RU2211406C2 - Microcontroller unit for automatic test and control over processes of lighting up of burner and burning - Google Patents

Abstract

FIELD: heat power industry, control over burners in boiler rooms, furnaces. SUBSTANCE: microcontroller unit for automatic test and control over processes of lighting up of burner and burning comprises burner, triggering unit, shut-off valve, sensor of flame presence, high-voltage transformer. Microcontroller unit is supplemented with microcontroller coupled through its zero line ( zero discharge ) of zero port to triggering unit coming in the form of Start button and through its zero ( zero discharge ), first ( first discharge ), second ( second discharge ) and third ( third discharge ) lines of first port correspondingly to first inputs of control unit of high-voltage transformer, unit controlling shut-off valve, commutation unit of motor for air pumping under pressure and unit controlling power supply. Second outputs of these elements are correspondingly connected to diagnostics units of high-voltage transformer, shut-of valve, motor and power supply and outputs of diagnostics units are coupled to microcontroller through its first ( first row ) and fourth ( fourth row ) lines of zero port correspondingly. Microcontroller is connected through its third port to communication unit of computer of upper level. First line ( first discharge ) of this port presents connection of output of microcontroller to input of communication unit and zero line ( zero discharge ) of this port is used to couple input of microcontroller to first output of communication unit connected to computer of upper level. Microcontroller unit is supplied from standard power supply source by connection of zero and phase of source to second and third inputs of unit controlling power supply. Microcontroller and other elements of circuit are energized by constant voltage of source. EFFECT: increased reliability of control over processes of lighting up and burning of burner, widened functional capabilities of control system thanks to insertion of new elements into circuit. 1 cl, 3 dwg

Description

 The invention relates to the field of energy, in particular to the control of burners in boiler rooms, furnaces, etc.

 A device for automatic control of the ignition of the burner, which includes connected by rigid logic elements for performing the ignition of the burner [1, 2, 3]. The disadvantage of these devices is that due to the implementation of devices on logical elements, reliability is reduced due to the large number of elements and their installation, and there is no possibility of simple pairing with a computer.

 The closest in technical essence and the achieved effect is a device for automatic control of the ignition of the burner, comprising a burner, a shut-off valve, a flame detector, a high-voltage unit, a “Start” command generator, a set of logic elements; all elements are interconnected by strict logic to perform ignition of the burner and control the presence of flame [4].

A disadvantage of the known device is that the implementation of logical functions on the elements of rigid logic leads to a significant increase in their number compared to applied ones, while not providing the following important tasks in control:
- monitoring the health status of individual units, which can lead to the ignition of the burner in case of non-compliance with the safety requirements for operation;
- the possibility of remote control of the burner and group control of the burners, which is explained by the absence in the prototype of the communication unit with the upper-level computer;
- the possibility of algorithmic synchronization of the control process due to the lack of a microcontroller and a communication unit with a top-level computer in the prototype, as a result of which it is impossible to change the burner operating mode according to a flexible program.

 The invention is aimed at improving the reliability of monitoring the process of ignition and combustion of the burner, improving the quality of control of a gas burner, including remote control, as well as expanding the functionality of the control system by introducing elements for using the device in various automation objects.

