ECargosens

Current design: central unit, measurement unit

The load monitoring system eCargosens (hereinafter - “System”) for vehicles with air suspension is designed to monitor the load of every axis of the vehicle’s chassis based on the measurement of the air pressure in the air suspension’s system.

The eCargosens system consists of one eCargosens DS central unit (hereinafter - “central unit”) and several measurement units or eCargosens Air sensors (hereinafter - “Sensor” or “Sensors”). The number of Sensors installed on the vehicle depends on the number of axes the vehicle has

The Sensors measure the air pressure and - subsequently - the weight (load). The central unit perfoms the function of receiving data from sensors via the BLE 5.0 LR channel (data transfer protocol - Escort BLE eCargosens) and their further transmission to a tracker device (for example, a GPS/GLONASS navigation terminal) via RS-485 interface (data transfer protocol - LLS).

More detailed technical specifications (central unit) are presented in the device's data sheet.

More detailed technical specifications (sensor) are presented in the device's data sheet.

Operating and data transmission principles

The Sensors must be connected to the air suspension system of the vehicle. They measure the air pressure in the air suspension and calculate the weight that is distributed onto a particular axis based on a calibration table that must be created and saved in their memory.

The Sensor(s) transmit their parameters to the central unit via Bluetooth 5.0 in accordance with the Escort BLE eCargosens data communication protocol.

The Sensors transmit their data packages every 2 seconds.

The air pressure is measured every 30 seconds but the measurement are filtered (median filtration 5) and then processed by a special algorithm.

The central unit then retransmits the data received from the Sensor(s) to a GPS tracker/gateway via the RS-485 interface in accordance with the LLS communication protocol.

The parameters transmitted by the Sensor(s):

- Weight or axle load in kg (provided that the calibration table is stored in a Sensor’s memory);

- Air pressure in Pa;

- Battery charge in V;

The parameters retransmitted by the central unit:

- Weight or axle load in kg (provided that the calibration table is stored in a Sensor’s memory); as received from the Sensor(s);

- Air pressure in Pa; as received from the Sensor(s);

- Battery charge in V; as received from the Sensor(s);

- RSSI as calculated by the central unit for every Sensor in particular;

Note for developers

The central unit retransmits the parameters as per the LLS protocol in response to the request for level and temperature (because the LLS protocol was initially designed for the transmission of fuel level sensor)

31$XX$06$CRC-8 Maxim (XX stands for the network address from 00 to FF in HEX (0…255 in DEC));

The data output is transmitted as 3E$XX$06$TT$LVLV$CRC-8 Maxim, where

XX -network address,

TT - temperature parameter (1 byte, HEX value),

LVLV - level value (2 bytes, little endian);

Thus, one network address is used to transmit one pair of parameters sent by the Sensor(s) and retransmitted by the central unit.

The Pressure readings is transmitted after it is divided by 100. F.e. the Pressure reading is 700345 Pa but the value transmitted via the RS-485 interface will be 7003.

Table 1. Parameter table

Pair of parameters (as indicated in the RS-485 settings of the central unit)	Temperature parameter	Level parameter
	RSSI	Weight
	RSSI	Pressure
	Vbat	Weight
	Vbat	Pressure
	RSSI	Vbat

ATTENTION! The tracker/gateway you plan to connect the central unit to must have the RS-485 interface, the LLS protocol and support as many network addresses as you need for the transmission of all relevant Sensor’s parameters.

Installation and configuration

Before installing the sensor you need to:

- Inspect the air suspension system;

- Measure the diameter of the tubes that connect the air springs of the air suspension and buy the fittings to be able to connect the Sensors’ tubes to the air suspension’s tubes;

The standard diameter of the Sensor’s tubes is ⌀ 10mm.

The Sensor’s connecting to the air spring is shown on the figures below:

Before installing the sensor be sure to write down their serial numbers and MAC addresses and what axis every Sensors is to be installed at:

Pairing Sensors with central unit

Once the sensors are installed, you need to pair them with the central unit and configure them.

To connect the central unit and configure it via the app, connect its red (PWR) and black (GND) wires to a power supply.

Run the app (available in AppStore and Play Market), ensure that the geolocation service of your smartphone is On and the app has the permission to access it. Enable the Bluetooth.

Android eCargosens: download here.

IOS eCargosens: download here.

Then select the language should it be necessary and press Start. Then tap on the central unit you need.

