JPH0223769B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a digital temperature control device for a combustor for controlling the operation of a combustion control device so as to maintain the temperature of a heat demand source at a predetermined value.

In order to safely control a combustor in a boiler or the like, it is necessary to set the temperature of boiler water that is to be heated, and to control the combustor so that this set temperature is always maintained. Analog type temperature control devices using potentiometers are generally used for this purpose, but there are many limitations in adding functions such as high limit and burnout, and it is difficult to improve control accuracy. However, it also has drawbacks such as limitations.

This invention digitally processes the detection signal obtained from the temperature detection terminal, controls the combustor with the digital signal, and digital temperature control that enables safe control at all times even in the event of a power outage. The purpose is to provide equipment.

An embodiment of the present invention will be described below with reference to the drawings. On the front of the front panel 1 shown in FIG. 1, in this example, a digital display 2 consisting of a 7-segment display element with two digits, nine display lamps 3, four push buttons 4a to 4d, an operation switch 5, and two display lamps 6 for identifying display contents.
is located. Also, on the digital display 2,
An indicator lamp 7 is provided which indicates that there is a fraction of 0.5 when lit. Note that the term "display lamp" refers to optical display elements such as light emitting diodes in general.

FIG. 2 shows the configuration of the digital temperature control device shown in FIG. 1. Microprocessor 11
has a CPU 12, and a RAM 13 and a ROM 14 are connected to this CPU 12. Further, a temperature signal obtained from a temperature detection end shown as a thermistor TH is converted into a digital signal by an A/D converter 15 and then input to the CPU 12. On the other hand, the input switch 16 consisting of the push buttons 4a to 4d and the operation switch 5 is used to give a desired command to the CPU 12, and the output according to this command is
The digital display 2 and display lamps 3, 6,
7 is displayed.

In this example, each of the display lamps 3 has "V1
"Off", "V1 On", "V2 Off", "V2 On",
The notations "H/L OFF", "Freeze ON", "Number of times", "Current number of times", and "Current temperature" are attached to show what the numerical values displayed on the digital display 2 mean. This display mode switching is performed sequentially each time the push button 4a labeled "Step" is pressed, and when a mode that requires setting is selected, the push button 4a labeled "Up" is pressed.
b, or a push button 4c labeled "down"
By pressing , it is possible to arbitrarily change the numerical value displayed on the digital display 2. With the desired numerical value displayed, press the pushbutton 4d labeled "Memory". When the number is displayed, the displayed value is written to the RAM 13. In this example, the combustor valve V
1. It is configured so that the on and off temperatures of V2, the off temperature of the high limit switch (H/L), the on temperature of the antifreeze switch, and the number of times that valve V1 is turned on can be set, and either valve V1 or V2 can be set. The number of times the switch is turned on is stored in the RAM 13.

Furthermore, the CPU 12 causes the digital display 2 to flash (blink in short cycles) since the set values have not been written to the RAM 13 immediately after the main power is turned on when the device is started to be used. Informs you that you need to perform configuration operations. A similar situation also occurs when there is a temporary power outage during use. In this case, RAM13
The setting data written in the ROM 14 will be lost, but at the same time as the power is restored, the CPU 12 will read out the contents of the ROM 14 and supply control signals to the combustor based on this data. The data written in advance in the ROM 14 is suitable for safely operating the combustor until the predetermined setting data is written in the RAM 13, and this changes the operation of the combustor. Various inconveniences caused by the stoppage can be avoided. Also, if two or more types of data are written in the ROM 14 so that the optimal data can be selected according to conditions such as the combustor rating, it is advantageous in that the same model can be applied to many types of combustors. It is.

