JPH0555995B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a temperature detection circuit that connects a resistor variable temperature sensing element and a resistor in series and outputs a voltage signal according to the detected temperature to the connection point. This invention relates to a floor heating temperature controller that uses this to detect room temperature and floor temperature to control the heat generation of a heat source of a floor heating machine in accordance with changes in room temperature.

[Prior art] Figure 3 shows a temperature detection circuit that connects a resistor-variable temperature sensing element and a resistor in series and outputs a voltage signal corresponding to the detected temperature to the connection point to detect room temperature and bed temperature. FIG. 2 is a circuit diagram illustrating an example of a conventional floor heating temperature controller that detects and controls heat generation from a heat source. In the figure, AC is the commercial AC power supply, and SW is the relay coil L.
It is a relay contact that is driven by the excitation of . While the relay contact SW is closed, the electric heater H is energized and generates heat. The electric heater H is arranged in the flooring using a known configuration. In addition, AC power supply AC,
A heat source control circuit is configured by the relay coil L and relay contact SW. DC is a DC power supply for control, and TH1 is a room temperature sensing Samystar as a variable resistance temperature sensing element having negative temperature characteristics, one end of which is connected to the positive output terminal of the DC power supply. This sammister Th1 is arranged in a control unit attached to a wall or the like, for example, so as to be able to detect temperature changes in the room temperature. thermistor
A series circuit including a voltage adjusting variable resistor VR1 and a resistor R1 is connected in series to the other end of TH1.
This resistor R1 improves the linearity of the thermistor characteristics. One end of a thermistor Th2 for floor temperature detection is connected to the negative output terminal of the DC power supply DC. It is provided on the front or back side. Further, a series circuit including a temperature deviation setting variable resistor VR2 and a resistor R2 is connected between the other end of the thermistor Th2 and the positive output terminal of the DC power supply DC. OP1 is variable resistor VR2
Comparator OP1 is a comparator that compares the first voltage signal output from the sliding terminal of variable resistor VR2 with the second voltage signal output from the sliding terminal of variable resistor VR2.
A power amplifier Amp is connected to the output terminal of the power amplifier Amp, and one end of the output terminal of the power amplifier Amp is connected to the other end of a relay coil L whose one end is connected to the negative output terminal of the DC power supply DC. In this example the thermistor
Th1, variable resistor VR1, and resistor R1 constitute a temperature detection circuit for room temperature detection, and the thermistor
Th2, variable resistor VR2, and resistor R2 constitute a temperature detection circuit for detecting bed temperature.

The correlation between this controller's room temperature and floor temperature is
The result is as shown in the graph shown in FIG. Since the resistance value of the thermistor Th1 decreases as the room temperature rises, the second voltage signal V2 input to the negative input terminal of the comparator OP1 changes in direct proportion to the change in the room temperature. On the other hand, as the temperature of the floor, that is, the temperature of the electric heater H increases, the resistance value of the thermistor TH2 decreases, so the first voltage signal V1 input to the positive input terminal of the comparator OP1 is inversely proportional to the temperature of the floor. and change. Note that in the specification of this application, the words "directly proportional" and "inversely proportional" do not mean that they are immediately linearly proportional, but rather refer to changes in the voltage signal that change depending on the characteristics of a variable resistance temperature sensing element such as a thermistor or posistor. It is used to distinguish whether the trends in the relationship are directly proportional or inversely proportional.

The comparator OP1 outputs the heat generation command signal S when the value of the first voltage signal V1, which changes in inverse proportion to the floor temperature, is greater than the second voltage signal V2, which changes in direct proportion to the room temperature. And heat generation command signal S
Only during the period when is being output, the relay coil L is excited, the contact SW is closed, and the electric heater H is energized. For example, in the graph of Figure 4, the room temperature is 0.
Since the second voltage signal V2 exhibits a small value when the temperature is 0.degree. C., the electric heater H is energized until the first voltage signal V1 becomes smaller than the second voltage signal V2. When the room temperature is too low, the electric heater H continues to generate heat at the maximum temperature (for example, 60° C.). When the room temperature rises due to floor heating, when other heating means such as a kerosene heater is used indoors, or when the room temperature rises due to sunlight (for example, when it reaches 10 degrees Celsius), the level of the second voltage signal V2 increases. increases as the room temperature rises. As a result, the first voltage signal V1 becomes lower than the level of the second voltage signal V2 before the floor temperature reaches the maximum temperature (for example, 60 degrees Celsius), so the power supply to the electric heater H is stopped at that point. Ru. Then, when the temperature of the electric heater H falls due to the stop of energization and the first voltage signal V1 becomes larger than the second voltage signal V2, the energization to the electric heater H is restarted. Thereafter, this operation is repeated, and the operating point moves on the curve according to changes in room temperature.

