DE3113608A1 - Regulation device - Google Patents

Abstract

The regulation device according to the invention is used for current and/or voltage regulation of an electrical heating element or, in general, for any electrical load. The regulation device has a temperature sensor and a temperature setting device, the two of which are connected to a processor. The processor emits an output signal to a load control stage which controls and/or regulates the current and/or voltage supply to the load.

Description

The invention relates to a control device and in particular

special a control device for controlling the current or. Power supply a burden.

The term 'control device "can be used in addition to the control in the sense of a closed loop also include pure control.

The present invention is based on household appliances, described in detail, for example, of electric pans, irons, etc., although this invention is not limited to such devices.

Rather, the control system according to the invention can also be used with other heating devices, such as space heaters and other facilities, for example at Cooking pots, kettles, pans, water boilers, Gaostern, ovens and the like. Used will.

Irons usually have an ironing plate, one with the ironing plate in thermal contact standing heating element as well as an on / off switch for on and Switching off the heating element. The on / off switch usually works with a bimetal 2 thermostat, which is attached to the bracket plate and the heating element always switches off when a with the on / off or. Setting switch set temperature is reached by the temperature of the ironing plate.

Correspondingly, electric frying pans and others have electric Cooking appliances also have a base plate and a thermal contact with the base plate, thermostatically controlled or regulated stimulus element.

However, the conventional on / off or setting switches have the Downside to that when using settings relatively low temperature not control or regulate sufficiently well and safely or controlled or regulated can be. Bi-metal 2 thermostats allow excessive temperature deviations, what first to cooking and then to complete interruption of the cooking process leads when the heating element is switched on and off. The conventional switches can also thermal overshoots and undershoots of the temperature of the bracket or Base plate, which is created by thermal delay of the bracket or base plate of the device caused, do not regulate or control to a sufficient extent.

The invention is therefore based on the object of a control device to create, with which a better regulation is possible and the disadvantages described conventional type can be avoided.

This object is achieved according to the invention with the characterizing part of claim 1 specified features solved.

With the control device according to the invention, a temperature control is possible over a wide temperature setting range and with a faster response possible.

The present invention thus creates control arrangements that in particular are suitable for irons, frying pans or corresponding electrical devices, around the electricity resp.

To regulate the power supply of such devices.

The control device according to the invention is in particular related Particularly advantageous with applications where the electrical energy is in pulse form or is provided to the load in the form of alternating current or alternating voltage.

The temperature sensor measures and monitors, among other things, the temperature the ironing plate or the base plate of the device.

The temperature sensor can be a sensor in the form of a temperature-dependent one Elements, preferably a high temperature thermistor or a thermistor for high temperatures that is in thermal contact with the ironing plate or the base plate of the device. The thermistor can have a positive or negative temperature coefficient.

Preferably the thermistor should have a negative temperature coefficient own. If the control device according to the invention for controlling an electrical Radiator, a space heater or the like. To be used, the temperature-sensitive Element can also be placed in any suitable location where temperature changes should be sensed.

The temperature sensing is used to measure the temperature on the surface the bracket or base plate. It should be noted in this context that the temperature change on the surface of the base or ironing plate due to the longer thermal path is smaller than at the point of the temperature sensor. the The location at which the temperature sensor is attached can be selected through investigations or determined in order to keep a thermal delay as small as possible.

The operating or setting device can be a control panel with a ~ Keyboard and / or with a T, temperature adjuster in the form of a setting disk, be about a potentiometer. The temperature adjuster can be used by the user of the device to set the desired operating temperature. The keypad can have several pressure or touch switches with low power consumption. The switches can be conductive rubber buttons or electrodes that switch when touched as they are commonly used in connection with integrated circuits will. An on / off switch for the device can be provided on the control panel be.

According to a preferred embodiment of the invention, the control device can have a timing device with which the heating element after a automatically switched off for a specified period of time. If such a timing device is provided, the possibility should preferably also be provided for this To set the time control device out of operation by hand.

A hand switch is required for this. By pressing the edge switch the control device can also be switched on and off.

According to a further preferred embodiment of the invention, has de control device several time switches with which the desired operating time each can be set.

Another preferred embodiment of the control device according to the invention has a display device, which consists of a suitable arrangement of display elements, can for example consist of several light-emitting diodes (LED diodes), to display the operating status of the control device. Preferably at least a display element provided for an intermittent or discontinuous Create display whenever the temperature is above or below the set temperature. This or each display element can always then a constant resp.

have continuous display when the temperature of the device the set temperature has been reached or corresponds to this.

In a preferred embodiment, the display instrument flickers quickly if the temperature is above the set temperature, and that Display element flickers slowly when the temperature is below the set Temperature is. In a further embodiment, the display elements the same or one similar alternating display, for example with a flicker frequency of 2 Hz when the temperature is above or below the desired or set temperature. The display device can also be designed so that it only shows when the temperature setting will be changed. The display device is preferably switched on when the temperature adjuster for a predetermined period of time, for example within is changed by at least 5% from 2 seconds.

The display element can light up continuously or continuously if the temperature of the bracket or base plate the desired, set temperature has reached. The continuous display should preferably not be affected by temperature fluctuations be influenced by changes or fluctuations in the bracket or base plate the thermal load (e.g. when pouring out).

