CN115453957A - Digital quantity input acquisition system - Google Patents
Digital quantity input acquisition system Download PDFInfo
- Publication number
- CN115453957A CN115453957A CN202211405241.5A CN202211405241A CN115453957A CN 115453957 A CN115453957 A CN 115453957A CN 202211405241 A CN202211405241 A CN 202211405241A CN 115453957 A CN115453957 A CN 115453957A
- Authority
- CN
- China
- Prior art keywords
- voltage
- meter
- state
- output voltage
- unit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/04—Programme control other than numerical control, i.e. in sequence controllers or logic controllers
- G05B19/042—Programme control other than numerical control, i.e. in sequence controllers or logic controllers using digital processors
- G05B19/0423—Input/output
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B2219/00—Program-control systems
- G05B2219/20—Pc systems
- G05B2219/24—Pc safety
- G05B2219/24215—Scada supervisory control and data acquisition
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Arrangements For Transmission Of Measured Signals (AREA)
Abstract
The present disclosure provides a digital quantity input acquisition system. The digital quantity input acquisition system comprises: an isolated transmission and signal conversion circuit including a first photocoupler, a second photocoupler and an operational amplifier, wherein the first and second photocouplers are substantially identical and the light emitters of the first and second photocouplers are connected in series, a first input terminal of the operational amplifier receives an input voltage from the instrument unit, a second input terminal is connected to the light receiver of the second photocoupler, and an output terminal is connected to the light emitter of the first photocoupler; and a micro control unit coupled with the isolation transmission and signal conversion circuit to receive the analog output voltage from the light receiver of the first photocoupler, perform analog-to-digital conversion on the analog output voltage to generate a digital output voltage, and determine whether the meter unit is in a power-on state, a power-off state or a wire-off state based on the magnitude of the digital output voltage.
Description
Technical Field
The disclosure relates to the field of industrial automatic control, and more particularly, to a digital quantity input acquisition system.
Background
The digital quantity input acquisition system is widely applied to the field of automatic control, and is mainly used for detecting confirmation signals of valves, switches and the like in an industrial field or controlling the industrial field through interlocking of the signals. The core idea of the digital quantity input acquisition system is to convert a field data input dry contact signal or a level type contact signal into TTL (Transistor-Transistor Logic) high and low levels which can be identified by a single chip microcomputer through the isolation of a photoelectric coupler, and detect the ON and OFF states of the field data input signal according to the TTL high and low levels.
An Optical Coupler (OC) is also called a photo isolator, and is called an optocoupler for short. The photocoupler is generally composed of a light emitter and a light receiver, which are located in the same sealed housing and are separated from each other by a transparent insulator. The light emitter receives the input of electrical signals and converts the input into optical signals, the light receiver receives the optical signals and converts the optical signals into electrical signals again for output, and therefore the electro-optic-electrical conversion is completed, and the input and output isolation function is achieved. Because the input and the output of the photoelectric coupler are isolated from each other, the electric signal transmission has the characteristics of unidirectionality and the like, thereby having good electric insulation capability and anti-interference capability. Common light emitters include light emitting diodes, and light receivers include photodiodes, phototransistors, and the like.
Fig. 1 shows a schematic diagram of a digital quantity input acquisition system according to the prior art. As shown in fig. 1, when the meter is ON with the power source, in the ON state (ON), the voltage at the output of the photocoupler is positive, and when the meter is OFF with the power source, in the OFF state (OFF), the voltage at the output of the photocoupler is zero. In this way, it is possible to determine whether the meter is in the energized state or the de-energized state from the output terminal voltage of the photocoupler.
However, the above digital input collecting system cannot distinguish whether the voltage at the output terminal of the photocoupler is zero due to the OFF state of the meter or the disconnection of the signal path between the meter and the photocoupler. In addition, when different meters are connected, due to the fact that input and output voltages of the photocouplers are different, software algorithms or hardware circuits (such as voltage dividing circuits and the like) need to be modified to be suitable for the corresponding meters. In addition, the digital input acquisition system may also have a problem of being unusable when devices in the system drift.
Signal path disconnection is one of the most common faults and it is necessary to diagnose such faults. One solution is to use the characteristic that linear photoelectric coupler can transmit analog quantity, and to represent and transmit three states of on, off and disconnection of instrument side by different analog quantity, thereby judging different states at the output end of linear photoelectric coupler according to different threshold values. However, linear photocouplers are relatively costly and not suitable for large-scale industrial applications. The other solution is to add an analog-to-digital conversion (ADC) unit at the instrument side to collect power-on, power-off and wire-break signals at the field side. However, this method also has the problems of complicated circuit and high price. Also, neither of these solutions addresses the applicability to different meters and the problem of device drift.
