diff --git a/sw/lib/ocaml/pprz.ml b/sw/lib/ocaml/pprz.ml
index 1b71b71a85..036327b4ee 100644
--- a/sw/lib/ocaml/pprz.ml
+++ b/sw/lib/ocaml/pprz.ml
@@ -40,6 +40,7 @@ type value =
 type field = {
     _type : _type;
     fformat : format;
+    alt_unit_coef : string option
   }
 
 type link_mode = Forwarded | Broadcasted
@@ -156,7 +157,8 @@ let field_of_xml = fun xml ->
   let t = ExtXml.attrib xml "type" in
   let t = if is_array_type t then ArrayType (type_of_array_type t) else Scalar t in
   let f = try Xml.attrib xml "format" with _ -> default_format t in
-  (String.lowercase (ExtXml.attrib xml "name"), { _type = t; fformat = f })
+  let auc = try Some (Xml.attrib xml "alt_unit_coef") with _ -> None in
+  (String.lowercase (ExtXml.attrib xml "name"), { _type = t; fformat = f; alt_unit_coef = auc })
 
 let string_of_values = fun vs ->
   String.concat " " (List.map (fun (a,v) -> sprintf "%s=%s" a (string_of_value v)) vs)
diff --git a/sw/lib/ocaml/pprz.mli b/sw/lib/ocaml/pprz.mli
index 058f72665b..1ab0ca43df 100644
--- a/sw/lib/ocaml/pprz.mli
+++ b/sw/lib/ocaml/pprz.mli
@@ -36,7 +36,11 @@ type _type =
 type value = 
     Int of int | Float of float | String of string | Int32 of int32
   | Array of value array
-type field = { _type : _type; fformat : format; }
+type field = {
+    _type : _type;
+    fformat : format;
+    alt_unit_coef : string option
+  }
 type link_mode = Forwarded | Broadcasted
 type message = { 
     name : string; 
diff --git a/sw/logalizer/plot.ml b/sw/logalizer/plot.ml
index f77a437279..6953308296 100644
--- a/sw/logalizer/plot.ml
+++ b/sw/logalizer/plot.ml
@@ -453,14 +453,18 @@ let load_log = fun ?factor (plot:plot) (menubar:GMenu.menu_shell GMenu.factory)
 	      Hashtbl.iter
 		(fun f v -> if not (List.mem f !l) then l := f :: !l)
 		fields;
-	      let l = List.map (fun f ->
-		let values = Hashtbl.find_all fields f in
-		let values = List.map (fun (t, v) -> (t, pprz_float v)) values in
-		let values = Array.of_list values in
-		Array.sort compare values;
-		(f, values))
-		  (List.sort compare !l) in
-	      (msg.Pprz.name, l))
+	      let sorted_fields = List.sort compare !l in
+
+	      let field_values_assoc = 
+		List.map
+		  (fun f ->
+		    let values = Hashtbl.find_all fields f in
+		    let values = List.map (fun (t, v) -> (t, pprz_float v)) values in
+		    let values = Array.of_list values in
+		    Array.sort compare values;
+		    (f, values))
+		  sorted_fields in
+	      (msg.Pprz.name, field_values_assoc))
 	      msgs in
 	  
 	  (* Store data for other windows *)
@@ -508,6 +512,7 @@ let screenshot = fun frame ->
   end
 
 
+(*****************************************************************************)
 let rec plot_window = fun init ->
   let plotter = GWindow.window ~allow_shrink:true ~title:"Log Plotter" () in
   plotter#set_icon (Some (GdkPixbuf.from_file Env.icon_file));