In this way, the display device can be on a for a desired cooking process (in the case of a cooking appliance) or a specific tissue (in In the case of an iron), draw attention to the temperature being too high. The display device is preferably arranged on the control panel.

The display elements can be operated with the switches on the control panel in association with. A display element can be assigned to the respective switch in this way ensure that the associated display element lights up when a switch is pressed, to indicate that that particular switch has been pressed.

The control device according to the invention can also be an acoustic Signal generator or an acoustic warning device exhibit. Of the acoustic signal generator is preferably combined with the optical display device and gives an audible warning if the temperature of the device changes. The acoustic signal generator can be a piezo sounder, which aslf sets a suitable sound frequency or is matched.

In a particularly advantageous embodiment of the piezo sounder gives this a discontinuous or intermittent tone with the same or a frequency similar to that of the display elements of the visual display. if the temperature reaches a newly set temperature, the piezo sounder can then emit a tone for a certain time, for example one second.

According to a further preferred embodiment of the invention, can the processor have a trigger circuit that controls the load switches.

The processor can also be a microprocessor, which in turn is a discrete integrated circuit in LSI design or a microprocessor on one is a single chip or in the form of a single component.

The processor ~ # advantageously measures a control unit and a Storage. It can also have a read-only memory. The microprocessor and the read only memory can be housed on a single microcomputer chip be. According to a further embodiment of the invention, the microcomputer a four-Bft element on a single chip, such as the one made by the company Hitachi is offered as type HMCS 42. The microcomputer can also be a four-bit component from National Semiconductor from the COPS family, such as the COP 311L circuit be. The processor receives information from the temperature sensor and supplied by the operating device and then processes this information. Preferably, the sensed temperature is continuously or repeatedly compared to the temperature set by the temperature adjuster.

The control device according to the invention preferably has one Daktsignalgenerator, which provides the processor with clock signals and a clock resp. Time control circuit, for example an RC oscillator circuit, which with connected to the processor. The clock signal frequency of the RC oscillator circuit can advantageously be 420 KHz. Circuits can be provided in the clock signal generator that determine the zero passages of the mains voltage. According to a preferred one Embodiment can be a 50 Hz (or a 60 Hz) square wave for timing and derived from the mains voltage for the zero-cross reference.

The load control stage of the present invention preferably stands in connection with the processor and regulates the voltage or current that is which is fed to the load, for example a resistance element that is heating up will. The processor can, in turn, control the load control level to reflect that of the load to regulate the electrical energy provided. When the load is electrical energy is provided in pulse form, the processor should control the load control stage, when the energy to be transmitted is the smallest. This causes interfering signals or a noise due to the switching operations is kept small and high-frequency filters or the like need not be used or only to a small extent.

The load control stage preferably has a solid-state or. a Semiconductor switch, for example a silicon-controlled rectifier or a riac on, with which is the current or voltage for the load is switched. The processor can interface with the load control stage or an interface element can be connected, according to a preferred bus routing form a switching element, for example a transistor.

The processor according to the present invention preferably has a trigger or control signal generator, which for the load control stage trigger or provides control pulses. Each trigger pulse is timed to match generated with the zero crossing of the mains voltage, thereby the previously described Keeping noise during the switching process small. The trigger pulses can or should have relatively short pulse durations in order to reduce the energy consumption or losses in the To keep the trigger circuit as low as possible. Preferably the trigger pulses Pulse durations of 100 / us.

The processor controls the load control stage by determining the length of time during which the electrical energy in a given rainy period or a predetermined control period, for example of 1 second, provided to the load are ## llte, determined. In a preferred embodiment of the invention can the processor has a duty cycle or a duty cycle between zero and fifty full Identify cycles of energy delivered every fifty cycles of the load should.

The processor preferably determines the pulse duty factor as a function on the temperature difference between the temperature sensor and that with the temperature adjuster set temperature. In addition, the processor can adjust the duty cycle in Define as a function of the speed at which the temperature changes If the temperature change rate on the temperature sensor is used for this is, the control device can the Power or voltage supply in a way that regulate the thermal overshoots that normally occur occur due to thermal delays in the base or bracket plate, small can be held. For example, if the load or the temperature setting suddenly changes, the response behavior of the control device in a sudden drop in temperature, for example when pouring in the cold one Cooking food can be significantly improved in this way.

According to a preferred embodiment of the invention, the calculates Processor the number of cycles of energy (the duty cycle) used during the should be delivered to the load in the following control period, in the following Way: N is equal to the number of cycles (0 to 50) provided by the load Energy.

PT is equal to the temperature set with the temperature adjuster (ob), FT is equal to the temperature (° C) determined by the temperature sensor Bracket or base plate of the device.

(23) is the index for the next control period.

(22) is the index for the current control period.

(T1) is the index for the previous control period.

Then n (T3) equals N (T2) plus A (PU (T2) - To (22)) -B (FR (T2) - FT (T1)).

The values for the coefficients A and B can be 3 and 2, respectively. It is however beneficial to these values on one Determine emulator in order to obtain optimal response times without excessive overshoots.

If the control device according to the invention in an electrical The iron used may be due to the thermal inertia of the ironing plate Existing thermal over-oscillation additionally by reducing the The energy provided by the load can be kept small if the temperature sensor determined temperature of the temperature set with the temperature adjuster approaching. The processor can reduce the duty cycle in such a way that that of the load supplied energy is reduced to 75% of the full energy if that from the temperature sensor detected temperature reaches a temperature which is 400 C below the set Temperature is. If the temperature sensor has a temperature of about 100 C below which measures the set temperature, the energy can be provided proportionally will.

