CN108801406A - Explosion-proof signal isolation circuit and its working method - Google Patents

Abstract

The invention relates to an explosion-proof signal isolation circuit and its working method. The explosion-proof signal isolation circuit is suitable for connecting a weighing sensor and sending the weighing signal to a signal processing circuit, which includes: a sampling capacitor, and a microprocessor module respectively Controlled first and second analog switch circuits; wherein the signal output terminal of the load cell is connected to the signal input terminal of the analog-to-digital conversion circuit in the signal processing circuit through the first analog switch circuit and the second analog switch circuit in sequence; and A sampling capacitor suitable for temporarily storing weighing signals is provided between the first analog switch circuit and the second analog switch circuit. The explosion-proof signal isolation circuit can effectively avoid the attenuation in the process of weighing signal transmission.

Description

Explosion-proof signal isolation circuit and its working method

technical field

The invention relates to the field of signal transmission, in particular to an explosion-proof signal isolation circuit and a working method thereof.

Background technique

Bridge-type load cells in daily life often use data lines to transmit data, and the transmission distance is different, so there will be signal attenuation, resulting in inaccurate weighing results.

And it also ignores the commonly used zener safety barrier's common ground requirement between the dangerous area and the safe area.

Therefore, based on the above problems, it is necessary to design an explosion-proof signal isolation circuit and weighing system.

Contents of the invention

The purpose of the present invention is to provide an explosion-proof signal isolation circuit and its working method, which uses analog switches to isolate signals and samples capacitors to store data, avoiding the attenuation in the process of weighing signal transmission.

In order to solve the above problems, the present invention provides an explosion-proof signal isolation circuit, comprising:

Sampling capacitance, and the first and second analog switch circuits respectively controlled by the microprocessor module; wherein

The signal output end of the weighing sensor is connected to the signal input end of the analog-to-digital conversion circuit through the first analog switch circuit, the sampling capacitor and the second analog switch circuit in sequence;

The microprocessor module opens the first analog switch circuit and closes the second analog switch circuit at the same time, so that the weighing signal is temporarily stored in the sampling capacitor; then closes the first analog switch circuit and simultaneously opens the second analog switch circuit to The weighing signal temporarily stored in the sampling capacitor is sent to the analog-to-digital conversion circuit.

Further, both the first analog switch circuit and the second analog switch circuit include two analog switches; wherein the microprocessor module is suitable for controlling the analog switches in the first analog switch circuit and the second analog switch circuit to be turned on or off alternately, In order to temporarily store or release the weighing signal in the sampling capacitor.

In yet another aspect, the present invention also provides a working method of an explosion-proof signal isolation circuit. The corresponding analog switch circuit is controlled by a microprocessor module, and the weighing signal output by the load cell is transmitted to a sampling capacitor in the form of a non-common ground. Temporary storage on the upper, and then disconnect the sampling capacitor from the load cell to release the weighing signal temporarily stored in the sampling capacitor.

Compared with the prior art, this embodiment has the following beneficial effects: when the weighing sensor transmits the weighing signal, the analog switch is used to isolate and transmit the weighing signal, and the weighing signal is transmitted to the subsequent circuit by using a sampling capacitor, Therefore, the explosion-proof signal isolation circuit can effectively avoid attenuation in the process of weighing signal transmission.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Fig. 1 shows the structural diagram of the explosion-proof signal isolation circuit of the present invention

In the figure, 1 is a bridge type load cell, 2 is a power isolation circuit, 3 is a sampling capacitor, 4 is an analog-to-digital conversion (ADC), 5 is a microprocessor module, the first analog switch 6, the second analog switch 7, The third analog switch 8 and the fourth analog switch 9 .

Detailed ways

The present invention is described in further detail now in conjunction with accompanying drawing. These drawings are all simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, so they only show the configurations related to the present invention.

