Troubleshooting a tank monitor

Replacing the batteries

All new modules come preinstalled with fresh batteries. If a module goes offline shortly after activation, depleted batteries may be the cause.
Battery life and performance can vary depending on several factors, including:

• Natural voltage degradation over time.

• Environmental conditions, such as extreme heat or cold.

• Device transmission frequency (how often the device sends data).

• Network signal strength, for both data and GPS connections.

The type of battery used is critical for proper operation. When a 4–20 mA sensor is connected to the gateway, you must use Lithium Thionyl Chloride (LTC) batteries.
Please take note that different types of LTC batteries exist:

• Spiral-type LTC batteries
  Preferred for our older types of tank monitoring, more specifically tank monitoring using a Digital Matter Eagle, as they can deliver the high peak current required for this model.

• Bobbin-type LTC batteries
  Preferred for our current type of tank monitoring, more specifically tank monitoring using a Digital Matter Hawk, as they can provide the stable current required for this model.

Opening the case and replacing the batteries:

1. Carefully open the case and remove the old batteries.

2. Insert the new LTC batteries, ensuring correct polarity.

3. Before closing the case, check the silicone seal for any signs of wear or damage.

   The seal must be intact to maintain the device’s waterproofing and environmental protection.

4. Close the case securely.

No GPS data

The module automatically attempts to obtain a GPS fix every 12 hours. In some cases, the module may fail to get a fix, most often when it is installed under metal or iron covers, or in other locations where satellite signals are obstructed.

• Optimal GPS Conditions
  For the best GPS performance, the module should have a clear view of the sky. Try to install it in a position where it can “see” open air and is not blocked by metal structures, tanks, or thick concrete.

• Forcing a New GPS Fix
  If no GPS data is being received, you can prompt the module to obtain a new fix by performing a manual reset by removing the batteries for at least 5 minutes. Once power is restored, the module will automatically attempt to acquire a new GPS fix.

GPS reception quality depends on several conditions:

• Geographical location (urban areas with tall buildings can interfere with signal).

• Installation position and orientation of the device on the asset.

• Whether the asset is located in open air or enclosed spaces.

If the module still fails to come online after resetting, test the device in a different location where you are confident there is strong GPS and network reception.
Ensure it is placed outside of any fuel tank housing or metal enclosure.

Warning!

If it takes an extended period searching for a GPS location (for example, when it cannot acquire a fix and uses its entire allotted search time), the battery will drain significantly faster.

To prevent unnecessary battery consumption, ensure the device has good GPS reception and a clear view of the sky during installation.

Manual GPS Fix (external button)

Some newer Hawk modules include a button on the side of the enclosure that allows you to manually trigger a GPS location attempt.

External button

Not all Hawk modules include this button. It is only present on the latest hardware revision.

When the button is pressed, the module will start a GPS acquisition process immediately, instead of waiting for the automatic 12-hour GPS interval.
This can be useful during installation or troubleshooting when you want to quickly verify whether the module is able to obtain a GPS position.

Important notes

• Pressing the button enables manual GPS acquisition mode.

• Once a GPS fix has been obtained, press the button again to disable this mode.

• If the button remains enabled, the module may continue attempting GPS acquisition, which can significantly increase battery consumption.

Future hardware revisions will include a spring-loaded button that automatically returns to its original position after being pressed.
As with normal operation, GPS reception depends on installation conditions. Ensure the device has a clear view of the sky and is not installed under metal covers or inside enclosed structures.

No sensor data

If no sensor data is being received, it’s usually due to a connection issue. Steps to check:

1. Verify the sensor connection.

   • Make sure the sensor is connected exactly as described in the installation manual.

   • Inspect all connectors, terminals, and cables for proper fit and alignment.

2. Check for loose or damaged contacts.

   • A loose or corroded connection may prevent data transmission.

   • Re-seat the connector if necessary, ensuring it clicks or fits firmly in place.

3. Confirm sensor type compatibility.

   • Ensure that the connected sensor type is supported by the module or gateway.

If the problem persists after confirming all connections, try testing the module with another sensor and vice-versa (if available) to determine whether the issue is with the sensor or the module.

No fuel level data is received, but other data is

If the module is transmitting other data correctly but no fuel level information appears, the issue may be related to how the level sensor is calibrated and linked.

The fuel level sensor relies on metadata that belongs to the specific asset it is linked to. When multiple assets are connected to the same gateway, the system encounters duplicate metadata. This duplication causes confusion in the portal, preventing it from determining which metadata set to use, and as a result, the fuel level is not calculated.

Caution!

Always maintain a one-to-one connection between a gateway and an asset.

Linking multiple assets to a single gateway will result in missing or incorrect data, including fuel level readings.

Fuel tank capacity does not correspond to the actual tank capacity

If the displayed fuel tank capacity differs from the actual capacity, the issue is most likely related to sensor calibration.
Verify the sensor calibration by checking the metadata. Recalibrate the sensor if necessary.

Major fluctuations are observed in the raw sensor data

Check if the sensor’s air tube is clogged or bent. The air tube is contained within the sensor cable, so avoid any sharp bends when mounting the sensor.
Also check the tank’s air vent for any blockages.

The raw sensor data indicates a value below 4mA

When the widget Lastknown Raw Sensor Data displays a value below 4mA, it is a clear indication that there is a problem with the sensor.
Either the sensor is connected incorrectly, or the tank’s air vent is clogged or blocked. Check the sensor connections and air vent.

The tank has just been filled and the data online does not match

If the displayed data does not immediately match the actual tank level after filling, this is normal behavior and typically resolves on its own.
When a tank is filled, the process can create temporary internal air pressure. This pressure may cause the sensor to report slightly inaccurate readings right after refueling. The system automatically corrects the reading during the next data reading.

Hint!

If the readings do not normalize after several measurement cycles, check if the air tube isn’t blocked or bent.

After calibration the updated volume does not appear immediately

The correct volume will be shown on the dashboard when the next measurement is received.

Also, liquids expand when they warm up, and contract when they cool down. For this reason, it is possible that a tank, after an initial calibration during the summer, needs to be recalibrated when refilled during the winter period. If, after a refill, you receive an unexpected notification that the tank needs to be calibrated, consider this reason.