RU2718364C1 - Software-hardware complex for gas boiler control - Google Patents

Abstract

FIELD: control systems.

SUBSTANCE: software-hardware complex for gas boiler control relates to heat engineering and can be used in single- and double-circuit domestic and industrial gas boilers. Hardware and software system comprises an electronic control system. Distinctive feature of the complex is that the electronic control system consists of a control module and a display module, wherein the control module comprises a central processing unit which performs a specially designed program for controlling operating conditions of the boiler, nonvolatile memory, an external communication interface, a unit for processing input signals from gas boiler sensors, unit for ignition of gas boiler, which includes controlled high-voltage transformer, ionization current detector connected to combustion chamber, blocks of potential outputs for connection of actuators of gas boiler, and indication module includes liquid crystal display and keyboard.

EFFECT: software and hardware system is a universal and reliable control system, which meets all requirements for safe operation of gas boilers, due to pre-installed optimized configuration of settings, and can be used for different types of gas boilers or for different hydraulic circuits.

1 cl, 2 tbl, 2 ex, 1 dwg

Description

The hardware-software complex for controlling a gas boiler belongs to the field of heat power and can be used in single and double-circuit domestic and industrial gas boilers.

Known control system of a heating boiler according to patent RU109534, comprising a firing module, gas pressure and water pressure sensors, water temperature and boiler gases, gas valves, while the firing module is made in the form of an automatic firing controller, its input and output connected through indicator block with relay sensors and with an ignition burner; with its input connected to the output of an additionally introduced control thermostat, and with its output, through the input of the gas valve block, with an ignition burner and a working burner. This system does not allow:

- manage a dual-circuit hydraulic circuit;

- control gas valves in the mode of full electronic modulation of power;

- Configure the specification of equipment connected to the system;

- set the boiler operation algorithms;

- connect the turbo nozzle and control the power of the turbo nozzle to ensure an economical mode of operation;

- control the temperature of the heating circuit depending on the temperature of the outside (outdoor).

Closest to the claimed control complex in technical essence is a heater for a heating system for domestic applications according to patent WO 2008099259, consisting of a gas boiler, an electronic control system connected via an interface to one or more room and external temperature sensors, a manual control panel that allows you to set water heating modes. Depending on the selected mode, various external devices are connected. These systems do not provide sufficient reliability, safety, versatility and are not optimized enough for mass production, and cannot be used in industrial applications, this system can also be used only in single-circuit heating boilers.

The present invention solves the technical problem of eliminating these drawbacks, namely, creating configurations of parameter settings for controlling a gas boiler, which allow controlling both single-circuit heating boilers and double-circuit ones with a different set and type of connected input and output devices.

The technical result consists in providing different types of gas boilers and different hydraulic circuits with a universal and reliable control system that meets all the safety requirements for the operation of gas boilers, due to a pre-installed optimized configuration of settings and a unit for accurately determining the ionization current (detecting the presence of a flame in the combustion chamber), not subject to the influence of external electromagnetic interference.

To solve the stated technical problem, as well as to achieve the claimed technical result, a hardware-software complex for controlling a gas boiler is proposed, comprising a control module and an indication module. The control module comprises a central processing unit executing a control program and boiler protection; non-volatile storage device in which data and settings for the operation of the boiler are stored; external communication interface RS-485, working on the ModBus RTU protocol; processing unit of input discrete non-potential signals from discrete sensors of a gas boiler; processing unit of input analog signals from temperature sensors of the boiler and pressure switch of the coolant circuit; the control unit coil of the valve modulator or valves of the gas boiler; a gas boiler ignition unit including a controllable high voltage transformer; ionization current detector connected to the combustion chamber; a block of discrete potential outputs for connecting actuators of a gas boiler; potential output unit with phase adjustment of the mains voltage for connecting a gas boiler turbo nozzle. The display module contains a liquid crystal display (LCD) and a keyboard.

