private Node SearchLoadport()
{
Node result = null;
var AvailableWafers = from job in JobManagement.GetJobList()
where job.NeedProcess
orderby job.AssignTime
select job;
if (AvailableWafers.Count() != 0)
{
result = NodeManagement.Get(AvailableWafers.First().Position);
}
return(result);
}