When such an operation is performed, the characteristics of the conventional controller shown in Figure 3 when the variable resistors VR1 and VR2 are fixed at specific reference positions (in case of zero deviation) are shown by the curve shown by the thick line. a, and the characteristics obtained by moving the sliders of the variable resistors VR1 and VR2 from their specific positions to create a temperature deviation are curves b, c, d, b', c', and d'. Therefore, by adjusting the variable resistors VR1 and VR2, the temperature can be adjusted with a deviation of a predetermined width (T).
For example, when the sensible temperature becomes high, changing the characteristic from curve a to curves b', c', and d' will lower the temperature of the floor relative to the room temperature, and the temperature at your feet will decrease. will go down. On the other hand, if the sensible temperature becomes lower, changing the characteristics from curve a to curves b, c, and d will raise the temperature of the floor relative to room temperature and the temperature at your feet will rise. will rise.

[Problem to be solved by the invention] Thermistor Th as a variable resistance temperature sensing element
Since the linearity of the characteristics of Th1 and Th2 is affected by the resistance value of the resistors connected in series, variable resistors VR1 and Th2 are used for variable adjustment of the voltage level as in the past.
When VR2 is used, there is a problem that the linearity of the temperature sensing element deteriorates because the resistance value connected in series to the variable resistance temperature sensing element changes, and the detection accuracy of the temperature detection circuit deteriorates.

In addition, in a floor heating temperature controller using such a temperature detection circuit, variable resistors VR1 and VR
2 and change the voltage level, as shown in the graph in Figure 4, the characteristic curves a, b, c, etc. do not become parallel, but the width increases as they go upwards. There is a tendency for the width to become narrower and wider as you go down. This tendency also applies to variable resistor VR1.
This is because the linearity of the characteristics of the temperature sensing element is affected by the presence of VR2. Therefore, with conventional controllers, even if the control unit commands temperature adjustment with the same deviation (for example, ±2 to 6 degrees Celsius),
Since the adjustment range is narrow when the room temperature is high, and wide when the room temperature is low, there has been a problem that a large discrepancy occurs between the adjustment command and the actual temperature change. The above problem also occurs when a POSISTOR having a positive temperature coefficient is used as the variable resistance temperature sensing element.

SUMMARY OF THE INVENTION An object of the present invention is to provide a floor heating temperature controller that does not cause a large deviation between a commanded temperature deviation and an actual temperature change using a temperature detection circuit with high detection accuracy.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a floor temperature detection device which is provided to detect the temperature of the floor heated by the heat generated by the heat generation source H for floor heating. a floor temperature detection circuit 2 in which a variable resistance temperature sensing element Th2 and a resistor R2 are connected in series and output a first voltage signal V1 that changes in accordance with changes in floor temperature to a connection point;
A variable resistance temperature sensing element Th1 for detecting room temperature and a resistor R1 are connected in series to output a second voltage signal V1 that changes according to changes in room temperature at the connection point. The bed temperature detection circuit 1 and the room temperature detection circuit 2 are provided with a room temperature detection circuit 1 in which one of the first voltage signal V1 and the second voltage signal V2 changes in direct proportion to a change in the detected temperature, and the other changes in direct proportion to a change in the detected temperature. The first voltage signal V1 and the second voltage signal V2 are configured to change in inverse proportion to changes in the detected temperature.
The following configuration is used in a floor heating temperature controller that outputs a heat generation command signal S to the heat source control circuits Amp, L, and SW so as to make the heat source H for floor heating into a heat generating state by comparing the temperature with the temperature.

