CN217600238U

CN217600238U - Weight signal's signal isolation module and monitored control system

Info

Publication number: CN217600238U
Application number: CN202221940065.0U
Authority: CN
Inventors: 张运良; 武欢欢; 张启志; 席军辉
Original assignee: Zhengzhou Kaideer Technology Development Co ltd; Henan Kaili Intelligent Equipment Co ltd
Current assignee: Zhengzhou Kaideer Technology Development Co ltd; Henan Kaili Intelligent Equipment Co ltd
Priority date: 2022-07-26
Filing date: 2022-07-26
Publication date: 2022-10-18
Anticipated expiration: 2032-07-26

Abstract

The utility model relates to the technical field of crane operation, in particular to a weight signal isolation module and a monitoring system, which comprises a weight sensor, a signal processing module and a signal isolation module, wherein the weight sensor is used for collecting weight signals and transmitting the weight signals to an overload instrument and the signal isolation module; the signal isolation module comprises a signal isolation amplifying circuit, a power supply isolation circuit, a control module and a communication module; the signal isolation amplifying circuit is connected with the weight sensor, the signal isolation amplifying circuit is connected with the control module, and the control module performs information interaction with the monitoring terminal through the communication module; the power circuit is connected with the control module through a power isolation circuit. Namely the utility model discloses a scheme can keep apart, enlarge the signal that weighing transducer gathered, avoids signal interference to the monitoring of hoist running state guarantees the safety of hoist operation.

Description

Weight signal's signal isolation module and monitored control system

Technical Field

The utility model relates to a hoist operation technical field, concretely relates to weight signal's signal isolation module and monitored control system.

Background

In the safe operation of the hoisting machinery, the hoisting weight is a very important index, and generally, an overload protection instrument is required to be configured when the hoisting machinery leaves a factory, and a control power supply is automatically cut off when the crane is overloaded so as to protect the mechanical structure of the crane.

In the requirements of the national standard hoisting machinery safety monitoring and management system GBT 28264-2017, the acquisition, early warning, storage and query of the hoisting capacity signal also require to be acquired, namely the signal is in a relatively important position in the monitoring system, so that the hoisting capacity signal is very important and is a necessary signal in the monitoring system.

Overhead hoist belongs to special equipment, needs carry out real time monitoring in the use, and present monitoring mode is usually based on-the-spot manual monitoring, operating personnel self-monitoring, modes such as monitoring during the shut down, is passive detection like this, or does not have comprehensive detection, when leading to the trouble that can't observe appearing in the use easily, can not in time discover, leads to the accident to appear.

At present, a monitoring system of a crane accesses a weight signal, and generally has three modes:

1. the monitoring signal of the monitoring system is obtained from an overload meter in a cab, namely the overload meter has 4-20MA analog quantity signal output and can be directly accessed;

2. acquiring a load lifting signal through communication transmission, and increasing a communication interface board to be in communication connection with an RS485 digital signal port of the overload meter, wherein the communication transmission needs to provide a Modbus protocol;

3. and by configuring the weight isolation amplifier, the signal of the weight sensor is directly processed into a 4-20mA signal required by the monitoring system and is transmitted to the monitoring system.

For the 3 rd mode, although the existing remote monitoring system for the running state of the crane can monitor the running state of the crane in real time and ensure the safe running of the crane, a single operational amplifier is usually adopted, but because the signal of the weight sensor is very weak and is easy to interfere, and the normal running of the original weighing system is also ensured, the requirement on the corresponding isolation amplifier module is higher.

Meanwhile, due to the fact that the crane lifting signals are monitored for a long time, the electronic elements in the monitoring system possibly have service life problems, and therefore the problem that the monitoring system only obtains the lifting signals of the overload meter or the weight sensor is unreliable is solved.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a weight signal's signal isolation module and monitored control system for solve present because the weight sensor signal is very faint, easily receive the interference problem.

The utility model provides a monitoring system of weight signal, including weighing transducer for gather the weight signal, and transmit to overload instrument and signal isolation module;

the signal isolation module comprises a signal isolation amplifying circuit, a power supply isolation circuit, a control module and a communication module; the signal isolation amplifying circuit is connected with the weight sensor, the signal isolation amplifying circuit is connected with the control module, and the control module performs information interaction with the monitoring terminal through the communication module; the power circuit is connected with the control module through a power isolation circuit.