In particular, if the control device according to the invention in a If the iron is used, the processor switches the power or voltage supply for the load whenever the device is in its rest position or not in use is. It was found that the change in the number of cycles of the the load provided energy in a control period regardless of the type of Load or heating element when the iron is not in use than when the iron is used.

The processor can therefore preferably have devices that determine whether the rate of change in the number of cycles of energy to be provided to the load or voltage is below a threshold value. The threshold can be set on the control panel can be set or permanently stored in the program.

The processor measures the length of time that the rate of change of the Cycles are below the threshold value, for example with a shutdown counter. Every time a change occurs that is greater than the threshold value, the switch-off counter is activated reset to zero. If the change is below the threshold, the Switch-off counter increased by one in its counter reading during a control period, until it reaches the shutdown count.

The switch-off counter reading can be selected accordingly.

The reading count is preferably 200 to 300 control periods or about 4 to 6 minutes.

When the count of the switch-off counter reaches the switch-off counter, the processor switches the power or

the voltage for the load. This will make the iron automatic off when left unattended or in its rest position stands.

The processor can also be used whenever the iron is not used and is in the horizontal position, a faster shutdown make.

For this purpose, the control system can have devices that determine whether the iron is in a horizontal or vertical position. The horizontal one The position-determining detector can be a mercury (gravity) switch that connected to the processor. When the horizontal position detecting detector detects that the iron is in its horizontal position, the processor decelerates the shutdown counter. For example, the processor can check the shutdown count reduce to about 30 control periods or to about 30 seconds.

According to a further preferred embodiment, the display device shows the shutdown on. For example, the display elements then light up during a short duration discontinuously or intermittently, followed by a relative longer pause follows, and this then becomes repeat until the device is reset. Preferably there is the discontinuous display of 12 switched on, 12 switched off, 12 switched on and 50 switched off Cycles. This display sequence can continue to run continuously when using a acoustic signal generator can the tones with the same order and with the same Frequency are delivered. The control devices can be switched off by turning off the power switch reset so that the device works normally again.

The processor can also use timing devices or

Have options for operating time setting such as this has already been described. The operating time setting switches the load control after a specified period of time has elapsed, for example by switching off the Trigger circuit off. The time control device can be operated by operating time setting switches can be controlled on the control panel. Preferably the timing device not affected when the temperature dial is turned back to its off position will. This disconnects the load from the power supply, but it should the state of the time setting or the possibility of bridging by manual operation are not influenced by it. The timers each serve to 'one each to choose another length of time. By switching several timers, the Operating time can be set cumulatively. When a timer is operated once and this switch is then pressed again, you have another Actuations have no effect until the setting time has expired or is canceled is done by manual operation.

According to a preferred embodiment of the invention, with the time switches operating times of 1/4 hour, 1/2 hour, 1 hour or 2 hours can be set.

Switching all four switches then results in a total operating time of 3 3/4 hours. The processor can use these times for the controller change to 1, 2, 4 or 8 hours for radiators etc.

The display elements of the display device show according to a preferred one Embodiment the time that remains until the load control stage of the Time control device is switched off automatically. The LED elements can also change their display state to the one remaining until automatic shutdown Display time.

By means of a manually operated override device, the time control device can be deactivated at any time. The display device can then when the set time has expired, display a discontinuous display, to indicate, for example, that the cooking process is complete.

If an acoustic signal generator is used, this can be switched off after emit acoustic signals at the set time.

When using a piezo sounder, this can last for a duration emit a tone of 1 second to indicate that the set time has expired.

After the set time has elapsed, according to a preferred embodiment intended to keep it warm. The warming arrangement keeps the pickling element respectively.

the load at a constant slightly elevated temperature after the set time has expired. The slightly elevated temperature should preferably above 600 C to prevent the formation or reproduction of bacteria.

The Wa # mhalteanordnung can contain or from a fixed element consist of a solid element, its resistance value, the desired holding temperature is equivalent to. The processor replaces the resistance value of the solid element the resistance value of the temperature adjuster.

The temperature sensor is preferably via a suitable interface, which can contain an analog-to-digital converter connected to the processor. Preferably the analog / digital converter consists of an integration capacitor. The condenser can be charged alternately by the temperature adjuster or the temperature sensor.

A rear capacitor is preferably reset by means of a transistor, which is controlled by the processor.

The analog / digital converter can be a Schmitt trigger that leads to The beginning of each charging period is switched on and with the Schmitt trigger switch-off level turns off. This is for both the temperature adjuster and the temperature sensor possible.

The advantage of the previously described analog / digital converter lies in that he only got the repetitive results for two consecutive ones Must provide control periods to determine whether the temperature adjuster has changed. An analog / digital converter of this type also enables large ones Changes in the absolute readings due to long-term changes (the are longer than 2 seconds) the clock frequency and the input or input threshold value of the processor.

The temperature sensor is preferably arranged or

set that the temperature adjuster and the temperature sensor are linear and have the same value at the same temperature.

According to a preferred embodiment, the inventive Control device on a safety shutdown. Switches in the event of excess temperatures the processor releases the load control stage.

