CPU224CN 型,端口0支持MPI协议

S7ONLINE (STEP7) ==>cp5611(MPI)
MPI 诊断无出错
VB代码:
PlcAdr1(0).adr = 2
PlcAdr1(0).SEGMENTID = 0
PlcAdr1(0).RACKNO = 0
PlcAdr1(0).SLOTNO = 2
PlcAdr1(1).adr = 0
PlcAdr1(1).SEGMENTID = 0
PlcAdr1(1).RACKNO = 0
PlcAdr1(1).SLOTNO = 0
res = load_tool(1, "S7ONLINE", PlcAdr1(0))
//res==0 没有出错

res = as200_vs_field_read(0, 10, value_byte(0))
//res==16386 4002 : connection not established
这种出错到底是什么问题.
请高手帮忙