Further, the overload meter further comprises a second communication module, and the overload meter transmits the detected weight signal to the monitoring terminal through the second communication module.

Further, the signal isolation amplifying circuit is composed of a resistor R6, a resistor R7, a sliding resistor RW8, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R13, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a photocoupler LOC 110U 2, a double diode BAV 99U 3, an operational amplifier LM 258U 4 and an operational amplifier LM 258U 5; one end of the resistor R6 is a weight signal input end, and the other end of the resistor R6 is connected with a pin 2 of an operational amplifier LM 258U 4, a pin 3 of a photoelectric coupler LOC 110U 2 and one end of a capacitor C1; the other end of the capacitor C1 is connected with one end of a resistor R7 and a pin 1 of an operational amplifier LM 258U 4; the other end of the resistor R7 is connected with a pin 1 of a photoelectric coupler LOC 110U 2; a pin 3 of the operational amplifier LM 258U 4 is connected with a third grounding end, a pin 8 and a pin 4 are respectively connected with a +15V voltage end and a-15V voltage end of a third power supply, and a pin 7 is in short circuit with a pin 6; the anode of the double diode BAV 99U 3 is connected with the +15V voltage end of a third power supply; pin 2 of the photocoupler LOC 110U 2 is connected with the cathode of the double diode BAV 99U 3, pin 4 and pin 5 are respectively connected with a third grounding end and a second grounding end, and pin 6 is connected with one end of the sliding resistor RW8 and pin 2 of the operational amplifier LM 258U 5 through a resistor R9; the other end of the sliding resistor RW8 is connected with a pin 1 of an operational amplifier LM 258U 5 and one end of a resistor R13 and a capacitor C2; the other end of the resistor R13 is connected with a pin 1 of an operational amplifier LM 258U 5; the other end of the capacitor C2 is connected with a pin 2 of an operational amplifier LM 258U 5; pin 3 of the operational amplifier LM 258U 5 is connected to the second ground terminal, pin 8 and pin 4 are connected to the +15V voltage terminal and the-15V voltage terminal of the second power supply, pin 7 is connected to one end of the resistor R10 and the capacitor C3, the other end of the resistor R10 is connected to one end of the capacitor C4, the other end of the capacitor C3 is connected to pin 6 of the operational amplifier LM 258U 5 and one end of the resistor R12, the other end of the resistor R12 and one end of the resistor R11 are connected to the other end of the capacitor C4, the other end of the resistor R11 is connected to the second ground terminal, wherein the two ends of the capacitor C4 are signal output terminals.

Further, the third power supply and the second power supply are voltages of +/-15V output by the power supply circuit through two power supply isolation modules E0515S-1WR3 respectively.

Further, the power supply of the weight sensor is also included, and comprises a resistor R1, a sliding resistor RW1, a resistor R3, a resistor R4, a triode FZT853Q1 and a voltage-stabilizing source TL 431U 1; one end of the resistor R1 is connected with a +15V voltage end of a third power supply and a collector of the triode FZT853Q1, and the other end of the resistor R1 is connected with a base electrode of the triode FZT853Q1 and a cathode of a voltage regulator TL 431U 1; the emitting electrode of the triode FZT853Q1 is connected with one end of a sliding resistor RW1, one end of the sliding resistor RW1 is connected with one end of a resistor R3, the other end of the resistor R3 is connected with a reference electrode of a voltage-stabilizing source TL 431U 1 and one end of a resistor R4 respectively, and the anode of the voltage-stabilizing source TL 431U 1 and the other end of the resistor R4 are connected with a third grounding end respectively.

And the differential front-end amplifying circuit is used for amplifying the differential signal of the weight sensor and accessing the signal input end of the signal isolation module.