Scroll down and tap Sensor settings. Enter the integrator’s password (666666 by default)

Tap on the + button. Enter the user password (000000 by default). Then enter the MAC of the sensor.

Then enter the MAC of the sensor. You can add as many sensors as you need (up to 10 sensors to one central unit) .

To disconnect the sensor, press and hold it until the Disconnect button appears then press it and delete the sensor.

Sensor calibration

To calibrate the Sensor, you need to weigh the axis it is installed at when the vehicle’s semi trailer or trailer is empty and when it is loaded at around 30-40% of max load. The load must be placed in a fashion that would ensure that the weight is distributed between the axes more or less equally.

You will need vehicle scales. Put them on an even surface. Make sure that once the axis is placed on the scales it remains on the same level as the other axes.

Then write down the Pressure value and the weight value. You need two pairs of Pressure - Weight values to save them in every Sensor’s memory.

After that, open the app, connect the central unit, open Sensor settings menu and select the sensor you need to calibrate.

When you connect the Sensor for the 1st time, you will be required to set up a password. From there on every time you connect the sensor the app will require you to enter the previously set password.

Once the sensor’s menu is open, you can see its current readings. Tap on the Calibrate button to open the calibration menu.

Next, press the + button. Then enter the Pressure reading (from the screen with the Sensor’s data) and Weight reading (from the scales) and tap Enter.

To edit the table, press and hold one of its lines then either add one more line, change the selected one or delete it.

After the table is finished tap on the Save button. Repeat the procedure of weighing and setting the table for every sensor.

You can add more than 2 lines should you have the possibility to weigh every axis while the load in the semi trailer is different but 2 lines will do in most cases. The max number of lines - 20.

RS-485 settings

To enable the transmission of the data the central unit receives from the Sensors paired with it via Bluetooth to a GPS tracker/gateway by means of the RS-485 interface, connect the central unit and open the RS-485 settings menu. Select one of the paired Sensors there.

Then select the pair of parameters you need transmitted and enable it. After that select the network address that will be used for the transmission of that pair from the central unit to the GPS tracker/gateway.

ATTENTION! Ensure that every pair of parameters in every Sensor’s menu is assigned a unique network address. If you have several other wired sensors connected to the same GPS tracker/gateway via the RS-485 interface, remember that they also already occupy one or several network addresses so you need to avoid assigning the central unit any of those network address.

For example, if there’s a wired FLS that had been assigned the network address 1, the address 1 cannot be assigned to the central unit.

Note that the app could be reading “All network addresses are free” but the app cannot check if there any other wired sensors connected to your tracker/gateway. It only checks what network addresses had been assigned to every paired Sensor in the central unit’s configuration.

Data view

You, your customer or the truck’s driver can access the current readings transmitted by the Sensors via the app.

Connect the central unit.

Then tap View data. On the next screen the app will show the readings of all Sensors paired with the central unit.

ATTENTION! When selecting the spot at which to install the central unit, be sure to check if the average RSSI of every sensor as measured within 2-3 minutes is within the -35 dBm to -100 dBm range. If it is not, try moving the central unit closer to the sensors to minimize the risks of connection losses in future!

How many sensors are required?

The general recommendation is to install as many as sensors as many axes the vehicle has. In other words: 1 axis = 1 sensor.

It is possible that in some cases, one sensor could be used to monitor the load on several axes provided that the air springs that support those axes are united into one suspension circuit.

The following are a few examples of possible installation of several sensors:

A and B are possible slots where the 2 sensors would have to be installed to monitor the load of every axis.

In this case it is possible that only one sensor could be installed either at point A or B.

However, you would need to be collecting the pressure readings of the sensor and have 2 virtual sensors on your monitoring platform (the calibration tables would have to be saved and applied in those virtual sensors).

In this case it is possible that only one sensor could be installed either at point A or B.

However, you would need to be collecting the pressure readings of the sensor and have 2 virtual sensors on your monitoring platform (the calibration tables would have to be saved and applied in those virtual sensors).

In this case either 6 or 3 sensors could be installed (1 or 2 per axis) to monitor the axle load.

It is still possible that the load distributed between the two out of three axes could be more or less equal and therefore 1 or 2 sensors could be enough.

However, if one of the axes is a liftable one, installing one sensor on it is obligatory.

Configuration of virtual sensor for steering (spring) axle

To calculate a total weight of a semi-trailer truck it’s necessary to weigh both the steering and the rear axis of a truck (dump truck) without a semi-trailer (if dump truck, without a cargo). If there are several front and\or rear axles, it’s necessary to weigh each.

