private static void WriteDataVariable(XmlWriter writer, DataVariable dataVariable)
{
writer.WriteStartElement("PDV");
var variableDdi = DetermineVariableDdi(dataVariable);
writer.WriteAttributeString("A", string.Format(CultureInfo.InvariantCulture, "{0:X4}", variableDdi));
writer.WriteAttributeString("B", dataVariable.IsoUnit.ConvertToIsoUnit(dataVariable.Value).ToString("F0", CultureInfo.InvariantCulture));
writer.WriteXmlAttribute("C", dataVariable.ProductId);
writer.WriteEndElement();
}