Further, the differential front-end amplifying circuit includes a resistor R2, a resistor R5, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a capacitor C5, and an amplifier INA126U6, wherein one end of the resistor R2 and one end of the resistor R14 are connected to a differential signal, the other end of the resistor R2 is connected to one end of the resistor R5, one end of the capacitor C5, and a pin 3 of the amplifier INA126U6, the other end of the capacitor C5 is connected to the other end of the resistor R14, one end of the resistor R16, and a pin 2 of the amplifier INA126U6, the other ends of the resistor R5 and the resistor R16 are respectively connected to a third ground terminal, a pin 8 and a pin 1 of the amplifier INA126U6 are connected to the resistor R15, a pin 7 and a pin 4 are respectively connected to a +15V voltage terminal and a-15V voltage terminal of a third power supply, the pin 5 is connected to the third ground terminal, and the pin 6 is connected to a signal input terminal of the signal isolation module through the resistor R17.

The utility model also provides a signal isolation module of the weight signal, which comprises a signal isolation amplifying circuit, a power isolation circuit, a control module and a communication module; the signal input end of the signal isolation amplifying circuit is connected with the weight sensor, the signal isolation amplifying circuit is connected with the control module, and the control module transmits signals through the communication module; the power circuit is connected with the control module through a power isolation circuit.

Further, the signal isolation amplifying circuit is composed of a resistor R6, a resistor R7, a sliding resistor RW8, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R13, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a photocoupler LOC 110U 2, a double-diode BAV 99U 3, an operational amplifier LM 258U 4 and an operational amplifier LM 258U 5; one end of the resistor R6 is a weight signal input end, and the other end of the resistor R6 is connected with a pin 2 of an operational amplifier LM 258U 4, a pin 3 of a photoelectric coupler LOC 110U 2 and one end of a capacitor C1; the other end of the capacitor C1 is connected with one end of a resistor R7 and a pin 1 of an operational amplifier LM 258U 4; the other end of the resistor R7 is connected with a pin 1 of a photoelectric coupler LOC 110U 2; pin 3 of the operational amplifier LM 258U 4 is connected with a third grounding end, pin 8 and pin 4 are respectively connected with a +15V voltage end and a-15V voltage end of a third power supply, and pin 7 is in short circuit with pin 6; the anode of the double diode BAV 99U 3 is connected with the +15V voltage end of a third power supply; pin 2 of the photocoupler LOC 110U 2 is connected with the cathode of the double diode BAV 99U 3, pin 4 and pin 5 are respectively connected with a third grounding terminal and a second grounding terminal, and pin 6 is connected with one end of the sliding resistor RW8 and pin 2 of the operational amplifier LM 258U 5 through a resistor R9; the other end of the sliding resistor RW8 is connected with a pin 1 of an operational amplifier LM 258U 5 and one end of a resistor R13 and a capacitor C2; the other end of the resistor R13 is connected with a pin 1 of an operational amplifier LM 258U 5; the other end of the capacitor C2 is connected with a pin 2 of an operational amplifier LM 258U 5; pin 3 of operational amplifier LM 258U 5 connects the second ground terminal, pin 8 and pin 4 connect the +15V voltage end of second power respectively, -15V voltage end, pin 7 is connected with resistance R10, the one end of electric capacity C3, the other end of resistance R10 is connected with the one end of electric capacity C4, the other end of electric capacity C3 is connected with pin 6 of operational amplifier LM 258U 5, the one end of resistance R12, the other end of resistance R12, the one end of resistance R11 is connected with the other end of electric capacity C4 respectively, the other end termination second ground terminal of resistance R11, wherein the both ends of electric capacity C4 are signal output.

Compared with the prior art, the beneficial effects of the utility model are that:

1. the scheme of the utility model adopts the signal isolation module, thereby improving the overall anti-interference capability of the system and the disturbance to the original electrical system; meanwhile, the power supplies of the components before and after isolation are also isolated, so that different isolated power supplies have different grounding ends, and mutual electrical interference is avoided.

2. The utility model discloses keep apart, the weight signal of enlargiing with the weight signal and the signal isolation module of overload instrument, all transmit to monitor terminal, monitor terminal can be than the size of two tunnel weight signals, has improved the reliability of control data.

Drawings

In order to illustrate the embodiments of the present invention or the technical solutions and advantages of the prior art more clearly, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the description below are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without inventive work.

