JPH0223977Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] The present invention relates to an abnormal state display device for displaying an abnormal state when an abnormal state occurs in a combustion safety device applied to an instantaneous water heater or the like. [Conventional Structure and Problems thereof] FIG. 1 shows the overall structure of an instantaneous water heater that uses petroleum as fuel. In Fig. 1, 1 is an electromagnetic pump for fuel supply, 2 is a nozzle, 3 is an igniter, and 4 is a fuel supply electromagnetic pump.
is a flame sensor, 5 is a fan, 6 is a combustion chamber, 7 is a heat exchanger, 8 is a water detection sensor, 9 is a chimney, 10 is a thermistor sensor, 11 is an outlet, 12 is a controller installed outdoors, 13 is a A remote controller installed indoors, 14 is an anti-seismic sensor. The controller 12 controls the set temperature set by the remote controller and the thermistor sensor 1.
Based on the hot water temperature detected by 0, the fan 5, igniter 3, and electromagnetic pump 1 are sequentially driven according to a predetermined sequence to perform combustion. This combustion heat is exchanged with water by a heat exchanger 7 disposed in the combustion chamber 6, and an operation for obtaining hot water at a desired temperature set by the remote controller 12 is achieved. This controller 12
The flame sensor 4 is installed to increase combustion safety.
By detecting the presence or absence of a flame, if a flame is detected in a sequence where no flame should exist, the combustion is stopped and the water detection sensor 8
It has a function to detect the presence of water and prevent dry firing, an anti-seismic sensor 14 to stop combustion in the event of an earthquake to prevent the risk of fire, and a function to detect a disconnection abnormality in the thermistor sensor 11. The occurrence of an abnormal condition is displayed on the remote controller 13 using a display means such as a lamp. These signal processing functions of the controller 12 are
Dedicated for combustion control with fail-safe function
Although it is executed by LSI, LSI is designed to reduce the number of output pins as much as possible because the number of output pins corresponds to the cost.
For example, as an example of a dedicated LSI, there is one that is provided with two output pins, an output pin A and an output pin B, for outputting an indication of an abnormal state. There are three output modes for each pin: Hi output, Lo output, and pulse output.
These two output pins A,
In theory, nine types of modes can be distinguished in B, but in reality, only four of these modes are used to indicate abnormal conditions for combustion. Table 1 shows the correspondence between the abnormal state of the combustion system shown in FIG. 1 and the output states of output pins A and B.

[Summary of the idea]