Disclosure of Invention
In view of at least one of the above problems, the present disclosure provides a new digital quantity input collecting system that enables output of different voltage values to identify different states of a meter when the meter is in different states of power-on, power-off and wire-break by using two substantially identical photocouplers for signal isolation and negative feedback, respectively.
In one aspect of the present disclosure, a digital quantity input acquisition system is provided. The digital quantity input acquisition system comprises: an isolated transmission and signal conversion circuit including a first photocoupler, a second photocoupler and an operational amplifier, wherein the first and second photocouplers are substantially identical and the light emitters of the first and second photocouplers are connected in series, a first input terminal of the operational amplifier receives an input voltage from an instrument unit, a second input terminal is connected to the light receiver of the second photocoupler, and an output terminal is connected to the light emitter of the first photocoupler; and a micro control unit coupled with the isolation transmission and signal conversion circuit to receive an analog output voltage from a light receiver of the first photo coupler, perform analog-to-digital conversion on the analog output voltage to generate a digital output voltage, and determine whether the meter unit is in a power-on state, a power-off state or a wire-off state based on a magnitude of the digital output voltage.
In some embodiments, the first optocoupler and the second optocoupler are in the same package.
In some embodiments, the micro control unit is configured to: determining whether the digital output voltage is substantially equal to a first voltage threshold or a second voltage threshold or zero, wherein the second voltage threshold is lower than the first voltage threshold; determining that the meter unit is in a powered-on state if it is determined that the digital output voltage is substantially equal to the first voltage threshold; determining that the meter unit is in a power-off state if it is determined that the digital output voltage is substantially equal to the second voltage threshold; and if the digital output voltage is determined to be zero, determining that the meter unit is in a disconnection state.
In some embodiments, when the meter unit is connected to the digital quantity input acquisition system, the meter unit is controlled to be powered on, and the micro control unit determines the digital output voltage when the meter unit is powered on as the first voltage threshold; and controlling the meter unit to be powered off, and the micro control unit determining the digital output voltage at the time of power off of the meter unit as the second voltage threshold.
In some embodiments, the digital quantity input acquisition system further comprises: a trigger unit configured to send a trigger signal to the micro control unit to trigger the micro control unit to determine the first voltage threshold and the second voltage threshold when the meter unit is connected to the digital input acquisition system.
In some embodiments, the digital quantity input acquisition system further comprises: the acquisition unit comprises a first resistor and a second resistor, wherein the first resistor is connected with the instrument unit and the first input end of the operational amplifier, and the second resistor is connected with the first input end of the operational amplifier and the ground.
In some embodiments, the digital quantity input acquisition system further comprises: a self-energizing unit configured to generate a positive electrical pulse substantially the same as an input voltage in a powered state for input to the first input of the operational amplifier when the micro-control unit determines that the meter unit is in a powered off state or a powered off state, and the micro-control unit is further configured to: determining whether a digital output voltage generated in response to the forward electrical pulse indicates that the meter unit is still in a power-off state or a wire-break state; and if the meter unit is still in the power-off state or the disconnection state, determining that the digital quantity input acquisition system has a fault.
In some embodiments, the digital quantity input acquisition system further comprises: a self-excitation unit configured to input a predetermined voltage to a first input terminal of the operational amplifier, and the micro control unit is further configured to: determining whether a digital output voltage generated in response to the predetermined voltage is changed; and if it is determined that the digital output voltage generated in response to the predetermined voltage changes, determining a rate of change of the digital output voltage, and updating the first voltage threshold and the second voltage threshold based on the rate of change.
In some embodiments, the meter unit comprises: a meter having a switch and a third resistor in parallel with the meter; and the positive pole of the power supply is connected with the instrument and the third resistor in series, and the negative pole of the power supply is grounded.
With the embodiments of the present disclosure, by using two substantially identical photocouplers for signal transformation and negative feedback, respectively, the output terminal can output different voltage values to identify different states of the meter when the meter is in different states of power-on, power-off, and disconnection. The scheme can be applied to various different meters, and the corresponding voltage threshold can be determined adaptively for the meter when the meter is accessed through the threshold adaptive function without modifying software algorithm or changing hardware. In addition, the present disclosure reuses the existing micro control unit having analog-to-digital conversion function, and does not need to add a dedicated analog-to-digital conversion circuit or use an expensive linear photocoupler on the field side, thereby reducing the cost. In addition, in some embodiments of the present disclosure, the self-excitation unit can be used to effectively identify the fault of the digital input acquisition system itself, and the transfer ratio calibration can be automatically performed to solve the problem of unavailability caused by the drift of device parameters, thereby greatly improving the usability of the digital input acquisition system.
This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
Drawings
The above and other objects, structures and features of the present disclosure will become more apparent from the following detailed description when read in conjunction with the accompanying drawings. In the drawings, several embodiments of the present disclosure are shown by way of example and not limitation. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale.
