DNM_GET_ATTR¶
| Parameter | Value |
|---|---|
| Library_File_Name | DeviceNet_AC500_V11.lib |
| Firmware | V1.1 |
| Type | Type_Function_Block_History |
| Group | Parameters |
The Function Block DNM_GET_ATTR can be used to read individual attributes from slave objects.
Every time a FALSE->TRUE edge is applied to input EN, DNM_GET_ATTR reads the data at its inputs and sends a corresponding request message to the Communication Module. Further FALSE->TRUE edges at input EN are ignored until the processing of the active requests is completed. The completion of the request processing is indicated by DONE = TRUE.
The DeviceNet™standard describes an abstract object model (see also System technology of the DeviceNet Communication Modules). There, different standard classes are defined which represent a kind of type definitions for the objects. In addition, further manufacturer-specific classes can be defined for a DeviceNet™ module. Objects are instances of the corresponding class. These objects contain attributes that can be read using the Function Block DNM_GET_ATTR.
Some objects have to be available in every DeviceNet™ module by default. Normally, these standard objects are not accessed by the user program during running operation, even though this is possible in principle. Access is usually restricted to optional additional objects or their attributes. These additional slave attributes can be displayed in SYCON.net by selecting Device configuration | Parameter data. This view displays a list of available attributes for the specific slave. Each entry contains the class ID (Class ID) and the instance number (Instance ID) of the object, the number (Attribute ID) and data type of the specific attribute, the valid access types (read/write) and an attribute description as well as the permitted limit values. This information can be used to select the desired CLASS_ID, INST_ID and ATTR_ID when using a Function Block of the type DNM_GET_ATTR. Furthermore, it can be used to determine the variable type required at Function Block input DATA (via ADR operator) in order to be able to store and interpret the received data.