Accessing hardware IOs via EC-Engineer

Previous: Configuring the runtime system for using EC-Master

In this article:

In Neuron Power Engineer:  Creating a project

If not already done, start Neuron Power Engineer and create a project in which you want to access the hardware IOs.

In EC-Engineer: Connecting to the fieldbus, scanning the fieldbus, exporting ENI-file, requesting ESI-files

Neuron Power Engineer needs the ENI-file ("EtherCAT Network Information" file) in XML-format that is created in →EC-Engineer. The following steps help you to create this ENI-file quickly. If you require more help on using EC-Engineer, see the documentation of EC-Engineer (menu Help within EC-Engineer).

  1. Start EC-Engineer. Most likely, the English language is already enabled. If not, do so in order to reproduce the following steps more easily.
    How to change the language in EC-Engineer (if German is enabled): menu Einstellungen – Sprache – Choose the English language.

  2. In EC-Engineer, connect to the EtherCAT fieldbus:

    1. In the Device Editor (Start Page), click TCP/IP — Remote Configuration.

    2. Select EtherCAT Master Unit (Class A) and click OK.

    3. In the Device Editor under Slaves connected to remote system, enter the IP-address of the PLC (of the Windows PC). Click Select.
      If you are using a Windows PC as PLC, mind that you do not enter the IP-address of the reserved network interface card.

    4. In menu Network, select Scan EtherCAT Network.
      Result: The EtherCAT fieldbus is found and scanned because of the entries in file RTSIO.cfg existing on the PLC. The project explorer of EC-Engineer displays one item Slave_xxxx (for each terminal on the fieldbus, observe that xxxx is a placeholder for the actual text).

    5. Make sure that the names of the variables (listed in the Device Editor, tab Variables) are →IEC-identifiers. If the names contain special characters, such as umlauts (ä, ö, ü) or ß, Neuron Power Engineer cannot access the hardware IOs.

  3. Click Export ENI in the toolbar. Save the ENI-file to any folder.
    The ENI-file may have any name. Example: EK1110.xml

Moreover, Neuron Power Engineer needs the ESI-files ("EtherCAT Slave Information" file) in XML-format. A ESI-file contains the EtherCAT device description and can be requested from the device manufacturer.

In Neuron Power Engineer: Dragging ENI-file and ESI-files into the project, creating a global-object, configuring PLC-object and include the GLOBALS section

Change to Neuron Power Engineer and perform the following steps:

  1. Drag the ENI-file and the ESI-files into any folder of the Neuron Power Engineer project.

  2. Enhance the PLC-object of the project as follows:

    1. Open the PLC-object representing the PLC to be addressed.

    2. Only required for the alternate scenario (engineering-PC ≠ PLC): Search for the line with ADDRESS or PORT and replace the entered IP address or port by the appropriate data for your PLC (details: see under "Configuring PLC within PLC-object").

    3. Search for the text part RESOURCE ... ON. Replace the platform entered behind ON by the appropriate platform:

      The PLC is:

      Enter this platform:

      Example for change line within the PLC-object

      a Windows PC

      WindowsX86 

      RESOURCE local ON WindowsX86 { ON_CHANNEL := LocalChannel }

       

    4. After this line, enter the specification for IO_IMPORT. Best practice is to use the template ioe provided by the content assist.
      Complete the inserted specification accordingly. Best practice is to use the content assist again whenever a content assist list is provided.

      Example for a resource with the ENI-file EK1110.xml that has been dragged to the folder 'src' 
      RESOURCE local ON WindowsX86 { ON_CHANNEL := LocalChannel }
      { IO_IMPORT PROVIDER := EtherCatProvider, SERVICE := EtherCAT, PARAMS := "src/EK1110.xml", GLOBALS := "src/GlobalsEK1110" }

      The attribute GLOBALS specifies the project-relative path and name for the global-object in which the declarations for the resource-global variables are to be created by Neuron Power Engineer later on. Here GlobalsEK1110 with folder src is specified.
      The attribute PARAMS specifies the project-relative path and name of the ENI-file on which basis the declaration will be created later on.

    5. After the line with IO_IMPORT, enter the specification for INCLUDE_GLOBALS and complete it by the name of the global-object as it has been specified for the attribute GLOBALS.
      Result, if the global-object does not exist: The specification for INCLUDE_GLOBALS is highlighted as faulty. Ignore this highlighting because the global-object will be created in a later step.

