\psset{framearc=.2,levelsep=4cm,
  armB=1cm,angleB=-180}
\def\psedge{\ncangle}
\def\TreeBox#1{\Tr{\psframebox{#1}}}
\pstree[treemode=R]{\TreeBox{Monitor}}
{
 \psset{offsetA=4pt}
 \TreeBox{Attitude Generator}
 \naput[npos=2.5]{{\small init}}
 \nbput[npos=2.5]{{\small stop}}
 \psset{offsetA=-4pt}
 \TreeBox{Normal Generator}
}