This is achieved by the fact that in the microcontroller device for automatic control and control of the ignition of the burner, including a burner, a start device, a shut-off valve, a flame detector, a high voltage transformer, according to the proposed solution, a microcontroller connected through its zero line (zero discharge) of the zero port with a device for starting, made in the form of the "Start" button of the device, and through its zero (zero), first (first), second (second) and third (third discharge) lines of the first port connected respectively to the first inputs of the high-voltage transformer control unit, the shut-off valve control unit, the air-injection motor switching unit and the power supply control unit, the second outputs of which are connected respectively to the diagnostics units of the high-voltage transformer, shut-off valve, motor, and power supply and the outputs of the diagnostic blocks are connected to the microcontroller through its first (in the first category), second (in the second category), third (in the third time poison) and fourth (the fourth category) zero line port, respectively. The first output of the power supply control unit is connected to the following inputs of the device elements:
- with the second input of the control unit of the high voltage transformer, connected with its first output with the input (primary winding) of the high voltage transformer, the output (secondary winding) of which is connected to the ignition electrode installed in the burner nozzle;
- with the second input of the switching unit of the air injection engine connected to its first output with the air injection engine;
- with the input of the air pressure sensor;
- the input of the gas pressure sensor, the output of which is connected to the input of the diagnostic unit of the gas pressure sensor, connected by its output on the fifth line (fifth category) of the zero port to the microcontroller;
- with the second input of the shut-off valve control unit, the first output of which is connected to the input of the shut-off valve, while the output of the air pressure sensor is connected to the input of its diagnostic unit, connected to the microcontroller by its sixth line (sixth discharge) output of the zero port and the sensor electrode the presence of a flame installed in the nozzle of the burner is connected to the input of the unit for detecting the presence of flame and diagnosing a false alarm, the output of which is connected through the seventh line (in the seventh category) of the zero port to the microcontroller th. The microcontroller is connected through its third port to a communication unit with a top-level computer. The first line (in the first category) of this port is the connection of the output of the microcontroller to the input of the communication unit, and the zero line (in the zero category) of this port is the microcontroller connected by its input to the first output of the communication unit with a top-level computer, the second output of which is connected by a two-wire twisted pair cable to Top-level computers. A standard power source is used to power the device, by connecting the zero and phase of the source with the second and third inputs of the power supply control unit, and the constant voltage of the source serves as the power supply for the microcontroller and other circuit elements.

 Comparative analysis with the prototype shows that the inventive device is characterized by the presence of new units: power supply control unit, power supply diagnostic unit, false alarm and flame detection diagnostic unit, high voltage transformer control unit, high voltage transformer diagnostic unit, air injection motor, engine switching unit air injection, air injection engine diagnostic unit, air pressure sensor, air pressure sensor diagnostic unit lack of air, a shut-off valve control unit, a shut-off valve diagnostic unit, a gas pressure sensor, a gas pressure sensor diagnostic unit, a microcontroller, a communication unit with a high-level computer, and their connections with other structural elements. The inventive combination of features is proposed for the first time, which meets the criterion of "novelty."

 A comparison of the proposed solutions with other technical solutions shows that the blocks of diagnosis, control, communication with upper-level computers are known.

 However, when they are introduced in this connection with the other elements of the circuit into the inventive device for monitoring and controlling the process of ignition of the burner and combustion, the above blocks can improve the reliability of monitoring the process of ignition and combustion of the burner, improve the quality of control of the gas burner, and also expand the functionality of the system management. This ensures that the claimed technical solution meets the criterion of "inventive step".

 Figure 1 shows a microcontroller device for automatic control and management of the process of ignition of the burner and combustion; figure 2 shows the block diagnosis of false alarms and registration of the presence of flame and its connection; figure 3 shows the relationship between the control unit, the diagnostic unit and the actuator (load).

 The microcontroller device for automatic control and control of the ignition of the burner (Fig. 1) contains the start button of the device 1, the power supply control unit 2, the power supply diagnostic unit 3, the false alarm diagnosis and detection unit 4, the flame sensor 5 electrode, ignition electrode 6, high-voltage transformer 7, control unit for high-voltage transformer 8, diagnostics unit for high-voltage transformer 9, air injection engine 10, switching unit for air injection engine 11, bl ok diagnostics of the air injection engine 12, air pressure sensor 13, diagnostic unit for air pressure sensor 14, shut-off valve 15, control unit for shut-off valve 16, diagnostic unit for shut-off valve 17, gas pressure sensor 18, diagnostic unit for gas pressure sensor 19, microcontroller 20, the communication unit with the upper level computer 21, the burner 22.

 The communication lines (Fig. 1) of the microcontroller 20 with peripheral devices will be designated as - PX. U. Here PX is a sign of the microcontroller port, where X is a digit indicating the port number (for example, P1 is the first port of the microcontroller), and U is a digit indicating the line (discharge) number of the port (for example, P3.1 is the first line ( first discharge) of the third port).