The load control stage is preferably always switched off when the temperature of the temperature sensor rises above 220 C. The load control stage can can also be switched off when the temperature sensor is no longer or no longer works properly or its connection is interrupted, or if the determined temperature corresponds to a very low temperature, for example 100 C. The display device can display such a safety shutdown. At a preferred embodiment of the display elements can these di skontinuously light up with two cycles at 2 Hz, whereupon the indicators light up a half Second no longer light up. This process can then be repeated. Using an acoustic signal generator, it can emit tones in the same way.

The power supply for the control device according to the present invention can be designed in any suitable manner. Preferably owned that Power supply a half-wave rectifier and a series resistor connected directly to the mains. The half-wave rectifier preferably has a series-connected diode. In addition, a Zener diode and one or more filter capacitors can also be used be provided.

According to a preferred embodiment of the invention, the control device a delay circuit and elements with which the processor is reset is when the current or the voltage in the control device 'stabilizes Has.

According to a further preferred embodiment of the invention is an energy regulator is provided to regulate the energy or the voltage or the current, the or

which is provided to the load, namely. using a Phase control of the AC power supply.

The energy regulator can be a temperature sensor in the range described above and a load control stage and preferably has a trigger circuit, with which the load control stage is controlled. The energy regulator can still operate controls as described above and which have a temperature adjuster, to allow the user to set the desired temperature. Preferably the temperature adjuster is a potentiometer.

The load control stage preferably has a solid-state or. Semiconductor switch, for example a triac connected in series with the load, its gate electrode receives the trigger pulses generated by the trigger circuit applied.

The timing of the triac's gate electrode Trigger pulses depending on the zero crossing of the supply voltage in the power supply unit determines the passage angle of the triac. The greater the delay of the trigger pulses is from zero crossing, the lower the energy reaching the load. the Trigger circuit generates trigger pulses with a delay that is relative to de Zero passage is changeable. The delay of the trigger impulses can be adjusted by means of of the temperature adjuster.

The trigger circuit preferably has at least one pulse delay circuit on, which can consist of a low-pass filter or an integrating circuit. Preferably the trigger circuit has two delay circuits, their time constants are each significantly shorter than the duration of the trigger pulses. For example the time constant of the delay circuits can be 1.5% or 3.3% of the pulse duration the trigger pulses. Each low-pass filter can have a resistor and a Capacitor include. The resistance of one of the two low pass filters includes preferably also the temperature adjuster.

The Tngger circuit can also be a threshold value arrangement, preferably contain a diac. The threshold value arrangement is provided for the dependency the trigger pulses from differences or changes in the triac gate electrode trajectories to keep it small.

In the trigger circuit, there are preferably two delay circuits used so that the triac will split safely even with small passage angles and Hysterysis effects can be kept small. The temperature sensor prevents overheating of the heating element or the load and preferably has a thermistor with negative Temperature curve. Preferably the thermistor is one of the two pulse delay circuits laid in parallel. The thermistor prevents trigger pulses to the load control stage when excess temperatures occur. The temperature at which the trigger pulses Above the thermistor can be derived by an additional, in series can be adjusted with the resistor lying on the thermistor.

The control device or the energy regulator according to the present Invention can preferably be in the handle of an iron, a frying pan, a electric saucepan or a corresponding device.

The invention is explained below with reference to the drawings, for example explained in more detail. They show: FIG. 1 a schematic representation of the inventive Control device, 2 shows the control device according to the invention for use in an iron, saucepan or equivalent Device, Fig. 3 shows a schematic circuit arrangement of an energy regulator according to a further embodiment of the invention, FIG. 4 shows the graphic representation the temperature / resistance characteristic of a high-temperature thermistor, FIG. 5 a schematic circuit arrangement for a preferred embodiment according to the invention a heating control circuit for use in an iron or equivalent Apparatus, Fig. 6 shows a schematic circuit arrangement of a preferred embodiment the inventive heating control circuit for use in an electrical Frying pan or a corresponding device, and FIG. 7 shows a schematic circuit arrangement a further embodiment of the inventive heating control circuit for a electric pan or an equivalent device.

The control device shown in FIG. 1 comprises a processor 10, a temperature sensor 11, an operating or. Setting device 13, a Clock generator 14, a memory 15, a display device 16 and a load control stage 18. The control device regulates the supply of the load 19 with that from the power supply unit 17 provided supply current.

The preferred heating control arrangement shown in FIG. 2 according to FIG The present invention includes a microcomputer 20, a thermistor 21 for high Temperatures connected to the microcomputer 20 via an interface 21a is.

A control panel 23, an LED display 24 and an acoustic signal generator 28 are connected to the microcomputer 20 via interfaces 23a, 24a or 28a, the via an interface 25a with a triac switch or a switch in the form a two-way thyristor 25 is in connection. The triac switch 25 is between the AC mains connection 27 and the stimulus element 26 of the device or the heating arrangement.

The energy regulator shown in FIG. 3 according to a further embodiment the invention comprises a trigger circuit 30, a temperature sensor 31, a Operating device 32 and a load control stage 33. The energy regulator is used Regulation of the electrical energy provided by the power supply 34 of the ~ load 35. The trigger circuit 30 receives a synchronization signal from the power supply unit 34.

