加载电流时报错，求解答

littlewhite22

ALLSEL,ALL
ASEL,S,AREA,,175
NSLA,S,1
D,ALL,VOLT,0
ASEL,S,AREA,,163
NSLA,S,1
F,ALL,AMPS,I!
运行时，提示error：The NODAL LOAD label of AMPS is not part of the currently active set. The current NODAL LOAD set if FLUX.
这是为什么啊？我环境选择MAGELC