 The device operates as follows. If the microcontroller 20 receives a signal on the P0.0 line that the "Start" button of device 1 has been pressed, or if the microcontroller 20 receives a signal to ignite the burner from the communication unit with upper-level computer 21 via the P3.0 line, the device starts its operation in according to the algorithm programmed in the microcontroller 20.

 First, the microcontroller 20 reads a signal about the operability of the power supply control unit 2, analyzing the information received via the P0.4 communication line from the power supply diagnostic unit 3, in the presence of a supply voltage, a signal is supplied from the microcontroller 20 to the power supply control unit 2 via the P1 communication line .3, which simultaneously supplies power to the control unit of the high-voltage transformer 8, the switching unit of the air injection motor 11, the air pressure sensor 13, the gas pressure sensor 18. After that, the microcontroller 20 switches to the diagnostic data processing routines of the listed blocks by reading the signals from the diagnostic block of the high-voltage transformer 9, the diagnostic block of the air injection engine 12, the diagnostic block of the air pressure sensor 14, the diagnostic block of the gas pressure sensor 19 via communication lines P0.1, P0. 3, P0.6, P0.5, respectively.

 If there are signals from the diagnostic blocks 3, 9, 12, 14, 19, indicating the serviceability of the electrical circuits of the diagnosed blocks, a burner ignition cycle is carried out.

 First, a purge cycle of the system is performed by turning on the air injection engine 10 by supplying a control signal from the microcontroller 20 via the P1.2 communication line to the air injection engine switching unit 11 and simultaneously interrogating the air pressure sensor 13 through the air pressure sensor diagnostics unit 14 via the P0 communication line. 6.

 After the purge time has ended, which is determined by the time interval in the program of the microcontroller 20, the latter interrogates the gas pressure sensor 18 through the diagnostic block of the gas pressure sensor 19 via the P0.5 communication line about the presence of sufficient gas pressure in the mains for operation of the burner. In case of sufficient gas pressure, the supply circuit of the shut-off valve 15, controlled by the block 16, is prepared through the gas pressure sensor 18, which brings the shut-off valve to a ready state for operation, while the microcontroller 20 constantly analyzes the operability of the shut-off valve 15 through control units 16 and diagnostics 17 shut-off valve via the P0.2 communication line during the entire burner operation cycle.

 At the same time, the microcontroller 20 supplies the control voltage to the primary winding of the high-voltage transformer 7 through the control unit of the transformer 8 via the P1.0 communication line, on the secondary winding of which there is a high voltage applied between the burner nozzle body 22 and the ignition electrode 6, and upon reaching a critical value, a breakdown occurs in the form of a spark between them.

 As a result of engine operation, air pressure is injected into the nozzle of burner 22 and, upon reaching a predetermined level, the microcontroller removes the ban on ignition of the burner. After that, a control signal is supplied from the microcontroller 20 to the shut-off valve control unit 16 via a communication line P1.1, which enables the switching circuits of the shut-off valve 15 and provides gas supply to the burner. The presence of a spark in the nozzle of the burner leads to ignition of the gas-air mixture.

 After that, the microcontroller 20 analyzes the presence of a flame by reading information on the P0.7 communication line from the false alarm diagnostic unit and detecting the presence of a flame 4 connected to the electrode of the flame presence sensor 5. In the event of a flame, the microcontroller 20 cuts off the power supply through the P1 communication line. 0 to the primary winding of the high voltage transformer 7. If after the ignition time, which is determined by the time interval in the program of the microcontroller 20, the flame does not appear, then the microcontroller 20 sn maet signal from the power supply control unit 2 through the communication line P1.3, with the closed shut-off valve 15 and turns off the air supply motor 10, and the program proceeds to the standby cycle a new launch.

 In the case of a successful ignition, the microcontroller 20 constantly analyzes the signals from all diagnostic blocks 3, 9, 12, 14, 17, 19 and the false alarm and flame detection unit 4, while all information signals are transmitted by the microcontroller 20 to the upper-level computer through the communication unit The upper level computer 21 on the communication line P3.1.

 Flame monitoring and block diagnostics continue continuously until the flame disappears or at least one block fails. If the flame went out or at least one unit failed, or the "Start" button of device 1 was pressed, or a signal was received to extinguish the burner from the communication unit with the upper level computer 21, then the microcontroller 20 removes the signal from the power supply control unit 2, when This closes the shut-off valve 15 and turns off the air supply motor 10, and the program goes into a waiting cycle for a new start.

