Analog quantity acquisition system and related electrical equipment

Abstract

The present disclosure provides an analog quantity acquisition system and an electrical device thereof. The analog quantity acquisition system comprises: a common analog-to-digital conversion unit; a plurality of first channel units connected to the common analog-to-digital conversion unit, wherein each first channel unit comprises a channel acquisition unit and a channel selection unit, wherein the channel acquisition unit is suitable for receiving and / or acquiring analog quantity input signals, and each channel selection unit comprises: a first isolation switch element and a second isolation switch element, wherein in use, one of the plurality of channel selection units is selected, and the other channel selection units in the plurality of channel selection units are turned off, thereby allowing the analog quantity signal obtained in the channel acquisition unit corresponding to the selected channel selection unit to be output to the analog-to-digital conversion unit via the selected channel selection unit, wherein the first isolation switch element (OPT2‑1) and the second isolation switch element (OPT2‑2) are both PhotoMOS photoelectric couplers.

Description

Technical Field

[0001] The present disclosure relates to the electrical field, and more particularly to an analog quantity acquisition system and associated electrical equipment. Background Art

[0002] Analog quantity acquisition systems are often used in industrial control situations, such as DCS, PLC, FCS, etc. The industrial field environment is complex, and electrical isolation is usually used to improve the reliability of the acquisition system.

[0003] In order to improve the volume ratio of the acquisition system, a single module usually integrates multiple acquisition channels, and the common ones are 4 channels, 8 channels, 16 channels, etc. The existing technology usually electrically isolates the control side and the acquisition side directly connected to the field equipment, and the isolation cost between channels is very high. In addition, each channel requires a separate set of analog-to-digital conversion (ADC) modules. Therefore, from the perspective of cost-performance balance, electrical isolation design between channels is rarely performed or the cost is very expensive. Failure to isolate channels may cause interference to spread, from a single channel failure to the entire module failure. In addition, there are many types of field transmitter signals, including 0~10mA, 4~20mA, 0~5V, -10V~10V, etc., which usually require different acquisition systems, resulting in a wide variety of types. Summary of the invention

[0004] The purpose of the present disclosure is to provide an improved analog quantity acquisition system.

[0005] According to the first aspect of the present disclosure, an analog quantity acquisition system is provided. The analog quantity acquisition system includes: a common analog-to-digital conversion unit; a plurality of first channel units connected to the common analog-to-digital conversion unit, wherein each first channel unit includes a channel acquisition unit and a channel selection unit, the channel acquisition unit is suitable for receiving and / or acquiring analog quantity input signals, and has a positive analog quantity output terminal and a negative analog quantity output terminal, wherein each of the channel selection units includes: a positive channel output terminal and a negative channel output terminal; and a first isolation switch element and a second isolation switch element, wherein the first isolation switch element is connected between the positive analog quantity output terminal and the positive channel output terminal, and the second isolation switch element is connected between the negative analog quantity output terminal and the negative channel output terminal; wherein in use, the first isolation switch element and the second isolation switch element of all the channel selection units can be controlled so that: one of the plurality of channel selection units is selected, and the other channel selection units in the plurality of channel selection units are turned off, thereby allowing the analog quantity signal obtained in the channel acquisition unit corresponding to the selected channel selection unit to be output to the analog-to-digital conversion unit via the selected channel selection unit, The first isolating switch element (OPT2-1) and the second isolating switch element (OPT2-2) are both PhotoMOS photocouplers.

[0006] It will be understood that according to the analog quantity acquisition system disclosed in the present invention, with the help of the special isolation voltage resistance capability of PhotoMOS (typically, the isolation voltage resistance can range from tens of V to hundreds of V), even in the disconnected state, a certain isolation voltage resistance capability can be achieved between the input terminals and output terminals of the same channel unit and between adjacent channels, thereby achieving isolation between channels with a single ADC, and supporting current acquisition, voltage acquisition, positive and negative voltage acquisition, small signal acquisition, etc., effectively improving the anti-interference ability and versatility of the acquisition system.

