diff --git a/lib/tdm_datamodel.hpp b/lib/tdm_datamodel.hpp
index 0ef9bb1..cf6ba16 100644
--- a/lib/tdm_datamodel.hpp
+++ b/lib/tdm_datamodel.hpp
@@ -15,316 +15,7 @@
 #include <chrono>
 #include <sstream>
 
-// -------------------------------------------------------------------------- //
-// format output of info strings for terminal and file table
-
-class format
-{
-
-private:
-
-  unsigned int width_;
-  bool tabular_;
-  bool header_;
-  char sep_;
-  std::vector<std::pair<std::string,std::string>> columns_;
-
-public:
-
-  format(int width = 25, bool tabular = false, bool header = false, char sep = ' '):
-    width_(width), tabular_(tabular), header_(header), sep_(sep)
-  {
-
-  }
-
-  void set_width(int width)
-  {
-    width_ = width;
-  }
-
-  void set_tabular(bool tabular)
-  {
-    tabular_ = tabular;
-  }
-
-  void set_header(bool header)
-  {
-    header_ = header;
-  }
-
-  void set_sep(char sep)
-  {
-    sep_ = sep;
-  }
-
-  void set_columns(std::vector<std::pair<std::string,std::string>> columns)
-  {
-    columns_ = columns;
-  }
-
-  std::string get_info()
-  {
-    std::stringstream ss;
-
-    for ( std::vector<std::pair<std::string,std::string>>::iterator it = columns_.begin();
-                                                                    it != columns_.end(); ++it )
-    {
-      if ( tabular_ )
-      {
-        // header or body of table
-        std::string entry = header_? it->first : it->second;
-
-        // make broad aligned columns for human reader
-        if ( sep_ == ' ' )
-        {
-          entry = entry.size() > width_-2 ? entry.substr(0,width_-2) : entry;
-          // if ( it == columns_.begin() && !header_ ) ss<<"  ";
-          ss<<std::setw(width_)<<std::left<<entry;
-        }
-        // make compressed csv like columns
-        else
-        {
-          ss<<entry;
-          if ( std::next(it,1) != columns_.end() ) ss<<sep_;
-        }
-      }
-      else
-      {
-        ss<<std::setw(width_)<<std::left<<(it->first+std::string(":"))<<it->second<<"\n";
-      }
-    }
-
-    return ss.str();
-  }
-};
-
-// define default formatter
-static format defformat(25,false,false,',');
-
-// join a list of strings
-static std::string join_strings(std::vector<std::string> &thestring, const char* sep = " ")
-{
-  std::string joined;
-  for ( std::vector<std::string>::iterator it = thestring.begin();
-                                           it != thestring.end(); ++it )
-  {
-    joined += std::next(it,1) != thestring.end() ? ( *it + std::string(sep) ) : *it;
-  }
-
-  return joined;
-}
-
-// -------------------------------------------------------------------------- //
-// tdm datatypes
-
-// https://zone.ni.com/reference/de-XX/help/370858P-0113/tdmdatamodel/tdmdatamodel/tdm_header_tdx_data/
-
-// define mapping of C++ supported datatypes to tdm datatypes
-
-// define mapping of locally supported datatypes to tdm datatypes
-// typedef short int eInt16Usi;
-// typedef int eInt32Usi;
-// typedef unsigned char eUInt8Usi;
-// typedef unsigned short int eUInt16Usi;
-// typedef unsigned int eUInt32Usi;
-// typedef float eFloat32Usi;
-// typedef double eFloat64Usi;
-
-// enum class tdmdatatype {
-//   eInt16Usi,
-//   eInt32Usi,
-//   eUInt8Usi,
-//   eUInt16Usi,
-//   eUInt32Usi,
-//   eFloat32Usi,
-//   eFloat64Usi
-// };
-