Next, in the Sensor configuration menu, press + the button and select the Add the head axle option.

After that a virtual sensor for a steering axle will be created and it will have a MAC FF:FF:FF:FF:FF:F1

In the settings fill the Number of rear axle №1 with a sensor’s number, that is installed on a rear axle. A sensor’s number is determined by its position from 1st to 10th in the list.

Enter the weight of a rear axle without a semi-trailer in Load of rear axle №

In case there are several rear axles, add another one by pressing the button then enter the number of a sensor installed on it and also its weight without a semi-trailer. To delete an accidentally created rear axle, press the + button.

Then enter the following aspects:

1) a weight of a truck (calculated by adding up the weight of all its axles without a semi-trailer) or the weight of a dump truck

2) a distance between the front axle center and the rear axle center

3) a distance between the front axle center and a trailing arm (or a gravity center of a dumper). The value should not be more than a distance between the front axle center and the rear axle center or totally equal to it.

4) a distance between the front steering axles (in case they are two); if there is only one steering axle, enter the minimum value of 51 cm.

5) select the 2 rear axles mode, if there are two steering axles

6) press the Save button

WARNING! The central unit computes a weight of a steering axle and a total weight of a semi-trailer truck, only if the calibration tables are saved in the sensors’ memory!!!

ATTENTION! To successfully use the "2 rear axles" mode, a second virtual steering axle with the same settings as the first must be added to the central unit. Both virtual sensors must have the "two rear axles" mode selected.

Configuring the virtual steering (spring) axle sensor when there are two sensors on the rear axle

In addition, one of the latest firmware versions (1.1.6) introduced a feature for calculating the steering axis when more than one sensor is installed on the drive axles (to calculate the average reading from two sensors per axle).

Below are screenshots of the settings:

After adding a virtual steering axis sensor with MAC address FF:FF:FF:FF:FF:F1, you need to access its settings by clicking on it.

1) In the settings, in the "Rear Sensor No. 1.1" field, enter the serial number of one of the sensors installed on the truck's rear axle (semi-trailer axles are not required).

The sensor's serial number is determined by its position in the list, numbered from 1 to 10 from top to bottom.

1.2) In the settings, in the "Rear Sensor No. 1.2" field, specify the serial number of the second sensor installed on the same rear axle of the truck (semi-trailer axles are not required). (Add by clicking the "+" button.)

The sensor's serial number is determined by its position in the list, numbered from 1 to 10 from top to bottom.

2) Enter the rear axle weight (without the semi-trailer) in the "Rear Axle Load No." field.

If the truck has multiple rear axles and each is equipped with two sensors, you must add another rear axle.

Use the "+" (plus) button to specify the serial number of the sensor installed on it and its weight without the semi-trailer. To delete an accidentally created rear axle, click the (Trash Can) button.

Next, you must specify:

1) the weight of the truck unit (the sum of the weights of all its axles, excluding the semi-trailer) or the weight of the dump truck

2) the distance from the center of the front axle to the center of the rear axles

3) the distance from the center of the front axle to the coupling device (the center of gravity of the dump body). This value cannot be greater than or equal to the distance from the center of the front axle to the center of the rear

4) The distance between the front steering axles (if there are two); if there is only one steering axle, enter the minimum value of 51 cm

5) Select the "two-axle truck" operating mode if there are two steering axles

6) Click "Save"

ATTENTION! The cab unit will calculate the weight of the steering axle and the total weight of the truck-trailer combination only if the calibration tables are stored in the sensors' memory!!!

ATTENTION! To successfully use the "two-axle tractor" mode, you must add a second virtual steering axle to the cab unit with the same settings as the first one. The "two-axle" mode must be selected for both virtual sensors.

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To delete a virtual sensor of a steering axle, hold its button until the Disconnect option appears.

To view the steering axle readings from a peripheral device (e.g a GPS tracker) via the RS-485 interface, go to the RS-485 configuration section to select a virtual sensor of a steering axle. Enable the Weight, RSSI parameter and set a certain network address for it.

To connect a central unit to an I5 indicator in order to view the sum of all the sensors, including the virtual sensor of a steering axle, configure the i5 so it’s able to read or request the network addresses that are set for the certain sensors in the central unit. In the I5’s Display settings select the TD total level option.

Connecting the cabin unit to the I-5 digital display

The eCargosens cabin unit is connected to the digital "I-5 Display" for data output to the screen in accordance with our general pinout shown below ("Connection to the GPS Terminal"). Simply connect lines A and B of the display to the cabin unit, and connect the display to the power source in the same way as the cabin unit.