[0007] In some embodiments, the first isolation switch element and the second isolation switch element are both PhotoMOS photocouplers.

[0008] In some embodiments, each channel acquisition unit further includes: a first external terminal and a second external terminal, and each channel acquisition unit is configured to receive and / or acquire a voltage analog input signal between the first external terminal and the second external terminal in a voltage mode.

[0009] In some embodiments, each channel acquisition unit further includes: a third external terminal and an acquisition resistor, wherein the acquisition resistor is connected between the first external terminal and the third external terminal, and each channel acquisition unit is further configured to receive a current analog input signal between the first external terminal and the third external terminal in a current mode, and output the voltage across the acquisition resistor as a voltage analog output signal to the analog-to-digital conversion unit via the selected channel selection unit.

[0010] In some embodiments, each first channel unit further includes a filtering unit, which is coupled between the channel acquisition unit and the channel selection unit and is used to filter the analog output signal from the channel acquisition unit.

[0011] In some embodiments, the filtering unit includes a low-pass filtering unit composed of a first resistor, a second resistor and a capacitor, wherein the capacitor is connected between the first resistor and the second resistor, an end of the first resistor opposite to the capacitor is connected to the positive analog output terminal, and an end of the second resistor opposite to the capacitor is connected to the negative analog output terminal.

[0012] In some embodiments, the filtering unit further includes: a third resistor, wherein the third resistor is connected between the positive analog output terminal and the negative analog output terminal.

[0013] In some embodiments, the analog quantity acquisition system also includes: a voltage / current mode switching unit, the voltage / current mode switching unit includes a third isolation switch element and a fourth isolation switch element, the third isolation switch element is connected between the acquisition resistor and the third external terminal, and the fourth isolation switch element is connected between the node between the acquisition resistor and the third isolation switch element and the negative analog quantity output terminal of the channel acquisition unit.

[0014] In some embodiments, the analog quantity acquisition system is configured to: be in a voltage acquisition mode when both the third isolation switch element and the fourth isolation switch element are disconnected, so as to allow the voltage analog quantity input signal to be received and / or acquired between the first external terminal and the second external terminal; and be in a current acquisition mode when both the third isolation switch element and the fourth isolation switch element are closed, so as to allow the current analog quantity input signal to be received between the first external terminal and the third external terminal.

[0015] In some embodiments, the third isolation switch element and the fourth isolation switch element are both PhotoMOS photocouplers.

[0016] In some embodiments, the analog quantity acquisition system also includes a common signal conditioning unit, which is connected between each of the channel selection units and the analog-to-digital conversion unit, and includes an amplifier unit and / or a common-mode gain unit, wherein the amplifier unit is configured to perform proportional adjustment on the analog quantity output signal obtained from the channel selection unit, and the common-mode gain unit is configured to perform common-mode gain adjustment on the obtained analog quantity output signal.

[0017] In some embodiments, the analog quantity acquisition system further includes a control unit, wherein the control unit is configured to communicate with the analog-to-digital conversion unit to receive and process the digital signal output by the analog-to-digital conversion unit.

[0018] In some embodiments, the control unit is further configured to control the opening or closing of all isolation switch elements in each of the first channel units.

[0019] In some embodiments, the analog quantity acquisition system further includes a plurality of isolated power supplies corresponding one-to-one to the plurality of first channel units, and each isolated power supply is suitable for supplying power to the corresponding first channel unit in an isolated manner.

[0020] In some embodiments, the analog quantity acquisition system also includes a fourth external terminal, which is provided by a power supply terminal of the isolated power supply. The fourth external terminal is suitable for allowing the instrument to be tested to be connected between the fourth external terminal and the first external terminal when the instrument to be tested requires power distribution, so that the distribution current signal of the instrument to be tested flows through the acquisition resistor, thereby realizing the acquisition of the distribution current signal with the help of the acquisition resistor.

[0021] According to a second aspect of the present disclosure, an electrical device is provided, which includes the aforementioned analog quantity acquisition system.

