EP0614047A1 - Electronic control device for gas burners of heating installations - Google Patents

Abstract

To simplify an electronic control device for gas burners of heating installations, the microcomputer MC of the automatic firing unit is extended to take over tasks from the heating regulator. The microcomputer or the device equipped therewith is provided with a signal generator SG, a comparator Ve, a controller R and a temperature watchdog. The signal generator generates, in particular, pulse-width-modulated control signals SST, which are used for controlling a D.C. motor M, which is used as drive element for an air blower G. The comparator compares rotational speed current values of the blower generated by a rotational speed sensor Fn with rotational speed desired values or limiting values stored in the memory SP and, as a function of the type and/or the magnitude of the difference values, triggers control signals SST or influences the latter. Furthermore, the microcomputer outputs control signals to the D.C. motor of the blower during the operational time of the burner as a function of parameters controlling the boiler temperature TK, and takes over temperature watchdog tasks. <IMAGE>

Description

The invention relates to an electronic control device for gas burners of heating systems of the type mentioned in the preamble of claim 1.

Control devices of this type are known as so-called burner controls (Sarkowski, Oil Fire Control Technology, 1964). The supply of air to the burner is controlled before the actual controller operation, in which the heating output is regulated as a function of the heat requirement, since the heating chamber must first be flushed with air. In this preparatory phase, certain test tasks also have to be performed. In the known control device, the blower for the air is driven by a motor with a constant speed and the amount of air conveyed per unit of time is controlled by a throttle valve, for which purpose a microcomputer can be used. An additional controller is used for the actual heating operation, which in turn can have a microcomputer. It is known to control the amount of combustible fluid, such as oil, supplied to the burner during regulator operation, for example by an oil pump, which in turn is dependent on the air supplied to the burner. The oil pump and that Blowers are driven by the same drive motor. The effort for the burner control on the one hand and the temperature controller on the other hand is relatively large.

It is also known (DE-OS 2 920 343) to control the valves for the air on the one hand and for the fuel on the other hand by motors, each of which has an interface to an associated one of two logic circuits which are connected to a microprocessor.

The invention has for its object to simplify such a control device.

The invention is claimed in claim 1 and further embodiments of the invention are claimed or described in the subclaims and in the description of the figures.

According to the invention, the burner control, the regulator and the temperature monitor are combined to form a uniform electronic control and regulating device, in which the microcomputer fulfilling the functions of the burner control takes over additional tasks of the controller and monitor. The microcomputer or the device equipped with the microcomputer is provided with a signal generator which, in particular, generates pulse-width-modulated, that is to say digital control signals, which a DC motor of the blower both during the preparation phase, in which the automatic burner control unit has to perform its main task, and during the actual one Controller operation, ie in the heating phase, and thereby control the air supply to the burner. In addition, it is advisable to provide the microcomputer or the device equipped with it with a comparator which stores the actual speed values of the direct current motor or blower in a memory, that is to say predetermined by a program Speed limit or setpoint values are compared. Depending on the type and / or size of the difference values, the control signals are triggered or influenced. In addition, the microcomputer or the device equipped with it also has the controller which influences the signal generator in such a way that control signals are also emitted to the DC motor of the blower during the operating time of the burner as a function of parameters regulating the burner output, which in turn preferably modulates the pulse width are. The speed of the fan is not regulated directly, which is why a separate control circuit for the drive motor is unnecessary. Nevertheless, the speed is corrected indirectly: According to. A certain power requirement is applied to the blower motor with a control signal in order to achieve a certain speed. If this was not achieved, however, then the power requirement in question would inevitably not be achieved either, so that the power requirement is automatically increased due to the remaining temperature control difference.

This enables a considerable simplification. It is thus possible to dispense with a double interface in favor of a single interface between the microcomputer or the device equipped with it and the drive element of the fan.

During the preparation phase, ie during the functioning of the burner control, the speed of the fan is detected by a Hall sensor in particular as a speed sensor in the drive motor of the fan. If the fan speed exceeds a minimum speed and a minimum air pressure is reached as a limit or setpoint on the burner, which can be determined by a pressure sensor, then the pre-purge time can begin, in which the microprocessor ensures that the fan runs at high speed runs in order to flush the boiler room and the chimney well with air within a short time.