-// base class for all tdm datatypes
-class tdmdatatype
-{
-protected:
-  short int sint16_;
-  int sint32_;
-  unsigned char uint8_;
-  unsigned short int uint16_;
-  unsigned int uint32_;
-  float float32_;
-  double float64_;
-public:
-  tdmdatatype(): sint16_(0), sint32_(0),
-                 uint8_(0), uint16_(0), uint32_(0),
-                 float32_(0.0), float64_(0.0) {};
-  friend std::ostream& operator<<(std::ostream& out, const tdmdatatype& num)
-  {
-    return num.print(out);
-  }
-  virtual std::ostream& print(std::ostream& out) const
-  {
-    out<<"tdmdatatype";
-    return out;
-  }
-};
-
-class eInt16Usi: public tdmdatatype
-{
-public:
-  eInt16Usi() { }
-  eInt16Usi(short int num) { sint16_ = num; }
-  // eInt16Usi& operator=(const eInt16Usi &num)
-  // {
-  //   // self-assignment check
-  //   if ( this != &num)
-  //   {
-  //     this->sint16_ = num.sint16_;
-  //   }
-	// 	return *this;
-  // }
-  friend std::ostream& operator<<(std::ostream& out, const eInt16Usi& num)
-  {
-    return num.print(out);
-  }
-  std::ostream& print(std::ostream& out) const override
-  {
-    out<<sint16_;
-    return out;
-  }
-};
-
-class eInt32Usi: public tdmdatatype
-{
-public:
-  eInt32Usi() { }
-  eInt32Usi(int num) { sint32_ = num; }
-  friend std::ostream& operator<<(std::ostream& out, const eInt32Usi& num)
-  {
-    return num.print(out);
-  }
-  std::ostream& print(std::ostream& out) const override
-  {
-    out<<sint32_;
-    return out;
-  }
-};
-
-class eUInt8Usi: public tdmdatatype
-{
-public:
-  eUInt8Usi() { }
-  eUInt8Usi(int num) { uint8_ = num; }
-  friend std::ostream& operator<<(std::ostream& out, const eUInt8Usi& num)
-  {
-    return num.print(out);
-  }
-  std::ostream& print(std::ostream& out) const override
-  {
-    out<<uint8_;
-    return out;
-  }
-};
-
-class eUInt16Usi: public tdmdatatype
-{
-public:
-  eUInt16Usi() { }
-  eUInt16Usi(int num) { uint16_ = num; }
-  friend std::ostream& operator<<(std::ostream& out, const eUInt16Usi& num)
-  {
-    return num.print(out);
-  }
-  std::ostream& print(std::ostream& out) const override
-  {
-    out<<uint16_;
-    return out;
-  }
-};
-
-class eUInt32Usi: public tdmdatatype
-{
-public:
-  eUInt32Usi() { }
-  eUInt32Usi(int num) { uint32_ = num; }
-  friend std::ostream& operator<<(std::ostream& out, const eUInt32Usi& num)
-  {
-    return num.print(out);
-  }
-  std::ostream& print(std::ostream& out) const override
-  {
-    out<<uint32_;
-    return out;
-  }
-};
-
-class eFloat32Usi: public tdmdatatype
-{
-public:
-  eFloat32Usi() { }
-  eFloat32Usi(int num) { float32_ = num; }
-  friend std::ostream& operator<<(std::ostream& out, const eFloat32Usi& num)
-  {
-    return num.print(out);
-  }
-  std::ostream& print(std::ostream& out) const override
-  {
-    out<<float32_;
-    return out;
-  }
-};
-
-class eFloat64Usi: public tdmdatatype
-{
-public:
-  eFloat64Usi() { }
-  eFloat64Usi(int num) { float64_ = num; }
-  friend std::ostream& operator<<(std::ostream& out, const eFloat64Usi& num)
-  {
-    return num.print(out);
-  }
-  std::ostream& print(std::ostream& out) const override
-  {
-    out<<float64_;
-    return out;
-  }
-};
-
-struct tdm_datatype {
-
-  std::string name_;
-  std::string channel_datatype_;
-  int numeric_;
-  std::string value_sequence_;
-  int size_;