[0022] It should also be understood that the contents described in the Summary of the Invention are not intended to limit the key or important features of the embodiments of the present disclosure, nor are they intended to limit the scope of the present disclosure. Other features of the embodiments of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. In the accompanying drawings, the same or similar reference numerals represent the same or similar elements.

[0024] Figure 1 A schematic diagram of the principle of an analog quantity acquisition system according to an example embodiment of the present disclosure is shown.

[0025] Figure 2Only CH1 in the first channel unit is taken as an example to illustrate a typical structure of the first channel unit according to an exemplary embodiment of the present disclosure.

[0026] Figure 3 A schematic diagram of connecting a main card and a redundant card in an analog quantity acquisition system according to an example embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0027] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as being limited to the embodiments described herein, which are instead provided for a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are only for exemplary purposes and are not intended to limit the scope of protection of the present disclosure.

[0028] As mentioned above, in order to improve the reliability of the analog quantity acquisition system, electrical isolation is usually adopted. However, the inventors have found that the prior art has the following disadvantages:

[0029] 1) The cost of isolating channels is very high, which results in that most existing technical solutions do not isolate channels on the acquisition side; however, in situations where interference is severe, channels may affect each other;

[0030] 2) The existing point-to-point isolation analog acquisition technology uses an independent ADC module for each channel, which is complex in circuit and expensive, and also affects the volume ratio, making it unsuitable for promotion; and

[0031] 3) The existing analog quantity acquisition system supports limited signal types. Different analog quantity acquisition systems are required in various occasions with various transmitters, resulting in a large number of system types and high development and maintenance costs.

[0032] The purpose of the present invention is to provide an improved channel isolation analog quantity acquisition system, which can overcome or alleviate the shortcomings of the prior art. For example, a single ADC can achieve channel isolation, and / or support current acquisition, voltage acquisition, positive and negative voltage acquisition, small signal acquisition, etc., effectively improving the anti-interference ability and versatility of the analog quantity acquisition system.

[0033] In order to understand the present invention more clearly, Figure 1 A schematic diagram of the principle of an analog quantity acquisition system according to an example embodiment of the present disclosure is shown.

[0034] like Figure 1As shown, the analog quantity acquisition system 1 includes a plurality of first channel units 10 (for example, including CH1, CH2, CH3, ... CHN) and a common analog-to-digital (A / D) conversion unit 20, wherein the plurality of first channel units 10 can constitute a plurality of acquisition channels for acquiring the required analog quantity input signals, and output the acquired analog quantity input signals to the common analog-to-digital (A / D) conversion unit 20. Typically, the plurality of first channel units 10 can constitute 4 (i.e., CH1-CH4), 8 (CH1-CH8) or 16 (CH1-CH16) acquisition channels, thereby facilitating the acquisition of various voltage or current signals.

[0035] In some embodiments, a signal conditioning unit 30 may be arranged between the multiple first channel units 10 and the common analog-to-digital (A / D) conversion unit 20 to perform signal conditioning on the analog signal output from the first channel unit 10 to facilitate reception and processing by the analog-to-digital (A / D) conversion unit 20.

[0036] As an example, the signal conditioning unit 30 may include an amplifier unit 31 and / or a common-mode gain unit 32. The amplifier unit 31 is used to perform impedance isolation on the differential signals on each channel and convert the differential signals. The common-mode gain unit 32 is used to boost the common-mode voltage, so that the negative voltage signal at the front end is converted into a positive voltage signal that can be recognized by the analog-to-digital (A / D) conversion unit 20.

[0037] In some embodiments, the amplification ratio of the amplifier unit 31 is configurable, which is achieved, for example, by a SENSE signal input to the instrumentation amplifier unit 31 .

