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？
; i: E2 p" h# W( S4 M" v  H) c
conveyor元素的input rule：
if nparts(coneyor001)<5
pull from buf1 with labor1 using path
else
$ m% n, k" @  G$ e+ Fwait
endif