Sensors

SEM stands for SEnsor Module. It collects data from sensors (listed below) from Communication Units and makes them available for internal usage to other SCALAR modules (internal API), and external usage to integrators (external API).
Sensor data is provided in a non-aggregated way. Sensor module’s intention is to be used by other modules as a source of truth about sensor data.

In some cases, sensor data is used for reporting (historical); in other cases, the latest value for a sensor might be requested; and in some other cases. Sensor module also provides raw sensor data to customers and/or integrators in form of Feed/bulk.

The following table includes a list of sensors that is used by events:

Reefer Compartments

These sensors are created for each related item, the default structure in the messageis:

"compartments": [ { "id": 1, "setPoint": 7, "evaporatorTemperature": 1.4, "returnAir": 0, "supplyAir": 0, "mode": "cooling" }, ...]

For each ID, the location of the object is created as the ID ID and a value is set to the value of setPoint, another for Return air, and so on,
This results in the 4 sensors created per compartment, if all 4 values are present (setPoint, returnAir, supplyAir, mode). If only one value is present, only one sensor is generated.
The above example for compartment 1, would create 5 sensors, all have the location 1 and the value would be 7 for setPoint, 0 for returnAir, 0 for supplyAir and “cooling” for mode.

Location/Zones

In some sensors, the location property inside the sensorValue object defines the location or zone of the sensor for the specific measurement.
E.g. in the tireTemperature sensor, it indicates the location of the tire.
For example, the temperature of the first wheel on the left of axis 1 should be indicated by the location value 17. For a mapping of the wheels with the number, see the paragraph wheel location logic. This logic is applied for the following sensors:

• tirePressure
• tireTemperature
• tirePressureStatus

The zone location is more straightforward and it refers to the actual zone with the same number. For example, if in the reeferLoggerTemperature object the location is 2, it means that it refers to the reefer temperature collected from zone 2 of the reefer. This logic applies for:

• reeferLoggerTemperature
• reeferLoggerHumidity
• reeferDigitalInput

Same for LIN sensors, the location indicates the contact sensor in the LIN enumeration. This logic applies for:

• linTemperature
• linContact

Wheel Location logic

The wheels are calculated from the mid-point 8, that means there is no wheel number 8. All the wheels will go from 0-7 or 9-F (15 in hexadecimal).
Also, the number of the wheel location also start from the mid-point, decreasing when on the left of mid-point and increasing when on the right. That means, when we have one wheel on the left it will have the number 7, if we add a second wheel in the same axle on the left side it will have the number 6 and so on.

When we have one wheel on the right it will have the number 9, if we add a second wheel in the same axle on the right side it will have the number A (10) and so on.

The following diagrams should help in understanding the Scalar format for wheel location.

Examples

• from integer to wheel position
• Decimal = 39; hex = 27 ==> axle 2, first wheel to the left
• Decimal = 41; hex = 29 ==> axle 2, first wheel to the right
• Decimal = 54; hex = 36 ==> axle 3, second wheel to the left
• Decimal = 58; hex = 3A ==> axle 3, second wheel to the right

from wheel position to integer

• axle 1, third wheel to the left = 21. In hexadecimal it is 15 (1 stands for axle 1 and 5 stands for third wheel, considering the first one has number 7, the second one has number 6 and so on). Converting 15 from hex to dec, we obtain 21
• axle 5, fifth wheel to the left = 83. Converting the position in hexadecimal we have 5 as first digit due to the axle 5; then we have 3 as second digit by considering the part in bold: 7 = wheel 1; 6 = wheel 2; 5 = wheel 3; 4 = wheel 4; 3 = wheel 5; 2 = wheel 6; 1 = wheel 7; = wheel 8. Then, by converting 53 from hex to dec, we obtain 83
• axle 1, fourth wheel to the right. The value is 28. We take 1 as first digit for the axle; then we take C because is the fourth wheel (9= wheel 1; A = wheel 2; B = wheel 3; C = wheel 4; D = wheel 5; E = wheel 6; F = wheel 7). Then, converting 1C from hex to dec, we obtain 28
• axle 4, first wheel to the right. 49 is the hexadecimal representation (4 for axle 4 and 9 for wheel 1 to the right). Converting it to decimal we obtain 73

Value mapping

Some properties contains a value as string which is mapped to an enumerator. In this section we document all the enumeration used by the sensor module
Pressure threshold status enum values

• extremeOverPressure
• overPressure
• normal
• underPressure
• extremeUnderPressure

Power Mode values

• invalid
• diesel
• electric

Operating Mode values for each zone

• invalid
• powerOn
• powerOff
• cooling
• heating
• defrost
• pretrip
• irregularShutdown
• compulsoryShutdown
• thermostatOff
• sleep
• diagnostics

Reefer Operating Mode values

• invalid
• cycleSentry
• continuous

Propulsion Charging Status values

• notCharging
• charging
• unknown

Battery Pack Level values

• critical
• low
• medium
• high
• full

Battery Pack Charging State values

• notCharging
• charging
• fullyCharged

Battery Pack Not Charging Reason values

• noPower
• temperatureIssue
• error

Measuring Units

Measuring unit define the metric unit that is applicable to the sensor value. If it cannot be defined, N/A will be returned. Here is the list of possible values:

• N/A → Not Applicable
• kilometer → Distance
• kilometers/hour → Distance/Hour (speed)
• kilogram → Weight
• hour → Time
• degree → Angle (min = 0°, max = 360°)

e.g. heading = angle of positioning

• celsius → Temperature in °C
• liter → Volume
• kilopascal → Pressure
• volt → Voltage (min = 9V, max = 32V)
  • millivolt → Voltage - 1/1000 of a volt
• kilowatt → Unit of Power
• kilowattHour → KWh - Kilowatts measured within an hour

Special Cases

• position
• percentage → (min = 0, max = 100)
• amount → defines the amount of data

e.g. satCount = number of satellites