If, by comparing the actual speed value recorded by the speed sensor with the air pressure determined by the pressure sensor (in particular a switch-like contact detector that emits a signal when a certain air pressure is reached), it is determined that the speed and air pressure are dependent on one another a confirmation that a certain fan speed has built up a certain air pressure at the burner. This confirmation is then made with the invention in the actual heating mode, i.e. while the controller is working, take advantage of the fact that only the speed sensor determines the speed and the air pressure sensor or switch or detector remains inoperative.

The invention also makes the use of direct speed control in the form of a separate control circuit unnecessary, as has already been stated. A further simplification of the invention is made possible by the fact that the function of a temperature monitor is also integrated, which makes an external thermostat unnecessary. The existing boiler sensor, which determines the boiler water temperature T _K , is used as an actual value transmitter for the monitor function. As a result, synergistic effects are achieved.

In addition, it is possible to use another microcomputer for certain tasks of the burner control unit, such as obtaining test results from function tests and outputting ignition signals to the ignition electrodes of the burner, which is less expensive due to the smaller number or the smaller scope of the tasks Modification can be selected can. This additional microcomputer is then connected to the main microcomputer through data exchange lines. The further microcomputer can be provided with an automatic timer or cooperate in order to interrupt or to release the control signals for a specific period of time.

Figur 1

eine schematische Darstellung der elektronischen Steuereinrichtung, mit der die drei Aufgaben sowohl eines Feuerungsautomaten als auch eines Temperaturreglers sowie eines Temperaturwächters in integrierter Bauweise nach der Erfindung lösbar sind;

Figur 2

ein schematisches Schaubild einer erfindungsgemäßen Steuereinrichtung,

Figur 3

ein zeitabhängiges Ablaufdiagramm von Funktionen von Aggregaten der Steuereinrichtung nämlich in der Vorbereitungsphase als Feuerungsautomat und in der Heizungsphase als Temperaturregler und Feuerungsautomat;

Figur 4

eine schematische Darstellung einer bevorzugten die Sicherheit erhöhenden Ausbildung der Erfindung;

Figur 5

die Lage der Schaltdifferenz in Bezug auf den Einstellwert der Kesselwassersolltemperatur sowie die Begrenzung durch den Temperaturwächter und

Figur 6

eine schematische Darstellung einer Testschaltung für die Funktion des Temperaturwächters.

Exemplary embodiments of the invention will now be explained in more detail with reference to the drawing. Show:

Figure 1

is a schematic representation of the electronic control device with which the three tasks of both an automatic burner control and a temperature controller and a temperature monitor can be solved in an integrated design according to the invention;

Figure 2

1 shows a schematic diagram of a control device according to the invention,

Figure 3

a time-dependent flowchart of functions of units of the control device namely in the preparation phase as an automatic burner control and in the heating phase as a temperature controller and automatic burner control;

Figure 4

a schematic representation of a preferred security enhancing embodiment of the invention;

Figure 5

the position of the switching difference in relation to the set value of the set boiler water temperature and the limitation by the temperature monitor and

Figure 6

is a schematic representation of a test circuit for the function of the temperature monitor.

According to FIG. 1, the control device, which is equipped with electronic components and is distributed, for example, on two printed circuit boards, is provided with a microcomputer MC, which both fulfills the functions of the burner control unit for burner B and also controls the temperature of the heating boiler HK as a function of the heat requirement. A further smaller microcomputer MC1 can have a data exchange relationship with the microcomputer MC, which has an automatic time switch which enables the delivery of control signals, for example an ignition signal Z, for a specific period of time. The flame sensor F _F emits output signals both to the microcomputer MC and to the other microcomputer MC1 used for monitoring purposes.

A setting device allows the programming of the microcomputer MC by entering data into the memory SP (EEPROM). The microcomputer MC initiates, in particular, pulse-width-modulated control signals S _ST in the signal generator SG, while the comparator V _e compares the actual speed value n with the programmed speed target values n _{TARGET in} order to initiate corresponding functions in the event of deviations or undershoots, Carry out lockouts or prevent certain processes from starting.

