Dim D0 As Integer
Dim iSize As Integer = 353
Dim btValue(iSize - 1) As Byte
Dim res As Integer
Dim value(8) As Byte
If 0 = readPLC.Open200(1, "S7ONLINE") Then
res = as200_vs_field_read(0, 2, D0)
res = as200_m_field_read(2, 1, value(0)) 'M
res = as200_e_field_read(2, 1, value(0)) 'I
res = as200_a_field_read(2, 1, value(0)) 'Q
If res = 0 Then
MessageBox.Show("PLC读取成功！")
End If
End If

readPLC.Open200执行是成功的，但是as200_vs_field_read执行失败，错误码为16386:connection not established
谁知道是什么原因？
急求解决办法！！！