diff --git a/src/lasp/lasp_common.py b/src/lasp/lasp_common.py
index 773ea41..8c25a02 100644
--- a/src/lasp/lasp_common.py
+++ b/src/lasp/lasp_common.py
@@ -82,6 +82,12 @@ class Qty:
         return (self.name == other.name and
                 self.unit_name == other.unit_name)
 
+    def toInt(self):
+        """
+        Convert quantity to its specific enum integer value
+        """
+        return self.cpp_enum.value
+
 
 
 @unique
diff --git a/src/lasp/lasp_measurement.py b/src/lasp/lasp_measurement.py
index 1b1607c..f62a8d4 100644
--- a/src/lasp/lasp_measurement.py
+++ b/src/lasp/lasp_measurement.py
@@ -51,6 +51,7 @@ from scipy.io import wavfile
 import os, time, wave, logging
 from .lasp_common import SIQtys, Qty, getFreq
 from .lasp_cpp import Window, DaqChannel, LASP_VERSION_MAJOR
+from typing import List
 
 
 def getSampWidth(dtype):
@@ -311,14 +312,14 @@ class Measurement:
         return chcfg
 
     @channelConfig.setter
-    def channelConfig(self, chcfg):
+    def channelConfig(self, chcfg: List[DaqChannel]):
         chname = []
         sens = []
         qtys = []
         for ch in chcfg:
             chname.append(ch.name)
             sens.append(ch.sensitivity)
-            qtys.append(SIQtys.fromInt(ch.qty))
+            qtys.append(SIQtys.fromCppEnum(ch.qty))
 
         self.channelNames = chname
         self.sensitivity = sens
@@ -332,11 +333,14 @@ class Measurement:
     def qtys(self, newqtys):
         if not len(newqtys) == len(self._qtys):
             raise ValueError('Invalid number of quantities')
-        qtys_json = [qty.to_json() for qty in newqtys]
+        qtys_int = [qty.toInt() for qty in newqtys]
         # Use setAttribute here, but thos store the jsonified version as well,
         # which we have to overwrite again with the deserialized ones. This is
         # actually not a very nice way of coding.
-        self.setAttribute('qtys', qtys_json)
+        with self.file('r+') as f:
+            # Update comment attribute in the file
+            f.attrs['qtys_enum_idx'] = qtys_int
+
         self._qtys = newqtys
 
     @contextmanager
diff --git a/src/lasp/pybind11/lasp_pyindatahandler.cpp b/src/lasp/pybind11/lasp_pyindatahandler.cpp
index 69af06f..aa3fb02 100644
--- a/src/lasp/pybind11/lasp_pyindatahandler.cpp
+++ b/src/lasp/pybind11/lasp_pyindatahandler.cpp
@@ -1,5 +1,5 @@
+/* #define DEBUGTRACE_ENABLED */
 #include <armadillo>
-#define DEBUGTRACE_ENABLED
 #include "arma_npy.h"
 #include "debugtrace.hpp"
 #include "lasp_ppm.h"