There is only a single interface SS between the microcomputer MC of the integrated unit and the blower motor M _G. The integration of the electronics of the burner control unit with the electronics of the temperature controller reduces the number of components required and also simplifies programming and control. Thus, a single signal generator SG is sufficient to generate and output the pulse-width-modulated control signals S _ST , which are used both for controlling the start-up program, ie the preparation phase (in the function of a burner control) as well as for regulation during burner operation (in the function as a temperature controller), ie in the heating phase.

The control signals S _ST are supplied in both phases to the DC motor M of the fan G, which is located in the connecting line VL to the burner B and builds up the pressure P _{A of} the air A supplied to the burner B. The, sensed by the speed sensor F, in particular a Hall sensor on the DC motor M actual rotational speed values _N are evaluated both in its function as a burner control as well as in the function as a controller.

The burner B (FIG. 2) is switched off due to the temperature monitor function as soon as the boiler water temperature T _{K reaches} a maximum limit value TK _max , as is shown schematically in FIG. 5 by the switch-off point of the monitor curve d. The temperature monitor releases operation again as soon as the release point of the monitor curve c is reached. The target temperature (setting value) for the boiler water temperature TK _SOLL , which can be set on the setpoint _{potentiometer, is} plotted on the abscissa, while the switching point according to the actual value of the boiler water temperature TK _{IST is} plotted on the ordinate. When the temperature monitor responds in accordance with the monitor curve d, the heating circuit pump is switched on (burner B had already been switched off when the temperature rose before the control curve b was exceeded). The heating circuit pump now remains in operation until the guard curve c is undershot. After falling below the guard curve c, the controller R can take over the burner control again. The burner start is triggered immediately after the switch-on curve a. Commissioning by a two-point controller R takes place according to curve a and the decommissioning by two-point controller R according to curve b. When commissioned by the two-point controller R according to the controller curve a, the burner B starts with, for example full performance, because the control deviation between the setpoint and actual value reaches its maximum size at that moment. As soon as the burner B generates heat, this control difference then decreases, so that the burner output is reduced in accordance with the decreasing control difference. The burner output can advantageously be reduced to 33 to 10% of the nominal output according to a selected degree of modulation 1: 3 to 1:10. It is thereby advantageously achieved that the burner B burns only at a low power at the moment of switching off given by the control curve b, so that an overshoot of the temperature turns out to be very small even if the heat requirement suddenly decreases. This reliably prevents the response of a safety temperature limiter present in such systems.

When controller R is switched off, the flow water pump continues to run for the set time. If the temperature monitor switches off, the pump continues to run until the release temperature (c) is reached. The watchdog function is also active when burner B is switched off and also activates the pump due to "residual heat".

According to FIG. 2, combustible fluid F, here gas, flows via a feed line ZL to the burner B of a heating boiler HK. The pressure of the fluid F is regulated by a valve V, in particular a pneumatic pressure regulator as a function of the air pressure P _A on the burner, maW: the gas pressure P _F is tracked to the air pressure P _A , which is determined by the fan speed, ie the speed n of the DC motor M _G is controlled, which in this example can be driven with 39 volts DC and can be set at speeds of up to 22 VA at speeds between approximately 200 and 6000 rpm. The valve V could also be formed by a ratio regulator.

In addition, air A is conducted to burner B via the connecting line VL. The air pressure P _A in the connecting line VL is determined by the air pressure sensor F _A. This does not necessarily output analog (corresponding to the actual air pressure P _A ) output signals to the comparator V _e , but an air pressure present signal LP is sufficient when a specific air pressure setpoint or limit value P _{AG is reached} in the connecting line VL . If this limit value P has not yet been reached, then no air pressure present signal LP occurs. The air pressure P _A can be adjusted by the speed of the fan G, which is driven, for example, by a 39 V DC motor M. The speed of which can be sensed as the actual speed value n _ACT using a speed sensor F _n , in particular the Hall sensor.

