CN201373881Y - Input signal circuit of signal transmitting meter - Google Patents
Input signal circuit of signal transmitting meter Download PDFInfo
- Publication number
- CN201373881Y CN201373881Y CN200920126702U CN200920126702U CN201373881Y CN 201373881 Y CN201373881 Y CN 201373881Y CN 200920126702 U CN200920126702 U CN 200920126702U CN 200920126702 U CN200920126702 U CN 200920126702U CN 201373881 Y CN201373881 Y CN 201373881Y
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- operational amplifier
- capacitor
- resistance
- input
- output
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- Indication And Recording Devices For Special Purposes And Tariff Metering Devices (AREA)
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Abstract
Disclosed is an input signal circuit of a signal transmitting meter. The input signal circuit comprises a power source and is characterized in that a capacitor C15 and a resistor R18 are in parallel connection between two output ends of the power source, one end of the capacitor C15 is connected with an output end of the power source, the other end of the capacitor C15 is grounded, one output end of the power source is connected with an in-phase input end of an operational amplifier 1 after the output end of the power source is in series connection with a resistor R14, a resistor R20 and a capacitor C 17 are in parallel connection between a reversed-phase input end and an output end of the operational amplifier 1, a 4 pin of the operational amplifier 1 is grounded, and an 8 pin is grounded via a capacitor C16. The input signal circuit has the advantages that the input and the output are both 4-20 mA standard industrial signals, stepping motors driven by low current signals are utilized to drive pointers, and dial scales are linear so as to better conform to using habits and thinking modes of people. Moreover, the input signal circuit has rapid modes of zero correction and full-scale correction, the function of multipoint linear fitting, the convenience of improving the linearity of the whole circuit, simple circuit structure, low cost and high reliability.
Description
Technical field
The utility model relates to a kind of input signal circuit of pointer digital instrument, and particularly relating to a kind of input and output is the input signal circuit of the distant signal transmission instrument of 4-20mA.
Background technology
At present, the signal transmission form of the engine used of part diesel motor and boats and ships is to adopt 4-20mA current return mode to transmit.Adopt the current delivery mode to be convenient to long-distance transmissions, also help system and detect abnormal conditions such as the short circuit in whole transmission loop and open circuit.
The instrument of domestic realization current return transmission mode generally adopts the digital display mode of LCD, LED, also has part to adopt the instrument of cross coil drive pointer.Adopt LCD, LED to show that tachometer gage does not meet traditional use habit in some occasion, on the equipment of motions such as boats and ships and engineering machinery, more do not meet people's use and driving habits; Adopt traditional cross coil driving device formula instrument, dial scale is generally non-linear, and serviceable life is short and generally be the indicating mode of nonlinear way, and is shorter and pointer is linear poor in the following life-span of rugged environment, is not suitable for people's linear thinking mode.In addition, the linearity adjustment of above-mentioned instrument and zero point, full scale adjustment bother very much, generally need regulate zero point and full scale repeatedly; The linearity correction of instrument more bother and precision low, must debug repeatedly just and can reach corresponding accuracy requirement.
Summary of the invention
At the defective of prior art, the purpose of this utility model is to propose the input signal circuit that a kind of input and output are the distant signal transmission instrument of 4-20mA.
In order to reach above-mentioned purpose of the present utility model, the input signal circuit of signal transmission instrument of the present utility model comprises power supply, shunt capacitance C15 and resistance R 18 between two output terminals of power supply, one end of capacitor C 15 is connected other end ground connection with an output terminal of power supply; An output terminal of power supply is connected at the in-phase input end of operational amplifier 1 with resistance R 14 series connection backs, parallel resistance R20 and capacitor C 17 between the inverting input of rail-to-rail operational amplifier 1 (U4A) and the output terminal, 4 pin ground connection of operational amplifier 1,8 pin are by capacitor C 16 ground connection; Be connected with the inverting input of operational amplifier again after 19 series connection of another output terminal of power supply and resistance R, resistance R 15, R16 are connected between the in-phase input end of the output terminal of operational amplifier 1 and operational amplifier 2, be parallel with resistance R 21 and capacitor C 18 between the inverting input of operational amplifier 2 and the output terminal, one end of resistance R 22 is connected with resistance R 21, other end ground connection; Be in series with capacitor C 13 between the output terminal of resistance R 16 and operational amplifier 2, the inverting input of operational amplifier 2 is by capacitor C 14 ground connection.
