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？
7 R" K  Q3 k' Z& M7 p, r( X) g- |
conveyor元素的input rule：
if nparts(coneyor001)<5
+ ?! M) I4 p* K# W+ w2 _: Wpull from buf1 with labor1 using path
  N* l- }& T9 a7 [$ Q; p$ v2 D! Uelse
/ U$ t4 ]+ c; G% N0 \6 O; b1 L4 Qwait
! D3 q* w" b$ s0 U! {5 Pendif