In the hardware and software complex for controlling a gas boiler, the central processor unit is designed to carry out a specially designed boiler control program that allows you to configure the parameters of the gas boiler within wide limits, which ensures the universality of this complex. Non-volatile storage device is designed to store archived data on the operation of the boiler and settings. An external communication interface using the ModBus RTU protocol is designed to connect the boiler to an external control device or to an Internet server, this allows you to organize a cascade connection scheme for several boilers or to perform telemetry and dispatch functions for the selected boiler. The processing unit for input discrete non-potential signals is designed to process input discrete non-potential signals coming from discrete sensors of a dry contact gas boiler. The analog signal processing unit is designed to process analog input signals coming from the boiler temperature sensors and the pressure switch of the coolant circuit. The modulator coil control unit is designed to connect and protect from one to four modulation coils of a gas valve or valves, depending on the set parameters. This unit is a current source. The ignition block of a gas boiler includes a high-voltage transformer with an output alternating voltage of 18 ... 20 kV connected to the ignition electrode of a gas boiler, and control means for this transformer. When this unit is turned on, a high-voltage arc arises between the ignition electrode and the body of the gas boiler, which ignites the gas. This unit is galvanically isolated from other control unit units. The ionization current detector is designed to detect the presence of a flame in the combustion chamber of a gas boiler and contains an ionization electrode of the gas boiler, as well as transistors modulating the useful signal with the mains phase to eliminate spurious noise and electromagnetic interference in the spectrum of the useful signal, which makes it possible to accurately and reliably determine the presence of flame in the combustion chamber of a gas boiler and eliminate erroneous ignition triggering. The block of discrete potential outputs is designed to connect the executive devices of the gas boiler (pumps, valves, and other auxiliary equipment) and provides control of the auxiliary equipment of the gas boiler and its protection. This unit contains a semiconductor active element with a zero voltage detector and is galvanically isolated from other blocks of the control module. The potential output unit with phase adjustment of the mains voltage is designed to connect the turbo nozzle of the gas boiler and allows you to adjust the power of the turbo nozzle with feedback according to the temperature of the coolant and, as a result, the vacuum pressure in the combustion chamber of the gas boiler, which improves the energy efficiency of the gas boiler. This unit contains a semiconductor active element with a zero voltage detector and is galvanically isolated from other blocks of the control module. The display module contains an LCD display and a keyboard. The use of semiconductor active elements in the gas boiler control module with zero voltage detectors increases the reliability, response speed and service life of the gas boiler control software and hardware complex.

As a result, the proposed hardware-software complex for controlling a gas boiler can operate in a dual-circuit hydraulic circuit; to support the connection of the pressure sensor of the heating circuit and the flow sensor or flow meter of the heating circuit or hot water supply (specified in the settings); perform the regulation of the set temperature according to the law of PID control, in contrast to the selected analogue, which performs the regulation of the set temperature according to the step-by-step scheme of direct heating; perform full electronic modulation of the power of the connected gas valves; provide the ability to connect a pilot burner; can work with open and closed combustion chambers; It has an external industrial communication interface for dispatching boiler operation and telemetry data acquisition. In addition, the selected analogue consists of several electronic modules, which increases the complexity of the assembly of a serial device and reduces the reliability of the system as a whole. The proposed hardware-software complex consists only of a control module, in which all the control and management units of the hardware-software complex are located, and an indication module that performs the tasks of providing a human-machine interface. In case of loss of contact between these modules, the control module can operate autonomously, since all settings and control parameters entered by the user are stored in non-volatile memory located in the control module.

Thus, the design of the hardware and software complex for controlling a gas boiler using a specially designed program that allows you to configure the parameters of the gas boiler within wide limits allows you to ensure the operation of not only a single-circuit gas boiler according to the heating scheme, but also a double-circuit one according to the heating and hot water supply and manage gas boilers in a wide range of capacities (from 18 kW to 1 MW).

Therefore, the totality of these design features implements the specified technical result, which consists in providing different types of gas boilers or different hydraulic circuits with a universal and reliable control system.

A diagram of a hardware-software complex for controlling a gas boiler is shown in FIG. 1, where:

1 - central processing unit;

2 - non-volatile storage device;

3 - external communication interface;

4 - processing unit of input discrete non-potential signals;

5 - block processing input analog signals;

6 - modulator coil control unit;

7 - ignition unit;

8 - ionization current detector;

9 - block discrete potential outputs;

10 - block potential output with phase adjustment;

11 - LCD display;

12 - keyboard.

