6.1.3.3 Object Diagnostics
This FunctionalGroup is used to organize diagnostic data from the AutoID Device. All diagnostics data of AutoID Devices shall be exposed below this FunctionalGroup. FunctionalGroups can be nested. The diagnostics data may also be exposed in other parts of the AutoID Device OPC UA Server Address Space.
A diagnostics point is represented by an OPC UA Variable Value. OPC UA Clients can read the Variable Values. Values can also be monitored for changes.
The FunctionalGroupType is defined in OPC 10000-100.
Predefined parameters for this FunctionalGroup are defined in Table 8 and described below.
Presence identifies if there currently is seen an AutoID Identifier (e.g. a code or a transponder) by the device. If supported by a device, it may show the concrete number of AutoID Identifiers.
The Logbook FunctionalGroup shall be provided if Logging values are supported for diagnostic purposes. Its predefined parameters are defined in Table 8 and described in the following list:
Parameter LogColumns specifies the column headings of the Logbook.
Parameter LastLogEntry specifies the last entry of the Logbook.
The LastAccess FunctionalGroup shall be provided if values for the last AutoID Identifier access are supported for diagnostic purposes. Its predefined parameters are described in the following list:
Parameter Client specifies the client application (interface) which was the originator of the AutoID Identifier access.
Parameter Command specifies executed command, including the Scan command. Dependend on the kind of the client application, the names of the commands may vary. When the client application is an OPC UA Client, the names shall correspond to the command names used within this specification, e.g. “ReadTag” for the execution of the ReadTag command.
Parameter Identifier specifies the AutoID Identifier which was accessed by the command. The DataType can be one of the DataTypes defined in the ScanData Union defined in 9.4.2. Due to the use case for limited OPC UA Clients, the DataType is normally String or ByteString.
Parameter Timestamp specifies the point of time the AutoID identifier (e.g. a transponder) was accessed by the command.
The Last Access Variable Values belong together logically. OPC UA does not ensure a consistent delivery of a list of Variable Values. Thus, there are several limitations and the Last Access Variables should only used with OPC Clients limited to Data Access functionality. It is recommended that complex applications use the AutoIdAccessEvents or RfidAccessEvents.
An OPC UA Server shall set all Variable SourceTimestamps with a consistent value if the Variables Values are updated. An OPC UA Client must ensure that it has a constent set of Values. The Client can use the DataChangeFilter STATUS_VALUE_TIMESTAMP_2 to receive updates for all Variables to verify if all necessary information is available or a Client can subscribe only for one Variable like Timestamp and then read the related Variables including a verification of the SourceTimestamp.