Index: /trunk/psModules/src/camera/pmHDUUtils.c
===================================================================
--- /trunk/psModules/src/camera/pmHDUUtils.c	(revision 7458)
+++ /trunk/psModules/src/camera/pmHDUUtils.c	(revision 7459)
@@ -5,5 +5,5 @@
 
 
-pmHDU *pmHDUFromFPA(pmFPA *fpa          // FPA for which to find HDU
+pmHDU *pmHDUFromFPA(const pmFPA *fpa    // FPA for which to find HDU
                    )
 {
@@ -12,5 +12,5 @@
 }
 
-pmHDU *pmHDUFromChip(pmChip *chip       // Chip for which to find HDU
+pmHDU *pmHDUFromChip(const pmChip *chip // Chip for which to find HDU
                     )
 {
@@ -25,5 +25,5 @@
 }
 
-pmHDU *pmHDUFromCell(pmCell *cell       // Cell for which to find HDU
+pmHDU *pmHDUFromCell(const pmCell *cell // Cell for which to find HDU
                     )
 {
@@ -38,5 +38,6 @@
 }
 
-pmHDU *pmHDUFromReadout(pmReadout *readout)
+pmHDU *pmHDUFromReadout(const pmReadout *readout // Readout for which to find HDU
+                       )
 {
     PS_ASSERT_PTR_NON_NULL(readout, NULL);
@@ -48,7 +49,7 @@
 
 // Get the lowest HDU
-pmHDU *pmHDUGetLowest(pmFPA *fpa, // The FPA
-                      pmChip *chip, // The chip, or NULL
-                      pmCell *cell // The cell, or NULL
+pmHDU *pmHDUGetLowest(const pmFPA *fpa, // The FPA
+                      const pmChip *chip, // The chip, or NULL
+                      const pmCell *cell // The cell, or NULL
                      )
 {
@@ -65,5 +66,5 @@
 }
 
-void pmHDUPrint(pmHDU *hdu,             // HDU to print
+void pmHDUPrint(const pmHDU *hdu,       // HDU to print
                 int level,              // Level at which to print
                 bool header             // Print header?
Index: /trunk/psModules/src/camera/pmHDUUtils.h
===================================================================
--- /trunk/psModules/src/camera/pmHDUUtils.h	(revision 7458)
+++ /trunk/psModules/src/camera/pmHDUUtils.h	(revision 7459)
@@ -6,22 +6,21 @@
 
 // Get the lowest HDU in the hierarchy, as supplied
-pmHDU *pmHDUGetLowest(pmFPA *fpa, // The FPA
-                      pmChip *chip, // The chip, or NULL
-                      pmCell *cell // The cell, or NULL
+pmHDU *pmHDUGetLowest(const pmFPA *fpa, // The FPA
+                      const pmChip *chip, // The chip, or NULL
+                      const pmCell *cell // The cell, or NULL
                      );
 
 // Find the HDU in the FPA hierarchy
-pmHDU *pmHDUFromFPA(pmFPA *fpa          // FPA for which to find HDU
+pmHDU *pmHDUFromFPA(const pmFPA *fpa    // FPA for which to find HDU
                    );
-pmHDU *pmHDUFromChip(pmChip *chip       // Chip for which to find HDU
+pmHDU *pmHDUFromChip(const pmChip *chip // Chip for which to find HDU
                     );
-pmHDU *pmHDUFromCell(pmCell *cell       // Cell for which to find HDU
+pmHDU *pmHDUFromCell(const pmCell *cell // Cell for which to find HDU
                     );
-
-pmHDU *pmHDUFromReadout (pmReadout *readout  // Readout for which to find HDU
-                        );
+pmHDU *pmHDUFromReadout(const pmReadout *readout // Readout for which to find HDU
+                       );
 
 // Print details about an HDU
-void pmHDUPrint(pmHDU *hdu,             // HDU to print
+void pmHDUPrint(const pmHDU *hdu,       // HDU to print
                 int level,              // Level at which to print
                 bool header             // Print header?