Attempt to add part at undefined sensor 1 on conveyor coneyor001？

dd13616

Attempt to add part at undefined sensor 1 on conveyor coneyor001是怎么回事？

conveyor元素的input rule：
if nparts(coneyor001)<5
5 a- b3 g& J( N) y  Ipull from buf1 with labor1 using path
+ q$ F! P- c+ m. {5 p/ }else
0 e- {' O( W4 x( Dwait
, M5 {( U! a4 I# Y5 s- r- F- @endif