Fig. 1 shows a schematic diagram of a digital quantity input acquisition system according to the prior art.
Fig. 2 shows a schematic block diagram of a digital quantity input acquisition system according to an embodiment of the present disclosure.
Fig. 3 shows a schematic diagram of the control logic of the micro control unit.
Detailed Description
Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While certain embodiments of the present disclosure are shown in the drawings, it is to be understood that the present disclosure may be embodied in various forms and should not be construed as limited to the embodiments set forth herein, but rather are provided for a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the disclosure are for illustration purposes only and are not intended to limit the scope of the disclosure. In some or all cases it may be evident that any of the embodiments described below may be practiced without employing the specific design details described below. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing one or more embodiments.
In the description of the embodiments of the present disclosure, the words "comprise" and variations such as "comprises" and "comprising" should be understood to be open-ended, i.e., "including but not limited to. The expression "based on" should be understood as "based at least in part on". The expression "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The expressions "first", "second" etc. may refer to different or the same objects. Other explicit and implicit definitions are also possible below.
Fig. 2 shows a schematic diagram of a digital quantity input acquisition system 10 according to an embodiment of the disclosure. The digital quantity input collection system 10 shown in fig. 2 may be connected to a meter unit 20 located at an industrial site, and collects a voltage signal from the meter unit 20 to determine whether the meter unit 20 is in a power-on state, a power-off state, or a wire-off state. Herein, the power-ON state refers to a state in which a meter (e.g., the meter 22 shown in fig. 2) in the meter unit 20 is connected to a power supply (e.g., the power supply 24 shown in fig. 2), which is generally referred to as a meter ON state, the power-OFF state refers to a state in which the meter 22 in the meter unit 20 is disconnected from the power supply 24, which is generally referred to as a meter OFF state, and the power-OFF state refers to a state in which a transmission channel between the meter unit 20 and the digital quantity input collecting system 10 is disconnected, which is generally referred to as a state in which the meter unit 20 does not access the digital quantity input collecting system 10.
As shown in fig. 2, in some embodiments, the digital quantity input acquisition system 10 may include an isolated transmission and signal conversion circuit 110 and a micro-control unit 120. The isolated transmission and signal transformation circuit 110 may include a first photo coupler 112, a second photo coupler 114, and an operational amplifier 116. The first photocoupler 112 includes a light emitter 1122 and a light receiver 1124, and the second photocoupler 114 includes a light emitter 1142 and a light receiver 1144. In fig. 2, the light emitters 1122 and 1142 are illustratively shown as light emitting diodes and the light receivers 1124 and 1144 are illustratively shown as phototransistors, but those skilled in the art will appreciate that the present invention is not limited thereto and that other optoelectronic devices may be used for the light emitters and light receivers. In the digital quantity input collecting system 10 shown in fig. 2, the first photocoupler 112 and the second photocoupler 114 are substantially identical and the light emitter 1122 of the first photocoupler 112 and the light emitter 1142 of the second photocoupler 114 are connected in series. Thus, a current If1 flowing through the light emitter 1122 of the first photocoupler 112 is equal to a current If2 flowing through the light emitter 1142 of the second photocoupler 114.
Here, the first photocoupler 112 and the second photocoupler 114 are substantially identical to each other, which means that the photoelectric characteristics, particularly, the Current Transfer Ratio (CTR), of the two photocouplers are substantially identical. The current transfer ratio is the ratio of the output current to the input current of the photocoupler. The current transfer ratio of the photocoupler is related to the magnitude of the input current and the external temperature (i.e., the package temperature) in addition to the device of the photocoupler itself. For each photocoupler, the current transfer ratio versus input current and the ambient temperature may be very complex. Herein, it is preferable to use two photo-couplers of the same production lot, and more preferable to use two photo-couplers in the same package as the first photo-coupler 112 and the second photo-coupler 114, so that the current transfer ratio CTR1 of the first photo-coupler 112 and the current transfer ratio CTR2 of the second photo-coupler 114 are substantially the same at the same time.
The operational amplifier 116 may have positive and negative inputs and an output. The operational amplifier 116 has a first input terminal (positive input terminal) receiving an input voltage Vi from the meter unit 20, a second input terminal (negative input terminal) connected to the light receiver 1144 of the second photocoupler 114, and an output terminal connected to the light emitter 1122 of the first photocoupler 112. In this way, the first photocoupler 112 can convert the input voltage Vi from the meter unit 20 into the output voltage Vo, and the second photocoupler 114 provides negative feedback to the operational amplifier 116 so that the input voltage at the second input terminal of the operational amplifier 116 is also stabilized at Vi.