The temperature control and the preparation phase are controlled by the controller R. In the heating phase, this controls, for example, the air supply as a function of actual temperature values, for example the room temperature T _R , the boiler temperature T _K , the outside temperature T _A and / or the flow temperature T _V , which are fed to controller R via an analog / digital converter A / D and are set in relation to set target values T _RSOLL . In this example, the controller R generates an output signal which corresponds to the speed setpoint n _TARGET and is compared in the comparator V with the actual speed value n _ACTUAL . Depending on the type (plus or minus) and / or the size of the difference between these two speed values, the control unit St _{G is} influenced, which in turn generates corresponding control signals S _ST . These are, in particular, pulse width modulated digital signals and control the speeds of the direct current motor M _G.

The pressure P _F for the combustible fluid F is regulated here depending on the air pressure P _A by controlling the regulator drive V.

WA:

die Wärmeanforderung durch den Regler

FS:

Flammensignal

LP:

Luftdruck-Präsent-Signal des externen Luftdruckprüfers (Kontakt) F_A

STB:

Sicherheitstemperaturbegrenzer

V:

Gasventil in der Zuleitung ZL

Z:

Zündsignal zum Zündaggregat

S_ST:

Steuersignal zum Gleichstrommotor des Gebläses

n_IST :

Drehzahl-Istwert abgeleitet vom Halldrehzahlfühler F_n

thl:

Zeit zum Kochlaufen des Gebläses G

tv:

Vorspülzeit

tbre:

Bremszeit für das Gebläse G

tz:

Zündzeit

ts:

Sicherheitszeit

tb:

Betriebszeit der Temperaturregelung

tn:

Nachspülzeit

t:

Zeit

A:

Startbefehl (Reglereinschaltung)

B:

Beginn des Brennerbetriebs

C:

Beginn der Außerbetriebsetzung

D:

Ende der Außerbetriebsetzung und Übergang in die Heimlaufzeit

Zum Zeitpunkt A gibt der Reglerteil der Steuereinrichtung einen Startbefehl an den Feuerungsautomatenteil derselben durch die Meldung "Wärmeanforderung" WA, wenn die Temperatur T_K im Brauchwasserkreislauf oder im Heizungskreislauf unter einen Mindestwert abgesunken ist. Während der Hochlaufzeit thl wird der Gleichstrommotor M_G des Gebläses G mit insbesondere pulsweitenmodulierten Steuersignalen S beaufschlagt, so daß sich dessen Drehzahl n_IST auf einen Maximalwert erhöht, sobald ein (einstellbarer) Sollwert (Drehzahl-Sollwert n_SOLL ) erreicht ist und der Luftdruckmelder F_A seinen Kontakt schließt und ein Luftdruck-Präsent-Signal LP abgibt. Es beginnt die Vorspülzeit tv. In diesem Zeitpunkt wird in der Verbindungsleitung VL ein bestimmter Luftdruck P_A erreicht. Um die Vorspülzeit gering zu halten, empfiehlt es sich, das Gebläse G während der Vorspülzeit tV auf Vollast laufen zu lassen. Über die Rückmeldung des Drehzahl-Istwerts n_IST und des Luftdruck-Grenzwerts P_AG (LP vorhanden) kann der Feuerungsautomat bei Erreichen der erforderlichen Mindestwerte sein Funktionsprogramm fortsetzen. Haben die Drehzahl und/oder der Luftdruck den vorbestimmten Grenzwert zu Beginn der Vorspülzeit tv nicht erreicht (kein LP vorhanden), erfolgt eine Störabschaltung.In the flow chart according to FIG. 3, the necessary signals are denoted in the rows WA to Z with thick lines and impermissible signals with thin lines. Here mean:

WA:

the heat demand from the controller

FS:

Flame signal

LP:

Air pressure present signal from the external air pressure tester (contact) F _A

STB:

Safety temperature limiter

V:

Gas valve in the ZL supply line

Z:

Ignition signal to the ignition unit

S _ST :

Control signal to the fan DC motor

n _IS :

Actual speed value derived from Hall speed sensor F _n

thl:

Time to run fan G

tv:

Pre-rinse time

tbre:

