阅读说明：本技术 一种二线式加热测温装置及其加热测温方法 (Two-wire heating temperature measuring device and heating temperature measuring method thereof ) 是由 史翰缨 史建军 韩潇 于 2020-12-28 设计创作，主要内容包括：本发明涉及电加热测温技术领域,特别涉及一种二线式加热测温装置及其加热测温方法。包括控制部分和负载部分；控制部分由主控单元M、加热电源E1、测控电源E2和换向开关K组成；负载部分由加热器R1、热敏电阻R2、隔离二极管D、导线A和导线B组成；所述主控单元M控制端S-1和S-2分别通过控制线与换向开关K连接,加热电源E1正极与换向开关K1-2连接,加热电源E1负极接地,测控电源E2正极经电阻R3与换向开关K2-3和温度数据端C连接,测控电源E2负极接地；加热器R1与所述热敏电阻R2串联,所述隔离二极管D与热敏电阻R2并联,二极管D正极接热敏电阻R2和导线A,二极管D负极接热敏电阻另一端和加热器R1。(The invention relates to the technical field of electric heating temperature measurement, in particular to a two-wire heating temperature measurement device and a heating temperature measurement method thereof. Comprises a control part and a load part; the control part consists of a main control unit M, a heating power supply E1, a measurement and control power supply E2 and a reversing switch K; the load part consists of a heater R1, a thermistor R2, an isolating diode D, a lead A and a lead B; the control ends S-1 and S-2 of the master control unit M are respectively connected with a reversing switch K through control lines, the positive electrode of a heating power supply E1 is connected with the reversing switch K1-2, the negative electrode of the heating power supply E1 is grounded, the positive electrode of a measurement and control power supply E2 is connected with the reversing switch K2-3 and a temperature data end C through a resistor R3, and the negative electrode of the measurement and control power supply E2 is grounded; the heater R1 is connected with the thermistor R2 in series, the isolating diode D is connected with the thermistor R2 in parallel, the anode of the diode D is connected with the thermistor R2 and the lead A, and the cathode of the diode D is connected with the other end of the thermistor and the heater R1.)

1. A two-wire heating temperature measuring device is characterized by comprising a control part and a load part; the control part consists of a main control unit M, a heating power supply E1, a measurement and control power supply E2 and a reversing switch K; the load part consists of a heater R1, a thermistor R2, an isolating diode D, a lead A and a lead B;

in the control part, control ends S-1 and S-2 of the main control unit M are respectively connected with a reversing switch K through control lines, the anode of a heating power supply E1 is connected with the reversing switch K1-2, the cathode of the heating power supply E1 is grounded, the anode of a measurement and control power supply E2 is connected with a reversing switch K2-3 and a temperature data end C through a resistor R3, and the cathode of the measurement and control power supply E2 is grounded; the main control unit M collects temperature data through C and controls the action of a reversing switch K through control ends S-1 and S-2, a lead A of a load part is connected with the reversing switch K1-1, and a lead B is connected with a reversing switch K2-1;

in the load part, the heater R1 is connected with the thermistor R2 in series, the isolating diode D is connected with the thermistor R2 in parallel, the anode of the diode D is connected with the thermistor R2 and a lead wire A, the cathode of the diode D is connected with the other end of the thermistor R2 and the heater R1, and the other end of the heater R1 is connected with a lead wire B.

2. The two-wire heating temperature measuring device according to claim 1,

the resistance value of the thermistor is larger than that of the heater.

3. The two-wire heating temperature measuring device according to claim 1, wherein: the current of the load part is alternating reversing direct current, the flowing direction of the forward current I1 is A → load → B during heating, and the flowing direction of the reverse current I2 is B → load → A during temperature measurement.

4. The two-wire heating temperature measuring device according to claim 1, wherein the load part and the control part are connected by two wires to realize the dual functions of heating and temperature measuring.