In addition, as shown in fig. 2, the second input terminal of the operational amplifier 116 is grounded through a resistor R1, the cathode of the light emitter 1142 (e.g., light emitting diode) of the second photocoupler 114 is grounded through a resistor R2, and the output voltage Vo of the first photocoupler 112 is grounded through a resistor R3 to generate a suitable voltage or current limit, which is not described herein again.
The micro control unit 120 is coupled with the isolated transmission and signal conversion circuit 110 to receive an output voltage Vo, which is an analog voltage, from the photo acceptor 1124 of the first photo coupler 112. The micro control unit 120 may analog-to-digital convert the analog output voltage Vo to generate a corresponding digital output voltage (for convenience, vo is still used to represent the digital output voltage), and determine whether the meter unit 20 is in a power-ON state (ON), a power-OFF state (OFF), or a wire-OFF state based ON the magnitude of the digital output voltage.
When the input current of the first photocoupler 112 is If1, the secondary side (photoreceiver 1124) output current Ic1 can be represented as:
when the input current of the second photocoupler 114 is If2 (If 2= If 1), the secondary side (light receiver 1144) output current Ic2 can be expressed as:
therefore, in the case where the first photocoupler 112 and the second photocoupler 114 are substantially the same, the output current is also the same, i.e., ic1= Ic2.
From the nature of the operational amplifier 116:
（3）
and is provided with
（4）
Thus, the output voltage Vo can be expressed as
When CTR1= CTR2, the output voltage Vo may be represented as
It can be seen that the output voltage Vo is linear with the input voltage Vi: vo = kVi, k is referred to as the transfer ratio of the isolated transfer and signal transformation circuit 110,
when CTR1= CTR2,
（8）
as shown in fig. 2, the meter unit 20 may include a meter 22 having a switch (shown schematically in the form of a switch) and a power source 24 in series with the meter 22. In order to provide different input voltages Vi (and thus different output voltages Vo) to the digital quantity input acquisition system 10 when the meter unit 20, more specifically, the meter 22, is in a power-off and power-off state, a resistor R6 is also connected in parallel to the meter 22. As shown in FIG. 2, the positive pole of power supply 24 is connected in series with meter 22 and resistor R6, and the negative pole is connected to ground.
When the switch of the meter 22 is turned on, the meter 22 is turned on with the power supply 24 and is in an energized state, and at this time, the current from the power supply 24 flows through the meter 22 and the resistor R6, and the current is large. If it is assumed that the impedance of the meter 22 is 0, then current flows only through the meter 22 at this time and the resistor R6 is short-circuited. When the switch of meter 22 is open, meter 22 is disconnected from power supply 24 and is in a power-off state, and current from power supply 24 flows only through resistor R6, and the current is small. When the meter unit 20 is disconnected from the transmission channel of the digital quantity input acquisition system 10, the meter 22 is in a disconnection state, and no current flows out of the meter unit 20. Therefore, by measuring the magnitude of the output voltage Vo, the micro control unit 120 can know the state of the meter unit 20.
If it is assumed that the impedance of meter 22 is 0 and the voltage provided by power supply 24 is V, then when meter 22 is in the energized state,
the input voltage Vi may be expressed as
The output voltage Vo may be represented as
That is, the MCU 120 collects the voltage
When the meter 22 is in the power-off state,
the input voltage Vi can be expressed as:
the output voltage Vo may be expressed as
That is, the MCU 120 collects the voltage
When the meter 22 is disconnected, the input voltage Vi of the operational amplifier 116 is 0, and the first photocoupler 112 and the second photocoupler 114 are not conducted, so that the voltage Vo collected by the micro control unit 120 is substantially zero.
Presently, conventional mcu 120 has one or more analog-to-digital conversion circuits, so that existing mcu 120 can be used herein to collect and convert analog output voltages to diagnose power-on, power-off, and power-off conditions of meter 22 without adding special analog-to-digital conversion devices on the field side. The analog-to-digital conversion circuitry of the mcu 120 can achieve a resolution of substantially 10 bits, which is fully sufficient for the diagnostic function described in the present invention.
Fig. 3 shows a schematic diagram of the control logic of the micro control unit 120. As shown in fig. 3, at block 310, the micro control unit 120 may determine whether the digital output voltage Vo is substantially equal to the first voltage threshold Vth1 or the second voltage threshold Vth2 or zero. Here, the second voltage threshold Vth2 is lower than the first voltage threshold Vth1.
If it is determined that the digital output voltage Vo is substantially equal to the first voltage threshold Vth1, the micro control unit 120 may determine that the meter unit 20 is in a powered state at block 320.
If it is determined that the digital output voltage Vo is substantially equal to the second voltage threshold Vth2, the micro control unit 120 may determine that the meter unit 20 is in a power-off state at block 330.
If the digital output voltage Vo is determined to be zero, the micro control unit 120 may determine that the meter unit 20 is in a wire-break state at block 340.