NOTE: If the pressure value is displayed on the indicator, due to technical limitations, only the first 5 digits of the pressure value will be shown in the window.

You can also display the total data from all sensors and the average data for each axis, but only one of the two at a time.

Connecting the cabin unit

If you need to connect the cabin unit only to the I-5—that is, if there will be no GPS tracker or other device to which the eCargosens system will be connected—you must connect the in-cab unit to the I-5, then select "Active Mode" in the mode settings and configure the polling interval (the I-5 will send requests).

If, however, the cabin unit will be used in conjunction with the I-5 indicator and a GPS tracker/terminal, you should select Passive Mode.

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To pair the cabin unit and the sensors, tap "Connect Sensors" (Fig. 13, 2). Then tap the "+" button (Fig. 14).

Next, select the "Wired" option, enter the network address (the value can range from 1 to 255), and click "Connect" (Fig. 23). If the I-5 is not configured to operate in active RS-485 mode, or if there is no GPS tracker/gateway or other device that could request data from the sensor so that the I-5 can listen to the sensor’s response and display its readings, the data from the sensor will be displayed as 0 (Fig. 24).

The sensor’s network address can be found and, if necessary, changed in the eCargosens mobile app

Important! Each sensor connected via the RS-485 interface must have a unique network address.

To have the I-5 send data requests to the cabin unit connected to it, open the Settings mode menu (Fig. 27, 4). Passive mode is set by default (Fig. 28).

If your eCargosens system will operate together with the I-5 indicator and a GPS terminal, leave Passive mode selected; no changes are necessary.

If the eCargosens system will operate only with the I-5 indicator, without a GPS terminal, select Active Mode. Then enter an interval in seconds ranging from 1 to 65 and click “Set” (Fig. 29). Next, click Save to apply the changes (Fig. 30).

After selecting the Active RS-485 mode and setting the interval, you will see the axle load sensor readings in the app.

RS-485 Configuration

After selecting the RS-485 polling mode, set the addresses for the sensors in the control unit and the I-5 display

To do this, connect to the eCargosens cabin unit and go to the RS-485 settings.

Next, click on the connected axle load sensor and select the addresses for transmitting the sensor data.

Example:

Next, connect the I-5 digital display to the eCargosens cabin unit via RS-485, and configure the RS-485 settings to send data to the same addresses you selected in the cabin unit for the axle load sensor parameters.

Example:

Important! The addresses in the eCargosens cabin unit and the I-5 digital display must match for the data to be displayed correctly:

Calibration of trailer axles when only one sensor is installed

In situations where only one sensor is installed on the semi-trailer but you need to display the weight of each axle separately on the I5 indicator screen or monitoring platform, you can use this method.

In the app's main menu, go to the RS485 Settings section and select the sensor installed on the semi-trailer. In this menu, you can configure RS485 data transmission to the required addresses. Select the options as shown in the image: "Weight, RSSI," "Pressure, RSSI," "Pressure, Battery Voltage(Vbat)"

Thus, the I5 display can provide information on the pressure and weight of the semi-trailer’s axles. The weight can be displayed on one of the I5 screens without recalculation, but to obtain the weights of the other axles, a calibration (weighing) table must be added in the corresponding menu of the display. When weighing the axles of a semi-trailer, the scales may show different masses on the axles even with the same load in the semi-trailer; therefore, the weighing tables for different axles may vary.

It is important to remember that pressure values transmitted via RS-485 are reduced by a factor of 100. For example, 65,000 Pa will be transmitted as 650; therefore, when creating the calibration table in the I5 indicator, the pressure value must be divided by 100 before entering it into the table.

You can upload the table itself to the I-5 display.

To do this, you need to:

1) Select the sensor in the I-5 display on the connection page and click on it; this will open the sensor settings menu:

2) Then click the red "Go to Calibration" button

Please note that you can import the table using an existing calibration file or enter the data manually.

3) If you select "Select a file" the file explorer on your smartphone will open. Navigate to the folder where you saved the calibration file and select the desired file.

4) Then select the "Apply calibration table" checkbox.

Central unit wiring

Useful links

• Datasheet Escort Axle Load Sensor eCargosens Air
• Datasheet Escort Central Unit eCargosens DS
• Product page
• Download materials
• Firmware update instruction (Central unit)
• Installation example (Video)