-  std::string description_;
-
-  const std::string get_info() { return get_info(defformat); }
-  const std::string get_info(format& formatter)
-  {
-    formatter.set_columns( { std::make_pair("name",name_),
-                             std::make_pair("channel_datatype",channel_datatype_),
-                             std::make_pair("name",name_),
-                             std::make_pair("value_sequence",value_sequence_),
-                             std::make_pair("size",std::to_string(size_)),
-                             std::make_pair("description",description_) } );
-
-    return formatter.get_info();
-  }
-};
-
-const std::vector<tdm_datatype> tdm_datatypes = {
-
-  {"eInt16Usi","DT_SHORT",2,"short_sequence",2,"signed 16 bit integer"},
-  {"eInt32Usi","DT_LONG",6,"long_sequence",4,"signed 32 bit integer"},
-
-  {"eUInt8Usi","DT_BYTE",5,"byte_sequence",1,"unsigned 8 bit integer"},
-  {"eUInt16Usi","DT_SHORT",2,"short_sequence",2,"unsigned 16 bit integer"},
-  {"eUInt32Usi","DT_LONG",6,"long_sequence",4,"unsigned 32 bit integer"},
-
-  {"eFloat32Usi","DT_FLOAT",3,"float_sequence",4,"32 bit float"},
-  {"eFloat64Usi","DT_DOUBLE",7,"double_sequence",8,"64 bit double"},
-
-  {"eStringUsi","DT_STRING",1,"string_sequence",0,"text"}
-
-};
+#include "tdm_format.hpp"
 
 // -------------------------------------------------------------------------- //
 // block of data
diff --git a/lib/tdm_datatype.hpp b/lib/tdm_datatype.hpp
new file mode 100644
index 0000000..a4bb3ee
--- /dev/null
+++ b/lib/tdm_datatype.hpp
@@ -0,0 +1,217 @@
+// -------------------------------------------------------------------------- //
+
+#ifndef TDMDATATYPE
+#define TDMDATATYPE
+
+// https://zone.ni.com/reference/de-XX/help/370858P-0113/tdmdatamodel/tdmdatamodel/tdm_header_tdx_data/
+
+// define mapping of C++ supported datatypes to tdm datatypes
+
+// define mapping of locally supported datatypes to tdm datatypes
+// typedef short int eInt16Usi;
+// typedef int eInt32Usi;
+// typedef unsigned char eUInt8Usi;
+// typedef unsigned short int eUInt16Usi;
+// typedef unsigned int eUInt32Usi;
+// typedef float eFloat32Usi;
+// typedef double eFloat64Usi;
+
+// enum class tdmdatatype {
+//   eInt16Usi,
+//   eInt32Usi,
+//   eUInt8Usi,
+//   eUInt16Usi,
+//   eUInt32Usi,
+//   eFloat32Usi,
+//   eFloat64Usi
+// };
+
+// base class for all tdm datatypes
+class tdmdatatype
+{
+protected:
+  short int sint16_;
+  int sint32_;
+  unsigned char uint8_;
+  unsigned short int uint16_;
+  unsigned int uint32_;
+  float float32_;
+  double float64_;
+public:
+  tdmdatatype(): sint16_(0), sint32_(0),
+                 uint8_(0), uint16_(0), uint32_(0),
+                 float32_(0.0), float64_(0.0) {};
+  friend std::ostream& operator<<(std::ostream& out, const tdmdatatype& num)
+  {
+    return num.print(out);
+  }
+  virtual std::ostream& print(std::ostream& out) const
+  {
+    out<<"tdmdatatype";
+    return out;
+  }
+};
+
+class eInt16Usi: public tdmdatatype
+{
+public:
+  eInt16Usi() { }
+  eInt16Usi(short int num) { sint16_ = num; }
+  // eInt16Usi& operator=(const eInt16Usi &num)
+  // {
+  //   // self-assignment check
+  //   if ( this != &num)
+  //   {
+  //     this->sint16_ = num.sint16_;
+  //   }
+	// 	return *this;
+  // }
+  friend std::ostream& operator<<(std::ostream& out, const eInt16Usi& num)