5. The two-wire heating temperature measuring device according to claim 1, wherein the main control unit M controls the reversing switch K to operate, and switches the heating power supply E1 and the measurement and control power supply E2 to reverse and circulate in a time-sharing manner, wherein the heating power supply E1 is switched on to heat when I1 flows through a load in a forward direction, and the heating power supply E2 is switched on to measure the temperature when I2 flows through the load in a reverse direction.

6. The two-wire heating temperature measuring device according to claim 1, wherein the reversing switch K is a double-pole double-throw mechanical switch or a switch formed by electronic circuits, and the electronic switch element inside the reversing switch K is a field effect transistor, a triode, a relay or a reversing H-bridge integrated circuit, and the switching action of the reversing switch K is controlled by the main control unit M.

7. The heating and temperature measuring method of the two-wire heating and temperature measuring device according to claim 1, wherein the working process comprises:

the main control unit controls the reversing switch to work in a reversing mode according to a certain rule, so that the power supply of the heating power supply is temporarily stopped, a reverse measurement and control power supply is provided in a gap of the temporary stop, namely, the reversing switch provides a temperature measurement time slot, during heating, the heating power supply E1 is connected with a load part in a forward direction, and the measurement and control power supply E2 is connected with the load part in a reverse direction;

during heating, a heating power supply E1 is connected with a load through a reversing switch K, the current is I1, and a diode D of the load part is conducted in the forward direction;

because the forward voltage drop of the diode D is small, the thermistor R2 is short-circuited, the heating voltage is almost transmitted to the two ends of the heater R1 without obstruction, and the heater R1 can heat normally;

when the temperature is measured, the heating power supply E1 is cut off, the measurement and control power supply E2 is reversely connected with the load part through the reversing switch K, the current is I2, the diode D of the load part is reversely cut off, the thermistor R2 is connected into a loop, the resistance value of the thermistor is far greater than that of the heater, so that the measurement and control voltage is almost completely applied to the two ends of the thermistor, and the voltage value on the connecting wire C is the temperature data signal reflected by the thermistor.

8. The heating and temperature measuring method of the two-wire heating and temperature measuring device as claimed in claim 7, wherein the temperature measuring circuit is connected in series with the heater resistor R1, but since the resistance of the thermistor R2 is hundreds of times of the resistance of the heater and the resistance of the heater changes slightly with temperature, the influence of the heater resistor on the temperature measuring accuracy is very limited and is ignored in most practical applications.

Technical Field

The invention relates to the technical field of electric heating temperature measurement, in particular to a two-wire heating temperature measurement device and a heating temperature measurement method thereof.

Background

The electric heating technology is generally applied to various fields due to the characteristics of cleanness, high efficiency and easy control, and along with the requirement of electric heating temperature control, a temperature measuring element is required to sense the heating temperature in real time. To ensure temperature measurement accuracy, the temperature measurement element is typically in close proximity to the heater, while the temperature measurement element transmits temperature parameters to the control unit via an independent wire.

In the prior art, a power supply line of a common heater is high-power and high-current, and a temperature measuring element and a control unit both work with low-power and low-signal. The difference of power supply parameters of the heater and the temperature measuring element is large, so that the heater and the temperature measuring element are respectively provided with independent circuits for connection, two-wire heating is commonly adopted, one to three-wire temperature measurement is additionally adopted, and three to five wires are required to ensure that the heating and the temperature measurement can work normally at the same time.

If let heating and temperature measurement use common circuit, heating and temperature measurement collinear work promptly, can reduce interconnecting link, realize heating temperature measurement integration combination, to simplifying electric heating system cost, especially to long distance heating system, have great practical meaning.

Disclosure of Invention

Therefore, the invention aims to provide a two-wire heating temperature measuring device and a heating temperature measuring method thereof, which simplify a heating circuit and reduce the connection cost of a heating load.

In order to achieve the purpose, the two-wire heating temperature measuring device and the heating temperature measuring method thereof are realized by adopting the following technical scheme:

a two-wire heating temperature measuring device comprises a control part and a load part. The control part consists of a main control unit M, a heating power supply E1, a measurement and control power supply E2 and a reversing switch K. The load part is composed of a heater R1, a thermistor R2, an isolation diode D, a lead A and a lead B.