Fig. 1 is a block diagram of a first embodiment of a monitoring system for a weight signal according to the present invention;

fig. 2 is a circuit diagram of the signal isolation amplifying circuit of the present invention;

FIG. 3 is a schematic diagram of a package for a photocoupler;

fig. 4 is a block diagram of the two-way power isolation module of the present invention;

fig. 5 is a power supply circuit diagram of the weight sensor of the present invention;

fig. 6 is a circuit diagram of the differential front-end amplifier of the present invention;

fig. 7 is a block diagram of a second embodiment of the monitoring system for weight signals according to the present invention.

Detailed Description

To further illustrate the technical means and effects of the present invention adopted to achieve the predetermined objects, the following detailed description of the embodiments, structures, characteristics and effects of the present invention will be made with reference to the accompanying drawings and preferred embodiments.

Example 1

As shown in fig. 1, the present invention provides an embodiment of a monitoring system for weight signals, which includes a weight sensor for collecting weight signals and transmitting the weight signals to an overload meter and a signal isolation module;

It should be noted that, because the overload meter does not have an analog or digital monitoring interface for outputting, in practical applications, an analog signal needs to be converted from the weight sensor (generally on the cart) to the monitoring system. This is equivalent to dividing the signal of the weight sensor into two parts, one part is sent to the overload meter, and the other part is sent to the monitoring system. In order not to affect the normal operation of the original system, the preamplifier is required to have an isolation function, signals of the weight sensors are small, and the preamplifier is required to have an amplification processing function and process the signals into standard signals of 4-20mA signals.

As shown in fig. 2, the signal isolation amplifying circuit in this embodiment is composed of a resistor R6, a resistor R7, a sliding resistor RW8, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R13, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a photocoupler LOC 110U 2, a double diode BAV 99U 3, an operational amplifier LM 258U 4, and an operational amplifier LM 258U 5; one end of the resistor R6 is a weight signal input end, and the other end of the resistor R6 is connected with a pin 2 of an operational amplifier LM 258U 4, a pin 3 of a photoelectric coupler LOC 110U 2 and one end of a capacitor C1; the other end of the capacitor C1 is connected with one end of a resistor R7 and a pin 1 of an operational amplifier LM 258U 4; the other end of the resistor R7 is connected with a pin 1 of a photoelectric coupler LOC 110U 2; pin 3 of the operational amplifier LM 258U 4 is connected with a third grounding end, pin 8 and pin 4 are respectively connected with a +15V voltage end and a-15V voltage end of a third power supply, and pin 7 is in short circuit with pin 6; the anode of the double diode BAV 99U 3 is connected with the +15V voltage end of the third power supply; pin 2 of the photocoupler LOC 110U 2 is connected with the cathode of the double diode BAV 99U 3, pin 4 and pin 5 are respectively connected with a third grounding end and a second grounding end, and pin 6 is connected with one end of the sliding resistor RW8 and pin 2 of the operational amplifier LM 258U 5 through a resistor R9; the other end of the sliding resistor RW8 is connected with a pin 1 of the operational amplifier LM 258U 5 and one end of the resistor R13 and the capacitor C2; the other end of the resistor R13 is connected with a pin 1 of an operational amplifier LM 258U 5; the other end of the capacitor C2 is connected with a pin 2 of an operational amplifier LM 258U 5; pin 3 of the operational amplifier LM 258U 5 is connected to the second ground, pin 8 and pin 4 are connected to the +15V voltage terminal and the-15V voltage terminal of the second power supply, respectively, pin 7 is connected to one end of the resistor R10 and the capacitor C3, the other end of the resistor R10 is connected to one end of the capacitor C4, the other end of the capacitor C3 is connected to pin 6 of the operational amplifier LM 258U 5 and one end of the resistor R12, the other end of the resistor R12 and one end of the resistor R11 are connected to the other end of the capacitor C4, the other end of the resistor R11 is connected to the second ground, wherein both ends of the capacitor C4 are signal output terminals. That is, the weight signal can be isolated and amplified by the signal isolation and amplification circuit.