In the invention of claim 1, a constant voltage circuit applies a constant voltage to both ends of the bed temperature detection circuit 2 and the room temperature detection circuit 1.
ZD1 to ZD3, C1, C2, SW1 to SW4 are provided, and voltage adjustable constant voltage sources VR3 and VR are provided for at least one of the bed temperature detection circuit 2 and the room temperature detection circuit 1.
4. Connect OP2 and OP3 in series. In order to prevent measurement errors from occurring due to differences in the characteristics of the Zener diode, the constant voltage circuit consists of one Zener diode ZD1 and the Zener diode ZD1.
Switch circuits SW1 to SW that alternately connect ZD1 in parallel to the floor temperature detection circuit 2 and room temperature detection circuit 1 with their cathodes facing the positive output terminal side of the DC power supply DC.
4, and a pair of capacitors C1 and C2 connected in parallel to the bed temperature detection circuit 2 and room temperature detection circuit 1, respectively.
It consists of

In the second aspect of the present invention, a thermistor is particularly used as the variable resistance temperature sensing element.

[Function of the invention] In the present invention, measurement can be performed by providing a constant voltage circuit that applies a constant voltage to both ends of a bed temperature detection circuit and a room temperature detection circuit, each of which is composed of a series circuit of a variable resistance temperature sensing element and a resistor. By keeping the conditions constant, the linearity characteristic of the variable resistance temperature sensing element improved by the resistor is maintained. Then, a constant voltage source with adjustable voltage is connected in series to at least one of the floor temperature detection circuit and the room temperature detection circuit, and a constant voltage source is connected in series to at least one of the floor temperature detection circuit and the room temperature detection circuit. The level of the voltage signal output from the connection point between the variable resistance temperature sensing element and the resistor is changed by the output voltage of the source. If the level of the voltage signal is changed using a constant voltage source in this way, the characteristics of the variable resistance temperature sensing element, which has been improved by the resistor, will not be affected, and the second
As shown in the figure, the temperature adjustment range can be kept constant regardless of changes in room temperature.

If a constant voltage circuit that applies a constant voltage to both ends of the room temperature detection circuit and the bed temperature detection circuit is provided separately for each of the room temperature detection circuit and the bed temperature detection circuit, the characteristics of the Zener diode used in each constant voltage circuit will change. Variations cause measurement errors. According to the present invention, since a constant voltage circuit is used in which one Zener diode is alternately connected in parallel to the room temperature detection circuit and the bed temperature detection circuit, measurement errors due to variations in the characteristics of the Zener diodes can be prevented from occurring.

[Examples] Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a circuit diagram of one embodiment, in which the same members as those of the conventional controller shown in FIG. 3 are given the same reference numerals as used in FIG. 3. In this embodiment, SW1 to SW4 are control switches such as transistors that are turned on and off according to a control signal CS, and these control switches SW1 to SW4 are connected to a thermistor TH for detecting room temperature.
1 and a resistor R1, and a floor temperature detection circuit 2 consisting of a thermistor TH2 and a resistor R2 for floor temperature detection are alternately connected to a DC power supply DC, and at the same time, a Zener diode ZD1 is connected to the detection circuit 1, A switch circuit is configured to connect both ends of 2 in parallel. Control switch SW1 and
SW2 and control switches SW3 and SW4 each form a pair and are alternately turned on and off in response to a control signal CS. Note that IV is an inverter circuit that inverts the control signal CS.

Capacitors C1 and C2 connected in parallel to the room temperature detection circuit 1 and the floor temperature detection circuit 2 are connected to the DC power supply DC when the corresponding control switches SW1 and SW2 or control switches SW3 and SW4 are in the on state. It constitutes an auxiliary power supply that applies a predetermined voltage to the room temperature detection circuit 1 and the bed temperature detection circuit 2 when the corresponding control switch is in the OFF state.

