IF DB50.JLZD THEN
DB50.JL_STA:=1;
ELSE IF DB50.JLZD=FALSE THEN
DB50.JL_STA:=0;
END_IF;
END_IF;
CASE DB50.JL_STA OF
1: IF DB50.XLW[1,1]OR DB50.XLW[1,2]OR DB50.ZJW[1,1] OR DB50.ZJW[1,2]THEN
Q[10,6]:=TRUE;

ELSE IF DB50.SLW[1,1] OR DB50.SLW[1,2] THEN

Q[10,6]:=FALSE;
DB50.JL_STA:=2;
END_IF;
END_IF;
2: IF DB50.XLW[2,1]OR DB50.XLW[2,2] OR DB50.ZJW[2,1] OR DB50.ZJW[2,2] THEN
Q[10,7]:=TRUE;
ELSE IF DB50.SLW[2,1] OR DB50.SLW[2,2] THEN
Q[10,7]:=false;
DB50.JL_STA:=3;
END_IF;
END_IF;
3: IF DB50.XLW[3,1]OR DB50.XLW[3,2]OR DB50.ZJW[3,1] OR DB50.ZJW[3,2] THEN
Q[11,0]:=TRUE;

ELSE IF DB50.SLW[3,1] OR DB50.SLW[3,2] THEN
Q[11,0]:=FALSE;

DB50.JL_STA:=0;
END_IF;
END_IF;
这段程序执行到2就停了，请问各位高手，是怎么了。我的要求是，如果A下料位是打开的，则A开始加料，加到上限位，则跳到B，依次向下。请各位指点一下