[gcs] indicate voltage/cell if number of cells is specified (#2732)

Add a define for BAT_NB_CELLS in the BAT section of the airframe file to
activate the display

conf/airframes/ENAC/fixed-wing/jp.xml

@@ -175,6 +175,7 @@
   <section name="BAT">
     <define name="CATASTROPHIC_BAT_LEVEL" value="9.3" unit="V"/>
     <define name="MilliAmpereOfAdc(_adc)" value="(_adc-632)*4.14"/>
+    <define name="BAT_NB_CELLS" value="3"/>
   </section>
 
   <section name="MISC">

sw/ground_segment/cockpit/live.ml

@@ -386,13 +386,16 @@ let get_rc_max_rate = fun af_xml ->
 
 let get_bat_levels = fun af_xml ->
   let default_catastrophic_level = 9.
-  and default_max_level = 12.5 in
+  and default_max_level = 12.5
+  and default_nb_cell = None in
   try
     let bat_section = ExtXml.child af_xml ~select:(fun x -> Xml.attrib x "name" = "BAT") "section" in
     let fvalue = fun name default ->
       try ExtXml.float_attrib (ExtXml.child bat_section ~select:(fun x -> ExtXml.attrib x "name" = name) "define") "value" with _ -> default in
-    fvalue "CATASTROPHIC_BAT_LEVEL" default_catastrophic_level, fvalue "MAX_BAT_LEVEL" default_max_level
-  with _ -> (default_catastrophic_level, default_max_level)
+    let fvalue_opt = fun name default ->
+      try Some (ExtXml.float_attrib (ExtXml.child bat_section ~select:(fun x -> ExtXml.attrib x "name" = name) "define") "value") with _ -> default in
+    fvalue "CATASTROPHIC_BAT_LEVEL" default_catastrophic_level, fvalue "MAX_BAT_LEVEL" default_max_level, fvalue_opt "BAT_NB_CELLS" default_nb_cell
+  with _ -> (default_catastrophic_level, default_max_level, default_nb_cell)
 
 let get_alt_shift = fun af_xml ->
   let default_plus_plus = 30.
@@ -528,10 +531,11 @@ let create_ac = fun ?(confirm_kill=true) alert (geomap:G.widget) (acs_notebook:G
     ac_notebook#page_num w#coerce = ac_notebook#current_page in
 
   (** Add a strip *)
-  let min_bat, max_bat = get_bat_levels af_xml in
+  let min_bat, max_bat, nb_cell_bat = get_bat_levels af_xml in
   let alt_shift_plus_plus, alt_shift_plus, alt_shift_minus = get_alt_shift af_xml in
   let icons_theme = get_icons_theme af_xml in
-  let param = { Strip.color = color; min_bat = min_bat; max_bat = max_bat;
+  let param = { Strip.color = color;
+                min_bat = min_bat; max_bat = max_bat; nb_cell_bat = nb_cell_bat;
                 alt_shift_plus_plus = alt_shift_plus_plus;
                 alt_shift_plus = alt_shift_plus;
                 alt_shift_minus = alt_shift_minus;

sw/ground_segment/cockpit/strip.ml

@@ -55,6 +55,7 @@ type strip_param = {
   color : string;
   min_bat : float;
   max_bat : float;
+  nb_cell_bat : float option;
   alt_shift_plus_plus : float;
   alt_shift_plus : float;
   alt_shift_minus : float;
@@ -197,6 +198,7 @@ let add = fun config strip_param (strips:GPack.box) ->
   let color = strip_param.color
   and min_bat = strip_param.min_bat
   and max_bat = strip_param.max_bat
+  and nb_cell_bat = strip_param.nb_cell_bat
   and alt_shift_plus_plus = strip_param.alt_shift_plus_plus
   and alt_shift_plus = strip_param.alt_shift_plus
   and alt_shift_minus = strip_param.alt_shift_minus in
@@ -307,7 +309,9 @@ object
     agl#set ~arrow value [0.2, (sprintf "%3.0f" value); 0.8, sprintf "%+.1f" climb]
   method set_bat value =
     let v = if value < 0.1 then "UNK" else (string_of_float value) in
-    bat#set value [0.5, v]
+    match nb_cell_bat with
+    | None -> bat#set value [0.5, v]
+    | Some nb -> bat#set value [0.3, v; 0.7, sprintf "%.1f /c" (value /. nb)]
   method set_throttle ?(kill=false) value =
     let background = if kill then "red" else "orange" in
     throttle#set ~background value (sprintf "%.0f%%" value)

sw/ground_segment/cockpit/strip.mli

@@ -55,6 +55,7 @@ type strip_param = {
   color : string;
   min_bat : float;
   max_bat : float;
+  nb_cell_bat : float option;
   alt_shift_plus_plus : float;
   alt_shift_plus : float;
   alt_shift_minus : float;