CN205540217U - Analog input device - Google Patents
Analog input device Download PDFInfo
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- CN205540217U CN205540217U CN201521016989.1U CN201521016989U CN205540217U CN 205540217 U CN205540217 U CN 205540217U CN 201521016989 U CN201521016989 U CN 201521016989U CN 205540217 U CN205540217 U CN 205540217U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P90/00—Enabling technologies with a potential contribution to greenhouse gas [GHG] emissions mitigation
- Y02P90/02—Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]
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Abstract
The utility model discloses an analog input device, including supply circuit, CPU module, communication circuit sum channel acquisition circuit, supply circuit is used for supplying power for whole AI module, passageway acquisition circuit is used for giving the CPU module with on -the -spot signal transmission, the CPU module is used for carrying out the communication through the control station of communication circuit and DCS system, passageway acquisition circuit is equipped with the common mode suppression circuit of height input impedance and common mode rejection ability, common mode suppression circuit is used for carrying out the differential mode to on -the -spot signal and enlargies, realizes the common mode rejection simultaneously. Through the utility model discloses a common mode suppression circuit who takes the common mode rejection can only enlarge the differential mode, and restraines the not too strong problem of AI module moderate resistance common mode interference ability in the solution DCS system to the common mode.
Description
Technical field
This utility model relates to DCS control system field, particularly relates to a kind of analog input device.
Background technology
In DCS control system, it is the most universal that AI Analog input mModule uses.It is frequently encountered by the field due to existing
Field environment is not so good, and transmission signal line has coupled common-mode signal, and when common-mode signal is bigger, the impact on signal is very big, leads
Cause signal detection is forbidden.The method typically now used is that input adds a voltage follow-up amplifier and carries out signals collecting, but
Be this voltage follow-up amplifier be common-mode signal can not to be suppressed, simultaneously because its input resistance is the lowest and in circuit
Resistance ratio matching degree requires the highest, so common mode inhibition capacity is not the strongest.
Summary of the invention
The purpose of this utility model is for the deficiencies in the prior art, it is provided that a kind of analog input device, by this
Differential mode can be only amplified by the common mode rejection circuit of utility model, and suppresses common mode, solves AI mould in DCS system
The problem that in block, anti-common mode disturbances ability is the strongest.
The purpose of this utility model is achieved in that a kind of analog input device, including power supply circuits, CPU module,
Telecommunication circuit and channel acquisition circuit, described power supply circuits are for whole AI module for power supply, and described channel acquisition circuit is used for
The signal of collection site equipment, and pass to CPU module, described CPU module is for by the control of telecommunication circuit Yu DCS system
Standing and correctly carry out communication, described channel acquisition circuit is provided with the common mode rejection circuit of band high input impedance, described common mode inhibition electricity
Road, for on-site signal is carried out differential mode amplification, realizes common mode inhibition simultaneously.The input of common mode rejection circuit is this analog quantity
The signal input part of input module.
Described common mode rejection circuit includes the first amplifier VC1A, the second amplifier VC1C, the 3rd amplifier VC1D and some electricity
Resistance, the in-phase input end of described second amplifier VC1C is for being connected with the first signal output part of field apparatus, and described second transports
The inverting input putting VC1C is connected with one end, one end of the 7th resistance RG of the 5th resistance R5 respectively, described 5th resistance R5
The other end and the second amplifier VC1C outfan connect, the other end of described 7th resistance RG respectively with the one of the 6th resistance R6
End, the inverting input of the 3rd amplifier VC1D connect, the other end of described 6th resistance R6 and the outfan of the 3rd amplifier VC1D
Connect, one end connection of the outfan of described second amplifier VC1C and the first resistance R1, the other end of the first resistance R1 respectively with
One end of second resistance R2, the in-phase input end of the first amplifier VC1A connect, the other end of the second resistance R2 and the first amplifier
The outfan of VC1A connects, and the outfan of described first amplifier VC1A is connected with channel acquisition circuit, described 3rd amplifier VC1D
In-phase input end for being connected with the secondary signal outfan of field apparatus, the outfan of the 3rd amplifier VC1D and the 3rd resistance
One end of R3 connects, the other end of the 3rd resistance R3 respectively with one end, the anti-phase input of the first amplifier VC1A of the 4th resistance R4
End connects, the other end ground connection of the 4th resistance R4.Common mode rejection circuit common mode inhibition capacity of the present utility model is very strong, such as 1-
5V input signal, uses tradition differential mode circuit, can only ensure that < common-mode voltage of 20mV will not produce impact to precision, and uses
The common mode rejection circuit of this utility model design, can be < on precision without impact under 1V common-mode signal.And it is of the present utility model common
Mould suppression circuit has the effect increasing input impedance, and positive and negative two ends input impedance is the biggest, more than 108Ohm, input impedance
High little to effect of signals.
Described first amplifier VC1A, the second amplifier VC1C, the 3rd amplifier VC1D use model to be the integrated transporting discharging of LM324A.