13 - discrete sensors of the gas boiler: overheating sensor for the coolant circuit, air pressure sensor;

14 - boiler temperature sensors: temperature sensor of the heating circuit, temperature sensor of the hot water circuit;

15 - analog pressure sensor;

16 - valves of a gas boiler;

17 - high voltage transformer;

18 - ignition electrode;

19 - ionization electrode;

20 - semiconductor active element;

21 - zero voltage detector;

22 - actuators of a gas boiler: heating circuit pump, hot water circuit pump, three-way valve, additional configurable potential output;

23 - turbo nozzle;

24 - control module;

25 - indication module;

26 - coolant circuit;

27 - combustion chamber.

The hardware-software complex for controlling a gas boiler (PAC) operates as follows.

In standby mode, the boiler is periodically tested for the presence of a flame in the combustion chamber (27). In case of flame detection, a corresponding alarm message is generated on the screen of the display module (25) and the boiler is blocked. Also tested is a water pressure sensor (15) and a protective thermal relay (13). In the event of an emergency, an alarm message is generated on the display module screen (25) and the boiler is blocked.

If conditions appear for starting the boiler:

1) A performance test of the air pressure sensor (13) connected to the processing unit of the input discrete non-potential signals (4) is carried out. If the test succeeds, the combustion chamber is pre-purged (27): if the boiler configuration with the closed combustion chamber is selected, the turbo nozzle (23) is switched on at 100% power, connected to the potential output unit with phase adjustment (10).

2) At the stage of preliminary purging of the combustion chamber (27), the pump of the corresponding circuit or the main pump (22) is turned on and the distribution of the coolant flow (26) using a three-way valve (22). If the “Closed chamber” configuration is selected, the turbo nozzle (23) is turned on and the pre-purge delay is maintained. At the end of this step, the air pressure sensor (13) is tested. If the air pressure sensor gives a signal that the necessary pressure is in the combustion chamber, the PAC proceeds to the ignition procedure, otherwise an alarm message will be generated on the display module (25) and the boiler will be blocked. The monitoring of the air pressure sensor (13) will end only at the transition to standby mode. As soon as the air pressure sensor (13) gives a signal to the control module (24) that there is no vacuum in the combustion chamber (27) - an alarm message will be generated on the display of the display module (25) and the function of safe boiler stop will be executed, then the boiler will be blocked .

3) The stage of ignition of the flame begins when the ignition unit (7) is turned on and supplies the control voltage to the high-voltage transformer (17), as a result of which a high-voltage arc is generated in the combustion chamber of the boiler (27) between the ignition electrode (18) and the body of the combustion chamber ( 27). The arcing delay is maintained, then the block of discrete potential outputs (9) supplies the control voltage to the gas valve (16). The gas valve (16) opens, the throughput (power) of the valve is regulated by the modulator coil control unit (6). After opening the gas valve (16), the ignition delay is maintained and the ionization current detector (8) measures the plasma ionization current flowing between the ionization electrode (19) and the boiler combustion chamber body (27). A plasma ionization current of 6 μA or more indicates that a stable flame is present in the combustion chamber of the boiler (27) and ignition has occurred. If there is no flame, the valve (16) is closed and the transition to the stage of preliminary purging of the combustion chamber of the boiler (27) is performed and then an attempt is made to ignite the flame again. In case of three unsuccessful ignition attempts, an alarm message is generated on the display of the display module (25), the boiler’s combustion chamber is purged and the boiler is blocked. If the ignition is successful, a transition to the step of regulating the set temperature of the coolant is performed.

4) The set temperature of the coolant is regulated according to the law of discrete PID control, where the input signal is the temperature of the coolant circuit measured by the input analog signal processing unit (5), measured by the boiler temperature sensors (14), and the output signal is the current value of the coil of the gas valve modulator ( 16) supplied to the gas valve (16) by the modulator coil control unit (6). Each circuit corresponds to a separate regulation procedure with its own coefficients. For more precise control of the set temperature of the coolant, control starts with heating the coolant circuit (26) at the minimum set power of the flame for a set time. The mathematical model of regulation and the power of the gas valve (16) is calculated by the central processing unit (1).

