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
% A5 ^, O/ M; l) D- E: Kpull from buf1 with labor1 using path
$ f- E" w! f; relse
; s9 j" ?( }/ ^wait
endif