The control part is provided with a manual control part and an electronic control part.

In the manual control part, a control end S of the main control unit M is connected with a reversing switch K through a control line, the positive electrode of a heating power supply E1 is connected with a reversing switch K1-2, and the negative electrode of the heating power supply E1 is grounded. The positive electrode of the measurement and control power supply E2 is connected with the reversing switch K2-3 and the temperature data end C through a resistor R3, and the negative electrode of the measurement and control power supply E2 is grounded. The main control unit M collects temperature data through the C and controls the action of the reversing switch K through the control end S. Load section conductor a is connected to commutation switch K1-1 and conductor B is connected to commutation switch K2-1.

In the electronic control part, control ends S-1 and S-2 of the main control unit M are respectively connected with a reversing switch K through control lines, the positive electrode of a heating power supply E1 is connected with the reversing switch K1-2, and the negative electrode of the heating power supply E1 is grounded. The positive electrode of the measurement and control power supply E2 is connected with the reversing switch K2-3 and the temperature data end C through a resistor R3, and the negative electrode of the measurement and control power supply E2 is grounded. The master control unit M collects temperature data through the C and controls the action of the reversing switch K through the control ends S-1 and S-2. Load section conductor a is connected to commutation switch K1-1 and conductor B is connected to commutation switch K2-1.

In the load portion, the heater R1 is connected in series with the thermistor R2, and the isolation diode D is connected in parallel with the thermistor R2. The anode of the diode D is connected with the thermistor R2 and the lead A, and the cathode of the diode D is connected with the other end of the thermistor and the heater R1. The other end of the heater R1 is connected with a lead B.

In the two-wire heating and temperature measuring device, the resistance value of the thermistor is larger than that of the heater.

The two-wire heating temperature measuring device is characterized in that the current of the load part is alternating reversing direct current, the flowing direction of the forward current I1 is A → load → B during heating, and the flowing direction of the reverse current I2 is B → load → A during temperature measurement.

The two-wire heating temperature measuring device can realize double functions of heating and temperature measuring only by connecting the load part and the control part through two wires.

The two-wire heating temperature measuring device is characterized in that the master control unit M controls the reversing switch K to act, the heating power supply E1 and the measurement and control power supply E2 are switched to reverse in a time-sharing mode to circulate, the heating power supply E1 is switched on, so that the I1 heats when flowing through a load in the forward direction, and the heating power supply E2 is switched on, so that the I2 measures the temperature when flowing through the load in the reverse direction.

The two-wire heating temperature measuring device is characterized in that the reversing switch K is a double-pole double-throw mechanical switch or a switch formed by electronic circuits, a field effect tube, a triode or a relay is used as an internal switch element, a reversing H-bridge integrated circuit can also be used, and the switching action is controlled by a main control unit M.

The heating temperature control system can be provided with a key, a display, a printer and other human-computer interaction circuits or output equipment according to requirements.

A heating temperature measurement method of a two-wire heating temperature measurement device comprises the working process:

the main control unit controls the reversing switch to work in a reversing mode according to a certain rule, so that the power supply of the heating power supply is temporarily stopped, and a reverse measurement and control power supply is provided in a gap of the temporary stop, namely, the reversing switch provides a temperature measurement time slot. During heating, the heating power supply E1 is connected with the load part in the forward direction, and the measurement and control power supply E2 is connected with the load part in the reverse direction during the temperature measurement time slot.

During heating, the heating power supply E1 is connected with the load through the reversing switch M, the current is I1, and the diode D of the load part is conducted in the forward direction. Since the forward voltage drop of the diode D is small, the thermistor R2 is short-circuited, the heating voltage is transmitted to both ends of the heater R1 almost without hindrance, and the heater R1 can be normally heated.

