Device data model and variables

Displaying device data model and running simple actions

Coiote IoT DM gives you the possibility to view and perform actions on the data model of individual devices defined by the LwM2M protocol. This view is available under the Objects panel of your device. Read this chapter to learn how to use the panel.

1. Search - use it to find a particular object. To find the object, type its name.

2. If checked, the changes you make to device objects will be applied immediately. Otherwise, you will have to wait for the device to trigger action execution or use the Execute tasks button (for devices in non-queue mode).

   Note

   The Apply immediately option is only available for devices in non-queue mode.

3. Use this button to add a new LwM2M object definition.

4. Division into objects.
5. The info icon - click it to see the object description.
6. Managing instances:
   • [A] - Use it to select another instance of an object if the object has instances.
   • [B] - Use it to add a new instance if an object allows it.
   • [C] - Use it to select another instance or remove it.
7. Search - use it to find a particular resource. To find the resource, type its name.
8. Use it to refresh data, track values (send an Observe task) and add additional attributes to a selected instance.
9. Use it to refresh data, track values (send an Observe task) and add additional attributes to a selected object.

10. The table with resources of an object instance.

    Note

    The icon displaying the status of execution is available after clicking on one of the action buttons located in the Actions column. If you click it, you will see additional information about execution.

11. Use it to refresh the resource.

12. Value tracking - use it to send an Observe task to the device and configure monitoring to collect data.
13. Attributes - use it to edit resource attributes or add new ones.
14. Use it to edit a value of a resource.
15. Execute - use it to send an Execute task to the device. Click the icon next to the button to add additional parameters.

Managing device variables

Use the Variables panel to add custom variables onto your device for the purpose of protocol tests and view the existing variables that the device has inherited. To enter the Variables panel, go to Device Management Center by clicking on a selected device name and choose the Variables tab.

Important

If the Variables tab is not visible in your Device Management Center, click the Configure visible tabs icon, drag and drop the Variables tab into the Selected tabs column, and click Confirm.

1. The Custom device variables list shows the variables that belong to this particular device.
   • To add a variable, click on Add, provide its name and value, and click Save. Note that every custom variable that you add will have the VARIABLE_ prefix.
   • To delete a previously added variable, click the Trash bin icon and click Save.
2. The Inherited variables list shows only the variables that the device inherits from the groups of devices that it belongs to. The list is view-only. To add a variable to this list, go to Device Groups and, in the Profiles panel, add an entry with the name beginning with VARIABLE_.
3. To search for variables in the table, use the search field above it.
4. To export existing variables, click the Export button. A .variables file will be downloaded onto your local drive.
5. To import variables, click the Import button. From your local drive, select a .variables file with variables. Any new variables contained in the file will be imported into the Custom device variables table

Using variables in test actions

To use device variables, enter the expression context by typing ${variable.<variableName>} while defining a test action. Remember that each variable is treated as a string, therefore, to use it as a different data type, you will have to cast it to the appropriate type. 

Using variables - example

Learn how to use device variables in Device tests in a few steps:

Use case: Testing the WRITE action on the LwM2M Server.1.Lifetime resource.

1. Add the variable:

   • In Device inventory, click on a selected device name to enter its Device Management Center.

   • Select the Variables tab.

     Tip

     If the Variables tab is not visible in the menu, use the settings button under the menu to add it: drag it from Available tabs and drop it in Selected tabs and click Confirm.

   

   • Click on Add and provide the following:
     • Name: lifetime120.
     • Value: 120.
   • Click Save.

2. Create a test and include the new variable in the appropriate format:

   • To add a new test, follow the steps in Creating your first test section, but including the adjustments below:
     • For example purposes, pick only the Write action.
     • In the Parameter name field, type LwM2M Server.1.Lifetime (note that the path may vary slightly depending on your device data model).

     • In the Value field, type ${variable.lifetime120.toInt}.

       Tip

       By default, the variable value is rendered as a string data type. To cast it to the integer data type, .toInt suffix is added to the created expression, as seen above.

3. Run the created test and check if the variable works correctly:

   • To run the test, follow the steps in Running the test on device using the test created in the previous step.
   • After the test is finished, check if the Lifetime resource value has changed on the device:
     • Go to the Objects panel of your device and under the LwM2M Server object, look for the Lifetime resource value:
     • If the value has changed accordingly, the variable can be now reused and populated to any other tests.

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Last update: July 18, 2023