RU211313U1 - Temperature, humidity and pressure meter - Google Patents

Abstract

The utility model relates to the technical field of measuring physical quantities, in particular to measuring instruments for ambient temperature, humidity and pressure, and can be used in distributed digital environmental monitoring systems based on lighting objects using the DALI profile protocol for them. The temperature, humidity and pressure meter contains digital sensors 5 and 6, which are connected in parallel by the system control bus I ² C 22 with the microcontroller 11, as an external interface, the DALI interface is used, implemented in bus 4, including the first 1 interface wire DALI + and the second 2 interface wire DALI-, combined with the circuit ground GND 3, the microcontroller 11, which has an interface input with a built-in pull-up resistor PULL-UP 12 and an output, is equipped with input 13 and output 18 transistor switches interacting with them, of which the input switch 13 is made on a bipolar npn transistor 14, the emitter of which is connected to the second 2 wire of the bus 4, the collector is connected to the interface input of the microcontroller 11 with the built-in pull-up resistor PULL-UP 12 turned on, and the emitter is connected to the second wire 2 of the mentioned bus 4, while the emitter junction of the transistor 14 is shunted by the resistor 15, included between the emitter and the base, and the base is connected through a series the current-limiting resistor 16 and the zener diode 17 are switched on with the first wire 1 of the said bus 4, and the output switch 18 is made on an n-type field-effect transistor 19, the drain of which is connected to the first 1 wire of the bus 4, the source is connected to the second 2 wire of the bus 4, and the gate connected to the interface output of the microcontroller 11. EFFECT: enabling the use of a temperature, humidity and pressure meter in distributed digital environmental monitoring systems based on lighting objects using the DALI profile protocol for them. 1 ill.

Description

The utility model relates to the technical field of measuring physical quantities, in particular to measuring instruments for ambient temperature, humidity and pressure, and can be used in distributed digital environmental monitoring systems based on lighting objects using the DALI profile protocol for them.

A temperature, humidity and pressure meter is known, containing a BME280 digital atmospheric temperature, humidity and pressure sensor and an ESP32 microcontroller connected by a ¹² C system control bus and equipped with a common power source (Voltik [Electronic resource]. - Access mode: https://voltiq. ru/web-server-sp32-with-bme280-weather-station/, admission is free - (03/10/2022).

The well-known meter is sufficiently simple and reliable. Its disadvantages include the impossibility of integrating it into distributed digital environmental monitoring systems based on lighting objects (road, urban, rural, etc.) using the DALI protocol profiled for them.

Closest to the claimed - the prototype - is a pressure, temperature and humidity meter containing a microcontroller, digital atmospheric sensors of temperature, humidity and pressure connected in parallel with it by the system control bus, a power source common to the sensors and the microcontroller and a visual interface (CN patent No. 104180850 B , published on February 8, 2017).

The mentioned prototype is quite functional and easy to manufacture and maintain, however, it has a significant drawback - it cannot be integrated into distributed digital environmental monitoring systems based on lighting objects (road, urban, rural, etc.) using the DALI profile protocol for them. due to the lack of an appropriate interface. Informational: such a distributed digital monitoring system was implemented as part of the KULON program of Sandraks LLC (www.kulon.su [Electronic resource]. - Access mode: https://www.kulon.su/catalog/products-QULON/, free - (03/10/2022) The advantages of using a lighting control system for environmental monitoring include its actual presence almost everywhere (there is no need to create a new network), a very wide and dense branching, the convenience of placing the corresponding meters on supports, brackets, panels, etc. lighting, its reliability and noise immunity.

The technical problem is to eliminate the noted shortcomings of the known technical solutions.

The technical result consists in enabling the use of a temperature, humidity and pressure meter in distributed digital environmental monitoring systems based on lighting objects using the DALI protocol profiled for them.