The heating control circuit shown in FIG. 5 comprises a four-bit microcomputer 50 formed on a single chip. The microcomputer stands over that Connections 11 and 14 to a suitable power supply unit, the one-way rectifier with a diode D1, a resistor Rl and a capacitor C1, which is clamped to -10 V via a Zener diode Zl.

The operating or setting device has a temperature setting potentiometer VR1 and a power switch (not shown).

The display device comprises an LED diode LD1. The LED diode current is limited by a resistor R5.

Via the connection 27 of the microcomputer 50, the load control stage Trigger pulses provided by microcomputer 50. The load control stage includes the Griac TRl and the driver transistor £ 1. The one pulse duration of about 100 / us (i.e. a duty cycle of 1%) having trigger pulses arrive via a Resistor R6 to the base connection of the transistor T1 to the supply current drain to keep it small. The trigger pulses are generated by the microcomputer at every zero crossing provided to the switching current and the related high frequency noise to keep it low.

The provision of the trigger pulses is related to the zero pass; input signal at input DO (connection 8) of the microcomputer, the input reference value is taken from a clamping circuit set comprising diodes D2, D3 and a resistor R4.

The triac switch TRl connects the mains connection with the heating element 51 when it is brought into the conductive state by the trigger pulses. the Supply or current regulation takes place in that per regulation period between O and 50 full cycles is chosen. For a network connection with 50 Bz this is Control period is one and for a control connection with 60 Hz the control period is 0.83 seconds.

The microcomputer is wired so that when it is switched on it of Network is reset. The internal clock frequency is controlled by external timing elements which include a resistor R3 and a capacitor C3. Changes of the control program are not required if from a network frequency of so Rz is transitioned to a network frequency of 60 Hz or vice versa.

The temperature sensor is in Fig. 5 in the upper right part of the circuit shown and consists of a thermistor 52, which is connected to an analog-to-digital converter can be connected. The analog-to-digital converter includes a total of the Reference numeral 53 provided Schmitt trigger, a reset transistor T2 and a Capacitor C2.

The microcomputer compares the resistance value of the thermistor 52 with the resistance value of the temperature setting potentiometer VR1. The calibration of the resistor vR1 and the series resistors R9 is chosen so that the resistance value from the sum of the resistors VRi and R9 approximately equal to the resistance value of the Ehermistor 52 is at a predetermined temperature.

The temperature control program keeps the resistance values of the potentiometer and the thermistor at the same value.

The microcomputer changes the heating input signal per control period once. The microcomputer calculates the number of times of cycle adjustment of the heating input signal using the temperature difference and the rate of change of the Temperature. This process is used to reduce thermal delays between the heating element and to compensate for the thermistor and to keep control overshoots as small as possible, if there is a large temperature difference due to a change in the potentiometer setting or occurs due to a sudden change in load.

The analog / digital converter has an integrating capacitor C2, which is at the negative connection of the supply source. The capacitor C2 becomes alternately via the potentiometer VR1 and the resistor R9 on the one hand or the Thermistor 52 charged by selecting terminals 19 or 20 of microcomputer 50. The charged capacitor is reset via transistor T2. The Schmitt trigger, which includes the transistors T3 and T4 and the resistors R10-R14, is at the beginning switched to the conductive state every charging period and at the Schmitt trigger switch-off level brought back into the non-conductive state. This occurs either with the potentiometer setting or the Thermi storwert.

The output signal of the Schmitt trigger corresponds to the resistance value of the potentiometer or the thermistor is modulated in its pulse width. This The output signal occurs at the collector of the transistor T4 and arrives at the connection 7 of the microcomputer 50. The successive pulses at this input 7 correspond to the thermistor or potentiometer resistance value.

When switching on the device and whenever the potentiometer value changes by more than 5% in two control periods, the LED diode LD1 lights up and shows a temperature difference compared to the set temperature.

If the thermistor temperature is too high, the LED diode lights up LDi twice per control period, i.e. H. it is switched on for 13 cycles and switched off for 12 cycles. If the thermistor temperature is too low, the LED diode LD1 lights up once per control cycle, d. H. it turns on for 25 cycles and for 25 cycles switched off. If, on the other hand, the temperature reaches the desired set value, the LED diode LD1 remains switched on and thus indicates that the correct Temperature is present.

The heating control circuit shown in FIG. 5 has one possibility to switch off when the device is not in use. The microcomputer 50 is programmed in such a way that it switches off the mains voltage after a delay time of 300 control periods (5 minutes) disconnects from the load when the device is not in use. The microcomputer 50 owns. a switch-off counter for this purpose. The switch-off counter is always then reset when there is a change in the number of cycles of the power supply to the heating element 51 is above a predetermined threshold value.

If this change falls below the threshold, the counter will count during every control period is counted further by one count until it reaches the switch-off time (300 periods) reached.

A mercury switch 54 is always in the conductive state when the device is in a horizontal position. In this way, the closed switch 54 the switch-off time from 300 periods to 30 periods (30 Seconds). In this way, the temperature rise is caused by switching off the supply voltage kept small when using the iron. standing on the ironing surface and left unguarded will.

The microcomputer 50 also has a safety shutdown device. When the device is switched on, the microcomputer asks for the thermistor / capacitor charging time and when this time falls below a value that is a very low temperature (-10 ° C), the microcomputer switches the power supply to the heating element away.