Here, the first voltage threshold Vth1 and the second voltage threshold Vth2 may be determined for each meter 22 by a meter adaptation process as described in detail below. Further, "substantially equal" means, for example, that it is within ± 5% to ± 10% of the corresponding voltage threshold, or the like.
In some other embodiments, instead of using the first voltage threshold Vth1 and the second voltage threshold Vth2, a single voltage threshold may be determined based on the entire circuit configuration, and the meter unit 20 may be determined to be in the power-on state when the digital output voltage Vo is greater than the voltage threshold, and the meter unit 20 may be determined to be in the power-off state when the digital output voltage Vo is less than the voltage threshold and greater than zero.
In some embodiments, the digital quantity input acquisition system 10 may further include an acquisition unit 130. As shown in fig. 2, the acquisition unit 130 may include a resistor R4 and a resistor R5, the resistor R4 being connected to the meter unit 20 and the first input of the operational amplifier 116, the resistor R5 being connected to the first input of the operational amplifier 116 and ground. In this way, resistors R4 and R5 may divide the voltage from meter unit 20 to provide an appropriate magnitude of input voltage Vi to isolated transmission and signal conversion circuit 110.
The first voltage threshold Vth1 and the second voltage threshold Vth2 may be determined when the meter unit 20 is first switched in to the digital quantity input collection system 10.
Specifically, when the meter unit 20 accesses the digital quantity input collecting system 10, the meter unit 20 may be controlled to be energized (i.e., so that the meter 22 is in the ON state). The micro control unit 120 may determine the digital output voltage Vo collected when the meter unit 20 is powered on as the first voltage threshold Vth1.
Further, the meter unit 20 may also be controlled to be powered OFF (i.e., so that the meter 22 is in the OFF state). The micro control unit 120 may determine the digital output voltage Vo collected when the meter unit 20 is powered off as the second voltage threshold Vth2.
In some embodiments, the above process may be repeated a plurality of times, and the statistics (e.g., the average) of the plurality of times are used as the first voltage threshold Vth1 and the second voltage threshold Vth2.
The above-described determination of the first voltage threshold Vth1 and the second voltage threshold Vth2 can be triggered by the triggering unit 140, i.e. into a threshold adaptation mode for the meter 22 when the meter 22 is first accessed.
In particular, the triggering unit 140 may be configured to send a triggering signal to the micro-control unit 120 to trigger the micro-control unit 120 to enter a threshold adaptation mode to determine the first voltage threshold Vth1 and the second voltage threshold Vth2 when the meter unit 20 accesses the digital quantity input acquisition system 10.
As shown in equations (11) and (14) above, the threshold matching mode is entered when the meter 22 first accesses the digital quantity input acquisition system 10.
By placing the meter 22 in the energization mode, the output voltage Vo (Vo = [ (CTR 1 × R3)/(CTR 2 × R1) ] [ R5/(R4 + R5) ] × V at this time can be detected as the first voltage threshold Vth1.
By placing the meter 22 in the power-off mode, the output voltage Vo (Vo = [ (CTR 1 × R3)/(CTR 2 × R1) ] [ R5/(R4 + R5+ R6) ]) V at this time can be detected as the second voltage threshold Vth2.
In this way, when different meters 22 are switched in, the corresponding voltage threshold can be conveniently determined by detecting the output voltage Vo without modifying the software algorithm or adjusting the resistance value of the voltage dividing circuit (R4, R5). I.e. with meter adaptation.
In some embodiments, the digital quantity input acquisition system 10 may further include a self-energizing unit 150 for further determining whether the power-off state or the wire disconnection state is caused by a failure of the digital quantity input acquisition system 10 itself when the micro control unit 120 determines that the meter unit 20 is in the power-off state or the wire disconnection state (e.g., receives the output voltage Vo corresponding to the power-off state or the output voltage Vo is 0).
Specifically, when the micro control unit 120 determines that the meter unit 20 is in the power-off state or the power-off state, the self-energizing unit 150 may generate a forward electric pulse to be input to the first input terminal of the operational amplifier 116, the forward electric pulse being substantially the same as the input voltage Vi when the meter unit 20 is in the power-on state. At this time, the micro control unit 120 is also configured to determine whether the digital output voltage Vo generated in response to the forward electrical pulse still indicates that the meter unit 20 is in a power-off state or a wire-break state. Here, the manner of determining that the meter unit 20 is in the power-off state or the wire-broken state is similar to that described above in conjunction with fig. 3.
In this case, if it is still determined that the meter unit 20 is in the power-off state or the wire-broken state, the micro control unit 120 may determine that the digital quantity input collecting system 10 itself malfunctions. That is, even if the input voltage Vi corresponding to the energized state is applied to the digital quantity input collecting system 10, the output voltage indicates the power-off state or the wire-off state due to an internal failure of the digital quantity input collecting system 10.