The problem is solved, and the technical result is achieved by the fact that the temperature, humidity and pressure meter, containing a microcontroller, digital atmospheric sensors of temperature, humidity and pressure connected in parallel with it by the system control bus and a power source common to the sensors and the microcontroller, is equipped with an interface bus that includes a positive the DALI+ wire and the negative DALI- wire connected to the circuit ground, and the microcontroller contains an interface input with a built-in pull-up resistor and an output and is equipped with input and output transistor switches, of which the input switch is made on a bipolar n-p-n transistor, the collector of which is connected to the interface input of the microcontroller with the built-in pull-up resistor enabled, the emitter is connected to the DALI interface bus wire, while the emitter junction of the transistor is shunted by a resistor connected between the emitter and the base, and the base is connected through series-connected current-limiting th resistor and a zener diode with a DALI+ interface bus wire, and the output switch is made on an n-type field effect transistor, the drain of which is connected to the DALI+ interface bus wire, the source is connected to the DALI-interface bus wire, and the gate is connected to the microcontroller interface output.

The utility model is illustrated by a drawing, which shows a block diagram of the claimed temperature, humidity and pressure meter.

Numerical positions in the drawing mean the following:

1 - DALI+ interface wire;

2 - interface wire DALI-, combined with circuit ground GND;

3 - circuit ground (GND);

4 - interface bus;

5 - digital atmospheric humidity and temperature sensor HTS221;

6 - digital atmospheric pressure sensor LPS22HB;

7 - external sensor supply voltage (VDD);

8 - ground/sensor case (GND);

9 - digital input / output of the sensor (SDA);

10 - serial clock input of the sensor (SCL);

11 - microcontroller type STM32;

12 - built-in pull-up resistor (PULL-UP) of the microcontroller input;

13 - input transistor key;

14 - bipolar n-p-n transistor;

15 - resistor shunting the emitter junction of the bipolar transistor;

16 - current limiting resistor;

17 - zener diode;

18 - output transistor key;

19 - n-type field effect transistor;

20 - zero-level fixing resistor;

21 - power supply;

22 - system control bus I ² C

In accordance with the claimed utility model, the temperature, humidity and pressure meter contains digital sensors (in the drawing - temperature and humidity sensor 5 HTS221 and pressure sensor 6 LPS22HB). Said sensors are connected in parallel by the system control bus I ² C 22 to the microcontroller 11 (digital input/output (SDA) 9 and serial clock input (SCL) 10 contacts of sensors 5 and 6 are connected to the corresponding contacts of the microcontroller 11). Contacts of external supply voltage (VDD) 7 and ground/case (GND) 8 of sensors 5 and 6 and the corresponding contacts of microcontroller 11 are connected to a common power supply 21. Microcontroller 11 is recommended to use STM32 type - it is compatible with digital sensors via I ² C control bus and, having an interface input with a built-in pull-up resistor, it can be adapted for interaction with a higher-level controller via the DALI protocol in the manner described below. Accordingly, the DALI interface implemented in bus 4, including the first 1 interface wire DALI+ and the second 2 interface wire DALI-, combined with circuit ground GND 3, was used as an interface. 12 and output, is equipped with input 13 and output 18 transistor switches interacting with them. The input switch 13 is made on a bipolar npn transistor 14, the emitter (hereinafter referred to as transistor elements correspond to their standard symbols on the symbols used in the present drawing) of which is connected to the second 2 wire of the bus 4, the collector is connected to the interface input of the microcontroller 11 with the built-in pull-up PULL-UP resistor 12, and the emitter is connected to the second wire 2 of the mentioned bus 4, while the emitter junction of the transistor 14 is shunted by a resistor 15 connected between the emitter and the base, and the base is connected through a series-connected current-limiting resistor 16 and a zener diode 17 (information: installation sequence resistor 16 and zener diode 17 one after another is not significant) with the first wire 1 of the mentioned bus 4. The output key 18 is made on an n-type field effect transistor 19, the drain of which is connected to the first 1 wire of the bus 4, the source is connected to the second 2 wire of the bus 4, and the gate is connected to the interface output of the microcontroller 1 one.

The claimed temperature, humidity and pressure meter operates as follows.