An audible signal generator or buzzer 55 is associated with the microcomputer connected, and emits an acoustic warning signal when the power supply is switched off away. The acoustic signal generator emits a continuous tone when the heating element is switched off some reason by the microcomputer from the power supply is switched off.

The microcomputer 50 reduces that provided to the heating element 51 Electricity whenever the temperature sensor detects a temperature that is approximately 400 C below the potentiometer setting temperature. If the from the temperature sensor the determined temperature is about 100 C below the potentiometer setting temperature, the supply current or the supply voltage is provided proportionally.

The heating control circuit shown in Fig. 6 comprises a four-bit microcomputer 60 on a single chip or

in the form of a single component. The microcomputer 60 is via ports Vcc and GND connected to a suitable power supply. The power supply contains a half-wave rectifier with a diode DlO, a resistor R20 and capacitors C10 and C117 over a Zener diode Z2 is clamped to 5.6 V. Diodes D11 and D12 hold the filter capacitor C10 of (50/60 Bz) square pulses free for the zero crossing input L6 or the switching inputs B1 and L5 of the microcomputer 50 can be used.

The control panel includes several time switch elements S2-S5 and one Manual switching element 56. The control panel also has a temperature setting potentiometer VR2 and a power switch (not shown). On the control panel or preferably in a place that is not accessible to the user, connecting links for keeping warm (connection G2), the 1/4/1 hour time setting (connection G1) and the 50/60 Ei setting (connection S1) must be provided.

With the time switches S2-S5, the timing devices of the Microcomputer operated or switched on. By pressing the switches S2-S5 the durations of 1/4, 1/2, 1 or 2 hours selected. Switching on multiple switches results in longer operating times, for example by switching on all four switches a total duration of 3 3/4 hours. By Connecting the connection GI to ground can quadruple the operating time raise. The choice of these links changes the way the switches work S2-S5 in such a way that switch-on times of 1, 2, 4 or 8 hours are achieved. At the The microcomputer interrupts the end of the switch-on times set in this way 60 automatically supplies power to the heating element 61.

The display device has LED diodes LD2-LD5 for setting the time and an LED diode LD6 for displaying the current status. The timing diodes LD2-LD5 light up when the time setting switch S2-55 is pressed. Be it noted that the connections L1-L5 of the microcomputer 60 inputs and Outputs or bidirectional inputs are. The resistors R2? -R26 limit each the current in the LED diodes LD2-LD6.

Trigger pulses are generated via the connection G3 of the microcomputer 60 the load control stage provided, which has a triac R2 and a driver transistor T7 has. The trigger pulses with a pulse duration of about 100 / us (i.e. one Duty cycle of about 1%) reach the.

Base electrode of transistor 27 around the supply current termination to keep it small. The trigger pulses are generated by the microcomputer at every zero crossing provided to the switching current and the associated high-frequency noise to keep it low.

The provision of the trigger impulses is based on the zero crossings of the power supply, whereby the zero crossings are sent to the microcomputer via the zero # crossings input L6 provided will. The reference input signal comes over the clamping diode D11 from the one-way rectified output signal of the auxiliary diode D10.

When the triac switch TR2 by the trigger pulses in the conductive State is replaced, current reaches the heating element 61. The regulation or control the supply current is determined by choosing between 0 to 50 full cycles in each Control period carried out. As already described, the control period is 1 second at a line frequency of 50 Hz and 0.83 seconds at a line frequency of 60 Hz.

The microcomputer is switched in such a way that it can after switching on is reset. A reset circuit resets the microcomputer after the supply voltage or the supply current has stabilized. The reset circuit comprises a delay circuit with a resistor R30, a capacitor C30 and a diode D13. The output signal of the delay circuit is at the reset (RESET) connection of the microcomputer 60. The clock frequency is set by external time setting elements, which have a resistor R31 and a capacitor C31 are set. These Clock frequency is set to 420 EHz.

The temperature sensor is shown in Fig. 6 on the right side of Fig. 6 shown. The #! # Temperature sensor contains a thermistor 62 which is connected to a Analog / digital converter is connected, which has a capacitor C20 and a reset transistor T6 shows.

The microcomputer compares the resistance value of the thermistor 62 with the resistance value of the temperature adjustment potentiometer VR2. The calibration of resistor # 2 and series resistor R21 is chosen such that VR2 + R21 at at any given temperature roughly equal to the resistance value of the thermistor 62 and the parallel resistor is R27. The diodes Dl4-D16 have the same characteristics on.

The temperature control program holds the resistance values of the potentiometer (including the series resistor R21) equal to the resistance of the thermistor (including the parallel resistor R27). The microcomputer provides the heating input signal once per rule period. The microcomputer calculates the number of times the cycle is set for the stimulus input signal using the temperature difference and the rate of temperature change, as previously described. The thermistor 62 has a negative temperature coefficient on. An advantageous resistance / temperature characteristic of the thermistor 62 is shown graphically in FIG.

The analog / digital converter has one with a positive supply source connected integration capacitor C20 and a transistor T5 as a threshold value comparator on.

The capacitor C20 is alternately used by the potentiometer VR2 + R21 or the thermistor 62 and the parallel resistor R27 by selecting the connection D7 or of the connection D2 of the microcomputer 60 discharged to ground potential. The condenser C20 is supplied by transistor 26, which receives its control signal from terminal L8 of the microcomputer 60 received, reset to the positive supply voltage.