Described channel acquisition circuit also includes that filter circuit and sample circuit, described filter circuit and sample circuit are arranged on
Between common mode rejection circuit and CPU module, the input of described common mode rejection circuit is used for receiving on-site signal, and described common mode presses down
The outfan of circuit processed is connected with the input of filter circuit, and the outfan of described filter circuit connects with the input of sample circuit
Connecing, the outfan of described sample circuit is connected with CPU module.Sample circuit ordinary circumstance is A/D convertor circuit.If CPU module is certainly
Band AD conversion function, channel acquisition circuit the most of the present utility model is without arranging A/D convertor circuit.Filter circuit is to filter signal
In the interference such as noise.
The first isolation circuit it is provided with between described CPU module and channel acquisition circuit.
The second isolation circuit it is provided with between described CPU module and telecommunication circuit.
Owing to have employed such scheme, owing to channel acquisition circuit of the present utility model is provided with the common mode of band high input impedance
Suppression circuit, common mode, for on-site signal is carried out differential mode amplification, is suppressed by described common mode rejection circuit.By this practicality
Differential mode can only be amplified suppressing common mode by novel common mode rejection circuit, have employed the AI input module of this circuit
Common mode rejection ratio is the highest, and input impedance is the biggest.
The utility model is described in further detail with detailed description of the invention below in conjunction with the accompanying drawings.
Accompanying drawing explanation
Fig. 1 is the theory diagram of analog input device of the present utility model；
Fig. 2 is the circuit diagram of common mode rejection circuit of the present utility model.
Detailed description of the invention
Seeing Fig. 1, a kind of analog input device, including power supply circuits, CPU module, telecommunication circuit and channel acquisition electricity
Road, described power supply circuits are for whole AI module for power supply, and described channel acquisition circuit is used for collection site signal, and by scene
Signal passes to CPU module.Described channel acquisition circuit is provided with the common mode rejection circuit of band high input impedance, described common mode inhibition
Circuit, for on-site signal is carried out differential mode amplification, realizes common mode inhibition simultaneously.The input of common mode rejection circuit is this simulation
The signal input part of amount input module.Described channel acquisition circuit also includes filter circuit and sample circuit, described filter circuit
With sample circuit is arranged between common mode rejection circuit and CPU module, the input of described common mode rejection circuit is used for receiving now
Field signal, the outfan of described common mode rejection circuit is connected with the input of filter circuit, the outfan of described filter circuit with
The input of sample circuit connects, and the outfan of described sample circuit is connected with CPU module.Sample circuit ordinary circumstance is that AD turns
Change circuit.If CPU module carries AD conversion function, channel acquisition circuit the most of the present utility model is without arranging A/D convertor circuit.
Filter circuit is that the noise etc. filtered in signal disturbs.Described CPU module connects EEPROM access circuit, can preserve some and set
Put parameter.The first isolation circuit it is provided with between described CPU module and channel acquisition circuit.Described CPU module is for by communication
Circuit carries out communication with the control station of DCS system.The second isolation circuit it is provided with between described CPU module and telecommunication circuit.Communication
Circuit is by the circuit of communication.By telecommunication circuit, CPU can communicate with control station.The core of telecommunication circuit is to adopt
Communication chip, such as SP485 etc..It, while connecing 485 buses of outside, connects the isolation circuit on limit.
See Fig. 2, described common mode rejection circuit include the first amplifier VC1A, the second amplifier VC1C, the 3rd amplifier VC1D with
And some resistance, the in-phase input end of described second amplifier VC1C for being connected with the first signal output part of field apparatus, institute
The inverting input stating the second amplifier VC1C is connected with one end, one end of the 7th resistance RG of the 5th resistance R5 respectively, and described
The other end of five resistance R5 and the outfan of the second amplifier VC1C connect, and the other end of described 7th resistance RG is electric with the 6th respectively
Resistance one end of R6, the inverting input of the 3rd amplifier VC1D connect, the other end of described 6th resistance R6 and the 3rd amplifier VC1D
Outfan connect, one end connection of the outfan of described second amplifier VC1C and the first resistance R1, another of the first resistance R1
End is connected with one end, the in-phase input end of the first amplifier VC1A of the second resistance R2 respectively, the other end of the second resistance R2 and the
The outfan of one amplifier VC1A connects, and the outfan of described first amplifier VC1A is connected with channel acquisition circuit, described 3rd fortune
The in-phase input end putting VC1D is connected for the secondary signal outfan with field apparatus, the outfan of the 3rd amplifier VC1D and
One end of three resistance R3 connects, the other end of the 3rd resistance R3 respectively with one end of the 4th resistance R4, the first amplifier VC1A anti-
Phase input connects, the other end ground connection of the 4th resistance R4.Described first amplifier VC1A, the second amplifier VC1C, the 3rd amplifier
VC1D uses model to be the integrated transporting discharging of LM324A.Common mode rejection circuit common mode inhibition capacity of the present utility model is very strong, such as
1-5V input signal, uses tradition differential mode circuit, can only ensure that < common-mode voltage of 20mV will not produce impact to precision, and makes
The common mode rejection circuit designed with this utility model, can be < on precision without impact under 1V common-mode signal.And it is of the present utility model
Common mode rejection circuit has the effect increasing input impedance, and positive and negative two ends input impedance is the biggest, more than 108.。
Seeing Fig. 2, if R1=R3, R2=R4, R5=R6. so can obtain according to electric circuit knowledge: Uout=-(Uin+-
Uin-)(1+2R5/RG)R2/R1 .Formula is pushed over, it can be seen that the difference of output voltage and input voltage has relation according to this.Think
The difference of input is amplified how many times with regard to corresponding value.Resistance R therein5, . RG R2,R1It is all that precision resistance can be according to specifically
Needing oneself to mate, like this, common-mode signal is just inhibited greatly at this circuit.The AI that have employed this circuit inputs mould
Block common mode rejection ratio is the highest.AI module actual measurement common mode exchange suppression voltage according to us can reach 250V.Ac, common mode direct current
Up to 1V, and before improving, it is respectively 40V.ac. 20mV.dc.