When the temperature is measured, the heating power supply E1 is cut off, the measurement and control power supply E2 is reversely connected with the load part through the reversing switch K, the current is I2, the diode D of the load part is reversely cut off, and the thermistor R2 is connected into a loop. Because the resistance value of the thermistor is far larger than that of the heater, the measurement and control voltage is almost completely applied to two ends of the thermistor. The voltage value on the connecting wire C at this time is the temperature data signal reflected by the thermistor.

The temperature measuring loop is connected with the heater resistor R1 in series, but the resistance value of the thermistor R2 is hundreds of times of that of the heater, and the resistance value of the heater changes slightly with the temperature, so the influence of the heater resistor on the temperature measuring precision is very limited, and can be ignored in most practical applications. In the case of special accuracy requirements, the thermometry data can be corrected by software to completely eliminate the effect of heater resistance.

The invention has the following beneficial effects:

1. the heating and temperature measurement share two connecting wires, so that the connecting wire loaded by the heater is simplified to the utmost extent, the heating and temperature measurement integration is realized in the real sense, and the construction cost and the maintenance cost of a heating control circuit can be obviously reduced.

2. Under the collinear condition of heating and temperature measurement, the high-power supply of the heater can be realized, and the small signal transmission of temperature measurement parameters can be realized, and the two are not influenced mutually. The precision of temperature measurement data can be guaranteed completely, and the practical effect is good.

3. The thermometric time slot is only in milliseconds. Because the temperature measuring time slot is short and has a longer time interval, and the heater generally has larger thermal inertia, the short interval of the heater stopping power supply at the moment of temperature measurement has little influence on the operation of the heater. The existence of the temperature measurement time slot can not be sensed in the actual use.

4. The structure of the load part is very simple, only one diode is used, and half of connecting wires are saved. The method has better economic value for a multi-load long-distance heating temperature measurement system.

5. The heater load uses only 2 wires, and the connection lines and the interface mode can be compatible with most of the traditional heater lines, so that the connection used by the equipment lines has great flexibility. When the method is used for measuring the temperature, the original connecting circuit of the heating system can be directly used without replacement.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a basic schematic diagram of the present invention (the control part does not include a main control unit, and the reversing switch is a mechanical switch);

fig. 2 is a schematic diagram of an embodiment of the present invention (the control part includes a main control unit, and the reversing switch is an electronic switch).

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in fig. 2, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functionality throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

Referring to fig. 1-2, a two-wire heating temperature measuring device includes a control portion and a load portion. The control part consists of a main control unit M, a heating power supply E1, a measurement and control power supply E2 and a reversing switch K. The load part is composed of a heater R1, a thermistor R2, an isolation diode D, a lead A and a lead B.

The control part is provided with a manual control part and an electronic control part.

In the manual control part, a control end S of the main control unit M is connected with a reversing switch K through a control line, the positive electrode of a heating power supply E1 is connected with a reversing switch K1-2, and the negative electrode of the heating power supply E1 is grounded. The positive electrode of the measurement and control power supply E2 is connected with the reversing switch K2-3 and the temperature data end C through a resistor R3, and the negative electrode of the measurement and control power supply E2 is grounded. The main control unit M collects temperature data through the C and controls the action of the reversing switch K through the control end S. Load section conductor a is connected to commutation switch K1-1 and conductor B is connected to commutation switch K2-1.

In the electronic control part, control ends S-1 and S-2 of the main control unit M are respectively connected with a reversing switch K through control lines, the positive electrode of a heating power supply E1 is connected with the reversing switch K1-2, and the negative electrode of the heating power supply E1 is grounded. The positive electrode of the measurement and control power supply E2 is connected with the reversing switch K2-3 and the temperature data end C through a resistor R3, and the negative electrode of the measurement and control power supply E2 is grounded. The master control unit M collects temperature data through the C and controls the action of the reversing switch K through the control ends S-1 and S-2. Load section conductor a is connected to commutation switch K1-1 and conductor B is connected to commutation switch K2-1.

In the load portion, the heater R1 is connected in series with the thermistor R2, and the isolation diode D is connected in parallel with the thermistor R2. The anode of the diode D is connected with the thermistor R2 and the lead A, and the cathode of the diode D is connected with the other end of the thermistor and the heater R1. The other end of the heater R1 is connected with a lead B.