Note that, in the photocoupler LOC110 in fig. 2 and 3, the reference ground of the pin 4 is the third ground GND3, and is the same as the reference ground of the output terminal of the weight sensor; the reference ground of pin 5 of the photo coupler LOC110 is the second ground GND2, and since the ground of pin 5 is the amplified output side and the two grounds are different, there is no electrical connection between the two grounds, and the mutual influence between the two grounds and the original electrical system is reduced to the maximum extent.

In fig. 2, the operational amplifier LM258 is selected as U4, and since no feedback resistor is designed between the pin 1 and the pin 2, it may be equivalent to an inverter circuit, that is, the operational amplifier LM258 performs amplification processing and then enters the negative end of the internal diode of the linear photocoupler through inversion; in addition, a pin 3 of the photoelectric coupler LOC110 is connected with a pin 1 of a direct output end of the U4 LM258, a pin 6 of the LOC110 is a linear output signal subjected to photoelectric isolation, and a positive signal (pin 1) is output after the linear output signal is subjected to inverse amplification of the U5 (LM 258). By adjusting the potentiometer of the sliding resistor RW8, the output range of the signal output terminal (I + out) can be adjusted.

In this embodiment, the U5 also adopts a dual operational amplifier LM258, in which an output pin 1 of one operational amplifier is connected to a non-inverting input terminal (pin 5 of U5) of the other operational amplifier after passing through a current limiting resistor R13. And the output of the pin 7 of the U5 is connected with a signal output end I + out through a 10-ohm current limiting resistor, and a reference end I-out of the signal output end is connected with an isolated output ground, namely a second grounding end GND2 through a 100-ohm current limiting resistor.

The parameters of the components in the signal isolation amplifying circuit are shown in table 1:

TABLE 1

It should be noted that, the key component of signal isolation is the linear optocoupler LOC110, and the LOC110 is different from a general optocoupler, and operates under a servo mode design to compensate the nonlinear time and temperature characteristics of the light emitting diode, in addition, the LOC110 can also couple an ac signal and a dc signal at the same time, and in view of this characteristic, it is referred to as the linear optocoupler LOC110 to play its greatest role in the isolation and amplification of the differential signal. The packaging diagram is shown in fig. 3: an infrared light emitting diode and two phototriodes are included to form an optical coupling. Wherein, the left phototriode in the upper drawing is used in a servo feedback mechanism to compensate the conduction current of the light emitting diode; the other phototriode is used for providing current isolation between the input and output circuits.

In this embodiment, the third power supply and the second power supply are voltages of ± 15V output by the power circuit through the two power isolation modules E0515S-1WR3, respectively, as shown in fig. 4. The power isolation module in the embodiment adopts a power isolation module E0515S-1WR3 of gold rising to the sun.

It should be noted that the golden sun raising power isolation module E0515S-1WR3 is an isolation module with single 5V input, double 15V (± 15V) output and 1W power, and the operational amplifier is powered by the ± 15V power source output in isolation. As the GND grounds before and after isolation of the photoelectric coupler are separated, two isolation modules E0515S-1WR3 are selected to isolate two grounds GND2 and GND3.

One power isolation module supplies power to the device before photoelectric isolation, and the reference ground is isolated by GND1 and then becomes GND3. And the other power isolation module supplies power to the device after photoelectric isolation, and the reference ground is isolated by GND1 and then becomes GND2. Therefore, the ground GND1 of the power supply end of the whole module, the ground GND2 in front of the photoelectric isolation and the ground GND3 in back of the photoelectric isolation are not a reference ground, namely, direct electrical connection does not exist between interference introduced in the front of the isolation and output in the back of the isolation, and the field interference is not introduced into the output end, so that the isolation effect of the whole module is ensured.

The whole isolation module in the embodiment is powered by DC24V, the generated ground is GND1, DC5V is converted by a DC-DC conversion circuit LM2592HV-5.0, the corresponding ground is also GND1, and a double 15V (+ -15V) power supply is output by the power isolation module.