 As the air supply engine 10, an asynchronous two-phase motor is used, which is installed on modern gas burners [5].

 The air pressure sensor 13 and the gas pressure sensor 18 are dry contact devices.

 Communication with the upper level computer is carried out by the microcontroller 20 through a serial interface via a two-wire twisted pair cable by preliminary amplification and matching of power signals in the communication unit with the upper level computer 21 [6, 7, 8].

 The device is powered from a standard power source [9], by connecting the zero and phase of the source with the second and third inputs of the power supply control unit. The microcontroller, as well as other circuit elements are powered by a constant voltage source: a power supply diagnostic unit, a false alarm diagnostic unit and a flame detection unit, a high voltage transformer control unit, a high voltage transformer diagnostic unit, an air injection motor switching unit, an air injection engine diagnostic unit, a diagnostic unit air pressure sensor, shut-off valve control unit, shut-off valve diagnostic unit, pressure sensor diagnostic unit gas, a communication unit with a top-level computer.

 Since the flame effect sensor uses the effect of the ionization current flowing in the presence of a flame between the electrode 5 and the burner nozzle body, it is possible that the sensor fails as a result of a short circuit of the electrode 5 with the burner nozzle body, which may occur, for example, in the event of a fall of the electrode on the housing during burnout (thinning) of the electrode 5. For the diagnosis of this phenomenon, a unit for diagnosing false alarms and detecting the presence of flame is used, one of the possible construction options which og shown in figure 2. This unit is connected to the electrode of the flame detector 5, the housing of the nozzle of the burner 22 and consists of a comparator 23, a galvanic isolation element 24, an electrical bias setting circuit. The electrode of the flame detector 5 is connected to the non-inverting input of the comparator 23, the inverting input of which is connected to the nozzle of the burner 22 through the bias circuit. The signal from the comparator 23 is fed through the galvanic isolation element 24 for analysis to the microcontroller 20 via the P0.7 communication line.

 A bias is applied to the inverting input of the comparator through an electric circuit, as a result of which the potential at this input becomes higher than at the non-inverting input, which is connected to the electrode of the flame detector, therefore, in the absence of a flame, the logic "0" is held at the output of the comparator. When a flame appears, an ionization current flows between the electrode 5 and the burner nozzle body, as a result of which the potential at the non-inverting input becomes higher than at the inverting input, therefore a logical “1” corresponding to the flame is formed at the output of the comparator. If the electrode 5 touches the burner body, then a logical “0” is held at the output of the comparator, since there is no ionization current between the electrodes, which corresponds to a signal about the absence of a flame.

 Actuators of devices 7, 10, 15 (primary winding of a high-voltage transformer, motor winding, winding of the shut-off valve electromagnet) located on burner 22 represent an electrical load for blocks 8, 11, 16. Since the power supply control unit 2 provides the supply voltage on the above blocks, the latter in turn are the loads for the power supply control unit. As you can see, each of the control and diagnostic channels (control channel of a high-voltage transformer, a motor switching channel, a shut-off valve control channel) contains the same type of blocks (controls, diagnostics, loads), which makes it possible to perform a circuit implementation of these channels in an identical structure, one of the possible options the construction of which is shown in Fig.3. At the input of the optocoupler isolation 26, a phase is fed through the RC circuit, while the first output of the optocoupler isolation is connected to the input of the load (corresponding actuator) 27, the output of which is connected to zero, and the second output of the optocoupler isolation 26 is connected to the input through the corresponding port of the microcontroller 20, the output of which is connected to the second input of the corresponding control unit of the actuating element 25, the first input of which is supplied with a phase, and the output is connected to the input of the load (the corresponding actuating element) 27. Existing Communication between the control unit, the diagnostic unit and the load (actuator) form an electric circuit consisting of an RC circuit, an optocoupler isolation 26 of the diagnostic unit, connected by its output to the microcontroller 20, the control unit for the actuator 25, the load (actuator) 27. Due to the presence of this circuit at the output of the optocoupler isolation 26 connected to the microcontroller 20, pulses are read last, the duty cycle of which depends on the time constant of the RC circuit and the load resistance. If pulses of a given duty cycle are formed when a supply voltage is applied to the output of the diagnostic unit, this signals the serviceability of the load circuits. In the event of a short circuit in the load circuit at the output of the diagnostic unit, pulses of a different duty cycle are generated due to the fact that the load resistance has changed. When the load circuit breaks at the output of the diagnostic unit, pulses are not formed.

