Variables

Overview of the variable types available in EnvisionSCADA and how they are referenced at runtime.

Updated 22 Oct 2026 5 min read

On this page (8 sections)

Overview
Variable Types
Device Variables
Local Variables
Client Variables
System Variables
Python Runtime Variables
Notes

Variables are the core data elements used throughout EnvisionSCADA. They represent live process values, internal application values, client-side runtime state, and system-generated information.

Variables are used in pages, alarms, events, schedules, actions, scripts, APIs, historian logging, and gateway services. Because of this, understanding the variable naming format is essential when configuring or troubleshooting a project.

EnvisionSCADA supports four main variable groups: device variables, local variables, client variables, and system variables. Each group has its own purpose and runtime naming convention.

Variable Types

The following variable types are available at runtime.

Variable Type	Runtime Name Format	Description
Device variable	DeviceName.VariableName	Variable linked to a configured driver device such as Modbus TCP, OPC UA, MQTT, Ethernet/IP, DNP3, ICMP, or Kafka-linked driver variables.
Local variable	LocalVariables.VariableName	Project variable stored locally inside EnvisionSCADA without an external device connection.
Client variable	client.VariableName	Browser-side runtime variable used by the current client session and page behavior.
System variable	SYSTEM.VariableName	Read-only or system-generated runtime information provided by EnvisionSCADA.

Device Variables

Device variables are the process values configured under a device driver page. They represent live values from PLCs, RTUs, field devices, protocols, and external systems.

The runtime reference format is DeviceName.VariableName. For example, a variable configured on a device named PLC1 with a variable name Pump1_Speed is referenced as PLC1.Pump1_Speed.

Device variables can include metadata such as units, scaling, historian settings, deadband, sample group, user groups, recipes, Modbus gateway address, OPC UA exposure, and write permissions depending on the driver type.

Local Variables

Local variables are internal project variables stored inside EnvisionSCADA. They are useful for calculations, intermediate states, script state memory, recipe support, and values that do not come directly from an external device.

The runtime reference format is LocalVariables.VariableName.

Local variables support the same general runtime usage as device variables. They can be displayed on pages, written by actions, historized, used in alarms and events, and accessed by scripts and schedules.

Client Variables

Client variables exist only in the active browser client. They are used for page interaction, popup state, embedded viewers, client-side language selection, and other runtime UI behavior.

The runtime reference format is client.VariableName. Client variables are handled directly in the browser and are not written to the server-side device variable dictionary.

Client variables are typically used in page scripts and object actions where local client-side state is required.

Client Variable	Description
client.LocalDate	Current client-side local date.
client.LocalTime	Current client-side local time.
client.SelectedLanguage	Selected client language name or display value used by the runtime.
client.SelectedLanguageCode	Selected client language code.
client.PageScale	Current client page zoom or scale state.
client.ViewportWidth	Width of the browser viewport in pixels. Updated on every window resize, so a Visibility expression such as client.ViewportWidth >= 1900 acts as a responsive breakpoint (for example a full navigation bar on full HD and wider, a Menu button below it).
client.ViewportHeight	Height of the browser viewport in pixels. Updated on every window resize.
client.PageLayer	Current client page layer state.
client.LayerX	Client-side layer-related runtime state.
client.AlarmBanner_...	Client-side Alarm Banner state variables created per banner object instance.

System Variables

System variables are generated by EnvisionSCADA and provide runtime information about the current user session, server state, licensing, redundancy, historian, metrics, alarms, events, schedules, and service execution times.

The runtime reference format is SYSTEM.VariableName.

Some system variables are fixed names, while others use a prefix followed by a dynamic suffix such as a severity number, schedule name, event name, or alarm name.