As shown in fig. 5, the power supply in this embodiment includes a resistor R1, a sliding resistor RW1, a resistor R3, a resistor R4, a triode FZT853Q1, and a voltage regulator TL 431U 1; one end of the resistor R1 is connected with a +15V voltage end of a third power supply and a collector of the triode FZT853Q1, and the other end of the resistor R1 is connected with a base of the triode FZT853Q1 and a cathode of a voltage stabilizing source TL 431U 1; the emitting electrode of the triode FZT853Q1 is connected with one end of a sliding resistor RW1, one end of the sliding resistor RW1 is connected with one end of a resistor R3, the other end of the resistor R3 is connected with a reference electrode of a voltage-stabilizing source TL 431U 1 and one end of a resistor R4 respectively, and the anode of the voltage-stabilizing source TL 431U 1 and the other end of the resistor R4 are connected with a third grounding end respectively.

Further, since the weight sensor generally uses a voltage dependent resistor to sense a signal and a fixed resistor to form a bridge structure, and the external part is four connection wires, the output signal is a differential signal, which is at a millivolt mv level, i.e. the signal is weak, and needs to be amplified and then isolated and output for use, therefore, in this embodiment, a differential front-end amplifying circuit is used to amplify the weight sensor, specifically:

as shown in fig. 6, the differential front-end amplifying circuit in this embodiment includes a resistor R2, a resistor R5, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a capacitor C5, and an amplifier INA126U6, wherein one ends of the resistor R2 and the resistor R14 are connected to a differential signal, the other end of the resistor R2 is connected to one end of the resistor R5, one end of the capacitor C5, and a pin 3 of the amplifier INA126U6, the other end of the capacitor C5 is connected to the other end of the resistor R14, one end of the resistor R16, and a pin 2 of the amplifier INA126U6, the other ends of the resistor R5 and the resistor R16 are respectively connected to a third ground terminal, a pin 8 and a pin 1 of the amplifier INA126U6 are connected to the resistor R15, a pin 7 and a pin 4 are respectively connected to a +15V voltage terminal and a-15V voltage terminal of a third power supply, the pin 5 is connected to the third ground terminal, and the pin 6 is connected to a signal input terminal of the signal isolation module through the resistor R17. The differential signal amplifying circuit is used for amplifying the differential signal of the weight sensor and is connected to the signal input end of the signal isolation module.

IN fig. 6, the amplification process of the front end of the differential front-end amplification circuit adopts a meter-specific operational amplifier INA126, where IN + and IN-represent the signal output end of the weight sensor, the supply voltage of the INA126 adopts the output voltage of the isolation power supply module, and the reference ground is GND3, so as to avoid mutual interference between the isolation module and the original system.

Wherein, according to the manual of INA126, the output voltage S1+ = (IN + -IN-) (R2/(R2 + R5)) (5 + 80/R15), the output voltage Vo =90 (IN + -IN-), namely the amplification factor is 90, is obtained by substituting R2, R5 and R15.

The signal isolation module of this embodiment adopts the mode design that power and signal are two kept apart, and the power is kept apart and is adopted the isolation module that 2 gold rose sun, and the signal is kept apart and is adopted the design of linear optoelectronic coupler, has improved the whole interference killing feature of system and the disturbance to original electrical system greatly. Practice proves that the effect is good, the problem in practical application is solved, and a road is paved for the weight acquisition work of the monitoring system.

Example 2

As shown in fig. 7, the present embodiment is different from embodiment 1 only in that a second communication module is further included, and the overload meter transmits the detected weight signal to the monitoring terminal through the second communication module.

The monitoring terminal in this embodiment can compare and analyze the two paths of weight signals according to the two paths of received weight signals, and when the two paths of weight signals are equal or approximately equal, the two paths of weight signals are considered to be accurate, otherwise, one path of weight signals is failed or abnormal, so that the accuracy of background monitoring is improved.

Furthermore, according to the result of the comparative analysis, the corresponding path can be overhauled or the device can be replaced, so that the weight signal can be monitored continuously.

The two paths of weight signals are as follows: one path is acquired through the signal isolation module, and the other path is acquired through the overload meter. Since a specific description has already been given in embodiment 1, redundant description is not repeated here.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention and not to limit it; although the present invention has been described in detail with reference to preferred embodiments, it should be understood by those skilled in the art that: the invention can be modified or equivalent substituted for some technical features; without departing from the spirit of the present invention, it should be understood that the scope of the claims is intended to cover all such modifications and variations.

