Vijeo Citect Technical Overview - Square D

System Architecture:
Data Quality
Tag extensions for each data tag provides a more holistic picture of your process through
improved real-time data values and traceability.
Tag Extensions
With the addition of tag extensions in Vijeo Citect
V7.20, each variable tag now represents data as a
collection of data quality and time stamp elements.
Operators can be informed about the value of each
real-time tag along with the last time of the value
change and the quality status. Data quality is split
into three groups - good, bad and uncertain - with
more detail available to provide additional analysis.
The tag data has a time stamp for when the data
value last changed and for when the quality last
changed.
Vijeo Citect provides real-time data quality and status
information. The ‘quality’ of the data is available
to the operators, allowing for better informed
processing decisions. Each tag data point contains
extensions that provides the data values along with
the associated quality and time stamp of the data
change. This allows each client access to not just the
data, but also information about when and how the
data was collected from the field.
Having the validated last known data values provides
operators with a clearer picture of the situation when
a field communication has failed. Understanding the
age and accuracy of the data can provide better
results from your control system calculations.
Tag Extensions
Vijeo Citect lets you choose what a client will display
during a communication outage, either an error
indication or the last known value. By default, tags
are displayed with a tool-tip that shows the last
known quality and time stamp of the tag.
Time-stamped data provides greater data
synchronisation. All variables are time-stamped
either at the I/O server or for some protocols (RTUbased)
at the source. Using the integrated quality and
time-stamped data, you can attain a more holistic
picture through improved real-time data values and
traceability.
Variable tag extensions provide functionality for
Tag Override and Control Inhibit. The Tag Override
function makes it possible to manually set the
variable value when there is an external device error.
This allows upstream systems to be unaffected when
operators using manual controls during the failure of
automatic sensors. Tag Control Inhibit functionality
ensures that critical system information can be
protected and inhibits the unauthorized writing of
data. Such functions are designed to enhance the
security of your process while increasing efficiency in
case of a false alarm.
Visualization of tag quality
Architecture
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