How can i get all values in a global set
Have a look at the answer given here to someone trying to solve this in the template. With a plugin you'd probably do it like so:

public function getFieldsByEntry($entryModel)
{
    $fields = array();
    $fieldLayoutFields = $entryModel-&gt;getFieldLayout()-&gt;getFields();
    foreach ($fieldLayoutFields as $fieldLayoutField)
    {
        $fields[] = craft()-&gt;fields-&gt;getFieldById($fieldLayoutField-&gt;fieldId);
    }
    return $fields;
}