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？
' q6 U: s) R) ^: \
conveyor元素的input rule：
if nparts(coneyor001)<5
pull from buf1 with labor1 using path
else
wait
endif