CODESYS Forge - CODESYS Forge / Talk / Engineering 🇬🇧: Direct Pointers in IOMapping for EtherCAT with IoDrvEthercatLib.ETCSlave

Using SDO, I can read the EtherCAT mappings and offsets from various registers like 0x1c12, 0x1c13, etc. When I obtain registers mapped in the PDOs and various offsets, I could technically access directly to the statusword, controlword, etc., if they are mapped. I have noticed that on IoDrvEthercatLib.ETCSlave_Diag I can find pointers to the input and output buffers. However, although the input buffer can be easily read by referring to what has been obtained from the SDOs, it is not possible to write to the output buffer, as it is overwritten in each cycle by the data from the IOMapping task. Is there a way, knowing an instance of IoDrvEthercatLib.ETCSlave_Diag, to obtain the pointer to the first data in the IOMapping? The offsets are identical to those of the PDOs, but obviously the data is a copy. For me, the cleanest thing would be to access the pointers on IOMapping, for DS402a devices to retrieve the key data and point them to internal references.

I need to know this as, having developed our own motion library, I would like to simplify the initial setup by eliminating unnecessary and nonsensical mappings that can lead users to unnecessary errors. In the current version that we have been using for years, we have to map everything manually. I would like to pass only the slave reference to the FB_init constructors and eliminate the mapping.

I have found a very interesting solution using:

IoConfigTaskMap
IoConfigConnectorMap
IoConfigChannelMap

The first is the list of IO tasks.
The second is the connector for each IO module in the IOMap.
The third is the individual input or output on the IOMap.

One of the properties of the connector is another pointer to a connector, which corresponds with the connector of the EtherCAT slave.
Through this information, it is possible to understand to which EtherCAT slave an IO connectormap corresponds.

I am attaching an FB that allows for the construction of an IO map and finding the pointer to the actual IOs in the IOMap based on the bitoffset.

FUNCTION_BLOCK IOExplorer
VAR_INPUT
END_VAR
VAR_OUTPUT
END_VAR
VAR
    inputChannels: COL.LinkedList;
    outputChannels: COL.LinkedList;
    ulintFactory: COL.UlintElementFactory;
END_VAR

METHOD inputAtBitOffsetOfConnector : POINTER TO BYTE
VAR_INPUT
    conn: POINTER TO IoConfigConnectorMap;
    bitOffset: UDINT;
END_VAR
VAR
    it: COL.LinkedListIterator;
    itf: COL.IElement;
    elem: COL.iUlintElement;
    channelInfo: POINTER TO ADVChannelInfo;
    bitOffsetR: UDINT;
END_VAR
    inputChannels.ElementIterator(it);
    WHILE it.HasNext() DO
        it.Next(itfElement => itf);
        __QUERYINTERFACE(itf, elem);
        {warning disable C0033}
        channelInfo := TO___UXINT(elem.UlintValue);
        {warning restire C0033}
        IF channelInfo^.connectorField = conn THEN
            IF bitOffsetR = bitOffset THEN
                inputAtBitOffsetOfConnector := channelInfo^.addr;
                RETURN;
            END_IF
            bitOffsetR := bitOffsetR + channelInfo^.size;
        ELSE
            bitOffsetR := 0;
        END_IF
    END_WHILE
    inputAtBitOffsetOfConnector := 0;
END_METHOD

METHOD outputAtBitOffsetOfConnector : POINTER TO BYTE
VAR_INPUT
    conn: POINTER TO IoConfigConnectorMap;
    bitOffset: UDINT;
END_VAR
VAR
    it: COL.LinkedListIterator;
    itf: COL.IElement;
    elem: COL.iUlintElement;
    channelInfo: POINTER TO ADVChannelInfo;
    bitOffsetR: UDINT;
END_VAR
    outputChannels.ElementIterator(it);
    WHILE it.HasNext() DO
        it.Next(itfElement => itf);
        __QUERYINTERFACE(itf, elem);
        {warning disable C0033}
        channelInfo := TO___UXINT(elem.UlintValue);
        {warning restire C0033}
        IF channelInfo^.connectorField = conn THEN
            IF bitOffsetR = bitOffset THEN
                outputAtBitOffsetOfConnector := channelInfo^.addr;
                RETURN;
            END_IF
            bitOffsetR := bitOffsetR + channelInfo^.size;
        ELSE
            bitOffsetR := 0;
        END_IF
    END_WHILE
    outputAtBitOffsetOfConnector := 0;
END_METHOD