55 rows

System Variable	Description
SYSTEM.BuildVersion	Current EnvisionSCADA build version.
SYSTEM.CurrentPage	Current runtime page.
SYSTEM.PageLibraryPath	Library path of the current page.
SYSTEM.PageNextAvailable	Indicates whether forward page navigation is available.
SYSTEM.PagePreviousAvailable	Indicates whether backward page navigation is available.
SYSTEM.UserName	Current logged-in user name.
SYSTEM.UserGroups	Current logged-in user groups.
SYSTEM.DefaultLanguage	System default language.
SYSTEM.SessionTimeout	Configured session timeout for the current user.
SYSTEM.SessionTimeoutTimer	Current elapsed session timeout timer for the user session.
SYSTEM.ActiveUsers	Information about active users.
SYSTEM.ServerDate	Current server date.
SYSTEM.ServerTime	Current server time.
SYSTEM.AuthorizationCode	Current license authorization code.
SYSTEM.LicenseStatus	Current license state such as licensed, demo, or unlicensed.
SYSTEM.DemoCounter	Remaining demo counter value.
SYSTEM.DemoResetTime	Demo reset timing information.
SYSTEM.LicenseExpiry	Expires On date of a Pilot License, as yyyy-MM-dd. Empty for a license without an Expires On date.
SYSTEM.LicenseDaysLeft	Whole days until the Expires On date of a Pilot License, 0 from that date on. Empty for a license without an Expires On date.
SYSTEM.TotalAlarms	Total alarm count.
SYSTEM.TotalAlarms_Severity1 ... SYSTEM.TotalAlarms_Severity4	Alarm counts per severity.
SYSTEM.TotalEvents	Total event count.
SYSTEM.AlarmCount_...	Dynamic alarm count variables created per alarm grouping or context.
SYSTEM.EventInfo_...	Dynamic event information variables created per event context.
SYSTEM.ScheduleInfo_...	Dynamic schedule execution status per schedule name.
SYSTEM.ScheduleInfoReset_...	Dynamic schedule reset status per schedule name.
SYSTEM.MetricsComputerName	Computer name of the server.
SYSTEM.MetricsManufacturer	Server hardware manufacturer.
SYSTEM.MetricsOperatingSystem	Operating system name.
SYSTEM.MetricsOperatingSystemVersion	Operating system version.
SYSTEM.MetricsFreeRAM	Free RAM.
SYSTEM.MetricsUsedRAM	Used RAM.
SYSTEM.MetricsTotalRAM	Total RAM.
SYSTEM.MetricsPercentageUsedRAM	Percentage of used RAM.
SYSTEM.MetricsPercentageCPU	CPU usage percentage.
SYSTEM.MetricsHistorianDbSize	Historian database size metric.
SYSTEM.RedundancyRoleLocal / SYSTEM.RedundancyRolePartner	Current local and partner redundancy roles.
SYSTEM.RedundancySyncStateLocal / SYSTEM.RedundancySyncStatePartner	Current redundancy synchronization state.
SYSTEM.RedundancyIPAddressLocal / SYSTEM.RedundancyIPAddressPartner	Configured local and partner redundancy IP addresses.
SYSTEM.RedundancyPortLocal / SYSTEM.RedundancyPortPartner	Configured local and partner redundancy ports.
SYSTEM.RedundancyBackfillLag / SYSTEM.RedundancyBackfillPercent	Redundancy backfill progress information.
SYSTEM.RedundancySwitchRequested	Requested redundancy role switch state.
SYSTEM.Participant1IPAddress / SYSTEM.Participant2IPAddress	Configured redundancy participant IP addresses.
SYSTEM.Participant1Port / SYSTEM.Participant2Port	Configured redundancy participant ports.
SYSTEM.ConfigDBversion / SYSTEM.HistorianDBversion	Current configuration and historian database version information.
SYSTEM.CurrentPointCount	Current Point Count: the points the license check compares with the License Point Count.
SYSTEM.ExternalSourcePointCount	Number of enabled Local variables with External Source enabled. In this version they are counted but not yet part of the license check; a future version adds them to the Current Point Count.
SYSTEM.AlarmServiceExecutionTime	Alarm service cycle execution time.
SYSTEM.EventServiceExecutionTime	Event service cycle execution time.
SYSTEM.ScheduleServiceExecutionTime	Schedule service cycle execution time.
SYSTEM.HistorianServiceExecutionTime	Historian service cycle execution time.
SYSTEM.ICMPDriverServiceExecutionTime	ICMP driver service execution time.
SYSTEM.ModbusTcpServerExecutionTime / SYSTEM.ModbusRtuServerExecutionTime / SYSTEM.OPCUAServerServiceExecutionTime	Gateway service execution times.
SYSTEM.StandbyDatabaseManagerExecutionTime	Standby database manager execution time.
SYSTEM.PythonServiceExecutionTime	Python service execution time.

Python Runtime Variables

Python scripts also create runtime status variables for each configured script. These variables are exposed with a System. prefix in the Python engine implementation.

The name suffix is the Python script name.

Variable	Description
System.PythonStatus_ScriptName	Current runtime state of the Python script.
System.PythonMsg_ScriptName	Last execution message or error text for the Python script.
System.PythonExecutionId_ScriptName	Execution identifier of the Python script run.

Notes

Device variables and local variables are published through the server-side variable dictionary. Client variables are handled in the browser and are used for client-specific runtime behavior.

Device and local variables can be historized depending on their configuration. System variables and client variables are informational runtime values and should be treated according to their specific use case.

Variable references in conditions, actions, scripts, and page bindings must use the exact runtime name, including the correct prefix and capitalization.

Something missing or wrong in this article? Contact us