+  {
+    return num.print(out);
+  }
+  std::ostream& print(std::ostream& out) const override
+  {
+    out<<sint16_;
+    return out;
+  }
+};
+
+class eInt32Usi: public tdmdatatype
+{
+public:
+  eInt32Usi() { }
+  eInt32Usi(int num) { sint32_ = num; }
+  friend std::ostream& operator<<(std::ostream& out, const eInt32Usi& num)
+  {
+    return num.print(out);
+  }
+  std::ostream& print(std::ostream& out) const override
+  {
+    out<<sint32_;
+    return out;
+  }
+};
+
+class eUInt8Usi: public tdmdatatype
+{
+public:
+  eUInt8Usi() { }
+  eUInt8Usi(int num) { uint8_ = num; }
+  friend std::ostream& operator<<(std::ostream& out, const eUInt8Usi& num)
+  {
+    return num.print(out);
+  }
+  std::ostream& print(std::ostream& out) const override
+  {
+    out<<uint8_;
+    return out;
+  }
+};
+
+class eUInt16Usi: public tdmdatatype
+{
+public:
+  eUInt16Usi() { }
+  eUInt16Usi(int num) { uint16_ = num; }
+  friend std::ostream& operator<<(std::ostream& out, const eUInt16Usi& num)
+  {
+    return num.print(out);
+  }
+  std::ostream& print(std::ostream& out) const override
+  {
+    out<<uint16_;
+    return out;
+  }
+};
+
+class eUInt32Usi: public tdmdatatype
+{
+public:
+  eUInt32Usi() { }
+  eUInt32Usi(int num) { uint32_ = num; }
+  friend std::ostream& operator<<(std::ostream& out, const eUInt32Usi& num)
+  {
+    return num.print(out);
+  }
+  std::ostream& print(std::ostream& out) const override
+  {
+    out<<uint32_;
+    return out;
+  }
+};
+
+class eFloat32Usi: public tdmdatatype
+{
+public:
+  eFloat32Usi() { }
+  eFloat32Usi(int num) { float32_ = num; }
+  friend std::ostream& operator<<(std::ostream& out, const eFloat32Usi& num)
+  {
+    return num.print(out);
+  }
+  std::ostream& print(std::ostream& out) const override
+  {
+    out<<float32_;
+    return out;
+  }
+};
+
+class eFloat64Usi: public tdmdatatype
+{
+public:
+  eFloat64Usi() { }
+  eFloat64Usi(int num) { float64_ = num; }
+  friend std::ostream& operator<<(std::ostream& out, const eFloat64Usi& num)
+  {
+    return num.print(out);
+  }
+  std::ostream& print(std::ostream& out) const override
+  {
+    out<<float64_;
+    return out;
+  }
+};
+
+struct tdm_datatype {
+
+  std::string name_;
+  std::string channel_datatype_;
+  int numeric_;
+  std::string value_sequence_;
+  int size_;
+  std::string description_;
+
+  const std::string get_info() { return get_info(defformat); }
+  const std::string get_info(format& formatter)
+  {
+    formatter.set_columns( { std::make_pair("name",name_),
+                             std::make_pair("channel_datatype",channel_datatype_),
+                             std::make_pair("name",name_),
+                             std::make_pair("value_sequence",value_sequence_),
+                             std::make_pair("size",std::to_string(size_)),
+                             std::make_pair("description",description_) } );
+
+    return formatter.get_info();
+  }
+};
+
+const std::vector<tdm_datatype> tdm_datatypes = {
+
+  {"eInt16Usi","DT_SHORT",2,"short_sequence",2,"signed 16 bit integer"},
+  {"eInt32Usi","DT_LONG",6,"long_sequence",4,"signed 32 bit integer"},
+
+  {"eUInt8Usi","DT_BYTE",5,"byte_sequence",1,"unsigned 8 bit integer"},
+  {"eUInt16Usi","DT_SHORT",2,"short_sequence",2,"unsigned 16 bit integer"},