5) When conditions for the termination of the start or regulation functions occur, the function of safe shutdown of the boiler is activated. This function includes a procedure for purging the combustion chamber of the boiler (27) to remove residual gas mixture and a procedure for pumping coolant circuits (26) to equalize the temperature of the coolant in the circuit. The procedure for pumping coolant circuits includes periodic switching on of pumps (22) and switching of a three-way valve (22) by a block of discrete potential outputs (9).

The functions of safe operation of the gas boiler are provided by an analog pressure sensor of the coolant circuit (15), discrete sensors of overheating of the coolant circuit and air pressure (13), an ionization current detector (8).

The block of discrete potential outputs (9) ensures the safe switching on and off of the executive devices of the gas boiler (22), switching the state of the semiconductor active element (20), only at the moment the mains voltage passes through the zero value. The moment of transition of the mains voltage through the zero value is determined by the zero detector of the mains voltage (21).

The task of choosing the type of boiler is solved by loading into a non-volatile memory (2) a special file with a pre-installed optimized configuration of parameter settings, which allows to optimize the serial production of a wide range of gas boilers.

The telemetry and dispatch tasks of the boiler are solved by connecting specialized equipment to the communication interface (3).

The man-machine interface is provided by an LCD display (11) and a keyboard (12) installed in the display unit (25).

PAK has the following specifications:

Table 1.

PAK options Technical data of the controlled parameter Supply voltage level. Alternating voltage 198 ... 242 V. The limits of modulation current regulation. 1 valve - 0 ... 170 mA;
2 valves - 0 ... 340 mA;
3 valves - 0 ... 500 mA;
4 - valves - 0 ... 660 mA. Type of modulation current Pulse width modulation. The frequency of the modulation current. 48 kHz. Modulation voltage. 0 ... 17 V. Voltage level of discrete input signals. DC voltage 11.95 ... 12.15 V. Current consumption of digital inputs. 3 ... 4 mA. Minimum ionization current threshold. 6 μA. Type of temperature sensors for domestic hot water and hot water circuit. NTC thermistors 10 kOhm, B = 3935. Voltage level of discrete output circuits. Alternating voltage 198 ... 242 V. Maximum output current of discrete outputs. 2.5 A. Voltage level of analog input circuits. DC voltage 0 ... 5 V. Insulation resistance of electrical circuits relative to the housing. - at least 10 megohms under normal climatic conditions (cold state);
- 1 MΩ at a relative humidity of 98% and a temperature of (25 +/- 2) ° С;
- 3 megohms at the maximum permissible temperature (hot condition). Dielectric strength of insulation of all input and output circuits. Not worse than 1500 V

Examples of PAK parameters when used in gas boilers of various capacities are discussed below. Table 2 presents the PAK parameters of a wall-mounted gas boiler with an output of 18 kW with a boiler and a floor-standing industrial boiler with an output of 100 kW.

Table 2.

