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
pull from buf1 with labor1 using path
& ~& I# G# X" t# a0 r' Telse
0 D: P7 [# q% ?8 D4 p! s. b; mwait
endif