[0038] Taking the -10V~10V signal commonly used in industrial control as an example, the amplification factor can be set to 1 / 10, so the signal passing through the amplifier unit 31 is -1~1V, and then after the common mode gain, assuming that the common mode gain is set to 1.2V, the signal is converted to ADC+ as 2.2V and ADC- as 0.2V. After signal conditioning, the large voltage signal exceeding the ADC acquisition is converted into a signal that can be effectively acquired by the ADC. It should be noted here that for the 0~10mA, 4~20mA, 0~5V, -10V~10V signals commonly used in industrial control, the amplification factor and common mode gain settings can use the same fixed parameters. When acquiring a signal with a large amplitude span, the control unit 40 (such as a CPU) to be described later can be used to adjust the amplification factor and common mode gain.

[0039] It should be understood that the signal conditioning unit 30 makes it easier to collect and process positive and negative voltage signals and small signals.

[0040] In the embodiment with the above-mentioned signal conditioning unit 30, the above-mentioned common analog-to-digital (A / D) conversion unit 20 can collect the output signal of the amplifier unit 31 in the signal conditioning unit 30 through the differential pair of ADC+ and ADC-, and send the collection result to the control unit 40 to be described later according to the preset logic. As an example, the above-mentioned analog-to-digital (A / D) conversion unit 20 can be a conventional ADC, and the common mode voltage collection voltage is 0~2.5V, and the differential mode is 0~2.5V.

[0041] Typically, the analog quantity acquisition system 1 may further include the above-mentioned control unit 40 (such as a CPU or an MCU), which, on the one hand, is used to communicate and connect in isolation with the common analog-to-digital (A / D) conversion unit 20 to receive the acquisition signal from the analog-to-digital (A / D) conversion unit 20, and perform other processing such as calibration and data conversion on the acquired signal; on the other hand, it is also suitable for controlling each switch in the plurality of first channel units 10 so that the entire acquisition system operates according to a preset logic.

[0042] Generally, the plurality of first channel units 10 are identical to each other. However, in some particular embodiments, without departing from the teaching of the present disclosure, the plurality of first channel units 10 may also be partially or completely different from each other.

[0043] In order to more clearly understand the specific implementation of the first channel unit, Figure 2 Only CH1 in the first channel unit 10 is taken as an example to illustrate a typical structure of the first channel unit according to an exemplary embodiment of the present disclosure. It should be noted that although the following description refers to the first channel unit CH1, the structure described can also be applied to other first channel units in the plurality of first channel units 10 if there is no contradiction.

[0044] like Figure 2 As shown, each first channel unit 10 may include a channel acquisition unit 11 and a channel selection unit 12 .

[0045] The channel acquisition unit 11 is used to receive and / or acquire analog input signals, and output the acquired analog input signals to the analog-to-digital (A / D) conversion unit 20 directly or after processing via the channel selection unit 12 .

[0046] In order to achieve channel isolation between multiple first channel units 10 and share the above-mentioned analog-to-digital (A / D) conversion unit 20, each channel selection unit 12 of the present invention is designed to include a first isolation switch element OPT2-1 and a second isolation switch element OPT2-2, wherein the first isolation switch element OPT2-1 can be connected between the positive analog output terminal 11a of the channel acquisition unit 11 and the positive channel output terminal AIN+ of the channel selection unit 12, and the second isolation switch element OPT2-2 is connected between the negative analog output terminal 11b and the negative channel output terminal AIN-.

[0047] The first isolation switch element OPT2 - 1 and the second isolation switch element OPT2 - 2 of each channel selection unit 12 are controllable (eg, controlled by the control unit 40 ), and are adapted to be turned off and on at the same time.

[0048] In particular, in the use of the above-mentioned analog quantity acquisition system 1, the first isolation switch element OPT2-1 and the second isolation switch element OPT2-2 of all channel selection units will be uniformly controlled so that: only one channel selection unit among the multiple channel selection units is enabled, and the other channel selection units among the multiple channel selection units are turned off, thereby allowing the analog quantity signal obtained in the channel acquisition unit corresponding to the enabled channel selection unit to be output to the common analog-to-digital (A / D) conversion unit 20 via the enabled channel selection unit.

