The DeviceHealth Interface includes Properties and Alarms that are commonly used to expose the health status of a Device. It is illustrated in Figure 10 and formally defined in Table 18.
Figure 10 – DeviceHealth Interface
Table 18 – IDeviceHealthType definition
Subtype of the BaseInterfaceType defined in OPC 10001-7
DeviceHealth indicates the status as defined by NAMUR Recommendation NE107. Clients can read or monitor this Variable to determine the device condition.
The DeviceHealthEnumeration DataType is an enumeration that defines the device condition. Its values are defined in Table 19.
Table 19 – DeviceHealthEnumeration values
|NORMAL||0||The Device functions normally.|
|FAILURE||1||Malfunction of the Device or any of its peripherals. Typically caused device-internal or is process related.|
|CHECK_FUNCTION||2||Functional checks are currently performed. Examples:
Change of configuration, local operation, and substitute value entered.
|OFF_SPEC||3||“Off-spec” means that the Device is operating outside its specified range (e.g. measuring or temperature range) or that internal diagnoses indicate deviations from measured or set values due to internal problems in the Device or process characteristics.|
|MAINTENANCE_REQUIRED||4||Although the output signal is valid, the wear reserve is nearly exhausted or a function will soon be restricted due to operational conditions e.g. build-up of deposits|
DeviceHealthAlarms shall be used for instances of the DeviceHealth Alarm Types specified in 5.12.