PcVue Solutions - HMI, SCADA, REPORTING

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Real-Time database

The Real-Time database is the core of PcVue and it is composed of a set of tags called "variables" that contain the data used to be displayed in mimics, trigger actions or record.
The following variable types are supported.

  • Bit - Logical or two state data
  • Alarm - A sub-type of bit with modified behavior
  • Register - Any analogue data (byte, word, double word, float etc.)
  • Text - String data

A variable could be:

  • An Internal variable – the data value is calculated in PcVue
  • An Equipment variable  - the data value is given by the communication layer

Associated Behaviors

 

Associated behavior adds features to a variable in addition to that provided by its main properties. The following is a summary of the main behaviors:

  • Threshold - Set bits when the value rises above or falls below a value. Used to generate alarms from analog values
  • Chronometer - Measure the period for which a bit has been set
  • Counter - Count how many times a bit has been set
  • Discrepancy – DCS style mechanism that checks that the value of one bit follows another within a configurable period. An alarm is generated if the check fails
  • Alarm – Acknowledge trace, Associated action (open a mimic or run a script), Masking by bit or expression
  • Event - Run a program or send a message (SMS or email) on change of value
  • Trend - Record the VTQ in an archive unit for replay through a Trend Viewer or export to a 3rd party application

Extended Attributes

 

Up to 16 free format extended text attributes can be configured for each variable. Extended attributes have many uses, for example you might want to include the name of the equipment manufacturer or the maintenance period. Up to 16 free format extended text attributes can be configured for each variable. can be used in mimic animation in the same way as a variable’s real-time value.
If you use the name of another variable as an extended attribute, when displayed, it shows the real time value of that variable. This can be used, for example, in the Alarm Viewer when you may want to show other values associated with the alarm.

Generic object

 

The branch concept of the hierarchical database let you easily build generic object (graphical symbols, program or mimic) :

The same generic object can be re-used in different variables contexts.

When you create a generic object you use just the variable name without any branch. The branch is supplied each time the object is instantiated.

generic obj

For example- A symbol represents an air conditioner. The symbol indicates if the air conditioner is on and the ambient temperature. When animating the symbol the variable names are used without a branch. For example TEMP_MES is used instead of B01.FLOOR02..THERMOSTAT01.TEMP_MES. The branch is supplied when symbol is inserted into a mimic.
The same symbol can be instantiated any number of times with different branches thereby displaying different variables.


Property Rich

 

Variable configuration is rich in properties with all variables having a Description, Source, Domain, Nature, and Command level plus properties specific to each variable type, Maximum, Minimum, Units, Associated Label etc.
For easy configuration, properties are grouped together with most having default values and those required less often in a separate configuration tab.

Value Time Quality

 

Each variable has three real time properties, value, quality and timestamp - also known as VTQ. The timestamp has millisecond resolution and is the time that the value last changed.
Timestamp can also be provided directly by the PLC by using one of our timestamped protocols.
Any variable can be configured to be shared on multi-station architectures and/or made available for third party software through several interfaces (OPC, webservices,…). In such case the VTQ is broadcasted.

The real time database, also called Variables Tree, is designed to organize the data in a structured way (or following standard like ISA88 for instance) using a branch system, reflecting the physical process.
The structured database helps to create projects that are both easier to understand and to maintain. Also, searching for information and navigation through the various areas of the application are made easier and more natural than with a non-structured database.

For example, to create a database for a building, you just have to enter each element of your building as a branch:

vtq

The configuration interface “Application Explorer” allows creating a variables tree easily and quickly using tools such as cut/copy/paste.