This invention was made in view of the above circumstances, and it provides indicators corresponding to the contents of the abnormality, and determines the contents of the abnormality that each of them means from the output status output from the two output pins of the LSI. An object of the present invention is to provide an abnormal state display device for a combustion safety device that allows a user to immediately know the content of the abnormality by operating a corresponding indicator. [Description of Embodiment] FIG. 3 shows an embodiment of the present invention. 21 is an LED for indicating thermistor disconnection, 22 is an LED for indicating dry firing,
23 is a non-ignition display LED, and 24 is a pseudo flame display LED. 25 is a timer circuit, which has a capacitor C1 and a transistor Q1, and turns on the transistor Q1 after a predetermined time period for charging the capacitor C1 when the power is turned on;
That is, it has a function of connecting point a to the common potential via the resistor R1 after a predetermined time has elapsed. 2
6 is a latch circuit, and transistors Q2 and Q
3, and when the potential at point a becomes Hi within a predetermined time set by the timer circuit 25 when the power is turned on, transistor Q2 turns on, transistor Q3 turns on, and further this transistor Q
It has a latch function in which transistor Q2 continues to be turned on even if the potential at point a returns to Lo when Q3 is turned on. When the latch circuit 26 operates, the potential at point b is connected to the DC power line via the transistor Q3, biasing the LED 24 for displaying a pseudo flame, and the potential at point c is connected to the common potential via the diode D1. , for non-ignition indication
This will disconnect the LED 23 from the DC power line. Q4 is a transistor whose base is connected to the output pin A, and whose collector is connected to the non-ignition display LED 23 and the pseudo flame display LED.
It is connected to the cathode side of 24. Q5 is also a transistor, its base is connected to output pin B, and its collector is connected to diode D.
2 and a diode D3, respectively, to the anode sides of the pseudo flame display LED 24 and the non-ignition display LED 23. Q6 is a transistor whose base is connected to point d of the collector of the transistor Q4 via the output pin B and the diode D4, and whose collector is connected to the dry firing display LED 22. Q7 is also a transistor, and its base is a differentiating circuit 2 consisting of a capacitor C2 and a resistor R2.
7 to the output pin B, and its collector is connected to the thermistor disconnection display LED 21. Next, the operation of the device of the present invention configured as described above will be explained. As shown in Table 1, when the thermistor is broken, a pulse output is output from the controller to output pin A and output pin B. If this abnormality does not occur within a predetermined time when the power is turned on, the latch circuit 26 will not operate and the potential at point a will be pulled to the common potential, so the pulse output from output pin A will be output from transistor Q2.
Only transistor Q4 is turned on and off without turning on and off the transistor Q4. On the other hand, since the pulse outputs of output pin A and output pin B are formed in synchronization, even if the pulse output of output pin A becomes Hi and turns on transistor Q4, transistor Q5 turns on at the same time. As a result, the anodes of the pseudo flame display LED 24 and the non-ignition display LED 23 are connected to the common potential via the diode D2 and the diode D3, so the non-ignition display LED 23 and the pseudo flame display LED 24 are turned off. I will continue. On the other hand, since the transistor Q7 is turned on and off at the pulse output period by the pulse output from the output pin B via the differentiating circuit 27, the thermistor disconnection indicating LED 21 lights up in a flicker state. At this time, the transistor Q6 is configured such that the pulse output of the output pin B is the pulse output of the transistor Q4.
d via diode D4 in synchronization with ON/OFF.
Since it flows to a point, it never turns on, and is used to indicate dry firing.
LED22 also never lights up. Therefore, in the case of a thermistor burnout abnormality in which the output of output pin A and output pin B becomes a pulse output, the thermistor burnout is displayed.
Only LED 21 will be displayed in fritzker mode. As shown in FIG. 3, when there is an abnormality in dry firing, the controller outputs a pulse output to output pin A and a Hi output to output pin B. As in the case of a thermistor disconnection, the pulse output from output pin A will turn ON/OFF only transistor Q4 without turning transistor Q2 ON/OFF, but since output pin B is always a Hi output, transistor Since Q5 is ON, diode D2
Bypassed by D3 and for non-ignition indication
The LED 23 and the pseudo flame display LED 24 continue to be turned off. On the other hand, the base potential of transistor Q6 is always equal to the output of output pin B.
Although it is a Hi output, transistor Q4 is ON/
Since it turns ON/OFF when it is turned OFF, the dry firing display LED 22 lights up in a flickering state. At this time, transistor Q7 is connected to output pin B.
Since the Hi output is cut off by the differentiating circuit 27, it will not turn on, and the thermistor disconnection display LED 21
It never lights up either. Therefore, when there is a dry firing abnormality in which the output of the output pin A is a pulse output and the output of the output pin B is a Hi output, only the dry firing display LED 22 is displayed in the flicker mode. As shown in Table 1, when a misfire occurs, the controller 12 outputs a pulse output to the output pin A and a Lo output to the output pin B. Since the output of output pin B is Lo, transistors Q6 and Q7 are not turned on, so the LED 22 for dry firing indication and thermistor disconnection indication are used.
LED 21 remains off. Since transistor Q5 is also OFF, the LED for indicating non-ignition
23 and the pseudo flame display LED 24 are not bypassed by the diodes D2 and D3 and are driven by the ON/OFF operation of the transistor Q4, but this abnormality must occur within a predetermined time when the power is turned on. Since the variation circuit 26 does not operate,
The potential at point b is disconnected from the DC power supply, and the pseudo flame display LED 24 will not light up. Therefore, only the LED 23 for indicating non-ignition is transistor Q.
It will be displayed in flicker mode according to the ON/OFF operation in step 4. In other words, when there is a misfire abnormality in which the output of output pin A is a pulse output and the output of output pin B is a Lo output, the misfire display LED 23
will be displayed in Fritzker mode. As shown in Table 1, in the case of a false flame abnormality, as well as in the case of a non-ignition abnormality, the controller sends a pulse output to output pin A, and output pin B
Lo output is output. However, since the check for a false flame is performed instantaneously when the power is turned on, if there is an abnormality in the false flame, the potential at point a is increased in a pulse manner within a predetermined time set by the timer circuit 25, and the latch circuit is activated. 26 will be working. As a result, point b is connected to the DC power line, power is supplied to the pseudo flame display LED 24, and transistor Q is turned on and off by the pulse output of output pin A.
4 causes this LED 24 to be displayed in the flicker mode. On the other hand, latch circuit 2
6 is operating, point C is connected to the common potential via transistor Q2, so the non-ignition indicator LED 23 is bypassed, and this LED 2
3 will never light up. Therefore, for pseudo flame display
Only LED 24 will be displayed in fritzker mode. In other words, when the power is turned on, output pin A
When there is a pseudo flame abnormality in which the output of pin B is a pulse output and the output of output pin B is a Lo output, it is used for displaying a pseudo flame.
Only LED 24 will be displayed in fritzker mode. Note that in the above embodiment, the LEDs 21, 22, 2
3 and 24 are each configured to be lit in flicker mode, but they may also be simply lit. [Effects of the present invention] As described above, according to this invention, when an abnormality is detected,
The abnormal state display signal output as a combination of Hi, Lo, and pulse from the two output pins of the LSI is input, and only the display corresponding to each abnormal state is operated, so the user can easily understand the abnormal state. It becomes possible to immediately and accurately recognize the state.

