Equipment system AutoTracker. Part 3. Some unconventional solutions implemented in the onboard unit
We continue to acquaint you with the AvtoTracker onboard equipment, and today we want to talk about a number of technologies implemented in the new version of the onboard AT-10 unit, which allow us to achieve outstanding results in vehicle monitoring.
In order for the monitoring equipment of the transport to efficiently perform its tasks, a block of logic is implemented in the block to control all the processes, which can be divided into several groups. First, it is the collection and processing of incoming data from the GPS, GSM module, communication interfaces with peripheral devices and sensors. Secondly, it is the storage of data and their interpretation. Third, this is data transfer.
Most elements of the block are more or less typical for all models of this type of equipment. We would like to tell you more about the components and technical solutions that are rarely found in such devices, and in this form are used only in the AutoTracker equipment.
Central control module with dual-processor configuration. The microcontroller, implemented on the ARM 9 processor, controls the entire logic of the unit, manages the data processing and control of the GPS and GSM modules, as well as the wireless interface and memory. An additional processor, which is essentially a simplified version of the main one, controls all interfaces. This allows you to solve 2 problems. Firstly, the main processor is unloaded, and secondly, the coprocessor forms a module with protection of the output power supply circuit through galvanic isolation, and in the case of, for example, a short circuit in the power supply circuit of peripheral devices, they are disconnected from the line. In this case, the device continues to work, and the program periodically polls peripheral connections. If the short circuit does not repeat - the block restores the standard modes of operation.
Multifunctional interface with customizable I / O modes. As a rule, it is not known in advance what kind of peripheral equipment will be connected to the onboard unit and through which ports. Therefore, the ports in the block are customizable, and can operate in various modes - digital, analog, pulse, etc. (only 10 modes). The diagram shows a typical custom port configuration, which includes the connection of a full-time automobile odometer and tachometer, further individual configuration of one multifunctional input (MFP) and one multifunctional input / output (MFHE). Multifunctional input provides for the connection of sensors. The multifunctional input-output can additionally realize the functions of a control output (used to connect a control relay). Tachometer and odometer connection ports are also multifunctional inputs, and if necessary, can also be used to connect sensors. The modes of operation of the ports of the block are configured in a special software system administration module, which will be described in more detail in the following posts.
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Radio interface RF-Host. Another technology not widely used in such devices. The radio module operates in the 868 MHz radio frequency band that is open for free use. The presence of this interface allows you to work with wireless sensors, such as temperature sensor, door opener, fuel level sensor.
AT-REF Sensor wireless temperature sensor operating in the 868 MHz band
In these frequency ranges, data transmission is not standardized, i.e. There are no specific data exchange protocols that must be met by radio transmitters operating in these frequency bands. Any developer has the full right to develop their own data exchange protocol in the 868 MHz frequency range, provided that this protocol ensures that the physical properties of the radio signal comply with the requirements of local legislative bodies (in Russia, with the requirements of the State Committee on Radio Frequencies, SCRF). This protocol was specifically designed to interface with AutoTracker wireless sensors. Low-current sensors that consume a minimum of electricity, are equipped with batteries, which are enough for 1.5-2 years of work, more energy-intensive devices still need to connect an external power supply.
In order for the monitoring equipment of the transport to efficiently perform its tasks, a block of logic is implemented in the block to control all the processes, which can be divided into several groups. First, it is the collection and processing of incoming data from the GPS, GSM module, communication interfaces with peripheral devices and sensors. Secondly, it is the storage of data and their interpretation. Third, this is data transfer.
Most elements of the block are more or less typical for all models of this type of equipment. We would like to tell you more about the components and technical solutions that are rarely found in such devices, and in this form are used only in the AutoTracker equipment.
Central control module with dual-processor configuration. The microcontroller, implemented on the ARM 9 processor, controls the entire logic of the unit, manages the data processing and control of the GPS and GSM modules, as well as the wireless interface and memory. An additional processor, which is essentially a simplified version of the main one, controls all interfaces. This allows you to solve 2 problems. Firstly, the main processor is unloaded, and secondly, the coprocessor forms a module with protection of the output power supply circuit through galvanic isolation, and in the case of, for example, a short circuit in the power supply circuit of peripheral devices, they are disconnected from the line. In this case, the device continues to work, and the program periodically polls peripheral connections. If the short circuit does not repeat - the block restores the standard modes of operation.
Multifunctional interface with customizable I / O modes. As a rule, it is not known in advance what kind of peripheral equipment will be connected to the onboard unit and through which ports. Therefore, the ports in the block are customizable, and can operate in various modes - digital, analog, pulse, etc. (only 10 modes). The diagram shows a typical custom port configuration, which includes the connection of a full-time automobile odometer and tachometer, further individual configuration of one multifunctional input (MFP) and one multifunctional input / output (MFHE). Multifunctional input provides for the connection of sensors. The multifunctional input-output can additionally realize the functions of a control output (used to connect a control relay). Tachometer and odometer connection ports are also multifunctional inputs, and if necessary, can also be used to connect sensors. The modes of operation of the ports of the block are configured in a special software system administration module, which will be described in more detail in the following posts.
')
Radio interface RF-Host. Another technology not widely used in such devices. The radio module operates in the 868 MHz radio frequency band that is open for free use. The presence of this interface allows you to work with wireless sensors, such as temperature sensor, door opener, fuel level sensor.
AT-REF Sensor wireless temperature sensor operating in the 868 MHz band
In these frequency ranges, data transmission is not standardized, i.e. There are no specific data exchange protocols that must be met by radio transmitters operating in these frequency bands. Any developer has the full right to develop their own data exchange protocol in the 868 MHz frequency range, provided that this protocol ensures that the physical properties of the radio signal comply with the requirements of local legislative bodies (in Russia, with the requirements of the State Committee on Radio Frequencies, SCRF). This protocol was specifically designed to interface with AutoTracker wireless sensors. Low-current sensors that consume a minimum of electricity, are equipped with batteries, which are enough for 1.5-2 years of work, more energy-intensive devices still need to connect an external power supply.
Source: https://habr.com/ru/post/151363/
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