Managing attributes

The Initiate Attribute node allows you to create, edit, and manage data attributes throughout your IoT Logic flow. This guide covers the basic attribute management actions (create, edit, delete) and essential operations, including autofill functionality for formula creation.

Creating attributes

Here's how to create a new attribute in the Initiate attribute node:

1. Click the Add attribute button

2. Enter a name for your attribute (e.g., "Speed mph")

3. Define the value expression (e.g., value('can_speed')/1.609)

4. Optionally configure generation time and server time, to do it, enable the Specify time attributes toggle
   For details, see Time settings for attributes

5. Click Save to confirm the node configuration

The new attribute is saved in the node and the configured calculation is applied immediately in the flow.

Time settings for attributes

Time settings give you control over timestamps associated with your attributes:

• Generation time: When the data was created

  • Use now() to set the current time in milliseconds

  • Use genTime('parameter_name', 0, 'valid') to use the parameter's own generation time

• Server time: When the data was received by IoT Logic

  • Use now() to set the current time in milliseconds

  • Use srvTime('parameter_name', 0, 'valid') to use the parameter's server time

  • Add offsets to adjust for time zones (e.g., srvTime('can_speed', 0, 'valid') + 120000 adds 2 minutes)

Time settings are important for data analysis and synchronization. Proper time configuration ensures that your data maintains chronological integrity throughout the flow.

Autofill attribute names

When creating calculation formulas, you need to reference existing attribute names from physical devices or calculated attributes from other nodes. To simplify this process and prevent misspellings, IoT Logic provides autofill functionality for attribute names.

To use autofill when building formulas:

1. Click in the Formula field.

2. Select the desired attribute from the appeared list, it supports manual text input for search purposes.

3. Click on the attribute name to insert it into your formula.

The selected attribute is automatically inserted in the ready-to-use format, with the highlighted attribute name: value('attribute_name', 0, ‘valid'). For your convenience, here’s the breakdown of autofilled elements:

• value - a syntax element of Navixy IoT Logic Expression Language.

• 'attribute_name' - the actual name of the data attribute coming from a physical device or another Initiate Attribute node.

• 0 - depth index, defining the exact historical value from 0 (the latest) to 12 (the oldest). It reflects the indexes shown in Data Stream Analyzer.

• ‘valid' - validity flag forcing only the non-null values to be considered.

When 'valid' is specified, the system automatically skips any null (empty) hiustoric values. This means the depth index will point to the most recent valid value rather than the most recent chronological value. For example, if your most recent reading (index 0) is null but the previous reading (index 1) contains actual data, the formula will use the index 1 value instead of the null value at index 0.

You can modify the parameters as needed - change the index number for historical values or adjust the validity flag.

The list is filtered based on your flow's data sources and matches what's visible in Data Stream Analyzer.

The autofill list displays only attributes that meet all of the following criteria simultaneously:

• Supported by devices - The attribute must be supported by at least one device currently added to your flow

• Actually transmitted - The device must have sent real data for this attribute (not just support it theoretically)

• Available in flow - This includes both device parameters and calculated attributes from other Initiate Attribute nodes within the same flow

Example: If your device supports both speed and temperature sensors but has only transmitted speed data (perhaps due to a faulty temperature sensor), the autofill list will show the 'speed' attribute but not 'temperature'. The temperature attribute will only appear once the device actually sends temperature readings, even though the device technically supports it.

Indexed attributes in autofill

Some data attributes contain multiple values indexed within a single attribute, such as readings from multiple analog sensors connected to a main telematics device. To use these attributes in calculations, you need to specify the exact index number corresponding to the specific sensor or input you want to reference.

For example, if you need to work with voltage readings from the third analog input on your device, this data comes through the attribute analog_2 (using zero-based indexing where the first input is index 0). In your formula, this would appear as value('analog_2', 0, 'valid').

Autofill handles this scenario for you as well:

• Indexed attributes are marked with icon in the autofill list.

• These entries display the available index range in square brackets, such as analog_[1..4] for attributes supporting five indexed values (indexes 1 through 4).

• When you select an indexed attribute, the cursor automatically positions at the end of the attribute name within the quotes, allowing you to immediately type the specific index number you need.

Editing existing attributes

To modify an existing attribute:

1. Open the node configuration window by hovering your mouse over the node to display quick actions, or double-clicking the node

2. Find the attribute you wish to edit in the attribute list

3. Make the needed changes in the text fields of the attribute properties: Attribute name, Formula or time settings

4. If you need to edit other attributes in this node, repeat step 3 for them

5. Click Save to apply your changes to the node configuration

When you edit an attribute, the changes will only apply to new data received after saving. Historical data already collected will not be recalculated.

Deleting attributes

To remove an attribute that is no longer needed:

1. Open the node configuration window by hovering your mouse over the node to display quick actions, or double-clicking the node

2. Find the attribute you wish to delete in the attribute list and hover your mouse over it to display a menu

3. Click the appeared menu and select Delete

4. Confirm your decision to delete the attribute

5. Click Save to apply your changes to the node configuration

When you delete an attribute, it will no longer be calculated for new data, but historical data containing this attribute will remain unchanged in the database.