It may be challenging to add completely different sensor types (a fuel level sensor and a fuel flowmeter) to one RS 485 interface of a GPS tracking device. The reason is the different data exchange protocol that corresponds to different sensor types. However, there is no such problem if we use the universal MODBUS protocol.

This article will explain how to connect Eurosens Dominator RS fuel level sensor and Eurosens Delta RS fuel flowmeter to Galileosky 7.0x GPS tracker.

1.Fuel level sensor configuration. Connect the sensor to the configurator. The fuel level sensor will take Address #1. Each sensor will have its own device address in RS485 network. Switch off the “Ignore” option. Switch on Modbus protocol.

Modbus fuel level sensor configuration

2.Fuel flowmeter configuration. Connect the meter to the configurator. The fuel flowmeter will take Address #2. Switch off the “Ignore” option. Switch on Modbus protocol.

Modbus fuel flowmeter configuration

3. Modbus configuration of Galileosky GPS tracking device.

The configuration should be done according to the GPS tracker manual. You may download it here. Please check there the correspondence of GPS tracker hardware and firmware versions.

Choose Modbus as RS 485 peripheral type.

Add both sensors to Modbus devices. Slave ID is the sensor address set up in the configurator.  Configure both sensors (devices) as described below.

Add the information about readable registers for each sensor (device). Fuel level sensor readable registers look the following way:

All the registers in Galileo configurator are numbered starting with one (1). So please don’t forget to add 1 (one) to eurosens Dominator registers. Register type – AI. The data type is described in the register description for Eurosens Dominator ( int16=unsigned 16bit, int32=signed 32bit), byte order– Big endian.

Let’s read the following registers: fuel temperature (register 0), output value for N sensor (register 1), fuel volume (register 3), sensor serial number (register 8). Fill in the GPS tracker configurator table correspondingly. If the sensor is connected, we will see immediately the values sent by the sensor.

Set up the registers for fuel flowmeter by analogy. You may download the register description here.

Let’s take the following registers as an example: fuel temperature in the supply chamber (register 7, int16), fuel temperature in the reverse chamber (register 11, int16), total fuel consumed (register 0, int32), total fuel passed through the supply chamber (register 4, int32), total fuel passed through the return chamber (register 8, int32).  Add 1 (one) to each register number and fill in the configurator chart.

Please note Tag tab. It can help you find the parameter you need in Wialon messages.

The data received on Wialon server-side – ext_1…10 (for Modbus parameters 0…9 consequently). While being sent to the server all Modbus parameters are multiplied by 100! Thus, to get sensor values as ext1…10, you will first need to divide by 100 and then apply the coefficient from Modbus registers description of eurosens sensors.