Example 1

Fig. 1 shows the structural diagram of the corresponding embodiment of the explosion-proof signal isolation circuit of the present invention; see Fig. 1, a kind of explosion-proof signal isolation circuit is provided in this embodiment, and the explosion-proof signal isolation circuit is suitable for connecting a load cell, And the weighing signal is sent to the signal processing circuit, which includes: a sampling capacitor 3, and first and second analog switch circuits controlled respectively by a microprocessor module 5; wherein the sampling capacitor 3 is suitable for collecting temporary weighing signal; the analog-to-digital conversion circuit (analog-to-digital conversion (ADC) in Fig. 1) in the signal processing circuit is suitable for performing analog-to-digital conversion and converting the weighing signal into a digital signal; the microprocessor module 5 is suitable for The converted digital signal outputs a corresponding weighing result; the first analog switch circuit includes a first analog switch 6, a second analog switch 7, and the second analog switch circuit includes a third analog switch 8 and a fourth analog switch 9. It is suitable for transmitting weighing signals by means of isolation control.

Optionally, the analog switch can also be realized by using an electronic switch.

The above-mentioned load cell is suitable for using a bridge-type load cell 1 , and the external power supply from a safe environment provides a safe excitation power supply to the load cell bridge 1 in a dangerous area through the power isolation circuit 2 .

In summary, in the explosion-proof signal isolation circuit provided by this embodiment, the weighing signal is collected by the bridge load cell 1, and then the microprocessor module controls the first analog switch 6 and the second analog switch circuit in the first analog switch circuit. The analog switches 7 are all closed, and the third analog switch 8 and the fourth analog switch 9 in the second analog switch circuit are both opened, so that the weighing signal (that is, the differential signal output by the load cell) temporarily stores the sampling capacitor 3; and then controls In the first analog switch circuit, the first analog switch 6 and the second analog switch 7 are opened, while the third analog switch 8 and the fourth analog switch 9 are closed in the second analog switch circuit, and the weighing signal temporarily stored by the sampling capacitor 3 is transmitted to the analog-to-digital conversion circuit; the analog-to-digital conversion circuit will convert the collected analog data into digital data and send it to the microprocessor module; the microprocessor module controls the first analog switch circuit to close, and at the same time, the second analog switch circuit is opened, The above-mentioned process is circulated, and the microprocessor module outputs the weighing result.

Example 2

On the basis of Embodiment 1, this Embodiment 2 also provides a working method of an explosion-proof signal isolation circuit. The corresponding analog switch circuit is controlled by a microprocessor module, and the weighing signal output by the load cell is in the form of a non-common ground. Transfer to a sampling capacitor for temporary storage, and then disconnect the sampling capacitor from the load cell to release the weighing signal temporarily stored in the sampling capacitor.

The microprocessor module 5 is adapted to firstly control the first analog switch circuit to be closed, while the second analog switch circuit is opened, so that the sampling capacitor temporarily stores the weighing signal, and then controls the first analog switch circuit to be opened, while the second analog switch circuit is opened. The circuit is closed, so that the weighing signal temporarily stored by the sampling capacitor is sent to the analog-to-digital conversion circuit in the signal processing circuit.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (4)

1. An explosion-proof signal isolation circuit, characterized in that, comprising: Sampling capacitance, and the first and second analog switch circuits respectively controlled by the microprocessor module; wherein The signal output end of the weighing sensor is connected to the signal input end of the analog-to-digital conversion circuit through the first analog switch circuit, the sampling capacitor and the second analog switch circuit in sequence; The microprocessor module opens the first analog switch circuit and closes the second analog switch circuit at the same time, so that the weighing signal is temporarily stored in the sampling capacitor; then closes the first analog switch circuit and opens the second analog switch circuit at the same time, to The weighing signal temporarily stored in the sampling capacitor is sent to the analog-to-digital conversion circuit. 2. The explosion-proof signal isolation circuit according to claim 1, characterized in that, Both the first analog switch circuit and the second analog switch circuit include two analog switches; wherein The microprocessor module is suitable for controlling the analog switches in the first analog switch circuit and the second analog switch circuit to be turned on or off alternately, so that the sampling capacitor temporarily stores or releases the weighing signal. 3. A working method of an explosion-proof signal isolation circuit, characterized in that, The corresponding analog switch circuit is controlled by the microprocessor module, namely The weighing signal output by the load cell is transferred to a sampling capacitor for temporary storage in the form of non-common ground, and then the sampling capacitor is disconnected from the load cell to release the weighing signal temporarily stored by the sampling capacitor. 4. The working method according to claim 1, characterized in that, The working method is suitable to be realized by using the explosion-proof signal isolation circuit as claimed in claim 1 or 2.