Documentation

Managing Sensors

Sensors collect additional data from your vehicles beyond basic GPS tracking. NexaBus supports fuel level monitors, eco-score sensors that measure driving behavior, a Driver Unique ID sensor used to identify which driver is behind the wheel for duty-hours compliance and driver ID confirmation, a wide range of standard vehicle telemetry attributes (Ignition, Motion, RPM, Battery, Odometer, Temperature, digital inputs/outputs, and more) reported directly by your GPS device, and CAN attributes read from the vehicle's own CAN bus through a CAN adapter — doors, seatbelts, lights, gear position, warning lamps and more.

Viewing Sensors

The Sensors table displays the following columns:

• ID: Unique identifier (hidden by default)
• Name: Your name for the sensor
• Device: Which GPS device the sensor is connected to, or "Multiple devices (N)" when it covers several
• Attribute: What the sensor measures (Fuel, Eco Score, Driver Unique ID, a CAN attribute, or one of many standard telemetry attributes such as Ignition, Motion, RPM, Battery, and Odometer)
• Parameter: The specific data field from the device
• Value: Current real-time reading from the sensor
• Sync Status: Connection status with the tracking server
• Actions: Edit and Delete options

On mobile devices, columns like ID, Name, Attribute, Parameter, and Sync Status are automatically hidden.

Sensor Grouping

When a device has multiple sensors, they are automatically grouped together in the table:

• Click the expand button to see all sensors for that device
• Group headers show the sensor count
• Configure aggregation settings for grouped sensors

Understanding Sensor Values

Different sensor types display values differently:

• Fuel sensors: Show current fuel level in liters (e.g., "45.50 L") after applying calibration
• Eco score sensors: Show a score from 0-10 with a rating badge:
  • 8.00-10: Excellent (green)
  • 6.00-7.99: Good (neutral)
  • 4.00-5.99: Not Good (yellow)
  • 2.00-3.99: Bad (orange)
  • 0-1.99: Very Bad (red)
• CAN sensors: Show the raw reported value. Flags read 1 when active and 0 when not (door open, seatbelt fastened, lamp lit); measured values such as engine RPM or coolant temperature show the number as reported. The Driver Safety report displays flag readings as Yes/No
• Driver Unique ID sensors: Show the raw driver identifier string reported by the device (e.g. an RFID/iButton badge code) rather than a number
• Other telemetry sensors (Ignition, Motion, RPM, Battery, Odometer, Temperature, digital inputs/outputs, etc.): Show the raw value reported by the device, with no calibration applied

Values update in real-time as your devices report data.

Searching for Sensors

Use the search field to find sensors. The search works across sensor name, attribute, parameter, and device name. Results update as you type.

Adding a Sensor

1. Click the Add Sensor button.
2. Complete the tabs:

General Tab

The fields are laid out in the order to fill them in: each one depends on the one before it.

• Name (Required): A descriptive name for the sensor (e.g., "Main Fuel Tank")
• Devices (Required): Select one or more devices from the dropdown. Picking several shows "N devices selected" rather than listing every name. The devices you pick decide which parameters are available, and — for Teltonika FMB140 trackers — whether the CAN list shows IO numbers, so they come first.
• Attribute (Required): What the sensor measures:
  • Fuel: Fuel level monitoring
  • Eco Score: Driver behavior/eco score
  • CAN: Values read from the vehicle's CAN bus. Selecting this reveals a second dropdown, next to the Attribute field, listing every CAN attribute, grouped the same way your tracker's configuration software groups them. When every selected device is an FMB140, each CAN attribute also shows its IO number underneath — see CAN Attributes below
  • Driver Unique ID: The driver identifier (e.g. an RFID/iButton badge code) some devices report per position. Used to attribute driving/duty time to the correct driver for the Duty Hours Violation and Driver ID Missing notification rules — only needed if your device doesn't already report this automatically; otherwise no sensor configuration is required
  • Other attributes: A wide range of standard vehicle telemetry is also available — Ignition, Motion, RPM, Battery, Odometer, VIN, Temperature 1-4, ADC 1-4, Input/Output 1-4, and more. These display the raw value reported by the device, with no calibration
• Parameter (Required): Select which data field the sensor reads. The list is built from what your selected devices are actually reporting, and you can only pick something they send — see Choosing the Right Parameter. It stays locked until at least one device is selected.

For Fuel sensors, this tab also has optional fill/drain detection settings, used by the Chart and Fuel reports:

• Filtration window (minutes): How much the raw sensor reading is smoothed before detecting fills/drains. Leave blank to use the default (3 minutes).
• Min fill volume: The smallest level increase counted as a refueling event. Leave blank to use the default (30 L for calibrated sensors, 500 raw units otherwise).
• Min drain volume: The smallest level decrease counted as a drain event. Leave blank to use the same default as Min fill volume.
• Fill stops only: When enabled, fills are only detected while the vehicle is not moving. Recommended for most sensors — eliminates false fills caused by fuel sloshing and sensor vibration during driving.
• Drain stops only: When enabled, drains are only detected while the vehicle is parked. Recommended to avoid counting normal driving consumption as drain events.

These only affect detection sensitivity — they don't change the calibration curve.