Parameter No. Description Range Setpoint power 18 kW Setpoint Power 100
kw 0 Linear compensation factor for an external temperature sensor. 0 ... 50 twenty twenty one Off / on regulation by an external temperature sensor (to calculate the coefficients, use the TEX software or the formula Tzad = ((P0-Tvnesh) * P2) / 10 + P0.). 0 ... 1 0 0 2 Non-linear coefficient of compensation of the external temperature sensor. 0 ... 50 ten ten 3 Ignition power. 5 ... 60 5 15 4 Maximum flame modulation power. 30 ... 100 one hundred one hundred 5 Minimum flame modulation power. 1 ... 15 one 5 6 Pump running time in DHW mode (s). 1 ... 240 60 60 7 Pump running time in heating mode (s). 1 ... 240 180 180 eight Delay to re-enable ignition in heating mode (min). The function is activated in case of boiler shutdown due to overheating. 1 ... 15 one 5 nine Standby time of the pump in standby (min). 0 ... 15 3 5 ten Standby time of the pump (min). 0 ... 15 one 3 eleven Pre-ventilation time before ignition (s). 5 ... 30 eight eight 12 Ventilation time after shutting off the gas valve (s). 5 ... 30 ten ten thirteen Time to reach the set temperature when working in heating mode (min). This delay is activated provided that at the time of ignition Tzad - Tism> = 10. 0 ... 30 3 ten 14 The maximum temperature of the heating circuit when operating in DHW mode. 50 ... 95 90 95 15 Office 3-stroke. direct / inverse valve. 0 ... 1 0 0 sixteen Operating time in minimum power mode after turning on the main burner (s). 0 ... 60 ten ten 17 3-way valve / DHW pump. 0 ... 1 0 0 18 Industrial boiler (+ 50 ... + 95) / household boiler (+ 35 ... + 85). 0 ... 1 one 0 19 Monothermal heat exchanger / bithermic heat exchanger. 0 ... 1 0 0 twenty Flow / cumulative mode. 0 ... 1 one 0 21 Standard antifreeze / E08 antifreeze. 0 ... 1 0 0 22 Remote Resolution 0 ... 1 one one 23 Loop time (s). 3 ... 240 3 thirty 24 The camera is closed / open. 0 ... 1 0 one 25 Discrete / analog pressure sensor. 0 ... 1 0 one 26 Discrete / pulse flow sensor. 0-10 ... 40 0 0 27 Reset to factory settings. 0 ... 1 0 0 28 The number of valves. 1 ... 4 one 4 29th Flow sensor (or flow meter, depends on P26): DHW / KO. 0 ... 1 0 0 thirty The period of inclusion of the function of protection against bacteria, days (active at P20 = 1). 0 ... 15 7 7 31 Kp KO. 1 ... 255 25 25 32 Ki KO. 1 ... 255 2 2 33 Kd KO. 1 ... 255 150 150 34 Kp dhw. 1 ... 255 12 12 35 Ki dhw. 1 ... 255 eight eight 36 Kd DHW. 1 ... 255 one one 37 f dhw. 1 ... 255 200 200 38 f KO. 1 ... 255 eight eight 39 Minimum pressure in KO bar (active at P25 = 1). 0.6 ... 1.5 0.8 40 Maximum pressure in KO bar (active at P25 = 1). 2 ... 7 6.8 41 Delay of inclusion of the main valve after ignition (s). 0 ... 180 0 15 42 Fan control (0-discrete, 1-fixed PWM reference, 2-calculation of PWM reference). 0 ... 2 2 0 43 Fan power at a fixed reference% (active at P42 = 1). 50 ... 100 75 75 44 DHW off delay (s). 0 ... 30 ten ten 45 Remote control version. 0 ... 1 one one 46 Device address on the ModBus network. 1 ... 255 one one 47 Maximum flame modulation power in DHW mode. 30 ... 100 60 60 48 The number of control stages in the KO mode. 1 ... 2 one one

Differences in configuration parameters are associated with the power of these boilers and the fact that the industrial boiler operates with an open chamber, that is, without forced ventilation. An industrial boiler has a single-circuit system, it works without a hot water supply mode, since usually in industrial systems the heating medium is supplied from a single collector to the heating and hot water supply circuits. The domestic boiler is connected to a boiler in which a constant temperature is maintained, and has a dual-circuit system - a heating circuit and a hot water supply circuit.

The above examples confirm that the PAK allows you to configure the parameters of the gas boiler in a wide range, ensure the operation of not only a single-circuit gas boiler according to the heating scheme, but also a double-circuit one according to the heating and hot water supply, and also control gas boilers of different capacities depending on domestic or industrial application.

Claims (1)

A hardware and software complex for controlling a gas boiler, comprising an electronic control system, characterized in that the electronic control system consists of a control module and an indication module, while the control module comprises a central processing unit that executes a specially designed program for controlling the operation modes of the boiler, a non-volatile memory device , external communication interface, processing unit of input signals from gas boiler sensors, gas boiler ignition unit, including control a high-voltage transformer, an ionization current detector connected to the combustion chamber, potential output blocks for connecting actuators of the gas boiler, and the display module contains a liquid crystal display and a keyboard.

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