The output signal of the threshold comparator is dependent on the resistance value of the potentiometer or the thernistor in its pulse width modulated. This output signal occurs and arrives at the emitter of transistor T5 to the connection L7 of the microcomputer 60. The successive pulses on this Input L7 corresponds to the resistance values of the thermistor or the potentiometer.

At the end of the set operating time, the microcomputer switches 60 to a "keep warm" mode to the heating element or the heater on a to keep a constant temperature of 650 C - by having a value of Resistance VR2 is selected, which corresponds to the desired holding temperature. In the holding mode, the analog / digital converter compares the (fixed) resistance VR2 with the thermistor 62 (and the parallel resistor R27) by connecting the connections G2 or D2 of the microcomputer 60 can be selected, respectively. When a holding operation is not required or desired, connection G2 can be connected to ground.

During the initial warm-up and after a change in the Temperature setting, the LED diode indicating the current status lights up LD6 to indicate that the temperature is not yet correct. While of warming up or cooling down, the LED diode, LD6 lights up with a frequency of 2 Hz. When the temperature has reached the new set temperature, lights up the LED diode LD6 constantly.

If a (not shown) piezo signal transmitter with the connection 5K of the microcomputer 60 is connected, it will sound at the same frequency, in which the LED diode LD6, which indicates the current state, also lights up.

The microcomputer 60 has a safety shutdown. When the Device, the microcomputer turns off the heating element when the value of the thermistor Equal to the value of resistor R27 for 30 seconds (i.e.

when the thermistor is in an open circuit). The power supply is also switched off when the temperature of the thermistor exceeds 2200 C.

In both cases, the triac is controlled except function is set, and the LED diode LD6 indicating the current status lights up at two cycles with a frequency of 2 Hz, followed by a half-second delay time follows. This then repeats itself over and over again.

If the piezo signal generator is connected, it will be with the same Frequency and modulated in the same way as the LED diode LD6.

In Fig. 7, a preferred embodiment of the temperature controller a temperature sensor in the form of a thermistor 72 and a temperature setting device in the form of a potentiometer VR3. The thermistor 72 is across a resistor R73 is connected to a trigger circuit which has low-pass RC filter circuits. The two RC circuits are in series and allow for small transmission angles a larger regulation, while at the same time keeping the hysterysis effect small will.

The output signal of the trigger circuit arrives via a diac or a two-way switching diode DC1 to the load control stage.

The load control stage has a triac TR3, which is connected to the heating element 71 is in series. The gate electrode of the triac receives the trigger pulses from the diac DCI supplied, which is provided to the dependency of the trigger, circuit to keep fluctuations or changes in the triac gate electrode characteristics small.

The trigger circuit receives trigger pulses directly from the network or from Power adapter. The trigger pulses are generated by a first delay circuit, which is a Potentiometer VR3 and a resistor R70 as well as a resistor R70 for this series-connected capacitor C70 and a second delay circuit delayed, which comprises a resistor R71 and a capacitor C71.

The series resistor R70 serves to protect the potentiometer VR3, by the series resistor R70 the charging current limited. The diac DC1 is conductive when the voltage on capacitor C71 has the diac breakdown voltage achieved.

The capacitor then discharges through the diac and controls the triac on. Because the triac is turned on with both polarities of the gate electrode signal is, the triac is controlled with each cycle of the mains frequency.

By using a double RC delay circuit, the phase angle expands, so that the triac even with small passage angles can be turned on.

The hysterysis behavior is improved because of the on the capacitor C71 the charge on the capacitor after the diac has been switched off C70 is partially restored.

The thermistor 72 is connected to the ironing surface or the ironing plate of the Device in terms of heat. By using a thermistor 72 with a negative temperature coefficient (val. Fig. 4), the thermistor conducts the trigger pulses always decreases to ground when the temperature of the thermistor is a set Value exceeds. This value can be increased by increasing the resistance value of the resistor R73 can be raised.

There are two chokes L70 and L71 as well as a capacitor C73 in the supply line in order to keep high-frequency radiation as low as possible.

The thermistor 72 must be able to operate continuously at 3000 C and should have a very low resistance at around 2500 C.

The invention has been described on the basis of preferred exemplary embodiments. However, numerous modifications and configurations are possible for the person skilled in the art without that this leaves the idea of the invention.

Claims (38)