Braking time for the fan G

tz:

Ignition time

ts:

Security time

tb:

Operating time of the temperature control

tn:

Rinse time

t:

time

A:

Start command (controller activation)

B:

Start of burner operation

C:

Start of decommissioning

D:

End of decommissioning and transition to home life

At time A, the controller part of the control device issues a start command to the burner control part thereof by the message "heat request" WA if the temperature T _K in the process water circuit or in the heating circuit is below a minimum value has sunk. During the run-up time thl, the direct current motor M _{G of} the blower G is acted upon with, in particular, pulse-width-modulated control signals S, so that its speed n _{ACT increases} to a maximum value as soon as an (adjustable) setpoint (speed setpoint n _SET ) is reached and the air pressure detector F _A closes its contact and emits an air pressure present signal LP. The pre-rinse time tv begins. At this time, a certain air pressure P _{A is} reached in the connecting line VL. In order to keep the pre-purge time short, it is advisable to let the fan G run at full load during the pre-purge time tV. Via the feedback of the _actual speed value n ACTUAL and the air pressure limit value P _AG (LP available) the automatic burner control can continue its function program when the required minimum values are reached. If the speed and / or the air pressure have not reached the predetermined limit value at the start of the pre-purge time tv (no LP available), a lockout occurs.

The speed n _{IST of} the fan G should exceed a minimum value of, for example, 2400 rpm during the pre-purge time tv.

During the braking time tbre, the speed of the fan G is reduced in accordance with lower pulse-width-modulated control signals S _ST .

An ignition signal Z is then applied to an ignition unit of the burner B during the ignition time tz, for example to ignition electrodes thereof, while the fan G continues to run at a speed of, for example, 40% of the maximum speed, but does not exceed the maximum value of 2900 rpm in this example. In the course of the ignition time tz, the valve in the supply line ZL opens, that is to say the setting unit V for the combustible fluid F, as a result of which the safety time ts begins, within which a flame signal must be determined by a flame sensor F _F , otherwise the lockout occurs. This safety time ts is, for example, up to 10 s, while the pre-rinsing time tv can be, for example, up to 50 s and the maximum braking time tbre is also of this order of magnitude.

If the flame message is present at the end of the safety time ts, the transition to the operating position takes place and the burner operating time tb begins, during which the fan speed n _{ACT is} dependent on the pulse-width-modulated control signals S _ST and this in turn is dependent on the output signals specified by controller R in one The speed range can be regulated, which is between approximately 600 and 6000 rpm, as the maximum value specification and plausibility limit, while the maximum speed is typically 4000 rpm. During the burner operating time tb, it is generally not necessary to monitor the air pressure, since the speed sensor Fn with its output signals regularly offers sufficient security.

If the flow temperature T _{V is} higher than the switch-off threshold, the burner operation is set by the controller R at the time C by switching off the supply of combustible fluid F to the burner B by the setting element V. However, the fan G can remain in operation in order to blow off combustion residues. During this time, the fan speed n _{ACT is} ramped up to full load (programmable), whereupon the home run follows as a regular transition to the standby phase.

A particularly preferred variant of the invention, which also has its own inventive significance, is explained with reference to FIG. 4:
The microcomputer MC is connected to the flame sensor via the resistor R. F _F connected. If the signal emitted (or not emitted) by the flame sensor F _F to the microcomputer MC does not match the value stored in the microcomputer MC, which expresses a malfunction, the microcomputer MC outputs an output signal to the control units SA and SA1, which in turn switch S and S1 in that process circuit P and, in the absence of a flame sensor signal that is necessary per se, the process in question, such as the introduction of gas into burner B, is interrupted. The signal from the flame sensor F _F is also passed in parallel to the branch leading via the resistor R to the microcomputer MC, namely via the further resistor R1 to the further microcomputer MC 1, which can, but does not have to, have a data exchange connection with the first microcomputer MC. If this additional microcomputer MC1 also detects a malfunction due to the absence (or occurrence) of output signals from the flame sensor F _F , then it outputs an output signal to the control units SA and SA1, which in turn control further switches S and S1, which are connected in series Process circuit P, here a relay for the gas valve V, are. Normally, switch S1 also responds when switch S responds. If, however, an error occurs in one of the two shutdown circuits, the process circuit P is nevertheless shut down, specifically via the second shutdown circuit by means of the further switch S1. This parallel connection of two monitoring circuits therefore ensures increased security.