METHOD scanIO
VAR_INPUT
END_VAR
VAR
    numTasks: DINT := IoConfig_Globals.nIoConfigTaskMapCount;
    tType: WORD;
    ioTask: POINTER TO IoConfigTaskMap;
    numCon: WORD;
    connector: POINTER TO IoConfigConnectorMap;    
    numCh: DWORD;
    channelInfo: POINTER TO ADVChannelInfo;
    iTsk: DINT;
    iCon: WORD;
    iCh: DWORD;
    i: DINT;
    _tmpConnList: COL.IList;
    elem: COL.IUlintElement;
    itf: COL.IElement;
    tmpCh: POINTER TO ADVChannelInfo;
    lastE: DINT;
    e: COL.COLLECTION_ERROR;
    e1: Error;
END_VAR
VAR_INST
    lF: COL.ListFactory;
END_VAR
    IF outputChannels.CountElements() > 0 OR inputChannels.CountElements() > 0 THEN
        RETURN;
    END_IF

    _tmpConnList := lF.CreateDynamicList(16, 16);

    //Iterate through all IO tasks
    FOR iTsk := 0 TO numTasks - 1 DO
        ioTask := ADR(IoConfig_Globals.pIoConfigTaskMap[iTsk]);
        //Store the type of the task (Input or Output)
        tType := ioTask^.wType;
        numCon := ioTask^.wNumOfConnectorMap;
        //Iterate through all connectors of the task
        FOR iCon := 0 TO numCon - 1 DO
            connector := ADR(ioTask^.pConnectorMapList[iCon]);
            numCh := connector^.dwNumOfChannels;
            //Iterate through all channels of the connector
            FOR iCh := 0 TO numCh - 1 DO
                //Create a new channel info object and fill it with the address, connector and size of the channel
                //Connectors is address of field connector in this case like EtherCAT slave
                //Address is the address of the IOMap
                //Size is the size of channel data in bits in IOMap
                channelInfo := __NEW(ADVChannelInfo);
                channelInfo^.addr := connector^.pChannelMapList[iCh].pbyIecAddress;
                channelInfo^.connectorField := connector^.pConnector;
                channelInfo^.size := connector^.pChannelMapList[iCh].wSize;

                //We put the channel info a temporary ordered list
                //Order is based on the address of IOMap
                lastE := TO_DINT(_tmpConnList.CountElements()) - 1;
                FOR i := 0 TO lastE DO
                    _tmpConnList.GetElementAt(udiPosition := TO_UDINT(i), itfElement => itf);
                    __QUERYINTERFACE(itf, elem);
                    {warning disable C0033}
                    tmpCh := TO___UXINT(elem.UlintValue);
                    {warning restire C0033}
                    //If the address of the channel is smaller than the address of the channel in the list
                    IF tmpCh^.addr > channelInfo^.addr THEN
                       //Insert the channel in the list at the current position
                       _tmpConnList.InsertElementAt(TO_UDINT(i), ulintFactory.Create(TO_ULINT(channelInfo)));
                       //Clear the channel info pointer
                       channelInfo := 0;
                       //Exit the loop
                       i := lastE + 1;
                    END_IF
                END_FOR
                //If the channel info is not 0, it means that the channel was not inserted in the list
                IF channelInfo <> 0 THEN
                    //Add the channel to the end of the list
                    elem := ulintFactory.Create(TO_ULINT(channelInfo));
                    _tmpConnList.AddElement(elem);
                END_IF
            END_FOR
            //Iterate temporary list and add the channels to the input or output list
            lastE := TO_DINT(_tmpConnList.CountElements()) - 1;
            FOR i := 0 TO lastE DO
                _tmpConnList.GetElementAt(udiPosition := TO_UDINT(i), itfElement => itf);
                __QUERYINTERFACE(itf, elem);
                {warning disable C0033}
                tmpCh := TO___UXINT(elem.UlintValue);
                {warning restire C0033}
                //If type is input, add the channel to the input list
                IF tType = TaskMapTypes.TMT_INPUTS THEN
                    e := inputChannels.AddElement(ulintFactory.Create(TO_ULINT(tmpCh)));
                //If type is output, add the channel to the output list
                ELSIF tType = TaskMapTypes.TMT_OUTPUTS THEN
                    e := outputChannels.AddElement(ulintFactory.Create(TO_ULINT(tmpCh)));
                ELSE
                    __DELETE(tmpCh);
                END_IF
            END_FOR
            //Clear the temporary list
            _tmpConnList.RemoveAllElements();
        END_FOR
    END_FOR
END_METHOD

Screenshot_20240213_151901.png

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Direct Pointers in IOMapping for EtherCAT with IoDrvEthercatLib.ETCSlave_Dia

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Direct Pointers in IOMapping for EtherCAT with IoDrvEthercatLib.ETCSlave_Dia