In the two-wire heating and temperature measuring device, the resistance value of the thermistor is larger than that of the heater.

The two-wire heating temperature measuring device is characterized in that the current of the load part is alternating reversing direct current, the flowing direction of the forward current I1 is A → load → B during heating, and the flowing direction of the reverse current I2 is B → load → A during temperature measurement.

The two-wire heating temperature measuring device can realize double functions of heating and temperature measuring only by connecting the load part and the control part through two wires.

The two-wire heating temperature measuring device is characterized in that the master control unit M controls the reversing switch K to act, the heating power supply E1 and the measurement and control power supply E2 are switched to reverse in a time-sharing mode to circulate, the heating power supply E1 is switched on, so that the I1 heats when flowing through a load in the forward direction, and the heating power supply E2 is switched on, so that the I2 measures the temperature when flowing through the load in the reverse direction.

The two-wire heating temperature measuring device is characterized in that the reversing switch K is a double-pole double-throw mechanical switch or a switch formed by electronic circuits, a field effect tube, a triode or a relay is used as an internal switch element, a reversing H-bridge integrated circuit can also be used, and the switching action is controlled by a main control unit M.

The heating temperature control system can be provided with a key, a display, a printer and other human-computer interaction circuits or output equipment according to requirements.

Example 1

The invention provides a two-wire heating temperature measuring device and a method thereof, wherein a basic principle diagram (manual control) is shown in figure 1, and the two-wire heating temperature measuring device comprises a control part and a load part. The control part consists of a heating power supply E1, a measurement and control power supply E2 and a reversing switch K. The load part is composed of a connecting lead A, a lead B, a heating resistor R1, a thermistor R2 and a diode D. In the control part, the positive pole of the heating power supply E1 is connected with a reversing switch K1-2, and the negative pole of the heating power supply E1 is grounded. The positive electrode of the measurement and control power supply E2 is connected with the reversing switch K2-3 and the temperature data end C through a resistor R3, and the negative electrode of the measurement and control power supply E2 is connected with a ground wire Gnd. And the control end S is connected with the reversing switch K. The reversing switches K1-3 and K2-2 are connected with a ground wire Gnd. Commutation switch K1-1 is connected to load section conductor a and commutation switch K2-1 is connected to conductor B. In the load portion, the heater R1 is connected in series with the thermistor R2, and the isolation diode D is connected in parallel with the thermistor R2. The anode of the diode D is connected with the thermistor R2 and the lead A, and the cathode of the diode D is connected with the other end of the thermistor and the heater R1. The other end of the heater R1 is connected with a lead B. The control end S controls the action of the reversing switch K, the figure 1 is a basic principle diagram, the reversing switch is a double-pole double-throw mechanical switch, the control end S can be understood as manual control, and temperature data can be read out from the end C of a lead by an external voltmeter.

The working process is as follows:

the S end of the control part (which can be understood as manual control) controls the reversing switch K to work in a reversing mode according to a certain rule, so that the power supply of the heating power supply is temporarily stopped, and a reverse measurement and control power supply is provided in the gap of the temporary stop, namely, the reversing switch provides a temperature measurement time slot.

When the heating state is realized, the reversing switch K is upward, the reversing switches K1-1 and K1-2 are connected, and the reversing switches K2-1 and K2-2 are connected. The positive pole of a heating power supply E1 is connected with a load part lead A through the connection point of a reversing switch K1-2 and K1-1, the negative pole of the heating power supply E1 is connected with a load part lead B through the connection point of a ground wire Gnd and reversing switches K2-2 and K2-1, and heating current I1 is formed. The heating current I1 starts from the anode of a heating power supply E1 and sequentially passes through a junction of a reversing switch K1-2 and K1-1, a lead A, a diode D, a heating resistor R1, a lead B, a junction of a reversing switch K2-1 and K2-2, a ground wire Gnd and the cathode of a return heating power supply E1 to form a loop. When heating, the diode D is conducted in the forward direction, the resistance value of the thermistor R1 connected in parallel with the diode D is larger, and the diode D is short-circuited, so that the heating current I1 basically does not flow through the thermistor. The forward voltage drop of the diode is small, and the influence on the heating power is small.