On the contrary, if the micro control unit 120 determines that the meter unit 20 is in the power-on state, it may be determined that it is not a malfunction of the digital quantity input collecting system 10 itself.
Additionally or alternatively, the self-excitation unit 150 may also determine whether the device shift of the isolated transfer and signal conversion circuit 110 occurs and adjust the first voltage threshold Vth1 and the second voltage threshold Vth2 accordingly according to whether the ratio of the output voltage Vo to the input voltage Vi of the isolated transfer and signal conversion circuit 110 (i.e., the transfer ratio of the digital quantity input acquisition system 10) changes.
Specifically, the self-energizing unit 150 is configured to input a predetermined voltage to a first input terminal of the operational amplifier 116, and the micro control unit 120 is configured to determine whether the digital output voltage Vo generated in response to the predetermined voltage is changed. If it is determined that the digital output voltage Vo generated in response to the predetermined voltage is changed, a rate of change of the digital output voltage Vo is determined, and the first and second voltage thresholds Vth1 and Vth2 are updated based on the rate of change.
For example, as described above, assuming that the transfer ratio of the isolated transfer and signal conversion circuit 110 is k (as shown in the above equations (7) and (8)), vo = kVi.
If the generated output voltage Vo changes to Vo ' when the same predetermined voltage is input as the input voltage Vi, the transfer ratio of the isolated transfer and signal conversion circuit 110 becomes k ' = Vo '/Vi. The rate of change α = Vo '/Vo = k'/k of the output voltage Vo.
In this case, in order that the device drift does not affect the judgment of the micro control unit 120, the first voltage threshold Vth1 and the second voltage threshold Vth2 may be modified to α × Vth1 and α × Vth2, respectively.
With the embodiments of the present disclosure, by using two substantially identical photocouplers for signal transformation and negative feedback, respectively, the output terminal can output different voltage values to identify different states of the instrument when the instrument is in different states of power-on, power-off, and wire disconnection. The scheme can be applied to various different meters, and the corresponding voltage threshold can be determined adaptively for the meter when the meter is accessed through the threshold adaptive function without modifying software algorithm or changing hardware. In addition, the present disclosure reuses the existing micro control unit having analog-to-digital conversion function, and does not need to add a dedicated analog-to-digital conversion circuit or use an expensive linear photocoupler on the field side, thereby reducing the cost. In addition, in some embodiments of the present disclosure, a self-excitation unit can be used to effectively identify a fault of the digital input acquisition system, and a transfer ratio calibration can be automatically performed to solve the problem of unavailability caused by device parameter drift, thereby greatly improving the usability of the digital input acquisition system.
Further, the present disclosure provides various example embodiments, as described and as shown in the accompanying drawings. However, the present disclosure is not limited to the embodiments described and illustrated herein, but may extend to other embodiments, as will be known or appreciated by those skilled in the art. Reference in the specification to "one embodiment," "the embodiment," "these embodiments," or "some embodiments" means that a particular feature, structure, or characteristic described is included in at least one embodiment, and the appearances of the phrases in various places in the specification are not necessarily all referring to the same embodiment.
Finally, although various embodiments have been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended drawings is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as example forms of implementing the claimed subject matter.
Claims (9)
1. A digital quantity input acquisition system comprising:
an isolated transmission and signal conversion circuit including a first photocoupler, a second photocoupler and an operational amplifier, wherein the first and second photocouplers are substantially identical and the light emitters of the first and second photocouplers are connected in series, a first input terminal of the operational amplifier receives an input voltage from an instrument unit, a second input terminal is connected to the light receiver of the second photocoupler, and an output terminal is connected to the light emitter of the first photocoupler; and
a micro control unit coupled with the isolation transmission and signal conversion circuit to receive an analog output voltage from a light receiver of the first photo coupler, perform analog-to-digital conversion on the analog output voltage to generate a digital output voltage, and determine whether the meter unit is in a power-on state, a power-off state, or a wire-off state based on a magnitude of the digital output voltage.
2. The digital quantity input acquisition system according to claim 1, wherein the first photocoupler and the second photocoupler are in the same package.
3. The digital quantity input acquisition system of claim 1, wherein the micro control unit is configured to:
determining whether the digital output voltage is substantially equal to a first voltage threshold or a second voltage threshold or zero, wherein the second voltage threshold is lower than the first voltage threshold;
determining that the meter unit is in a powered-on state if it is determined that the digital output voltage is substantially equal to the first voltage threshold;
determining that the meter unit is in a power-off state if it is determined that the digital output voltage is substantially equal to the second voltage threshold; and
and if the digital output voltage is determined to be zero, determining that the meter unit is in a disconnection state.