[0049] As an example, the first isolation switch element OPT2-1 and the second isolation switch element OPT2-2 of the channel selection unit in the first channel unit 10, such as the channel unit CH1, are both enabled, while the first isolation switch element OPT2-1 and the second isolation switch element OPT2-2 of the channel selection units in the other channel units CH2 to CHN in the first channel unit 10 are both controlled to be turned off. In this case, only the analog signal received and / or collected by the channel acquisition unit 11 connected to the channel selection unit 12 in the channel unit CH1 can be output to the common analog-to-digital (A / D) conversion unit 20 via the enabled channel selection unit. Since only the channel selection unit 12 in the channel unit CH1 is enabled, isolation between different channel units CH1, CH2, CH3, and CHN can be achieved.

[0050] In particular, the first isolation switch element OPT2-1 and the second isolation switch element OPT2-2 can be PhotoMOS photocouplers, which can be implemented using the same control logic and controlled by the control unit 40. It should be understood that when the PhotoMOS photocoupler is disconnected, the PhotoMOS has a certain isolation withstand voltage capability, ranging from tens of V to hundreds of V, depending on the model, that is, the PhotoMOS in the disconnected state has a certain electrical isolation capability between the input terminal IN1+ and the output terminal AIN+ of the channel unit. Similarly, there is also a certain isolation capability between the input terminal IN1+ or IN1- of the first channel unit and the input terminals IN2, IN3...INN of other channel units. It should also be understood that by utilizing the characteristics of PhotoMOS in combination with the logic of single-shot strobe acquisition, isolation between channels of a single ADC is achieved.

[0051] In some embodiments, Figure 2 As shown, the channel acquisition unit 11 may include at least two external terminals, such as a first external terminal IN1+ and a second external terminal IN1-. The first external terminal IN1+ and the second external terminal IN1- are suitable for receiving and / or acquiring a voltage analog input signal between the first external terminal IN1+ and the second external terminal IN1- in a voltage mode.

[0052] In some embodiments, Figure 2 As shown, the channel acquisition unit 11 may also include a third external terminal GND1 and an acquisition resistor RJ1, the acquisition resistor RJ1 is, for example, connected between the first external terminal IN1+ and the third external terminal GND1, and each of the above-mentioned channel acquisition units 11 is also configured to receive a current analog input signal between the first external terminal IN1+ and the third external terminal GND1 in the current mode, and output the voltage across the acquisition resistor RJ1 as a voltage analog output signal to the above-mentioned common analog-to-digital (A / D) conversion unit 20 via the corresponding selected channel selection unit 12. As an example, the acquisition resistor RJ1 can be implemented by a precision resistor, and 100 ohms are generally selected for industrial control, and other types of resistors can also be used.

[0053] In some embodiments, each first channel unit 10 may further include a filtering unit 15 , wherein the filtering unit 15 is coupled between the channel acquisition unit 11 and the channel selection unit 12 , and is used to filter the analog output signal (eg, current or voltage) from the channel acquisition unit 11 .

[0054] As an example, the filtering unit 15 may include a low-pass filtering unit composed of a first resistor R1, a second resistor R2 and a capacitor C1 connected in series, wherein the capacitor C1 is connected between the first resistor R1 and the second resistor R2, the end of the first resistor R1 opposite to the capacitor is connected to the positive analog output terminal 11a, and the end of the second resistor R2 opposite to the capacitor is connected to the negative analog output terminal 11b. In addition, the filtering unit 15 may also include: a third resistor R3, wherein the node between the first resistor R1 and the third resistor R3 is connected to the positive analog output terminal 11a of the channel acquisition unit 11, and the node between the second resistor R2 and the third resistor R3 is connected to the negative analog output terminal 11b of the channel acquisition unit 11.