+  {"eUInt32Usi","DT_LONG",6,"long_sequence",4,"unsigned 32 bit integer"},
+
+  {"eFloat32Usi","DT_FLOAT",3,"float_sequence",4,"32 bit float"},
+  {"eFloat64Usi","DT_DOUBLE",7,"double_sequence",8,"64 bit double"},
+
+  {"eStringUsi","DT_STRING",1,"string_sequence",0,"text"}
+
+};
+
+#endif
+
+// -------------------------------------------------------------------------- //
diff --git a/lib/tdm_format.hpp b/lib/tdm_format.hpp
new file mode 100644
index 0000000..c4e3e4e
--- /dev/null
+++ b/lib/tdm_format.hpp
@@ -0,0 +1,105 @@
+// -------------------------------------------------------------------------- //
+
+#ifndef TDMFORMAT
+#define TDMFORMAT
+
+// format output of info strings for terminal and file table
+class format
+{
+
+private:
+
+  unsigned int width_;
+  bool tabular_;
+  bool header_;
+  char sep_;
+  std::vector<std::pair<std::string,std::string>> columns_;
+
+public:
+
+  format(int width = 25, bool tabular = false, bool header = false, char sep = ' '):
+    width_(width), tabular_(tabular), header_(header), sep_(sep)
+  {
+
+  }
+
+  void set_width(int width)
+  {
+    width_ = width;
+  }
+
+  void set_tabular(bool tabular)
+  {
+    tabular_ = tabular;
+  }
+
+  void set_header(bool header)
+  {
+    header_ = header;
+  }
+
+  void set_sep(char sep)
+  {
+    sep_ = sep;
+  }
+
+  void set_columns(std::vector<std::pair<std::string,std::string>> columns)
+  {
+    columns_ = columns;
+  }
+
+  std::string get_info()
+  {
+    std::stringstream ss;
+
+    for ( std::vector<std::pair<std::string,std::string>>::iterator it = columns_.begin();
+                                                                    it != columns_.end(); ++it )
+    {
+      if ( tabular_ )
+      {
+        // header or body of table
+        std::string entry = header_? it->first : it->second;
+
+        // make broad aligned columns for human reader
+        if ( sep_ == ' ' )
+        {
+          entry = entry.size() > width_-2 ? entry.substr(0,width_-2) : entry;
+          // if ( it == columns_.begin() && !header_ ) ss<<"  ";
+          ss<<std::setw(width_)<<std::left<<entry;
+        }
+        // make compressed csv like columns
+        else
+        {
+          ss<<entry;
+          if ( std::next(it,1) != columns_.end() ) ss<<sep_;
+        }
+      }
+      else
+      {
+        ss<<std::setw(width_)<<std::left<<(it->first+std::string(":"))<<it->second<<"\n";
+      }
+    }
+
+    return ss.str();
+  }
+};
+
+// define default formatter
+static format defformat(25,false,false,',');
+
+// join a list of strings
+static std::string join_strings(std::vector<std::string> &thestring, const char* sep = " ")
+{
+  std::string joined;
+  for ( std::vector<std::string>::iterator it = thestring.begin();
+                                           it != thestring.end(); ++it )
+  {
+    joined += std::next(it,1) != thestring.end() ? ( *it + std::string(sep) ) : *it;
+  }
+
+  return joined;
+}
+
+#endif
+
+// -------------------------------------------------------------------------- //
diff --git a/lib/tdm_reaper.hpp b/lib/tdm_reaper.hpp
index 43a574c..edc694b 100644
--- a/lib/tdm_reaper.hpp
+++ b/lib/tdm_reaper.hpp
@@ -20,6 +20,7 @@
 
 #include "pugixml.hpp"
 #include "tdm_datamodel.hpp"
+#include "tdm_datatype.hpp"
 
 // -------------------------------------------------------------------------- //