Described rail-to-rail operational amplifier 2 (U4B) output signal Vout is connected to Chip Microcomputer A/D input port, is sent to the inner A/D modular converter of single-chip microcomputer, and the digital signal that obtains is more respectively as the input data of stepper motor output and V/I.
The input and output of a kind of stepper motor driven pointer digital instrument of the present utility model are 4-20mA standard industry signal, employing can be little the stepper motor that drives of current signal drive pointer, and dial scale is linear, the use habit and the mode of thinking that more meet people, the utility model also adopts zero correction efficiently and full scale correcting mode, the function that also has the linear multi match, be convenient to improve the linearity of entire circuit, the power supply and the processing mode of entire circuit are simple, do not need negative supply and circuit output carrying out amplitude limit, circuit structure is simple, the low but reliability height of cost.
Description of drawings
Accompanying drawing is a circuit diagram of the present utility model.
Embodiment
For making the above-mentioned purpose of the present utility model, feature and advantage can more obvious easy understanding, below special in conjunction with the utility model one preferred embodiment, be described in detail below:
Referring to accompanying drawing, shunt capacitance C15 and resistance R 18 between two output terminals of power supply, an end of capacitor C 15 is connected other end ground connection with an output terminal of power supply; An output terminal of power supply is connected at the in-phase input end of operational amplifier 1 with resistance R 14 series connection backs, parallel resistance R20 and capacitor C 17 between the inverting input of operational amplifier 1 and the output terminal, and 4 pin ground connection of operational amplifier 1,8 pin are by capacitor C 16 ground connection; Be connected with the inverting input of operational amplifier again after 19 series connection of another output terminal of power supply and resistance R, resistance R 15, R16 are connected between the in-phase input end of the output terminal of operational amplifier 1 and operational amplifier 2, be parallel with resistance R 21 and capacitor C 18 between the inverting input of operational amplifier 2 and the output terminal, one end of resistance R 22 is connected with resistance R 21, other end ground connection; Be in series with capacitor C 13 between the output terminal of resistance R 16 and operational amplifier 2, the inverting input of operational amplifier 2 is by capacitor C 14 ground connection; Rail-to-rail operational amplifier 2 (U4B) output signal Vout is connected to Chip Microcomputer A/D input port, is sent to the inner A/D modular converter of single-chip microcomputer, and the digital signal that obtains is more respectively as the input data of stepper motor output and V/I.
In the circuit, R18 is a current sampling resistor, realizes the conversion of I/V, and this resistance is converted into the 4-20mA electric current of input the voltage of 40mV-200mV, the in-phase amplifier that this voltage is formed through rail-to-rail operational amplifier U4A, enlargement factor is (1+R20/R19)=8.5; Amplifying the back voltage range is 0.34V-1.7V; R15, R16, C13, C14, R22, R21 composition enlargement factor are 2 second-order low-pass filter; Rail-to-rail operational amplifier 2 (U4B) output voltage V out; corresponding voltage value is 0.68V-3.4V; this voltage has satisfied the requirement of Chip Microcomputer A/D input voltage amplitude range (0V-5V); after adopting rail-to-rail operational amplifier; the power supply mode of this circuit is the single power supply mode; the voltage that supply voltage is identical with single-chip microcomputer, the A/D mouth that is input to single-chip microcomputer does not need to add voltage stabilizing diode or other holding circuit.
The resistance value that R18 adopts in the circuit is lower, and uses 100 Ω, 250 Ω different in the industry usually, makes can be connected in series many instrument in the 4-20mA current return.
The operational amplifier of this circuital current sampling utilization is the single power supply operational amplifier; The power supply and the processing mode of entire circuit are simple, do not need the output of negative supply and circuit to carry out amplitude limit, and circuit structure is simple, the low but reliability height of cost.