[0055] It will be understood that the above R1, R2, and C1 can form a low-pass filter at both ends of the differential signal, and the role of R3 is to provide a stable state for the voltage mode to prevent the acquisition system from being in a high-impedance state when no load is connected, which is easily disturbed. The filter unit 15 is placed before the channel selection unit 12. The purpose of this is to make the signals of all channels always in a stable state, so that there is no obvious charging and discharging process after the channel is selected, and it is easy to achieve signal stability and reduce the acquisition time.

[0056] It should be understood that the above voltage mode and current mode are selectable. In order to achieve this selectable operation, in some embodiments, the analog quantity acquisition system may further include a voltage / current mode switching unit, which includes a third isolation switch element OPT1-1 and a fourth isolation switch element OPT1-2. The third isolation switch element OPT1-1 is connected between the above acquisition resistor RJ1 and the above third external terminal GND1, and the fourth isolation switch element OPT1-2 is connected between the node between the acquisition resistor RJ1 and the third isolation switch element OPT1-1 and the negative analog quantity output terminal 11b of the channel acquisition unit 11.

[0057] In an embodiment having the above-mentioned voltage / current mode switching unit, in use, the analog quantity acquisition system 1 can be configured to: be in a voltage acquisition mode when both the third isolation switch element OPT1-1 and the fourth isolation switch element OPT1-2 are disconnected, so as to allow the voltage analog quantity input signal to be received and / or acquired between the first external terminal IN+ and the second external terminal (IN-); and be in a current acquisition mode when both the third isolation switch element OPT1-1 and the fourth isolation switch element OPT1-2 are closed or turned on, so as to allow the current analog quantity input signal to be received between the first external terminal IN+ and the third external terminal GND1.

[0058] According to the design, the third isolation switch element OPT1-1 and the fourth isolation switch element OPT1-2 are controllable (for example, implemented by the same control logic of the control unit 40). In particular, in some embodiments, the third isolation switch element OPT1-1 and the fourth isolation switch element OPT1-2 may be PhotoMOS photocouplers. However, in other embodiments, the third isolation switch element OPT1-1 and the fourth isolation switch element OPT1-2 may also be other types of isolation switch elements, such as magnetic isolation switch elements, capacitive isolation switch elements, etc.

[0059] In order to achieve point-to-point isolation between the above-mentioned multiple first channel units, in some embodiments, the analog quantity acquisition system 1 may also include an isolation power supply 50 corresponding to the multiple first channel units one by one, and the function of each isolation power supply 50 is to supply power to the corresponding first channel unit 10 in isolation from each other, so that the power supply of each channel unit is independent of each other.

[0060] For example, Figure 2 As shown, the channel unit CH1 in the first channel unit 10 has a corresponding isolated power supply 50, and the isolated power supply 50 can be externally connected to a 24V power supply, which can supply power to the channel unit CH1. As an example, the power supply terminal of the channel unit CH1 can be marked as 24V1, the power supply terminal of the isolated power supply of the channel unit CH2 can be marked as 24V2, and so on.

[0061] In order to facilitate the detection of passive instruments, in some embodiments, the power supply terminal 24V1 may also include a fourth external terminal 24V1 as an analog quantity acquisition system, so as to be used when the instrument under test is in the power distribution mode. For example, when the instrument under test requires power distribution, the fourth external terminal 24V1 allows the instrument under test to be connected between the fourth external terminal and the first external terminal IN+, so that the power distribution current signal of the instrument under test can flow through the acquisition resistor RJ1, thereby realizing the acquisition of the power distribution current signal with the help of the acquisition resistor RJ1.

[0062] Table 1 below is a wiring diagram of different signal types, taking CH1 as an example.

[0063] Table 1

[0064]

[0065] From the above description, it can be understood that with the help of the above first, second, third and fourth external terminals, the connection of distribution current, non-distribution current, voltage (including positive and negative signals, small signals, etc.) instruments can be achieved.

[0066] In some embodiments, the plurality of first channel units 10 may be located on a module on an integrated circuit board. In the case where the analog quantity acquisition system includes only one module having the channel unit, the module may be referred to as a main card (or single card), and the analog quantity acquisition system will work in single card mode.

