Variables

A variable is the most fundamental data unit in inSCADA. A temperature measurement, a motor status, an energy meter — each one is a variable.

Creating a Variable

Menu: Runtime → Variables → New Variable

Field	Required	Description
Name	Yes	Variable name (unique within the project)
Type	Yes	Data type
Unit	No	Engineering unit (°C, kW, V, A, bar…)
Description	No	Description
Connection / Device / Frame	Yes	Which connection it belongs to
Active	Yes	Active/inactive

Data Types

Type	Description	Example
Float	Decimal number	25.4, 230.1, 0.95
Integer	Whole number	100, -5, 0
Boolean	True/False	true, false
String	Text	”Recipe-A”, “Running”

Variable Structure (Example)

{
  "id": 23227,
  "name": "ActivePower_kW",
  "dsc": "Total active power",
  "type": "Float",
  "unit": "kW",
  "projectId": 153,
  "connectionId": 153,
  "deviceId": 453,
  "frameId": 703,
  "isActive": true,
  "fractionalDigitCount": 2,
  "engZeroScale": 0.0,
  "engFullScale": 1000.0,
  "logType": "Periodically",
  "logPeriod": 10,
  "keepLastValues": true,
  "valueExpressionType": "CUSTOM",
  "valueExpressionCode": "var t = new Date().getTime() / 1000; return (Math.sin(t / 60) * 150 + 450 + Math.random() * 30).toFixed(2) * 1;"
}

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Scaling

The raw value is converted to the engineering value through linear transformation.

Parameter	Description
engZeroScale	Engineering unit lower limit
engFullScale	Engineering unit upper limit
rawZeroScale	Raw value lower limit
rawFullScale	Raw value upper limit

Conversion Formula

Eng = engZeroScale + (raw - rawZeroScale) ×
      (engFullScale - engZeroScale) / (rawFullScale - rawZeroScale)

Example: 4-20mA Sensor → 0-100°C

Parameter	Value
rawZeroScale	4 (mA)
rawFullScale	20 (mA)
engZeroScale	0 (°C)
engFullScale	100 (°C)

• Raw: 4mA → Eng: 0°C
• Raw: 12mA → Eng: 50°C
• Raw: 20mA → Eng: 100°C

Scaling in Real-Time Value Response

{
  "value": 359.91,
  "extras": { "raw_value": 606.56 },
  "flags": { "scaled": true }
}

value is the scaled engineering value, extras.raw_value is the raw value.

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Logging (Historical Data)

Variable values can be recorded to the time series database.

Logging Types

Type	Description
Periodically	Records at fixed intervals (logPeriod seconds)
When Changed	Records only when the value changes
None	No recording

Logging Parameters

Parameter	Description
logPeriod	Recording period (seconds). 10 = every 10 seconds
logThreshold	Minimum change threshold (optional). Filters out small fluctuations
logMinValue / logMaxValue	Valid value range. Values outside this range are not logged
keepLastValues	Keep the last values list in memory

Fractional Digit Count

fractionalDigitCount determines the number of decimal places to display:

Value	Display
0	350
1	350.5
2	350.48
3	350.483

---

Value Expression

A custom JavaScript formula can be assigned to a variable. This formula runs on every read cycle, and its result becomes the variable’s value.

Expression Types

Type	Description
NONE	No expression, raw value is used
CUSTOM	Inline JavaScript code
REFERENCE	Shared Expression reference (space level)

Example: Simulation

// Sine wave (ActivePower_kW)
var t = new Date().getTime() / 1000;
return (Math.sin(t / 60) * 150 + 450 + Math.random() * 30).toFixed(2) * 1;

Example: Unit Conversion

// Fahrenheit → Celsius
var fahrenheit = value; // raw value
return ((fahrenheit - 32) * 5 / 9).toFixed(1) * 1;

Example: Conditional Logic

// Calculate efficiency from two variables
var input = ins.getVariableValue("Input_kW").value;
var output = ins.getVariableValue("Output_kW").value;
if (input > 0) {
    return ((output / input) * 100).toFixed(1) * 1;
}
return 0;

---

Pulse Feature

Pulse mode can be assigned to Boolean variables:

Parameter	Description
isPulseOn	ON pulse active
pulseOnDuration	ON pulse duration (ms)
isPulseOff	OFF pulse active
pulseOffDuration	OFF pulse duration (ms)

Pulse mode is used for momentary command sending (e.g., motor start button — ON when pressed, automatically OFF when released).

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Write Limits

Parameter	Description
setMinValue	Minimum writable value
setMaxValue	Maximum writable value

When these parameters are set, write commands outside the range are rejected. Used to prevent operator errors.

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Managing Variables with Scripts

// Read real-time value
var val = ins.getVariableValue("ActivePower_kW");
// → { value: 359.91, extras: { raw_value: 606.56 }, dateInMs: ... }

// Bulk read
var vals = ins.getVariableValues(["ActivePower_kW", "Voltage_V", "Current_A"]);

// Write value
ins.setVariableValue("Temperature_C", {value: 55.0});

// Variable information
var info = ins.getVariable("ActivePower_kW");
// → { name: "ActivePower_kW", unit: "kW", type: "Float", logPeriod: 10 ... }

Detailed API: Variable API → | REST API →