To sum up, the circuit signal workflow of present embodiment is as follows: 4-20mA normalized current signal is converted into voltage signal through resistance R 18, realizes the conversion of I/V; The in-phase amplifier that this voltage is formed through rail-to-rail operational amplifier U4A, amplifying the back voltage range is 0.34V-1.7V; Pass through R15 again, it is that 2 second-order low-pass filter is converted to 0.68V-3.4V voltage that R16, C13, C14, R22, R21 form enlargement factor; This voltage is sent into Chip Microcomputer A/D input port; This voltage signal is sent to the A/D modular converter of single-chip microcomputer inside, by the A/D modular converter aanalogvoltage of importing is carried out sample quantization, is converted to digital quantity; The data that sampling obtains are sent to stepping electricity and D/A output more respectively, are used for indication and the output D/A conversion and the 4-20mA output of stepper motor.
The data that obtain of sampling are converted into the drive waveforms of stepper motor by software algorithm, and stepper motor drives the pointer rotation, indication corresponding rotating speeds value on linear index dial.
The data that sampling obtains are exported 10 position digital signals by the SPI interface of single-chip microcomputer simultaneously, be converted into the voltage signal of 0.4V-2.0V by 10 D/A converter U7 (TLC5615), by translation circuit, export the 4-20mA constant current source, thereby realized the linear transformation of V-I.
On the ship control system that the utility model can be used for exporting, realize that the signals collecting of the 4-20mA that engine transmits and the linearity of data show, meet the linearity indication of traditional habit, and disposable by corresponding fail-test, satisfy the high reliability request of ship control system under rugged environment.
Certainly; the utility model also can have other embodiment; under the situation of spirit that does not deviate from the utility model and essence; the person of ordinary skill in the field works as can make various corresponding changes according to the utility model, but these corresponding changes all should belong to the protection domain of the utility model claim.
Claims (2)
1. the input signal circuit of a signal transmission instrument comprises power supply, it is characterized in that: shunt capacitance C15 and resistance R 18 between two output terminals of power supply, and an end of capacitor C 15 is connected other end ground connection with an output terminal of power supply; An output terminal of power supply is connected at the in-phase input end of operational amplifier 1 with resistance R 14 series connection backs, parallel resistance R20 and capacitor C 17 between the inverting input of operational amplifier 1 and the output terminal, and 4 pin ground connection of operational amplifier 1,8 pin are by capacitor C 16 ground connection; Be connected with the inverting input of operational amplifier again after 19 series connection of another output terminal of power supply and resistance R, resistance R 15, R16 are connected between the in-phase input end of the output terminal of operational amplifier 1 and operational amplifier 2, be parallel with resistance R 21 and capacitor C 18 between the inverting input of operational amplifier 2 and the output terminal, one end of resistance R 22 is connected with resistance R 21, other end ground connection; Be in series with capacitor C 13 between the output terminal of resistance R 16 and operational amplifier 2, the inverting input of operational amplifier 2 is by capacitor C 14 ground connection.
2. the input signal circuit of signal transmission instrument according to claim 1, it is characterized in that: the signal of the output end vo ut of operational amplifier 2 is connected to Chip Microcomputer A/D input port, be sent to the inner A/D modular converter of single-chip microcomputer, the digital signal that obtains is more respectively as the input data of stepper motor output and V/I.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200920126702U CN201373881Y (en) | 2009-03-19 | 2009-03-19 | Input signal circuit of signal transmitting meter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200920126702U CN201373881Y (en) | 2009-03-19 | 2009-03-19 | Input signal circuit of signal transmitting meter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201373881Y true CN201373881Y (en) | 2009-12-30 |
Family
ID=41499966
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200920126702U Expired - Lifetime CN201373881Y (en) | 2009-03-19 | 2009-03-19 | Input signal circuit of signal transmitting meter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201373881Y (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105162451A (en) * | 2015-08-26 | 2015-12-16 | 长沙奥托自动化技术有限公司 | Current conversion device for soft starter |
| CN110061710A (en) * | 2019-05-30 | 2019-07-26 | 杭州欧贲科技有限公司 | Highly integrated charge amplifier circuit |
-
2009
- 2009-03-19 CN CN200920126702U patent/CN201373881Y/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105162451A (en) * | 2015-08-26 | 2015-12-16 | 长沙奥托自动化技术有限公司 | Current conversion device for soft starter |
| CN105162451B (en) * | 2015-08-26 | 2018-06-12 | 长沙奥托自动化技术有限公司 | A kind of current transfer device for soft strater |
| CN110061710A (en) * | 2019-05-30 | 2019-07-26 | 杭州欧贲科技有限公司 | Highly integrated charge amplifier circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20091230 |