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
9 I3 V( l( C! _. ~5 r1 Gpull from buf1 with labor1 using path
! G0 f& @. [) ?# Y6 d0 \else
  h5 e' I" r5 c, y; H' bwait
endif