No connection to the target system, but there are error messages

Basic symptoms:

  • The Values of Variables view does not display values for the variables but ---. Moreover, the message Information for variable could not be determined is displayed.

  • The Error Log view displays the message Unexpected error at target and/or Cannot connect to target system.

Additional symptom, variant 1: In the Instance view, the displayed text for Connection state switches between Offline and Online very fast.

Cause

An old version of the runtime system is installed on the target system. Neuron Power Engineer requires a more current version of the runtime system.

Solution

Install and use the version of the runtime system which has been released for the current version ofNeuron Power Engineer. See "Release-Notes für aktuelle Version" which version of the runtime system has been released for the current Neuron Power Engineer version. 

Additional symptom, variant 2: In the Instance view, the connection state Online is displayed, but the text Error is displayed under Excecution state and Code Identification.

Cause

A TCF agent is already used on the target system. As the →runtime system is using a TCF agent as well and both TCF agents are using the default port 1534, Neuron Power Engineer cannot establish the connection to the target system.

Solution

Configure the runtime system so that a different port is used for the connection to the target system.

  1. Terminate the runtime system that is running on the target system.

  2. Change to sub-directory PLC of the runtime system installation directory.

  3. Open file RTSIO.cfg in any text editor and search for the following line:

    Original line 
    #AddSymbol TCF.ServerUrl TCP:0.0.0.0:1534

  4. Delete the comment character # and enter a free port instead of 1534.
    Use a high port ≥ 1024. If in doubt, ask an administrator which port you can use.

    Example for changed line 
    AddSymbol TCF.ServerUrl TCP:0.0.0.0:2000

  5. Save the changed file RTSIO.cfg.

  6. Restart the runtime system on the target system.

  7. In Neuron Power Engineer: Correct the port number within the PLC-object for the target system (see "Configuring PLC within PLC-object"). Then load the application onto the target system.

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