      Example 
      RESOURCE local ON WindowsX86 { ON_CHANNEL := LocalChannel }
      { IO_IMPORT PROVIDER := EtherCatProvider, SERVICE := EtherCAT, PARAMS := "src/EK1110.xml", GLOBALS := "src/GlobalsEK1110" }
      {INCLUDE_GLOBALS GlobalsEK1110}

    6. Declare several tasks and label one of those tasks as IO task. See under "Assigning more program types (= creating new instances)" for details on the procedure.
      (info) Take care that the IO-task is responsible for accessing the bus when using the EC-master. If the cycle time is too high, it is possible that the in- and output modules pass into a failsafe state. Subsequently, the application might not receive data from them or write data to them any longer. As experiences has shown, an INTERVAL in the range of a few milliseconds (e.g. 2 ms) is fitting. Moreover, a high priority (a small number) should be assigned to the IO-task, if the EC-master is used. 

      Example for a test structure with an IO-task 
      TASK DefaultTask(INTERVAL := TIME#500ms, PRIORITY := 38229);
      { IO } TASK FastTask(INTERVAL := TIME#2ms, PRIORITY := 2);   (* This is the IO-task. *)

      As an option you are able to specify the IO service for the IO task as this IO service has been defined with the specification for IO_IMPORT.

      Example for a test structure with an IO task and IO service 
      TASK DefaultTask(INTERVAL := TIME#500ms, PRIORITY := 38229);
      { IO := EtherCAT } TASK FastTask(INTERVAL := TIME#2ms, PRIORITY := 2);

    7. Declare several program instances and assign the previously declared tasks accordingly:

      Example for several program instances 
      PROGRAM Program1 WITH DefaultTask :
          Program1;
      PROGRAM AccessIO WITH FastTask:
          Program1;

      See under "Assigning more program types (= creating new instances)" for details on the procedure.

    8. Save the PLC-object: menu File – Save

  3. Synchronize the resource with the ENI-file: context menu of the PLC-object, command Synchronize with IO Providers
    Result: The specified global-object (here: GlobalsEK1110) is created or updated. The required declarations for the resource-global variables are created in its GLOBALS section. These resource-global variables represent the hardware IOs, their physical addresses have already been specified (after the keyword AT).

    Example for the synchronized content 
    /***** Generated File - DO NOT EDIT - Last updated: 2017-04-24 09:41:41 *****/
    /** generated from RESOURCE "myResource" with the following directive: **/
    /** { IO_IMPORT PROVIDER := EtherCatProvider, SERVICE := EtherCAT, PARAMS := "src/EK1110.xml", GLOBALS := "src/GlobalsEK1110" } **/
    GLOBALS GlobalsEK1110
      VAR_GLOBAL
        Slave_1002EL1008Channel1Input AT %IX1.0.0 : BOOL;
        Slave_1002EL1008Channel2Input AT %IX1.0.1 : BOOL;
        Slave_1004EL3102Channel1Status AT %IB1.1 : BYTE;
        Slave_1004EL3102Channel2Value AT %IW1.5 : INT;      
      END_VAR
    END_GLOBALS

  4. Do not change the resource-global variables

    Neuron recommends to

    • not change the name of the GLOBALS section.
      Reason: Otherwise the corresponding reference for INCLUDE_GLOBALS within the PLC-object cannot be resolved.

    • not change these resource-global variables.
      Reason: The declarations of the resource-global variables are synchronized and updated, if the command Synchronize with IO Providers is selected (see "Considering changed hardware IOs" for details on the update procedure).

In Neuron Power Engineer:  Accessing the declared variables within the ST-code

Now you are able to access the declared global variables in the context of →POUs by using →external variables:

  1. Open an ST-object.

  2. In the ST-object, declare an external variable – in particular within the declaration of the POU where the access is necessary. Access is possible within the declaration of the program, the declaration of a function block or the declaration of a function.

    Example for declarations of external variables

    		 
    VAR_EXTERNAL
        Slave_1002EL1008Channel1Input : BOOL;
        Slave_1002EL1008Channel2Input : BOOL;
        Slave_1004EL3102Channel1Status : BYTE;
        Slave_1004EL3102Channel2Value : INT;
    END_VAR

    See "Declaration of external variables in ST" on the syntax required for the external variable.

  3. In the ST-object, use the external variable within the declaration of the POU (e.g. enter it within an assignment).

  4. Save the ST-object: menu File – Save

Possibilities for diagnostics

After you have concluded these steps, you can access the hardware IOs within the ST-code. 

The article "Considering changed hardware IOs" lists steps to perform when hardware IOs on the EtherCAT-Feldbus are changed. The article "Physical addresses that are based on EC-Master and EC-Engineer" contains background information on the physical addresses.