 Thus, the use of the proposed microcontroller device for automatic control and control of the process of ignition of the burner and combustion allows, in comparison with the existing prototype, to increase the reliability of monitoring the process of ignition and combustion of the burner, to expand the functionality of the control system, and also significantly reduce the number of elements in the device due to that instead of logic elements a microcontroller is used.

Bibliography:
1. USSR author's certificate 1084544, cl. F 23 N 5/24.

 2. Copyright certificate of the USSR 1495580, cl. F 23 N 5/24.

 3. Copyright certificate of the USSR 1495581, cl. F 23 N 5/24.

 4. Copyright certificate of the USSR 1477992, cl. F 23 N 5/24 (prototype).

 5. Tokarev B. F. Electric machines. Textbook allowance for universities. - M .: Energoatomizdat, 1990.

 6. Stashin V.V., Urusov A.V., Malogontseva O.F. Designing digital devices on single-chip microcontrollers. - M.: Energoizdat, 1990.

 7. Horsetail S.T. Microprocessors and Microcomputers in automatic control systems: Reference book / S.T. Horsetail, N.N. Varlinsky, E.A. Popov. / Under the general. ed. S.T. Horsetail. - L .: Engineering, Leningrad Branch, 1987.

 8. Brodin VB, Shagurin I.I. Microcontrollers. Architecture, programming, interface. - M .: Publishing house ECOM, 1999.

 9. Schreiber B. 300 power supply circuits. Rectifiers Switching power supplies. Linear stabilizers and converters: Per. with fr. - M.: DMK Press, 2001.

Claims (1)

 A microcontroller device for automatic monitoring and control of the burner ignition process and combustion, comprising a burner, a start device, a shut-off valve, a flame detector, a high voltage transformer, characterized in that it contains a microcontroller connected through its zero line to the zero port to the startup device in the form of the "Start" button of the device, and through its zero, first, second and third lines of the first port, connected respectively with the first inputs of the control unit of the high-voltage transport a formor, a shut-off valve control unit, an air injection engine switching unit and a power supply control unit, the second outputs of which are connected respectively to the diagnostic blocks of the high-voltage transformer, shut-off valve, motor and power supply, and the outputs of the diagnostic units are connected to the microcontroller through its first, second, the third and fourth lines of the zero port, respectively, while the first output of the power supply control unit is connected to the second input of the high voltage transformer control unit a mator connected with its first output to the input of a high-voltage transformer, the output of which is connected to the ignition electrode installed in the nozzle of the burner; with the second input of the switching unit of the air injection engine connected to its first output with the air injection engine; with the input of the air pressure sensor and the input of the gas pressure sensor, the output of which is connected to the input of the diagnostic block of the gas pressure sensor, connected by its output along the fifth line of the zero port to the microcontroller; with the second input of the shut-off valve control unit, the first output of which is connected to the shut-off valve input, while the output of the air pressure sensor is connected to the input of its diagnostic unit, connected by its output along the sixth line of the zero port to the microcontroller, and the flame sensor electrode installed in the nozzle burner, connected to the input of the flame detection and false alarm diagnostics unit, the output of which is connected through the seventh line of the zero port to the microcontroller connected through its third port to the communication link with the upper-level computer, the first line being the connection of the microcontroller output to the input of this unit, and the zero line the microcontroller is connected by its input to the first output of the communication unit with the upper level computer, the second output of which is connected by a two-wire twisted pair cable to the upper level computer, for power supply The device serves as a standard power source by connecting the zero and phase of the source with the second and third inputs of the power supply control unit, and the constant voltage of the source serves as a power supply for the microcontroller and other lementov scheme.

Images