According to a further embodiment of the invention, this security is increased if the further microcomputer MC1 is constructed differently, for example is equipped with other electronic components, and in particular if it is also programmed differently than the first microcomputer MC. Would namely certain influences both the first monitoring circuit with the microcomputer MC and the other connected in parallel Set the monitoring circuit with the additional microcomputer MC1 from the normal function if both are constructed and programmed the same, so the risk is further reduced if the additional microcomputer MC1 is constructed and / or programmed differently.

In order to achieve such a different structure, it is recommended to use a much simpler and therefore also cheaper one for the additional microcomputer MC1 than the first microcomputer MC, which anyway has far more extensive tasks both for the function as a burner control unit and for the function as a temperature controller and Guardian has to take over, while the other microcomputer MC1 mainly serves for process monitoring and the mutual function control with the microcomputer MC. This further microcomputer MC1 can also be used for the mutual checking of the two microcomputers via the data exchange connections shown in broken lines, for example to mutually check a ROM test comparison value and a key comparison value.

An advantage of this integration of the electronic control device, which is arranged in particular on, for example, only two printed circuit boards, is that it is unnecessary to use a separate control device with the associated components on the one hand for the burner control and on the other hand for the temperature controller. Thus, a single signal generator SG is sufficient to generate and deliver the pulse-width-modulated control signals S _ST , which perform their task both for controlling the start-up program (in the function as an automatic burner control unit) and for regulating the temperature during burner operation (in the function as a controller). The actual speed values sensed by the Hall speed sensor F _n n _ACTUALS are evaluated not only during the start-up program (function as automatic burner control), but also during the controlled burner operation for control and regulation.

The air pressure switch or sensor F _A ensures that when the burner controls are operated, ie in the "start-up phase", sufficient air pressure is always built up for purging the burner chamber and chimney. If there is a great demand for heat during normal operation, e.g. by switching on additional radiators and tap water, which requires a high speed of the fan G and - depending on it - the gas pressure P _A , then it is advisable to check the air pressure sensor F _A if a certain one is exceeded Speed setpoint n _SET . During the operation of the temperature controller R, uz in modulating operation, the speed of the fan G can decrease so much with a low heat requirement that the air pressure sensor F _A no longer responds. In this case, the use of an additional air pressure sensor could be recommended, which responds to lower air pressure corresponding to a lower fan speed. One or the other air pressure sensor can then be used depending on the speed range.

The air pressure sensor F _{A also} responds to the safety test, according to which there is a brief switch-off and restart at least once every 24 hours using the automatic burner control. In order to save such a second air pressure sensor, it is advantageous to query the switching state of the air pressure sensor F _A each time a high heat requirement occurs, which results in a high speed n of the fan G that the air pressure sensor F _A must respond. If the air pressure sensor F _A does not respond, the system is switched off and the starting procedure is repeated.

In the circuit shown in FIG. 6, the temperature sensor for the boiler temperature T _K , which is integrated in the temperature monitor function, is connected to the analog / digital converter A / D via a circuit F consisting of a filter and a series resistor and via an input circuit E. which is at the entrance of the microcomputer MC or in this itself. In addition, the connection point between the circuit F consisting of filter and series resistor and the input circuit E of the analog / digital converter A / D is connected to ground on the one hand via a switch S4 and to voltage U with, for example, 5 V via another switch S3. The microcomputer MC now carries out a rough test of the A / D conversion in that it closes the switch S3 one after the other, for example first, in order to close the voltage U of 5V and then, when the switch S3 is open again, the switch S4 to connect ground via the input circuit E to the analog / digital converter A / D. The A / D conversion with regard to the correct choice of the A / D channel and with regard to the correct result must result in the A / D conversion result matching the known expected value (FF or 0). The occurrence of this expected value assumes that the resolution of the analog / digital converter A / D is 8 bits; the value "0" corresponds to the voltage OV (input is ground) and the value "FF" corresponds to the voltage 5V (input to + 5V). In addition, the short-circuit or interruption of the boiler water temperature sensor (boiler sensor) with the boiler water temperature T _{K is recognized} . For this purpose, the circuit is designed so that the voltage value generated by the boiler sensor is in a certain voltage range, for example between 1 and 4 volts. If, on the other hand, there is a short circuit or an interruption in this line to the boiler sensor, so that the boiler water temperature T _K can no longer be reliably integrated into the temperature monitor function, an A / D voltage will be outside the voltage range of between 1 and 4V in this example. The switches S3, S4 are expediently designed as transistors.

