Is the device you are trying to communicate with connected to the
Is the PC and the device connected to the network?
Is the TCP/IP protocol installed?
Is the IP address in use by another application?
Is the COM port in use by another application or are the settings
Is the device (PLC) you are trying to communicate with connected
to the power supply?
Is the cable between PLC and PC or IPC connected correctly?
Have you analyzed the Diagnose Viewer entries (which errors have
Are the Driver settings (connection settings) correct, e.g.
link address and section no.?
Is the Variable
addressing correct, e.g. does the Net address match the one in
the driver configuration; do the indicators/data points with the
entered FUN (Function Type) and
INF (Information Number) exist
in the PLC?
Did you choose a time interval for the General Interrogation (GI)
that is long enough (at least 15 minutes recommended)?