Next, the operation will be explained according to the flowchart shown in FIG. At the same time as the start by turning on the power, all the memory contents of the RAM 13 are first cleared, and then the step switch is turned on by the push button 4a to set the off point of the valve V1. In this setting operation, as described above, push the pushbutton 4b or 4c to set the value displayed on the digital display 2 so that it is the desired off point, and then press the pushbutton 4d to set this value.
It is completed by writing to RAM13. When it is confirmed that the newly set V1 off point value is within the appropriate range, push button 4a is pressed to proceed to the next V1 on point setting operation. If the value is incorrect, such as higher than the temperature, the display on the digital display 2 is flashed to notify that the set value is incorrect, and an operation is performed to prohibit switching of the selection mode. Similar setting operations are performed sequentially for the V1 on point, V2 on point, H/L off point, freeze on point, and number of valve operations. On the other hand, the number of pushbuttons 4a necessary for performing setting operations is 1.
If the button is not pressed once, the fixed setting value previously written in the ROM 14 is used.

Next, when the operation switch 5 is turned on, it is checked whether there is a burnout in the thermistor TH and whether there is a heat demand, and then a signal to ignite the burners V1 and V2 is output. . This causes the combustor to enter a normal combustion state, and at the same time a count signal is supplied to a counter that counts the number of operations. Therefore, if the temperature detected by the thermistor TH is, for example, 25°C, if the current count display mode is selected by operating the pushbutton 4a, "1" will be displayed on the digital display 2, and the current temperature will be displayed. If you select the mode, "25" will be displayed.

Both valves V1 and V2 of the combustor are open while the water temperature of the boiler is low to supply fuel to the burner at the maximum flow rate. ), valve V1 closes, the fuel supply flow rate decreases, and the second
It is assumed that the valve V2 is used in such a manner that the valve V2 also closes when the V2 off point (for example, 80° C.), which is the set temperature of the valve V2, is reached. Therefore the thermistor
When the detected temperature of TH reaches the V1 off point, CPU1
2 generates the V1 off signal and then generates the V2 off signal when the V2 off point is reached. Also, if the detected temperature drops in this state, the V2 on signal or V
1. The operation to generate the V2 ON signal and maintain the boiler water temperature at the set value is automatically performed. Additionally, if the water temperature of the boiler abnormally rises to the H/L off point for some reason, the CPU 12 will issue an emergency stop signal and valves V1 and V2 will be turned off instantly, and at the same time a predetermined failure indication will appear on the digital display 2. It will be done. This operation is similarly performed when burnout occurs due to disconnection of the thermistor TH.

As described above, according to the present invention, the set temperature of the combustor can be easily and accurately set, so controllability is greatly improved, and in the event of a power outage, a predetermined temperature can be set in advance. Since the combustor is controlled by commands from the ROM, which stores set values, a high level of safety can be ensured, and the digital display will not flash until the specified temperature is set. ,
Informs you that you need to perform configuration operations. Furthermore, since two or more types of temperature setting values are written in the ROM, there is an advantage that the same model can be applied to various types of combustors.

[Brief explanation of drawings]

FIG. 1 is a front view of the panel surface of a digital temperature control device according to an embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of the device, and FIG. 3 is a flowchart thereof. 1...Front panel, 2...Digital display, 3
...Display lamp, 4a to 4d...Push button, 5...Operation switch, 6,7...Display lamp, 11...Microprocessor, 12...CPU, 13...RAM, 14...
ROM, 15...A/D converter, 16...input switch, TH...thermistor.

Claims (1)

[Claims] 1 Heated by a RAM containing the temperature set value set by the input switch, a ROM containing two or more temperature set values, a digital display that displays information, and a combustor. a temperature detector that generates a detected temperature value corresponding to the temperature of the heated part; and a temperature sensor that is connected to the combustor to heat the heated part until the detected temperature value matches the temperature set value read from the RAM. If the temperature set value written in the RAM is lost due to a temporary power outage, the temperature set value suitable for safely operating the combustor will be read from the ROM. a central processing unit that supplies an operating signal to the combustor based on the read temperature setting value and flashes the display on the digital display until a predetermined temperature setting is performed after power outage recovery; Temperature control device.