A temperature, humidity and pressure meter (a plurality of temperature, humidity and pressure meters) is installed on the elements of the lighting infrastructure, mainly on road lighting poles. Interrogation and data collection of the temperature, humidity and pressure meter (a plurality of temperature, humidity and pressure meters) is carried out via the DALI interface from a higher-level controller (not shown), which simultaneously performs the lighting control function. Recall that the DALI interface is a bidirectional two-wire digital interface, oriented for primary use in lighting technology. DALI wires (DALI+ and DALI-) are powered from the outside by a special 12-22 V power supply with a current limiting function, normalized in value within the limits specified in the standard (0.25 A). The DALI wires 1 and 2 between the higher-level controller and the microcontroller 11 of the temperature, humidity and pressure meter transmit bit streams of data bidirectionally. In turn, sensors 5 and 6 respectively measure the temperature, humidity and pressure of the environment. The microcontroller 11 periodically interrogates sensors 5 and 6 via the system control bus I ² C 22, and at the same time it operates under the control of a higher controller (not shown), communicating with it via the 4 DALI bus through the input transistor switch 13 and transmitting to it the measured temperature values, humidity and pressure through the output transistor switch 18. As mentioned above, the output transistor switch 18 includes an n-type field effect transistor 19. When the gate of the transistor 19 of the key 18 is received from the microcontroller 11 of a high level, the key 18 opens and closes the DALI + wire to GND, forming a low level on the bus 4. Since the bus power supply 4, as mentioned above, has a normalized current limit, the current flowing through key 18 is also normalized in magnitude. When the key 18 arrives at the gate from the low level microcontroller 11, the key 18 closes and opens the DALI+ and GND wires, a high level is formed on bus 4. Accordingly, the sequence of high and low levels (bits) forms a sequential binary code. The bit stream itself is formed by the microcontroller 11. The input key 13 includes a bipolar n-p-n transistor 14. At a low level on the DALI + wire, the voltage at the base of the transistor 14 of the key 13 is also low, the key 13 is also closed at the interface input of the microcontroller 11, which has a pull-up enabled to a high level (built-in pull-up resistor PULL UP 12 enabled), there is a high level. At a high level on the DALI+ wire, exceeding the sum of the stabilization voltage of the zener diode 17 and the voltage drop at the emitter junction of the key 13, the base current flows through the input circuit of the key 13, the key 13 is open, and a low level is formed at the interface input of the microcontroller 11. Processing of the received bit stream is also carried out by the microcontroller 11.

The conducted field experiments and the results of computer simulation showed that the bidirectional digital interface formed in the claimed manner in the temperature, humidity and pressure meter allows the meter (a plurality of meters) to be used in distributed digital environmental monitoring systems based on lighting objects using the DALI profile protocol for them, providing the required measurement quality.

The foregoing allows us to conclude that the identified problem has been solved, and the claimed technical result - enabling the use of a temperature, humidity and pressure meter in distributed digital environmental monitoring systems based on lighting objects using the DALI protocol profiled for them - has been achieved.

Claims (1)

A temperature, humidity and pressure meter containing a microcontroller, digital atmospheric temperature, humidity and pressure sensors connected in parallel with it by the system control bus, and a power source common to the sensors and the microcontroller, characterized in that it is equipped with an interface bus that includes a positive DALI + wire and a negative wire DALI-, combined with circuit ground, and the microcontroller contains an interface input with a built-in pull-up resistor and an output and is equipped with input and output transistor switches, of which the input switch is made on a bipolar n-p-n transistor, the collector of which is connected to the interface input of the microcontroller with a built-in pull-up resistor , the emitter is connected to the wire of the DALI interface bus, while the emitter junction of the transistor is shunted by a resistor connected between the emitter and the base, and the base is connected through a series-connected current-limiting resistor and a zener diode to the DAL wire I+ of the interface bus, and the output switch is made on an n-type field effect transistor, the drain of which is connected to the DALI+ wire of the interface bus, the source is connected to the DALI- interface bus wire, and the gate is connected to the interface output of the microcontroller.

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