1.7.2.4. Driver info

A device is typically operated by a driver. This is usual for an IO-device, but unusual for a PLC-device. In this section some general information for the driver can be specified.

Example:

<DriverInfo needsBusCycle="false" UpdateIosInStop="true" StopResetBehaviour="SetToDefault">
    <RequiredLib libname="IoStandard" vendor="System" version="3.5.11.0" identifier="iostandardlib" />
</DriverInfo>

XML-Tag	Description
needsBusCycle	Specifies, if the device needs a separate bus cycle. If this attribute is TRUE, the corresponding IO-driver get a cyclic call to is IoDrvStartBusCycle() interface method. The context of this call can be specified by the user (see ICmpIoDrv)
UpdateIosInStop	If TRUE, the option “Update IO while in stop” in dialog “PLC settings” of the device editor will be activated.
StopResetBehaviour	Defines the default selection for option “Update IO while in stop” in dialog “PLC settings” of the device editor.
RequiredLib	Defines a library that is added when a device is added in the project. The IO standard is required by the IO configuration and must be compatible with the controller implementation. An IoStandard.library for the device must therefore be specified here Instead of a fix library name a library placeholder (attribute “placeholderlib”) can be specified here. This will effect that, when the device is included to the project, each the currently available corresponding customer-specific library will be included.
defaultBusCycleTask	Defines the default bus cycle task; example: defaultBusCycleTask=”MainTask” Note: This setting overwrites a possibly available “useSlowestTask” resp. the basic default setting (=task with the shortest cycle time will be used as bus cycle task).
useSlowestTask	If TRUE, the task with the longest cycle time will be used as bus cycle task. Otherwise the task with the shortest cycle time or – if defined – the “defaultBusCycleTask” (see above) will be used.
RequiredCyclicTask taskpou	Specifies a cyclic task which shall automatically be added to the Task Configuration, when the device is inserted in the device tree. The task is defined by the attributes “taskname” and “priority”, see example below. Setting “taskpou” allows to specify a POU, which should be added to the configuration of the above defined task. Regard that this only means, that the POU name will be entered in the task configuration, not however that the POU itself will be created in the project ! Example: <RequiredCyclicTask taskname=”Ethercat” priority=”2” cycletime=”t#6ms”> <taskpou>Test_Pou1</taskpou> <taskpou>Test_Pou2</taskpou> </RequiredCyclicTask>
RequiredExternalEventTask taskpou	Corresponds to the above described “RequiredCyclicTask” setting; for automatically adding an external event task to the task configuration when inserting the device Example: <RequiredExternalEventTask taskname=”EthercatEvent” priority=”2”> <taskpou>Test_Pou3</taskpou> <taskpou>Test_Pou4</taskpou> </RequiredExternalEventTask>

Note

For complete documentation on the particular device description elements see the xsd schema provided by device_description_schema.

Note

If libraries, having the same library name and vendor name, are requested by a father object as well as by a child object (a child object is an object indented below the father object in the device tree), only that library version will be included which is requested by the father object.

Adding libraries and function blocks

Example:

<DriverInfo needsBusCycle="false">
    <RequiredLib identifier="IoDrvSercos3" libname="IoDrvSercos3" placeholderlib="IoDrvSercos3" vendor="CODESYS GmbH" version="3.1.2.0">
        <FBInstance basename="$(DeviceName)" fbname="Sercos3Slave">
            <Initialize methodName="Initialize" />
        </FBInstance>
    </RequiredLib>
</DriverInfo>

With the DriverInfo and RequiredLib elements it is possible to get libraries added to the project automatically as soon as the user adds a specific device in the configuration tree. The library is selected by libname, vendor and version and must match with the information from the library file.

The identifier element selects the namespace as it is shown in the library manager of the project.

With the element placeholderlib an unique name is defined. The placeholder itself is defined in the device description of the PLC in the target settings section and it will override the libname, vendor and version attribute. Optionally an attribute “loadAsSystemLibrary=true|false” can be added: If it is “false”, the library will be inserted as a “normal” library (black writing). If it is “true” (default) or missing, the library will be inserted as a “system library” (grey writing).

With this placeholder mechanism it is possible to select a specific library version by only changing the PLC device description. All other description files (master, slaves) do not need to be changed.

The FBInstance entry effects that automatically a function block will be created for each device. The basename $(DeviceName) will be replaced by the actual device name in the device tree. Also combinations like $(DeviceName)_abc are possible. It the device is renamed in the device tree for example to “Drive1” then the function block will be named Drive1_abc.

With “Initialize” a special method could be declared, which will be called automatically when downloading the project.

The declaration for the Initialize method must be exactly as follows:

METHOD Initialize : UDINT
VAR_INPUT
    wModuleType : UINT;
    dwInstance : UDINT;
    pConnector : POINTER TO IoConfigConnector;
END_VAR

For complete documentation see the information given by the xsd schema.