ix>&nbsp;=&nbsp;</td>
      <td class=PDefaultValue width=100%>null</td>
      <td class=PAfterParameters nowrap>)</td></tr>
      </table></td></tr>
    </table></blockquote>
<div class=CBody><p>Starts the heartbeat monitor.&nbsp; If <i>e</i> is null then whatever event was previously set is used.&nbsp; If no event was previously set then a warning is issued.&nbsp; It is an error if the monitor is currently running and <i>e</i> is specifying a different trigger event from the current event.</p></div></div>