Control device claims 1. Control device for regulation the current or Power supply to a load, not shown a temperature sensor (11, 21, 31, 52, 62, 73), an operating device (13, 23, 32), a processor (10, 20, 30, 50, 60) that works with the temperature sensor and the operating device is connected and emits an output signal, and a Load control stage (18, 33) that controls the current or Power supply of the load (19, 26, 35, 51, 61, 71) depending on from the output signal of the processor. 2. Control device according to claim 1, characterized in that the operating device has a temperature adjuster (VR1, VR2, VR3) for setting the desired operating temperature. 3. Control device according to claim 1 or 2, characterized in that that the temperature adjuster is a potentiometer # (VR1, VR2, VR3) (Fig. 5, 6, 7). 4. Control device according to one of claims 1 to 3, characterized in that that the temperature sensor is a temperature-sensitive element '(21, 52, 62, 72) (Fig. 2, 5, 6, 7). 5. Control device according to one of claims 1 to 4, characterized in that that the temperature-sensitive element is a thermistor (21, 52) for high temperatures is (Fig. 2.5). 6. Control device according to one of claims 1 to 5, characterized in that that the thermistor has a negative temperature coefficient. 7. control unit according to one of claims 1 to 6, characterized in that that the thermistor is placed in the connection with the load. 8. Control device according to one of claims 1 to 7, characterized in that that the load control stage comprises a semiconductor switch (TRi, UR2, TR3) - (Fig. 5, 6, 7). 9. Control device according to one of claims 1 to 8, characterized in that that the semiconductor switch is an Eriac, which is between the power supply and the load is in series, and the gate electrode is supplied with the output signal of the processor receives. (Figures 5, 6, 7). 10. Control device according to one of claims 1 to 9, characterized in that that the output signal shows original trigger pulses that trigger the semiconductor switch. 11. Control device according to one of claims 1 to 10, characterized in that that the processor is a microprocessor. 12. Control device according to one of claims 1 to 11, characterized in that that the processor is a microcomputer (20, 50, 60) (Figs. 2, 5, 6). 13. Control device according to one of claims 1 to 12, characterized in that that the processor determines the electrical resistance value of the temperature adjuster and of the temperature-sensitive element for regulating the current or voltage supply the load compares. 14. Control device according to one of claims 1 to 13, characterized in that that the processor matches the resistance value of the temperature adjuster and the temperature-sensitive Element keeps essentially the same. 15. Regulatory device mg according to one of claims 1 to 14, characterized in that that the output signal has a variable duty cycle. 16. Control device according to one of claims 1 to 15, characterized in that that a pulse duty factor of 100 ° /> corresponds to a control period. 17. Control device according to one of claims 1 to 16, characterized in that that the processor the duty cycle for a control period depending on the difference between the temperature set with the ~ temperature adjuster and the temperature of the temperature sensitive element, as well depending on the Difference between the temperature of the temperature sensitive element during the calculated in the last two previous control periods. 18. Control device according to one of claims 1 to 17, characterized in that that the processor switches off the output signal after an adjustable period of time. 19. Control device according to one of claims 1 to 18, characterized in that that the operating device has at least one switch (S2-S6) with which the time is set (Fig. 6). 20. Control device according to one of claims 1 to 19, characterized in that that the processor has devices for a holding operation (Fig. 6). 21. Control device according to one of claims 1 to 20, characterized by a display device (16, 24, Ei) 1, LD2-LD6), which is connected to the processor in Connection. 22. Control device according to one of claims 1 to 21, characterized in that that the display device has at least one light-emitting (LED) diode (cd1, LD2-LD6) (Fig. 5, 6). 23. Control device according to one of claims 1 to 22, characterized in that that the display device always gives a discontinuous display when the temperature determined by the temperature sensor above or below that of the operating device set temperature. 24. Control device according to one of claims 1 to 23, characterized in that that the continuous display shows continuously whenever the from Temperature sensor determines the temperature set with the control device Temperature reached. 25. Control device according to one of claims 1 to 24, characterized by an acoustic signal generator (28) which is connected to the processor (#ig. 2, 6). 26. Control device according to one of claims 1 to 25, characterized in that that the acoustic signal generator is a siren or a horn. 27. Control device according to one of claims 1 to 26, characterized in that that the processor always switches off the output signal when the temperature sensor detected temperature corresponds to a very low or a very high temperature. 28. Regeleinrìcht mg according to one of claims 1 to 27, characterized in that that the processor has a shutdown counter that every time the anchor the duty cycle between successive control periods below a threshold value is counted further by one counter reading and is always reset when this change is above this threshold and that the processor receives the output signal always switches off when the count of the counter reaches a specified number reached at regular periods. 29. Control device according to one of claims 1 to 28, characterized through at least one with the processor related Switch (54) with which the specified number of control periods is changed (Fig. 5). 30. Control device according to one of claims 1 to 29, for the energy control an AC powered load, characterized in that the processor a trigger circuit (30) (Fig. 3). 31. Control device according to one of claims 1 to 30, characterized in that that the trigger circuit has at least one delay circuit (R70, C70; R71, C71) to delay the AC pulses from the power supply unit (Fig. 79. 32. Control device according to one of claims 1 to 31, characterized in that that the trigger circuit has a first (R70, C70) and a second, with the first series-connected delay circuit (R71, V71) whose time constants is in each case significantly smaller than the period of each alternating current pulse (Fig. 7). 33. control unit according to one of claims 1 to 32, characterized in that that each delay circuit is an RO integrator circuit. (Fig. 7). 34. Control device according to one of claims 1 to 33, characterized in that that the resistance element of the first RC circuit is the temperature adjuster (VR3) contains (Fig. 7). 35. Control device according to one of claims 1 to 34, characterized in that that the temperature-dependent element (72) the capacitor (C71) of the second RC circuit (R71, C71) is parallel (Fig. 7). 36. Control device according to one of claims 1 to 35, characterized by a threshold value element (DGl), which is between the processor output for the output signal and the gate electrode (Fig. 7). 37. Control device according to one of claims 1 to 36, characterized in that that the threshold value element (DC1) is a diac (Fig. 7). 38. Control device according to one of claims 1 to 37, for use in an electric iron, electric saucepan, or electric Pan, characterized in that the load is a heating element and the load control stage is a pickling element control stage (Figs. 2, 5, 6 and 7).