When the temperature is measured, the reversing switch K faces downwards, the reversing switch K1-1 is connected with the K1-3, and the K2-1 is connected with the K2-3. The positive electrode of the measurement and control power supply E2 is connected with a load part lead B through a resistor R3 and a junction of reversing switches K2-3 and K2-1, and the negative electrode of the measurement and control power supply E2 is connected with a load part lead A through a ground wire Gnd and a junction of reversing switches K1-3 and K1-1, so that a temperature measurement current I2 is formed. The temperature measurement current I2 starts from the positive electrode of the measurement and control power supply E2 and sequentially passes through a resistor R3, a junction of a reversing switch K2-3 and K2-1, a lead B, a heating resistor R1, a temperature measurement resistor R2, a lead A, a junction of the reversing switch K1-1 and K1-3, a ground wire Gnd and the negative electrode of the return measurement and control power supply E2 to form a loop. When the temperature is measured, the current I2 reversely flows, the diode is reversely cut off to present high impedance, and the thermistor R2 is connected to a loop. The temperature parameter value of the thermistor is collected through a lead C point (which can be connected with a voltmeter). When the temperature is measured, the heating resistor R1 is connected in series in the loop, and the resistance value of the heating resistor R1 is far smaller than that of the thermistor R2, so the influence of the heating resistor R1 on the temperature measurement precision can be ignored.

Example 2

Fig. 2 is a schematic diagram of an embodiment of the invention (electronic control), compared to the basic schematic diagram of fig. 1 (manual control): 1. a control unit M is added. 2. The battery figures are eliminated, and only E1 and E2 respectively represent a heating power supply and a measurement and control power supply, E1 and E2 are direct current power supplies, and negative poles of E1 and E2 are both connected with a ground wire Gnd (not shown in the figure). 3. The reversing switch K is changed from a mechanical switch to an electronic switch. 4. The control end is changed into 2 control signal lines S-1 and S-2 from a manual control end S.

The control part consists of a heating power supply E1, a measurement and control power supply E2, a main control unit M (embedded software built in a single chip microcomputer) and a reversing switch K. The load part is composed of a connecting lead A, a lead B, a heating resistor R1, a thermistor R2 and a diode D. In the control part, the positive pole of the heating power supply E1 is connected with a reversing switch K1-2, and the negative pole of the heating power supply E1 is grounded (not shown in the figure). The positive electrode of the measurement and control power supply E2 is connected with the reversing switch K2-3 and the temperature data end C through a resistor R3, and the negative electrode of the measurement and control power supply E2 is connected with a ground wire Gnd. And control ends S-1 and S-2 of the main control unit M are connected with a reversing switch K. The temperature data end C of the main control unit M is connected with a resistor R3 and a reversing switch K2-3. The reversing switches K1-3 and K2-2 are connected with a ground wire Gnd. Commutation switch K1-1 is connected to load section conductor a and commutation switch K2-1 is connected to conductor B. In the load portion, the heater R1 is connected in series with the thermistor R2, and the isolation diode D is connected in parallel with the thermistor R2. The anode of the diode D is connected with the thermistor R2 and the lead A, and the cathode of the diode D is connected with the other end of the thermistor and the heater R1. The other end of the heater R1 is connected with a lead B.

