模拟总是有警告

下一个奇迹911

总是警告  Block: DECA     Model: DECANTER  *   WARNING
      PX       WAS SPECIFIED AS AN L2-KEY COMPONENT BUT IS NOT
      PRESENT IN THE INLET STREAM. SPECIFICATION IGNORED.


   Block: PUMP     Model: PUMP
  *   WARNING
      MIXED SUBSTREAM HAS ZERO FLOW.  BLOCK BYPASSED.


   Block: DSTWU    Model: DSTWU
  *   WARNING
      ZERO FEED TO THE BLOCK.  BLOCK BYPASSED.
是怎么回事？？？求助