Claims

1. A monitoring system of weight signals is characterized by comprising a weight sensor, a signal isolation module and a weight signal processing module, wherein the weight sensor is used for acquiring weight signals and transmitting the weight signals to an overload instrument and the signal isolation module;

2. The system for monitoring a weight signal of claim 1, further comprising a second communication module, wherein the overload meter transmits the detected weight signal to the monitoring terminal through the second communication module.

3. The monitoring system for a weight signal according to claim 1, wherein the signal isolation amplifying circuit is composed of a resistor R6, a resistor R7, a sliding resistor RW8, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R13, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a photocoupler LOC 110U 2, a double diode BAV 99U 3, an operational amplifier LM 258U 4 and an operational amplifier LM 258U 5; one end of the resistor R6 is a weight signal input end, and the other end of the resistor R6 is connected with a pin 2 of an operational amplifier LM 258U 4, a pin 3 of a photoelectric coupler LOC 110U 2 and one end of a capacitor C1; the other end of the capacitor C1 is connected with one end of a resistor R7 and a pin 1 of an operational amplifier LM 258U 4; the other end of the resistor R7 is connected with a pin 1 of a photoelectric coupler LOC 110U 2; pin 3 of the operational amplifier LM 258U 4 is connected with a third grounding end, pin 8 and pin 4 are respectively connected with a +15V voltage end and a-15V voltage end of a third power supply, and pin 7 is in short circuit with pin 6; the anode of the double diode BAV 99U 3 is connected with the +15V voltage end of a third power supply; pin 2 of the photocoupler LOC 110U 2 is connected with the cathode of the double diode BAV 99U 3, pin 4 and pin 5 are respectively connected with a third grounding end and a second grounding end, and pin 6 is connected with one end of the sliding resistor RW8 and pin 2 of the operational amplifier LM 258U 5 through a resistor R9; the other end of the sliding resistor RW8 is connected with a pin 1 of an operational amplifier LM 258U 5 and one end of a resistor R13 capacitor C2; the other end of the resistor R13 is connected with a pin 1 of an operational amplifier LM 258U 5; the other end of the capacitor C2 is connected with a pin 2 of an operational amplifier LM 258U 5; pin 3 of operational amplifier LM 258U 5 connects the second ground terminal, pin 8 and pin 4 connect the +15V voltage end of second power respectively, -15V voltage end, pin 7 is connected with resistance R10, the one end of electric capacity C3, the other end of resistance R10 is connected with the one end of electric capacity C4, the other end of electric capacity C3 is connected with pin 6 of operational amplifier LM 258U 5, the one end of resistance R12, the other end of resistance R12, the one end of resistance R11 is connected with the other end of electric capacity C4 respectively, the other end termination second ground terminal of resistance R11, wherein the both ends of electric capacity C4 are signal output.

4. The system for monitoring a weight signal of claim 3, wherein the third power supply and the second power supply output ± 15V for the power circuit through two power isolation modules E0515S-1WR3.

5. The monitoring system for the weight signal according to claim 4, further comprising a power supply of the weight sensor, wherein the power supply comprises a resistor R1, a sliding resistor RW1, a resistor R3, a resistor R4, a transistor FZT853Q1, a voltage regulator TL 431U 1; one end of the resistor R1 is connected with a +15V voltage end of a third power supply and a collector of the triode FZT853Q1, and the other end of the resistor R1 is connected with a base electrode of the triode FZT853Q1 and a cathode of a voltage regulator TL 431U 1; the emitting electrode of the triode FZT853Q1 is connected with one end of a sliding resistor RW1, one end of the sliding resistor RW1 is connected with one end of a resistor R3, the other end of the resistor R3 is connected with a reference electrode of a voltage-stabilizing source TL 431U 1 and one end of a resistor R4 respectively, and the anode of the voltage-stabilizing source TL 431U 1 and the other end of the resistor R4 are connected with a third grounding end respectively.