The working process is as follows:

in a heating state, the main control unit M controls the reversing switch K through S-1 to enable K1-1 to be connected with K1-2 and K2-1 to be connected with K2-2, and controls the reversing switch K through S-2 to enable K1-1 to be disconnected with K1-3 and K2-1 to be disconnected with K2-3 (equivalent to that a mechanical switch is upwards in the figure 1). The positive pole of a heating power supply E1 is connected with a load part lead A through the connection point of reversing switches K1-2 and K1-1, the negative pole (not shown in the figure) of the heating power supply E1 is connected with a load part lead B through the connection point of a ground wire Gnd and reversing switches K2-2 and K2-1, and heating current I1 is formed. The heating current I1 starts from the positive electrode of a heating power supply E1, and sequentially passes through a junction of a reversing switch K1-2 and K1-1, a lead A, a diode D, a heating resistor R1, a lead B, a junction of a reversing switch K2-1 and K2-2, a ground wire Gnd and a negative electrode (not shown in the figure) of a return heating power supply E1 to form a loop. When heating, the diode D is conducted in the forward direction, the resistance value of the thermistor R1 connected in parallel with the diode D is larger, and the diode D is short-circuited, so that the heating current I1 basically does not flow through the thermistor. The forward voltage drop of the diode is small, and the influence on the heating power is small.

In the temperature measuring state, the main control unit M controls the reversing switch K through S-1 to disconnect K1-1 and K1-2 and disconnect K2-1 and K2-2, and controls the reversing switch K through S-2 to connect K1-1 and K1-3 and connect K2-1 and K2-3 (equivalent to that the mechanical switch in FIG. 1 is downward). The positive electrode of the measurement and control power supply E2 is connected with a load part lead B through a resistor R3 and a junction of reversing switches K2-3 and K2-1, the negative electrode of the measurement and control power supply E2 is connected with a load part lead A through a ground wire Gnd and a junction of reversing switches K1-3 and K1-1, and temperature measurement current I2 is formed. The temperature measurement current I2 starts from the positive electrode of the measurement and control power supply E2 and sequentially passes through a resistor R3, a junction of a reversing switch K2-3 and K2-1, a lead B, a heating resistor R1, a temperature measurement resistor R2, a lead A, a junction of the reversing switch K1-1 and K1-3, a ground wire Gnd and the negative electrode of the return measurement and control power supply E2 to form a loop. When the temperature is measured, the current I2 reversely flows, the diode is reversely cut off to present high impedance, and the thermistor R2 is connected to a loop. The temperature parameter value of the thermistor is collected by the main control unit M through a lead C point. When the temperature is measured, the heating resistor R1 is connected in series in the loop, and the resistance value of the heating resistor R1 is far smaller than that of the thermistor R2, so the influence of the heating resistor R1 on the temperature measurement precision can be ignored.

The control unit M adopts a 51 series single chip microcomputer or other series single chip microcomputers, and embedded software is arranged in the control unit M. The heating temperature measuring system can be connected with a keyboard, a display and other man-machine interaction equipment or recording equipment such as a printer, a memory and the like as required.

The invention relates to a two-wire heating temperature measurement system and a heating temperature measurement method thereof. The control part consists of a main control unit, a heating power supply, a measurement and control power supply and a reversing switch. The load part consists of a heater, a thermistor and an isolating diode. In the control part, the main control unit is connected with a reversing switch, and the reversing switch is connected with the heating power supply, the measurement and control power supply and the load part. In the load part, the heater is connected in series with the thermistor, and the isolation diode is connected in parallel with the thermistor. The invention adopts a diode isolation method for the heater and the thermistor, controls the direct current power supply to alternately pass through the heater in the forward direction and the reverse direction, realizes the heating and temperature measuring integrated combination of the load by heating the heater in the forward direction and measuring the temperature by the thermistor in the reverse direction, and only two wires are needed for connecting the load. The combination mode is very simple, so that the high-power high-voltage heater and the small-signal low-voltage temperature measuring element share two conducting wires to realize collinear work, and the two parts do not influence each other. The method solves the problem that the temperature measuring element in the traditional heater needs to lead out the lead independently, reduces the heating and temperature measuring leads from four lines to two lines, can reduce the cost of a heating and temperature measuring system, can be compatible with the common heater without the temperature measuring element conveniently, and increases the flexibility of the use of equipment.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made in the above embodiments by those of ordinary skill in the art without departing from the principle and spirit of the present invention. The scope of the invention is defined by the appended claims and their full range of equivalents.