4. The digital quantity input collection system of claim 3, wherein upon access of said meter unit to said digital quantity input collection system,
controlling the meter unit to be powered on, and the micro control unit determining a digital output voltage at the time of the meter unit being powered on as the first voltage threshold; and
controlling the meter unit to power down, and the micro control unit determining a digital output voltage at the time of the power down of the meter unit as the second voltage threshold.
5. The digital quantity input acquisition system of claim 4, further comprising:
a trigger unit configured to send a trigger signal to the micro control unit to trigger the micro control unit to determine the first voltage threshold and the second voltage threshold when the meter unit is connected to the digital quantity input acquisition system.
6. The digital quantity input acquisition system of claim 1, further comprising:
the acquisition unit comprises a first resistor and a second resistor, wherein the first resistor is connected with the instrument unit and the first input end of the operational amplifier, and the second resistor is connected with the first input end of the operational amplifier and the ground.
7. The digital quantity input acquisition system of claim 1, further comprising:
a self-energizing unit configured to generate a forward electrical pulse substantially the same as the input voltage in the energized state for input to the first input of the operational amplifier when the micro-control unit determines that the meter unit is in the de-energized state or the de-energized state, and the micro-control unit is further configured to:
determining whether a digital output voltage generated in response to the forward electrical pulse indicates that the meter unit is still in a power-off state or a power-off state; and
and if the meter unit is still in the power-off state or the wire-break state, determining that the digital quantity input acquisition system has a fault.
8. The digital quantity input acquisition system of claim 3, further comprising:
a self-excitation unit configured to input a predetermined voltage to a first input terminal of the operational amplifier, and the micro control unit is further configured to:
determining whether a digital output voltage generated in response to the predetermined voltage is changed; and
if it is determined that the digital output voltage generated in response to the predetermined voltage changes, a rate of change of the digital output voltage is determined, and the first voltage threshold and the second voltage threshold are updated based on the rate of change.
9. The digital quantity input acquisition system of claim 1, wherein the meter unit comprises:
a meter having a switch and a third resistor in parallel with the meter; and
and the anode of the power supply is connected with the instrument and the third resistor in series, and the cathode of the power supply is grounded.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211405241.5A CN115453957B (en) | 2022-11-10 | 2022-11-10 | Digital quantity input acquisition system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211405241.5A CN115453957B (en) | 2022-11-10 | 2022-11-10 | Digital quantity input acquisition system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115453957A true CN115453957A (en) | 2022-12-09 |
| CN115453957B CN115453957B (en) | 2023-02-17 |
Family
ID=84295535
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211405241.5A Active CN115453957B (en) | 2022-11-10 | 2022-11-10 | Digital quantity input acquisition system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115453957B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117234193A (en) * | 2023-11-10 | 2023-12-15 | 浙江国利信安科技有限公司 | Calibration device for a control system |
| CN117406653A (en) * | 2023-12-12 | 2024-01-16 | 浙江国利信安科技有限公司 | Analog output device and industrial controller |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201766570U (en) * | 2010-09-13 | 2011-03-16 | 杭州三和电控设备有限公司 | Passive 4-20 mA signal isolation receiving circuit based on linear photo coupler |
| CN102916689A (en) * | 2012-11-12 | 2013-02-06 | 北京广利核系统工程有限公司 | Digital value acquisition circuit with fault diagnosis capacity |
| CN106059563A (en) * | 2016-07-13 | 2016-10-26 | 上海富电科技有限公司 | Control guide signal collection circuit |
| CN206321689U (en) * | 2016-12-09 | 2017-07-11 | 广州视源电子科技股份有限公司 | A kind of voltage isolation circuit and high_voltage isolation detect circuit |
| CN107065716A (en) * | 2016-12-20 | 2017-08-18 | 中核控制系统工程有限公司 | A kind of digital quantity acquiring circuit with dynamic diagnosis failures |
| CN208299783U (en) * | 2018-05-10 | 2018-12-28 | 比亚迪股份有限公司 | Digital quantity signal Acquisition Circuit |
| WO2019080080A1 (en) * | 2017-10-27 | 2019-05-02 | 深圳欣锐科技股份有限公司 | Bidirectional isolated digital dcdc power supply and control method |
| CN111103862A (en) * | 2018-10-25 | 2020-05-05 | 比亚迪股份有限公司 | Digital quantity acquisition circuit with self-diagnosis function |