6. The system for monitoring a weight signal according to claim 4, further comprising a differential front-end amplifying circuit for amplifying the differential signal of the weight sensor and connecting to the signal input terminal of the signal isolation module.

7. The system for monitoring the weight signal according to claim 6, wherein the differential front-end amplifying circuit comprises a resistor R2, a resistor R5, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a capacitor C5 and an amplifier INA126U6, one ends of the resistor R2 and the resistor R14 are connected to the differential signal, the other end of the resistor R2 is connected to one end of the resistor R5, one end of the capacitor C5 and a pin 3 of the amplifier INA126U6, the other end of the capacitor C5 is connected to the other end of the resistor R14, one end of the resistor R16 and a pin 2 of the amplifier INA126U6, the other ends of the resistor R5 and the resistor R16 are respectively connected to a third ground terminal, a pin 8 and a pin 1 of the amplifier INA126U6 are connected through the resistor R15, a pin 7 and a pin 4 are respectively connected to a +15V voltage terminal and a-15V voltage terminal of a third power supply, the pin 5 is connected to the third ground terminal, and the pin 6 is connected to a signal input terminal of the signal isolation module through the resistor R17.

8. A signal isolation module for weight signals is characterized by comprising a signal isolation amplifying circuit, a power supply isolation circuit, a control module and a communication module; the signal input end of the signal isolation amplifying circuit is connected with the weight sensor, the signal isolation amplifying circuit is connected with the control module, and the control module transmits signals through the communication module; the power circuit is connected with the control module through a power isolation circuit.

9. The signal isolation module for the weight signal according to claim 8, wherein the signal isolation amplifying circuit is composed of a resistor R6, a resistor R7, a sliding resistor RW8, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R13, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a photocoupler LOC 110U 2, a double diode BAV 99U 3, an operational amplifier LM 258U 4, and an operational amplifier LM 258U 5; one end of the resistor R6 is a weight signal input end, and the other end of the resistor R6 is connected with a pin 2 of an operational amplifier LM 258U 4, a pin 3 of a photoelectric coupler LOC 110U 2 and one end of a capacitor C1; the other end of the capacitor C1 is connected with one end of a resistor R7 and a pin 1 of an operational amplifier LM 258U 4; the other end of the resistor R7 is connected with a pin 1 of a photoelectric coupler LOC 110U 2; pin 3 of the operational amplifier LM 258U 4 is connected with a third grounding end, pin 8 and pin 4 are respectively connected with a +15V voltage end and a-15V voltage end of a third power supply, and pin 7 is in short circuit with pin 6; the anode of the double-diode BAV 99U 3 is connected with the +15V voltage end of a third power supply; pin 2 of the photocoupler LOC 110U 2 is connected with the cathode of the double diode BAV 99U 3, pin 4 and pin 5 are respectively connected with a third grounding end and a second grounding end, and pin 6 is connected with one end of the sliding resistor RW8 and pin 2 of the operational amplifier LM 258U 5 through a resistor R9; the other end of the sliding resistor RW8 is connected with a pin 1 of an operational amplifier LM 258U 5 and one end of a resistor R13 capacitor C2; the other end of the resistor R13 is connected with a pin 1 of an operational amplifier LM 258U 5; the other end of the capacitor C2 is connected with a pin 2 of an operational amplifier LM 258U 5; pin 3 of the operational amplifier LM 258U 5 is connected to the second ground terminal, pin 8 and pin 4 are connected to the +15V voltage terminal and the-15V voltage terminal of the second power supply, pin 7 is connected to one end of the resistor R10 and the capacitor C3, the other end of the resistor R10 is connected to one end of the capacitor C4, the other end of the capacitor C3 is connected to pin 6 of the operational amplifier LM 258U 5 and one end of the resistor R12, the other end of the resistor R12 and one end of the resistor R11 are connected to the other end of the capacitor C4, the other end of the resistor R11 is connected to the second ground terminal, wherein the two ends of the capacitor C4 are signal output terminals.

10. The signal isolation module for weight signals as claimed in claim 9, wherein the third power supply and the second power supply output ± 15V for the power circuit through two power isolation modules E0515S-1WR3, respectively.