Calculations Tab

This tab appears only for Fuel and Eco Score sensors — all other attributes (CAN attributes, Driver Unique ID, and the standard telemetry attributes like Ignition, RPM, Battery, etc.) need no calibration, so Name, Attribute, Devices, and Parameter are all that's required for those:

For Fuel Sensors:

Configure calibration data to convert raw sensor readings into accurate fuel volume:

1. Calibration Points View:
   • Enter pairs of sensor level (X) and fuel in liters (Y)
   • Add multiple points for accurate calibration
   • Import from CSV using the import button
2. Coefficients View:
   • Shows calculated slope (a) and intercept (b) for each segment
   • Formula: Y = aX + b
   • Click Generate to calculate coefficients from calibration points
3. Chart View:
   • Visual representation of calibration curve
   • Shows min/max values and data points

For Eco Score Sensors:

View how eco scores are calculated:

• Formula: ECO Score = 10 / (Events / (Distance x (Allowed Events / 100)))
• Monitored Events:
  • Harsh acceleration
  • Harsh braking
  • Harsh cornering
  • Over-speeding
  • Excessive idling
  • High RPM (requires OBD device)

3. Click Create Sensor.

CAN Attributes

CAN attributes are values the vehicle publishes on its own data bus and your tracker forwards, provided a CAN adapter is fitted and configured. They are organised into four groups:

• Parameters: Measured values — vehicle speed, engine RPM, fuel level, mileage, engine temperature, accelerator pedal position, battery level, range, and the combined door-status value
• Security Flags (SSF): Ignition, engine running, individual doors, hood and trunk, handbrake and footbrake, gear position, central locking and factory alarm states
• Control Flags (CSF): Lights (sidelights, dipped and full beam, fog lights), air conditioning, cruise control, seatbelts and passenger presence
• Indicator Flags (ISF): Dashboard warning lamps — check engine, ESP, battery charging, low tire pressure, and the general warning lamp

Two of these have a job elsewhere in NexaBus: Driver's Seatbelt and Dipped Headlights are what the Driver Safety report and its Seatbelt Not Used and Headlights Not Used notification rules read. Create those two as CAN sensors if you want those rules to work.

Which CAN values are available depends on the vehicle and on how the tracker's CAN adapter is configured. An element the vehicle doesn't support, or one that isn't enabled in the tracker, simply never appears in the parameter list.

IO Numbers for FMB140 Trackers

When every selected device has its model set to FMB140, each CAN attribute in the dropdown shows the Teltonika IO number that carries it — for example io90 under Door Status, or io84, io89 under Fuel Level (litres and percent). You can also type an IO number into the search box to find its attribute.

CAN attributes that none of your selected devices are sending are greyed out and can't be picked. Picking an available one selects its parameter for you.

The numbers are only shown for the FMB140 because other trackers, including other Teltonika models, number these elements differently. If the selection includes any device of another model, or a device with no model set, the list shows names only. The device model is set on the Devices page.

Choosing the Right Parameter

The attribute says what a sensor means; the parameter says where the value comes from. These are separate because there is no universal numbering across manufacturers — the same physical door switch arrives under a different data field on a different tracker brand, and sometimes even between models from the same brand.

So NexaBus never guesses the parameter for you. It lists exactly what your selected devices have reported, and:

• You must choose a parameter. A sensor cannot be saved without one.
• It must be one your devices actually send. If none of the selected devices reports it, the sensor is rejected — it would be created but would never produce a value.

If you don't recognise which data field corresponds to a CAN attribute, check the element list in your tracker's configuration software: the field name here matches the element you enabled there. On FMB140 trackers the CAN dropdown shows the IO number for you — see IO Numbers for FMB140 Trackers.

Sensor Grouping and Aggregation

When multiple sensors measure the same attribute on a device, you can configure how their values are combined:

1. Click the group configuration button on a grouped row.
2. Create calculation groups and assign sensors.
3. Choose an aggregation method for each group:
   • Sum: Add all values together
   • Average: Calculate the mean value
   • Min: Use the lowest value
   • Max: Use the highest value
4. Choose a final aggregation method to combine groups.
5. Preview shows the calculated result.

This is useful for vehicles with multiple fuel tanks or sensors.

Devices Missing a Parameter

A parameter one device reports isn't necessarily reported by all of them — a vehicle without the right adapter, or a tracker configured differently, won't send it.

When you select more than one device and then pick a parameter that some of them don't send, a View missing parameters button appears under the Parameter field showing how many are affected. Click it to see:

• Which of the selected devices don't report that parameter
• Which of them have no position data at all yet — a different problem, and worth fixing first

You can still save the sensor. It will be created for every selected device, but it will stay empty on the ones listed. Either remove those devices from the selection, or enable the matching element in their tracker configuration.

The button only appears with two or more devices selected. With a single device, a parameter it doesn't report is blocked outright rather than warned about.

Editing a Sensor

1. Find the sensor in the table.
2. Click the actions menu (three dots) in that row.
3. Select Edit.
4. Update the configuration as needed.
5. Click Update Sensor.

Deleting a Sensor

1. Find the sensor in the table.
2. Click the actions menu (three dots) in that row.
3. Select Delete.
4. Confirm the deletion.

Sync Status

Sensors sync with the NexaBus server to ensure accurate data:

• Syncing: Spinning icon indicates sync in progress (yellow)
• Synced: Check icon confirms successful connection (green)
• Outdated: Alert icon indicates data may be stale - click to refresh (yellow)
• Failed: Error icon indicates sync failed - click to retry (red)
• N/A: Dash indicates no devices assigned

Sync status updates automatically in real-time.

Real-Time Value Updates

Sensor values update automatically via WebSocket connection:

• No page refresh needed
• Values update as devices report new data
• Fuel values apply calibration formulas automatically
• Eco scores normalize to 0-10 scale

Pagination

The table displays 10 sensors per page. Use the pagination controls at the bottom to navigate:

• First and Last page buttons
• Previous and Next page buttons
• Current page indicator showing "Showing X to Y of Z"

Permissions

You need the appropriate permissions to add, edit, or delete sensors. If these options are not visible, contact your administrator to request access.