[0067] In some further embodiments, the analog quantity acquisition system may further include a backup module (also referred to as a redundant card) having the same structure as the above-mentioned module, wherein each of the multiple second channel units of the redundant card is suitable for receiving the same signal input as a corresponding first channel unit of the multiple first channel units of the main card, and the multiple second channel units are also connected to a common analog-to-digital (A / D) conversion unit.

[0068] As an example, Figure 3 A schematic diagram of the connection of the main card and the redundant card in the analog quantity acquisition system according to an example embodiment of the present disclosure is shown. It should be understood that the control unit 40 can control the first, second, third and fourth isolation switch elements in the main card and the redundant card to realize whether to enable the main card or the redundant card to collect the input signal. That is, according to the design of the present disclosure, only one of the main card and the redundant card always works, while the other does not work. When the main card is enabled, the analog quantity acquisition system can be regarded as enabling the single card mode, and when the redundant card is enabled, it can be regarded as turning on the redundant mode.

[0069] Table 2 below shows a working state switch configuration table of the main card in the single card mode or the redundant mode, taking the acquisition channel CH1 as an example.

[0070] Table 2

[0071]

[0072] The specific implementation of the analog quantity acquisition system according to the present disclosure is described above with reference to various embodiments. It will be understood that the analog quantity acquisition system according to the present disclosure has the following advantages:

[0073] a) Support single ADC to achieve channel isolation, simple circuit;

[0074] b) Support multiple signal types, including positive, negative and small signals;

[0075] c) Support single card and redundant mode;

[0076] d) The solution adopted by the present invention is simple and easy to promote.

[0077] It should be understood that, in addition to the above-described analog quantity acquisition system, the present disclosure may also relate to an electrical device, which may include the above-described analog quantity acquisition system.

[0078] Although the present invention has been described and illustrated in detail in the drawings and the foregoing description, these descriptions and explanations should be considered illustrative or exemplary rather than restrictive; the present invention is not limited to the disclosed embodiments. Other variations of the disclosed embodiments can be understood and practiced by those skilled in the art in practicing the claimed invention by studying the drawings, the disclosure, and the appended claims.

[0079] In the claims, the word "comprising" does not exclude other elements, and the indefinite article "a" or "an" does not exclude a plurality. A single element or other unit may fulfil the functions of a plurality of items set out in the claims. The mere fact that certain features are recited in mutually different embodiments or dependent claims does not mean that a combination of these features cannot be used to advantage. The scope of protection of the present application covers any possible combination of the various features recited in the various embodiments or dependent claims without departing from the spirit and scope of the present application.

[0080] Furthermore, any reference signs in the claims shall not be construed as limiting the scope of the present invention.

Claims

1. An analog quantity acquisition system, characterized in that: include: a common analog-to-digital (A / D) conversion unit (20); A plurality of first channel units (10) are connected to the common analog-to-digital (A / D) conversion unit (20), wherein each first channel unit (10) comprises a channel acquisition unit (11) and a channel selection unit (12), the channel acquisition unit (11) being suitable for receiving and / or acquiring analog input signals and having a positive analog output terminal (11a) and a negative analog output terminal (11b), Each of the channel selection units (12) comprises: Positive channel output terminal (AIN+) and negative channel output terminal (AIN-); as well as The first isolating switch element (OPT2-1) and the second isolating switch element (OPT2-2), The first isolating switch element (OPT2-1) is connected between the positive analog output terminal (11a) and the positive channel output terminal (AIN+), and the second isolating switch element (OPT2-2) is connected between the negative analog output terminal (11b) and the negative channel output terminal (AIN-); Wherein, in use, the first isolation switch element (OPT2-1) and the second isolation switch element (OPT2-2) of all the channel selection units (12) can be controlled so that: one of the plurality of channel selection units (12) is enabled, while the other channel selection units in the plurality of channel selection units (12) are disabled, thereby allowing the analog quantity signal obtained in the channel acquisition unit (11) corresponding to the enabled channel selection unit (12) to be output to the analog-to-digital (A / D) conversion unit (20) via the enabled channel selection unit (12); The first isolating switch element (OPT2-1) and the second isolating switch element (OPT2-2) are both PhotoMOS photocouplers.

