Hi le51,
The variable is not empty because I use a var_dump($institucion) in this View (listar.volt) and it devolve a array. I show here:
object(Phalcon\Mvc\Model\Resultset\Simple)[51]
  protected '_type' => int 0
  protected '_result' => 
    object(Phalcon\Db\Result\Pdo)[52]
      protected '_connection' => 
        object(Phalcon\Db\Adapter\Pdo\Postgresql)[46]
          protected '_eventsManager' => null
          protected '_descriptor' => 
            array (size=4)
              ...
          protected '_dialect' => 
            object(Phalcon\Db\Dialect\Postgresql)[48]
              ...
          protected '_connectionId' => int 1
          protected '_sqlStatement' => null
          protected '_sqlVariables' => null
          protected '_sqlBindTypes' => null
          protected '_transactionsWithSavepoints' => int 0
          protected '_pdo' => 
            object(PDO)[47]
              ...
          protected '_affectedRows' => null
          protected '_transactionLevel' => int 0
          protected '_type' => string 'pgsql' (length=5)
          protected '_dialectType' => string 'postgresql' (length=10)
      protected '_result' => null
      protected '_fetchMode' => int 2
      protected '_pdoStatement' => 
        object(PDOStatement)[53]
          public 'queryString' => string 'SELECT "institucion"."id_institucion", "institucion"."rif", "institucion"."nombre", "institucion"."tipo" FROM "institucion"' (length=123)
      protected '_sqlStatement' => string 'SELECT "institucion"."id_institucion", "institucion"."rif", "institucion"."nombre", "institucion"."tipo" FROM "institucion"' (length=123)
      protected '_bindParams' => null
      protected '_bindTypes' => null
      protected '_rowCount' => int 2
  protected '_cache' => null
  protected '_isFresh' => boolean true
  protected '_pointer' => int -1
  protected '_count' => int 2
  protected '_activeRow' => null
  protected '_rows' => null
  protected '_errorMessages' => null
  protected '_hydrateMode' => int 0
  protected '_model' => 
    object(Institucion)[45]
      public 'id_institucion' => null
      public 'rif' => null
      public 'nombre' => null
      protected '_dependencyInjector' => 
        object(Phalcon\DI\FactoryDefault)[5]
          public '_services' => 
            array (size=24)
              ...
          public '_sharedInstances' => 
            array (size=8)
              ...
          public '_freshInstance' => boolean true
      protected '_modelsManager' => 
        object(Phalcon\Mvc\Model\Manager)[43]
          protected '_dependencyInjector' => 
            object(Phalcon\DI\FactoryDefault)[5]
              ...
          protected '_eventsManager' => null
          protected '_customEventsManager' => null
          protected '_readConnectionServices' => null
          protected '_writeConnectionServices' => null
          protected '_aliases' => null
          protected '_hasMany' => null
          protected '_hasManySingle' => null
          protected '_hasOne' => null
          protected '_hasOneSingle' => null
          protected '_belongsTo' => null
          protected '_belongsToSingle' => null
          protected '_hasManyToMany' => null
          protected '_hasManyToManySingle' => null
          protected '_initialized' => 
            array (size=1)
              ...
          protected '_sources' => 
            array (size=1)
              ...
          protected '_schemas' => null
          protected '_behaviors' => null
          protected '_lastInitialized' => 
            &object(Institucion)[45]
          protected '_lastQuery' => null
          protected '_reusable' => null
          protected '_keepSnapshots' => null
          protected '_dynamicUpdate' => null
          protected '_namespaceAliases' => null
      protected '_modelsMetaData' => null
      protected '_errorMessages' => null
      protected '_operationMade' => int 0
      protected '_dirtyState' => int 1
      protected '_transaction' => null
      protected '_uniqueKey' => null
      protected '_uniqueParams' => null
      protected '_uniqueTypes' => null
      protected '_skipped' => null
      protected '_related' => null
      protected '_snapshot' => null
  protected '_columnMap' => null
  protected '_keepSnapshots' => boolean false
So, If I detele this view (listar.volt) and print variable in the controller (InstitucionController.php) on this way, it's all right:
$institucion = institucion::find(); 
foreach ($institucion as $obj) {
    echo $obj->nombre." - ".$obj->rif."<br>";
}
But I need print variable in the view not in controller. I think which problem can be in how pass variable to the "View".
Error: Notice: Access to undefined property Institucion::name in C:\wamp\www\sistema_vit\cache\volt\c%%%%wamp%%www%%sistema_vit%%app%%views%%institucion%%listar.volt.php on line 23