A resistor R3 and a variable resistor are connected to both ends of the DC power supply DC.
A voltage dividing circuit consisting of VR3 is connected in parallel, the voltage dividing point of the voltage dividing circuit is connected to the plasma input terminal of operational amplifier OP2, and the negative input terminal of operational amplifier OP2 is connected to the output terminal. This operational amplifier OP2 constitutes a buffer circuit, which includes a resistor R3, a variable resistor VR3, and an operational amplifier OP2.
A first constant voltage source with a small internal impedance and which can be adjusted in voltage is configured. Further, a voltage dividing circuit consisting of a resistor R4 and a variable resistor VR4 is connected in parallel to both ends of the DC power supply DC, and the voltage dividing point of the voltage dividing circuit is connected to the positive input terminal of the operational amplifier OP3. The negative input terminal is connected to the output terminal. This operational amplifier OP
3 constitutes a buffer circuit, and a second constant voltage source whose voltage can be adjusted is constituted by a resistor R4, a variable resistor VR4, and an operational amplifier OP3. The output voltages of operational amplifiers OP2 and OP3, set by changing the resistance values of variable resistors VR3 and VR4, are added to the voltage output from the connection point between thermistor TH1 and resistor R1 and the connection point between thermistor TH2 and resistor R2. . By changing the output voltages of the first and second constant voltage sources in this way, it is possible to The levels of the first and second voltage signals V1 and V2 can be changed without affecting the linearity of thermistors Th1 and Th2 adjusted by resistors R1 and R2. In addition, since the Zener diode ZD1, which constitutes a part of the constant voltage circuit, is connected in parallel to the room temperature detection circuit 1 and the floor temperature detection circuit 2, the constant voltage source is connected in series to the detection circuit, and the first and second Even if the voltage signal level is changed, the measurement conditions are always held constant.

In this embodiment, a case where temperature deviation is actually adjusted will be described. FIG. 2 shows the temperature adjustment characteristics of room temperature and bed temperature obtained in this example.
Curve A is the case when the reference temperature deviation is zero,
The variable resistor VR4 is positioned at an intermediate position, and the variable resistor VR3 is finely adjusted to determine the characteristic with zero deviation. The variable resistor VR3 is adjusted in a factory or the like, and the temperature deviation is normally set using the variable resistor VR4 which is variable in steps (for example, at 2° intervals). As seen in FIG. 2, according to this embodiment, with the above-mentioned configuration, Samystar TH1 and Th
The linearity of the characteristic curves A, B, C, D,
B', C' and D' become approximately parallel. Therefore, regardless of the room temperature, there will not be a large deviation between the temperature deviation commanded or indicated by the variable resistor VR2 and the actual temperature change.

Next, the operation of the above embodiment will be explained. When the power switch (not shown) is turned on, the control signal CS is output from the oscillation circuit (not shown), and the control signal CS is output to the control switches SW1 and SW2 and the control switches SW3 and SW.
4 repeats conduction and cutoff alternately. control switch
When SW1 and SW2 are closed, the current flows from the positive output terminal of the DC power supply to the switch SW1
Thermistor Th1, resistor R1, and capacitor C1 → output terminal of operational amplifier OP2 → operational amplifier
Flows through the path from the ground terminal of OP2 to the negative output terminal of the DC power supply. As a result, thermistor TH1 and resistance R
1, a second voltage signal V2, which is directly proportional to the change in room temperature according to the characteristics of the thermistor TH1, is connected to the thermistor TH1.
is output. This voltage signal V2 is the sum of the voltage obtained by dividing the constant voltage appearing across the Zener diode ZD1 by the resistance value of the thermistor Th1 and the resistor R1, and the constant voltage output from the operational amplifier OP2 constituting the buffer circuit. Become. Capacitor C
1 is charged to the voltage across the Zener diode ZD1 and discharged through the thermistors TH1 and R1 after the control switches SW1 and SW2 are opened, so that the second voltage signal V2 continues to be output.

When control switches SW1 and SW2 open and control switches SW3 and SW4 close, the current similarly flows from the positive output terminal of the DC power supply to the switch.
It flows through the path of SW3 → resistor R2 and thermistor Th2 and capacitor C2 → output terminal of operational amplifier OP3 → ground terminal of operational amplifier OP3 → negative output terminal of DC power supply DC. As a result, thermistor TH2
A first voltage signal V1 that is inversely proportional to the change in bed temperature is outputted to the connection point between the thermistor TH2 and the resistor R2, depending on the characteristics of the thermistor TH2. This voltage signal V1 is converted to a voltage obtained by dividing the constant voltage appearing across the Zener diode ZD1 by the resistance value of the thermistor Th2 and the resistor R2, and the operational amplifier OP forming the buffer circuit.
The value is the sum of the constant voltage output from 3. Capacitor C2 is charged to the voltage across Zener diode ZD1, and control switches SW3 and SW4 are charged.
The first voltage signal V1 is also constantly output because it is discharged through the thermistor TH2 and R2 after it is opened.