2. The analog quantity acquisition system according to claim 1, wherein each channel acquisition unit (11) further comprises: A first external terminal (IN1+) and a second external terminal (IN1-), each channel acquisition unit (11) is configured to receive and / or acquire a voltage analog input signal between the first external terminal (IN1+) and the second external terminal (IN1-) in a voltage mode.

3. The analog quantity acquisition system according to claim 2, wherein each channel acquisition unit (11) further comprises: A third external terminal (GND1) and a collection resistor (RJ1), the collection resistor (RJ1) being connected between the first external terminal (IN1+) and the third external terminal (GND1), each channel collection unit (11) being further configured to receive a current analog input signal between the first external terminal (IN+) and the third external terminal (GND1) in a current mode, and output the voltage across the collection resistor (RJ1) as a voltage analog output signal to the analog-to-digital (A / D) conversion unit (20) via the selected channel selection unit (12).

4. The analog quantity acquisition system according to claim 1, wherein each first channel unit (10) further comprises a filtering unit (15), wherein the filtering unit (15) is coupled between the channel acquisition unit (11) and the channel selection unit (12), and is used for filtering the analog quantity output signal from the channel acquisition unit (11).

5. The analog quantity acquisition system according to claim 4, wherein the filtering unit (15) comprises a low-pass filtering unit composed of a first resistor (R1), a second resistor (R2) and a capacitor (C1), wherein the capacitor (C1) is connected between the first resistor (R1) and the second resistor (R2), an end of the first resistor (R1) opposite to the capacitor is connected to the positive analog quantity output terminal (11a), and an end of the second resistor (R2) opposite to the capacitor is connected to the negative analog quantity output terminal (11b).

6. The analog quantity acquisition system according to claim 5, wherein the filtering unit (15) further comprises: A third resistor (R3), the third resistor (R3) is connected between the positive analog output terminal (11a) and the negative analog output terminal (11b).

7. The analog quantity acquisition system according to claim 3 further comprises: A voltage / current mode switching unit, the voltage / current mode switching unit comprising a third isolation switch element (OPT1-1) and a fourth isolation switch element (OPT1-2), the third isolation switch element (OPT1-1) being connected between the acquisition resistor (RJ1) and the third external terminal (GND1), the fourth isolation switch element (OPT1-2) being connected between a node between the acquisition resistor (RJ1) and the third isolation switch element (OPT1-1) and a negative analog output terminal (11b) of the channel acquisition unit (11).

8. The analog quantity acquisition system according to claim 7, wherein the analog quantity acquisition system is configured to: be in a voltage acquisition mode when both the third isolation switch element (OPT1-1) and the fourth isolation switch element (OPT1-2) are disconnected, so as to allow the voltage analog quantity input signal to be received and / or acquired between the first external terminal (IN+) and the second external terminal (IN-); and be in a current acquisition mode when both the third isolation switch element (OPT1-1) and the fourth isolation switch element (OPT1-2) are closed, so as to allow the current analog quantity input signal to be received between the first external terminal (IN+) and the third external terminal (GND1).

9. The analog quantity acquisition system according to claim 3 further comprises a fourth external terminal (24V1), wherein the fourth external terminal (24V1) is provided by a power supply terminal of an isolated power supply (50), and the fourth external terminal (24V1) is suitable for allowing the instrument to be tested to be connected between the fourth external terminal (24V1) and the first external terminal (IN1+) when the instrument to be tested requires power distribution, so that the distribution current signal of the instrument to be tested flows through the acquisition resistor (RJ1), thereby realizing the acquisition of the distribution current signal with the aid of the acquisition resistor (RJ1).

10. An electrical device, characterized in that: It comprises the analog quantity acquisition system according to any one of claims 1 to 9.

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