Using the Variable Selector

The Variable Selector displays PcVue's variables in a dialog box that is independent of the Application Explorer. It is the developer's main tool to select a variable name when required as a configuration property. For example, in an animation. It can also be used to view the current value and quality of any variable.

The Variable Selector is available from an ellipsis button adjacent to any field where the name of a variable has to be entered. It can also be opened using the menu command Configure.Variable.Selector. Show Picture

The Variable Selector has two panes. The left displays the branches and the right any variables for the selected branch. Branches and variables are displayed in alphanumeric order.

The right pane has several columns that can be turned on and off from the right click context menu.

• Name - The name not including the branch. Always displayed.
• Description - The description as entered in the Description property of the variable's configuration.
• Value - The current value.
• Timestamp - The time that the value last changed.
• Quality - The quality or status of the variable.
• Watchcount - The number of processes subscribed to the variable. See explanation below.
• Domain - The domain as entered in the Domain property of the variable's configuration.
• Nature - The nature as entered in the Nature property of the variable's configuration.

Filtering the variables that are displayed in the right pane

The variables that are displayed in the right pane can be filtered using the following tools.

• Variable type and kind - Bit, alarm, register or text, HMI variables.
• Domain and/or nature.
• Source - Filter by the source of the variable, all, internal only, or I/O only filtered by the name of any data acquisition networks that have been configured.

Variable Quality

The quality provides an indication of the validity of the variable's value. A variable may still have a valid real-time value even with a quality other than good. When a variable is used in an animation, if the quality is anything other than good, a special color or a question mark will be displayed instead of its value. The following abbreviations are used to indicate a variables' quality.

Abbreviation	Condition
	Good - Indicated by a null value in the quality field.
NS	Not set (invalid) - The variable may still have a value but it is no longer being updated.
DE or NS DE	Dependent - The variable is invalid because the variable from which it is derived is disabled. NS indicates that the value is not initialized, typically during the start-up for internal variables.
EXP or NS EXP	Expression - The variable is invalid because one or more variables in the expression from which it is derived is invalid. NS indicates that the value is not initialized, typically during the start-up for internal variables.
OP or NS OP	Operator - The variable has been masked by the operator. This will happen if an Alarm is disabled in an Alarm Display. NS indicates that the value is not initialized, typically during the start-up for internal variables.
M[n] or NS M[n]	Masked - The variable has been masked by a SCADA Basic script. The level of the mask [1 to 4] is also shown. NS indicates that the value is not initialized, typically during the start-up for internal variables.
DIS or NS DIS	Disabled - The variable has been disabled by using the inhibit tick box in its configuration or a SCADA Basic script.
NS COM	Communication - The variable source is unavailable (typically due to a communication failure).
NS L<	The value of the variable is less than its specified minimum.
NS L>	The value of the variable is greater than its specified maximum.
NS FMT	Format error. For example, a floating-point variable does not confirm to the IEEE format.
NS WD	Equipment life indicator not refreshed. When using specialist variable treatment - WATCHDOGEQT.
NS LAN	Not Set (invalid) - Displayed on a client for a variable that has NS quality on the server.
NS COM LAN	Communication - Displayed on a client for a variable that has NS COM quality on the server.
NS SPEC	Unavailable (invalid for specific reason) - In cases a quality flag is provided by the device, the variable is considered invalid because the configuration requires to set the status to Unavailable for the last received quality flag.
SIM	The variable is simulated, its Simulated property is set to True and it has a valid value.
SIM NS	The variable is simulated, its Simulated property is set to True but no valid value is set.

About the Watchcount

The watchcount property is the number of processes or modules, that are currently subscribed to the variable. The following processes each add to the watchcount:

• Permanent scan - The Permanent Scan attribute is set either in the variable's properties or via the global property in Variable Settings.
• Used in a mimic - Each time the variable is used in an open mimic,
• Event - Each event that is attached to a variable,
• Expression - Each expression in which the variable is used,
• A third-party component connected and subscribed via a server interface such as the OPC server, the Web Services Toolkit...