In addition to the saving of components and interfaces when integrating a burner control, a temperature controller and a temperature monitor in one and the same device with a microcomputer, the invention surprisingly also simplifies the function. This eliminates the need for interlocking separate assemblies, since the microcomputer does not follow any commands from the controller as long as the burner control unit executes its program after a starting process (start-up phase).

Claims (10)

Electronic control device for gas burners of heating systems with a microcomputer, which outputs control signals to an ignition device for the burner and to a drive motor for a fan as a function of stored limit or setpoint data and / or actual value data determined by sensors is provided with at least one automatic time switch in which at least one predetermined safety time can be programmed, during which certain burner conditions must be fulfilled,
characterized by
that the microcomputer (MC) has a signal generator (SG) for generating control signals (S _ST ) for the drive motor (M _G ) of the air blower (G) during operation as a burner control unit and also during the regulation of the temperature with the aid of a Temperature controller (R) and also performs control tasks in the controller operation of the heating system by controlling the air supply to the burner (B) by the microcomputer (MC) control signals during the operating time (tb) of the burner (B) depending on the boiler temperature (T _K ) regulating parameters, such as room temperature (T _R ), outside temperature (T _A ), flow temperature (T _V ), via the same Interfaces such as those of the burner control unit also deliver to the drive motor (M _G ) of the blower (G). Control device according to claim 1,
characterized by
that the microcomputer (MC) outputs digital pulse-width-modulated control signals (S _ST ) to the drive motor (M _G ) designed as a DC motor. Control device according to claim 1 or 2,
characterized by
that the microcomputer (MC) exchanges data with another microcomputer (MC1) that performs additional monitoring tasks of an automatic burner control. Control device according to claim 3,
characterized by
that the further microcomputer (MC1) is also provided with an automatic timer which interrupts the delivery of control signals for a certain period of time. releases. Control device according to one of the preceding claims,
characterized by
that a Hall sensor serves as a speed sensor (F _n ). Control device according to one of the preceding claims,
characterized by
that the microcomputer (MC) has a comparator (V _e ) and a controller (R), of which the comparator (V _e ) actual speed values (n _ACTUAL ) of the blower (G) generated by a speed sensor (F _n ) with the speed limit or setpoint values (n _SET ) stored in the memory (SP) and depending on Art and / or size of the difference values triggers or influences control signals (S _ST ). Control device according to one of the preceding claims,
characterized by
that the microcomputer (MC) air pressure values (P _AG , LP) sensed by an air pressure sensor (F _A ) in the connecting line (VL) between the fan (G) and the burner (B) with a stored air pressure limit value (P ' _AG ) compares and triggers lockout or start prevention depending on the type and / or size of the difference value. Control device according to claim 7,
characterized by
that the air pressure sensor (F _A ), which acts as an air pressure monitor, is then interrogated if the current speed setpoint (n _SET ) is greater than a specific predetermined speed setpoint (n _SET ) as an indication of high heat demand (WA) for a certain time. Control device in particular according to one of claims 3-7,
characterized by
that the other microcomputer (MC1) is constructed and programmed unlike the first microcomputer (MC) and fulfills monitoring tasks with the first microcomputer (MC) and controls switches (S, S1) connected in series in the relevant process circuit (P). Control device according to one of the preceding claims,
marked by
the combination with a temperature monitor, the output signal of which is derived from the temperature sensor of the boiler water temperature (T _K ).

Images