRAname;      /* pointer to character string naming this instance */
     int TRAstate;	/* not used */
-    int TRAposNode1;    /* number of positive node of end 1 of t. line */
-    int TRAnegNode1;    /* number of negative node of end 1 of t. line */
-    int TRAposNode2;    /* number of positive node of end 2 of t. line */
-    int TRAnegNode2;    /* number of negative node of end 2 of t. line */
+    const int TRAposNode1;    /* number of positive node of end 1 of t. line */
+    const int TRAnegNode1;    /* number of negative node of end 1 of t. line */
+    const int TRAposNode2;    /* number of positive node of end 2 of t. line */
+    const int TRAnegNode2;    /* number of negative node of end 2 of t. line */
     int TRAintNode1;    /* number of internal node of end 1 of t. line */
     int TRAintNode2;    /* number of internal node of end 2 of t. line */
 
diff --git a/src/spicelib/devices/urc/urcdefs.h b/src/spicelib/devices/urc/urcdefs.h
index aab20f9cb..4adbb88c4 100644
--- a/src/spicelib/devices/urc/urcdefs.h
+++ b/src/spicelib/devices/urc/urcdefs.h
@@ -24,9 +24,9 @@ typedef struct sURCinstance {
                                              * current model*/
     IFuid URCname;  /* pointer to character string naming this instance */
     int URCstate;	/* not used */
-    int URCposNode;   /* number of positive node of URC */
-    int URCnegNode;   /* number of negative node of URC */
-    int URCgndNode;   /* number of the "ground" node of the URC */
+    const int URCposNode;   /* number of positive node of URC */
+    const int URCnegNode;   /* number of negative node of URC */
+    const int URCgndNode;   /* number of the "ground" node of the URC */
 
     double URClength;   /* length of line */
     int URClumps;   /* number of lumps in line */
diff --git a/src/spicelib/devices/vbic/vbicdefs.h b/src/spicelib/devices/vbic/vbicdefs.h
index 4f7078567..65032f91e 100644
--- a/src/spicelib/devices/vbic/vbicdefs.h
+++ b/src/spicelib/devices/vbic/vbicdefs.h
@@ -25,10 +25,10 @@ typedef struct sVBICinstance {
     IFuid VBICname;  /* pointer to character string naming this instance */
     int VBICstate;   /* pointer to start of state vector for vbic */
 
-    int VBICcollNode;   /* number of collector node of vbic */
-    int VBICbaseNode;   /* number of base node of vbic */
-    int VBICemitNode;   /* number of emitter node of vbic */
-    int VBICsubsNode;   /* number of substrate node of vbic */
+    const int VBICcollNode;   /* number of collector node of vbic */
+    const int VBICbaseNode;   /* number of base node of vbic */
+    const int VBICemitNode;   /* number of emitter node of vbic */
+    const int VBICsubsNode;   /* number of substrate node of vbic */
     int VBICcollCXNode; /* number of internal collector node of vbic */
     int VBICcollCINode; /* number of internal collector node of vbic */
     int VBICbaseBXNode; /* number of internal base node of vbic */
diff --git a/src/spicelib/devices/vccs/vccsdefs.h b/src/spicelib/devices/vccs/vccsdefs.h
index 68042e82a..2f2f6e040 100644
--- a/src/spicelib/devices/vccs/vccsdefs.h
+++ b/src/spicelib/devices/vccs/vccsdefs.h
@@ -24,10 +24,10 @@ typedef struct sVCCSinstance {
     IFuid VCCSname; /* pointer to character string naming this instance */
     int VCCSstates;         /* state info */
 
-    int VCCSposNode;    /* number of positive node of source */
-    int VCCSnegNode;    /* number of negative node of source */
-    int VCCScontPosNode;    /* number of positive node of controlling source */
-    int VCCScontNegNode;    /* number of negative node of controlling source */
+    const int VCCSposNode;    /* number of positive node of source */
+    const int VCCSnegNode;    /* number of negative node of source */
+    const int VCCScontPosNode;    /* number of positive node of controlling source */
+    const int VCCScontNegNode;    /* number of negative node of controlling source */
 
     double VCCSinitCond;    /* initial condition (of controlling source) */
     double VCCScoeff;       /* coefficient */
diff --git a/src/spicelib/devices/vcvs/vcvsdefs.h b/src/spicelib/devices/vcvs/vcvsdefs.h
index 5325424a5..92880c992 100644
--- a/src/spicelib/devices/vcvs/vcvsdefs.h
+++ b/src/spicelib/devices/vcvs/vcvsdefs.h
@@ -25,10 +25,10 @@ typedef struct sVCVSinstance {
     IFuid VCVSname; /* pointer to character string naming this instance */
     int VCVSstates; /* state info */
 
-    int VCVSposNode;    /* number of positive node of source */
-    int VCVSnegNode;    /* number of negative node of source */
-    int VCVScontPosNode;    /* number of positive node of controlling source */
-    int VCVScontNegNode;    /* number of negative node of controlling source */
+    const int VCVSposNode;    /* number of positive node of source */
+    const int VCVSnegNode;    /* number of negative node of source */
+    const int VCVScontPosNode;    /* number of positive node of controlling source */
+    const int VCVScontNegNode;    /* number of negative node of controlling source */
     int VCVSbranch; /* equation number of branch equation added for v source */
 
     double VCVSinitCond;    /* initial condition (of controlling source) */
diff --git a/src/spicelib/devices/vsrc/vsrcdefs.h b/src/spicelib/devices/vsrc/vsrcdefs.h
index b14d70bcc..1c28fee5e 100644
--- a/src/spicelib/devices/vsrc/vsrcdefs.h
+++ b/src/spicelib/devices/vsrc/vsrcdefs.h
@@ -27,8 +27,8 @@ typedef struct sVSRCinstance {
     IFuid VSRCname; /* pointer to character string naming this instance */
     int VSRCstate;  /* not used */
 
-    int VSRCposNode;    /* number of positive node of source */
-    int VSRCnegNode;    /* number of negative node of source */
+    const int VSRCposNode;    /* number of positive node of source */
+    const int VSRCnegNode;    /* number of negative node of source */
 
     int VSRCbranch; /* equation number of branch equation added for source */