This utility model is not limited solely to above-described embodiment, without departing substantially from technical solutions of the utility model spirit
In the case of carry out the technical scheme of few modifications, protection domain of the present utility model should be fallen into.
Claims (6)
1. an analog input device, it is characterised in that: include power supply circuits, CPU module, telecommunication circuit and channel acquisition electricity
Road, described power supply circuits are for whole AI module for power supply, and described channel acquisition circuit is used for collection site signal, and by scene
Signal passes to CPU module, and described CPU module is for carrying out communication by the control station of telecommunication circuit Yu DCS system, described logical
Road Acquisition Circuit is provided with the common mode rejection circuit of band high input impedance, and described common mode rejection circuit is for poor to on-site signal
Mould amplifies, and realizes common mode inhibition simultaneously.
Analog input device the most according to claim 1, it is characterised in that: described common mode rejection circuit includes the first fortune
Putting (VC1A), the second amplifier (VC1C), the 3rd amplifier (VC1D) and some resistance, the homophase of described second amplifier (VC1C) is defeated
Entering end to be connected for the first signal output part with field apparatus, the inverting input of described second amplifier (VC1C) is respectively with the
One end of five resistance (R5), one end of the 7th resistance (RG) connect, the other end of described 5th resistance (R5) and the second amplifier
(VC1C) outfan connects, the other end of described 7th resistance (RG) respectively with one end, the 3rd amplifier of the 6th resistance (R6)
(VC1D) inverting input connects, and the other end of described 6th resistance (R6) and the outfan of the 3rd amplifier (VC1D) connect,
One end of the outfan of described second amplifier (VC1C) and the first resistance (R1) connects, the other end of the first resistance (R1) respectively with
One end of second resistance (R2), the in-phase input end of the first amplifier (VC1A) connect, the other end and first of the second resistance (R2)
The outfan of amplifier (VC1A) connects, and the outfan of described first amplifier (VC1A) is connected with channel acquisition circuit, and the described 3rd
The in-phase input end of amplifier (VC1D) is used for being connected with the secondary signal outfan of field apparatus, the output of the 3rd amplifier (VC1D)
End is connected with one end of the 3rd resistance (R3), the other end of the 3rd resistance (R3) respectively with one end of the 4th resistance (R4), first
The inverting input of amplifier (VC1A) connects, the other end ground connection of the 4th resistance (R4).
Analog input device the most according to claim 2, it is characterised in that: described first amplifier (VC1A), the second fortune
Put (VC1C), the 3rd amplifier (VC1D) uses model to be the integrated transporting discharging of LM324A.
Analog input device the most according to claim 1, it is characterised in that: described channel acquisition circuit also includes filtering
Circuit and sample circuit, described filter circuit and sample circuit be arranged between common mode rejection circuit and CPU module, described common mode
The input of suppression circuit is used for receiving on-site signal, and the outfan of described common mode rejection circuit connects with the input of filter circuit
Connecing, the outfan of described filter circuit is connected with the input of sample circuit, and the outfan of described sample circuit is with CPU module even
Connect.
5. according to the analog input device described in claim 1 or 4, it is characterised in that: described CPU module and channel acquisition electricity
The first isolation circuit it is provided with between road.
Analog input device the most according to claim 1, it is characterised in that: between described CPU module and telecommunication circuit
It is provided with the second isolation circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201521016989.1U CN205540217U (en) | 2015-12-09 | 2015-12-09 | Analog input device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201521016989.1U CN205540217U (en) | 2015-12-09 | 2015-12-09 | Analog input device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205540217U true CN205540217U (en) | 2016-08-31 |
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ID=56762700
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201521016989.1U Active CN205540217U (en) | 2015-12-09 | 2015-12-09 | Analog input device |
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| Country | Link |
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| CN (1) | CN205540217U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105759750A (en) * | 2015-12-09 | 2016-07-13 | 重庆川仪自动化股份有限公司 | Analog quantity input module of DCS |
-
2015
- 2015-12-09 CN CN201521016989.1U patent/CN205540217U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105759750A (en) * | 2015-12-09 | 2016-07-13 | 重庆川仪自动化股份有限公司 | Analog quantity input module of DCS |
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