When the room temperature is low, the level of the second voltage signal V2 is lower than the level of the first voltage signal V1, the heat generation command signal S continues to be output from the comparator OP1 to the amplifier Amp, and an exciting current flows through the relay coil L. The switch SW continues to remain conductive. Therefore, the electric heater H continues to dissipate heat. When the electric heater H continues dissipating heat for a certain period of time, the bed temperature increases and the level of the first voltage signal V1 decreases.
When the room temperature rises due to heat generation from the electric heater H or other causes and the second voltage signal V2 increases, the first voltage signal V2 increases.
The level of the voltage signal V1 becomes lower than the level of the second voltage signal V2, and as a result, the heat generation command signal S is stopped and the electricity supply to the electric heater H is stopped. As time passes and the temperature of the room temperature or the floor falls, the first voltage signal V1 becomes larger than the second voltage signal V2 again, and the electricity supply to the electric heater H is restarted. This operation is repeated thereafter.

If you feel that the room temperature is high, step the slider of variable resistor VR4 counterclockwise to obtain the temperature deviation, that is, to change the characteristics to B', C', and D' in Figure 2. The voltage output from the operational amplifier OP3 can be reduced by rotating the operational amplifier OP3. On the other hand, if you feel that the room temperature is low, turn the slider of variable resistor VR4 clockwise to change the characteristics to B, C, and D in Figure 2, so that the output from operational amplifier OP3 is All you have to do is increase the voltage.

In the above embodiment, one Zener diode ZD1 is connected to the room temperature detection circuit 1 and the floor temperature detection circuit 2.
Since it is configured to be used as a constant voltage means, it is possible to prevent measurement errors from occurring due to variations in the characteristics of the Zener diode.

Although the above embodiment uses a thermistor as the variable resistance temperature sensing element, the present invention is of course applicable to the case where a POSISTOR having a positive temperature coefficient is used as the variable resistance temperature sensing element. It is. Note that when a POSISTOR is used in the embodiment shown in FIG.
input to the negative input terminal of the second voltage signal V
2 may be input to the plus input terminal of the comparator OP1.

Furthermore, in the above embodiment, even if the positions of thermistor Th1 and resistor R1 are changed, and the positions of resistor R2 and thermistor Th2 are changed, the first voltage signal V1 is input to the negative input terminal of comparator OP1 in the same manner as described above. input the second voltage signal V2 to the comparator
All you have to do is input it to the positive input terminal of OP1.

Further, in the above embodiment, a combination of a variable resistor and a buffer circuit is used as the voltage-adjustable constant-voltage power supply, but it is of course possible to use other known voltage-adjustable constant-voltage power supplies. . Note that the constant voltage power supply may be placed anywhere in the circuit as long as it can apply voltage to the detection circuits 1 and 2. For example, in the embodiment shown in FIG. Of course, it can also be placed between them.

Further, in each of the above embodiments, the electric heater H is used as the heat source, but it goes without saying that an electrically controllable oil boiler or gas boiler can be used as the heat source. In this case, steam and hot water will circulate under the floor as a heat transfer medium.

Furthermore, in the above embodiment, the relay switch SW is used to control the energization of the electric heater H, but the heat generation command signal S causes the light emitting diode to emit light, and the light emitted from the light emitting diode is received by the phototransistor. Of course, the supply of electricity to the electric heater H may be controlled by turning on/off the transistor.

Further, in each of the above embodiments, the temperature deviation is changed in a stepwise manner by mainly changing the voltage applied to the bed temperature detection circuit 2 in a stepwise manner, but the voltage applied to the room temperature detection circuit 1 is mainly changed in a stepwise manner. Of course, the temperature deviation may be changed accordingly.