[Brief explanation of the drawing]

Fig. 1 is a schematic vertical sectional view showing an instantaneous water heater equipped with a combustion safety device to which the abnormal state display device of the present invention is applied, Fig. 2 is a circuit diagram of a conventional abnormal state display device, and Fig. 3 1 is a circuit diagram of an abnormal state display device according to an embodiment of the present invention; FIG. 2... Burner, 3... Igniter, 4... Flame sensor, 5... Fan, 6... Combustion chamber, 7... Heat exchanger, 8... Water detection sensor, 10... Thermistor sensor, 12... Controller, 13... Remote controller, 14... Anti-seismic sensor, 21...
...LED for indicating thermistor disconnection, 22...LED for indicating dry firing, 23...LED for indicating non-ignition, 24...
...LED for pseudo flame display, 25...Timer circuit,
26... Latch circuit, 27... Differential circuit.

Claims (1)

[Scope of utility model registration request] An abnormality that uses the output of an element that outputs each abnormal state of thermistor disconnection, dry firing, non-ignition, and false flame as a combination of Hi, Lo, and pulse from two output pins, and displays a display corresponding to each abnormal state. The status display device includes a timer circuit that outputs an output after a certain period of time after power is turned on, and a first circuit that receives an output from the first output pin in the event of a misfire and drives a misfire display.
switch element, and the above-mentioned first switch element when detecting a false flame.
A latch circuit that is latched by the output from the second output pin, prevents the operation of the non-ignition indicator and drives the false flame indicator, and outputs the output from the second output pin when dry firing is detected. a second switch element that receives the signal and drives a dry-burning display, and a third switch element that drives a thermistor disconnection display with an output supplied from the second output pin via a differential circuit when a thermistor disconnection is detected. An abnormal condition display device for a combustion safety device equipped with a switch element.