| CN112595887A (en) * | 2020-12-03 | 2021-04-02 | 和远智能科技股份有限公司 | High-voltage digital quantity acquisition circuit and working method thereof |
| CN216697026U (en) * | 2021-12-23 | 2022-06-07 | 山东新松工业软件研究院股份有限公司 | PLC analog output isolation circuit |
-
2022
- 2022-11-10 CN CN202211405241.5A patent/CN115453957B/en active Active
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201766570U (en) * | 2010-09-13 | 2011-03-16 | 杭州三和电控设备有限公司 | Passive 4-20 mA signal isolation receiving circuit based on linear photo coupler |
| CN102916689A (en) * | 2012-11-12 | 2013-02-06 | 北京广利核系统工程有限公司 | Digital value acquisition circuit with fault diagnosis capacity |
| CN106059563A (en) * | 2016-07-13 | 2016-10-26 | 上海富电科技有限公司 | Control guide signal collection circuit |
| CN206321689U (en) * | 2016-12-09 | 2017-07-11 | 广州视源电子科技股份有限公司 | A kind of voltage isolation circuit and high_voltage isolation detect circuit |
| CN107065716A (en) * | 2016-12-20 | 2017-08-18 | 中核控制系统工程有限公司 | A kind of digital quantity acquiring circuit with dynamic diagnosis failures |
| WO2019080080A1 (en) * | 2017-10-27 | 2019-05-02 | 深圳欣锐科技股份有限公司 | Bidirectional isolated digital dcdc power supply and control method |
| CN208299783U (en) * | 2018-05-10 | 2018-12-28 | 比亚迪股份有限公司 | Digital quantity signal Acquisition Circuit |
| CN111103862A (en) * | 2018-10-25 | 2020-05-05 | 比亚迪股份有限公司 | Digital quantity acquisition circuit with self-diagnosis function |
| CN112595887A (en) * | 2020-12-03 | 2021-04-02 | 和远智能科技股份有限公司 | High-voltage digital quantity acquisition circuit and working method thereof |
| CN216697026U (en) * | 2021-12-23 | 2022-06-07 | 山东新松工业软件研究院股份有限公司 | PLC analog output isolation circuit |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117234193A (en) * | 2023-11-10 | 2023-12-15 | 浙江国利信安科技有限公司 | Calibration device for a control system |
| CN117234193B (en) * | 2023-11-10 | 2024-03-01 | 浙江国利信安科技有限公司 | Calibration device for a control system |
| CN117406653A (en) * | 2023-12-12 | 2024-01-16 | 浙江国利信安科技有限公司 | Analog output device and industrial controller |
| CN117406653B (en) * | 2023-12-12 | 2024-02-27 | 浙江国利信安科技有限公司 | Analog output device and industrial controller |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115453957B (en) | 2023-02-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN115453957B (en) | Digital quantity input acquisition system | |
| CN109581233B (en) | Device for detecting positive and negative monolithic voltages of fuel cell and control method thereof | |
| KR20020041463A (en) | I2c opto-isolator circuit | |
| CN113606761A (en) | Current loop communication circuit and air conditioner | |
| CN220709309U (en) | Switch detection circuit and device | |
| CN114221321B (en) | Automatic voltage polarity conversion circuit and method for direct-current power supply | |
| CN208092205U (en) | A kind of closed-loop detection circuit for detecting relay output state | |
| CN212781276U (en) | Polling scanning type switch detection circuit | |
| CN101013523A (en) | High-voltage isolation apparatus of high-voltage power supply | |
| CN210225388U (en) | Photoelectric isolation module compatible with NPN and PNP type sensors | |
| CN213244008U (en) | Self-adaptive device for protecting strong light attack and calibration parameters of single photon detector | |
| CN212008876U (en) | Circuit for monitoring working state of switching power supply | |
| CN215809187U (en) | Current loop communication circuit and air conditioner | |
| CN213937869U (en) | Isolated switching value signal tri-state detection circuit | |
| CN209375659U (en) | Optical module and optical communication equipment | |
| CN108107301B (en) | Optocoupler testing device | |
| CN213213422U (en) | Direct current input switching value acquisition circuit and direct current switching value acquisition device | |
| CN109743052B (en) | Isolation communication circuit for realizing self-checking | |
| CN218850757U (en) | Key scanning circuit | |
| CN219997272U (en) | Detection circuit | |
| CN213547491U (en) | Signal input circuit and signal input device that sensor was used | |
| CN217037194U (en) | Photoelectric receiving circuit, photoelectric communication circuit and device | |
| CN221174855U (en) | Elevator signal transmission line circuit break detection circuit | |
| CN218331733U (en) | Power-on state detection circuit and electronic equipment | |
| CN106776437B (en) | Communication circuit, working method thereof and analog signal acquisition and output system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| PE01 | Entry into force of the registration of the contract for pledge of patent right |
Denomination of invention: Digital input acquisition system Effective date of registration: 20230825 Granted publication date: 20230217 Pledgee: Hangzhou branch of Bank of Nanjing Co.,Ltd. Pledgor: ZHEJIANG GUOLI XIN'AN TECHNOLOGY Co.,Ltd. Registration number: Y2023330001851 |
|
| PE01 | Entry into force of the registration of the contract for pledge of patent right |