[Effects of the Invention] According to the invention of claim 1, a constant voltage circuit that applies a constant voltage to both ends of the bed temperature detection circuit and the room temperature detection circuit is provided, and at least one of the bed temperature detection circuit and the room temperature detection circuit is provided with voltage adjustment. By connecting possible constant voltage sources in series, it is possible to create a large difference between the commanded temperature deviation and the actual temperature change without changing the characteristics of the variable resistance temperature sensing element, which has been improved by the resistor. You can adjust the temperature without having to worry about it. In particular, according to the present invention, since one Zener diode is used for applying a constant voltage to the bed temperature detection circuit and the room temperature detection circuit, there is an advantage that measurement errors due to characteristic errors of the Zener diode can be prevented from occurring.

According to the second aspect of the invention, since the thermistor, which is the cheapest and has the best characteristics, is used as the variable resistance temperature sensing element, it is possible to provide a highly accurate and inexpensive controller.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of an embodiment of a floor heating temperature controller.
Fig. 2 is a graph showing the temperature control characteristics of the embodiment shown in Fig. 1, Fig. 3 is a circuit diagram of a conventional floor heating temperature controller,
FIG. 4 is a graph showing the temperature control characteristics of a conventional floor heating temperature controller. DC...DC power supply, AC...Alternating current power supply, L...Reed coil, SW...Reed switch, H...Electric heater (floor heating heat source), Th1 and Th2...
Thermistor (variable resistance temperature sensing element), R1~R
7...Resistor, ZD1~ZD3...Zener diode, OP1~OP3...Operation amplifier, SW1~SW
4... Control switch, VR1-VR2... Variable resistor.

Claims (1)

[Scope of Claims] 1. A resistor is connected in series with a variable resistance temperature sensing element for detecting floor temperature, which is provided to detect the temperature of a floor heated by heat generated by a heat generating source for floor heating. a bed temperature detection circuit that outputs a first voltage signal that changes according to a change in the temperature of the floor to the connection point; and a resistance-variable temperature sensing element for room temperature detection that is provided to detect the room temperature. and a resistor are connected in series, and a second
a room temperature detection circuit that outputs a voltage signal, and the bed temperature detection circuit and the room temperature detection circuit are configured such that one of the first voltage signal and the second voltage signal changes in direct proportion to a change in the detected temperature. , the other is configured to change in inverse proportion to a change in the detected temperature, and generates heat so that the first voltage signal and the second voltage signal are compared to bring the heat generating source for floor heating into a heating state. A floor heating temperature controller that outputs a heat generation command signal to a source control circuit, further comprising: a constant voltage circuit that applies a constant voltage to both ends of the floor temperature detection circuit and the room temperature detection circuit; A constant voltage source whose voltage can be adjusted is connected in series to at least one of the detection circuits; A floor heating temperature controller comprising: a switch circuit connected in parallel to a floor temperature detection circuit and the room temperature detection circuit; and a pair of capacitors connected in parallel to the floor temperature detection circuit and the room temperature detection circuit, respectively. 2 A floor temperature detection thermistor and a resistor, which are installed to detect the temperature of the floor heated by the heat generated by the heat generation source for floor heating, are connected in series, and the connection point is connected to the temperature change of the floor. The first variable changes in inverse proportion.
a floor temperature detection circuit that outputs a voltage signal of , and a room temperature detection thermistor and a resistor provided to detect the room temperature are connected in series, and a second voltage signal that changes in direct proportion to the change in the room temperature is connected at the connection point. a room temperature detection circuit that outputs a voltage signal, and sends a heat generation command to a heat source control circuit to cause the floor heating heat source to be in a heat generating state for a period in which the first voltage signal is greater than the second voltage signal. In a floor heating temperature controller that outputs a signal, a constant voltage circuit that applies a constant voltage to both ends of the floor temperature detection circuit and the room temperature detection circuit is provided, and at least one of the floor temperature detection circuit and the room temperature detection circuit is provided with a constant voltage circuit that applies a constant voltage to both ends of the floor temperature detection circuit and the room temperature detection circuit. Adjustable constant voltage sources are connected in series, and the constant voltage circuit connects one Zener diode and the Zener diode with its cathode facing the positive output terminal side of the DC power supply, and alternately connects the bed temperature detection circuit and the A floor heating temperature controller comprising: a switch circuit connected in parallel to a room temperature detection circuit; and a pair of capacitors connected in parallel to the floor temperature detection circuit and the room temperature detection circuit, respectively.