CN205105221U - On --spot instrument data case based on optical cable transmission - Google Patents
On --spot instrument data case based on optical cable transmission Download PDFInfo
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- CN205105221U CN205105221U CN201520826076.XU CN201520826076U CN205105221U CN 205105221 U CN205105221 U CN 205105221U CN 201520826076 U CN201520826076 U CN 201520826076U CN 205105221 U CN205105221 U CN 205105221U
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- optical cable
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Abstract
The utility model discloses an on - -spot instrument data case based on optical cable transmission, microcontroller is drawn together to on -the -spot instrument data case and bag, and this microcontroller connection is 4-20mA's electric current signal input at least all the way, on -the -spot instrument data case still includes photoelectricity data modem, and these photoelectricity data modem connects microcontroller, photoelectricity data modem passes through the optical cable and connects the chemical enterprises DCS system. Photoelectricity data modem passes through the optical cable and connects the receiving terminal, and the receiving terminal restores into 4-20mA signal of telecommunication with it after accepting the light signal again.
Description
Technical field
The utility model belongs to technical field of electric equipment, particularly a kind of field instrument data box based on optical cable transmission.
Background technology
Be widely used in chemical enterprise DCS system PLC system etc., import control system into by the data-signal that scene is a large amount of, run through pre-set procedure auto-control by system.4 ~ 20mA electric current loop is the normalized current interface of industrial automation data sample and transform, and it changes the small signal simulation amount of various transducer dress into normalized current ring interface, to improve transmission range and to reduce interference.But, at many severe operational environments or require in explosion-proof higher environment, by 4 ~ 20mA electric current loop signal Long Distant Transmit without distortion, conventional electric wire must be applied and is difficult to meet the demands, the transmission of each signal needs independently pair of control line, can not doubling.A large amount of wirings makes to interfere with each other between signal, and band electrical wiring, once have damage or short circuit, can regard it as chain reaction, infringement equipment.
Utility model content
The purpose of this utility model is to provide a kind of field instrument data box based on optical cable transmission.
The technical solution of the utility model is, a kind of field instrument data box based on optical cable transmission, and described field instrument data box comprises microcontroller, and this microcontroller connects the current signal input of at least one road 4 ~ 20mA,
Described field instrument data box also comprises photooptical data modulator-demodulator, and this photooptical data modulator-demodulator connects described microcontroller,
Described photooptical data modulator-demodulator connects chemical enterprise DCS system by optical cable.
Described photooptical data modulator-demodulator connects receiving terminal by optical cable, after receiving terminal accepts light signal, then is reduced into 4 ~ 20mA signal of telecommunication.
The utility model adopts optical fiber with it at a high speed, long distance, and distortion is little, and antijamming capability is strong, and explosion-proof, the advantages such as lightning protection, replace the signal of telecommunication with light signal.Make field instrument data box reduce the wiring of electric wire, reduce wiring cost, reduce the Installation and Debugging cycle, make the reading of signal and transmit more stable, reliably, safety.
Accompanying drawing explanation
Fig. 1 is the utility model principle of work and power schematic diagram.
Fig. 2 is photooptical data transfer principle figure in the utility model embodiment.
Embodiment
As shown in Figure 1, a kind of field instrument data box based on optical cable transmission, described field instrument data box comprises microcontroller, this microcontroller connects the current signal input of at least one road 4 ~ 20mA, described field instrument data box also comprises photooptical data modulator-demodulator, this photooptical data modulator-demodulator connects described microcontroller, and described photooptical data modulator-demodulator connects chemical enterprise DCS system by optical cable.
As shown in Figure 2, field instrument data box receives the current signal of 4 on-the-spot ~ 20mA, light signal is converted the electrical signal to by fibre optic modem, by the setting of program, by the signal of telecommunication setting stepwise of multichannel, receiving terminal can be delivered to, after having receiving terminal to accept light signal by an optical cable, 4 ~ 20mA signal of telecommunication will be reduced into again, for equipment use.Wherein,
1. photodetector
Photoelectric detector is first critical component of optical receiver, and its effect converts the light signal sent by optical fiber to the signal of telecommunication.Photoelectric detector mainly contains PIN photodiode and avalanche photodide APD two kinds.PIN pipe uses simple, only need the reverse biased of 10 ~ 20V, but PIN pipe does not have gain.APD pipe has the gain of 10 ~ 200 times, can improve the sensitivity of optical receiver, but needs the bias voltage of more than tens volts, and gain characteristic is more serious by the impact of temperature
2, preamplifier
Through the faint signal code that photoelectric detector detects, flow through after load resistance sets up signal voltage, carry out pre-amplification by preamplifier.Except photoelectric detector performance quality affects except the sensitivity of optical receiver, the sensitivity of preamplifier on optical receiver has very important impact.For this reason, preamplifier must be low noise, wide band amplifier.
3. main amplifier
Main amplifier is used to provide high gain, and the output signal of preamplifier is amplified to the level needed for applicable decision circuit.The output signal level of preamplifier is generally mV magnitude, and the output signal level of main amplifier is generally 1 ~ 3V.
4, equalizer
When light transmits in a fiber, owing to being subject to the impact of dispersion, signal, by generation distortion and broadening, will make to influence each other between code element, will occur error code.The effect of equalizer carries out shaping to the digital pulse signal of the distortion that main amplifier exports, and makes it to become the waveform being conducive to most adjudicating, intersymbol interference is minimum, be generally raised cosine wave
5, judgement regeneration and timing extraction
Namely judgement is compare by a decision level and equalizer output signal, when the voltage signal exported in the judgement moment is higher than decision level, is then judged as " 1 " code, otherwise is judged as " 0 " code.Like this, can obtain one with the digital pulse signal that transmitting terminal sends at the output of judgement regenerative circuit is the consistent digital pulse sequence be made up of rectangular pulse substantially.In order to accurately determine " judgement moment ", just need from signal code stream, extract timing information accurately and being used for demarcating, consistent with transmitting terminal to ensure.This work has been come by " timing extraction " circuit.
6, peak detector and AGC amplifier
The digital pulse signal be made up of a raised cosine wave taking-up part is delivered to peak detector and carries out detection, the direct current signal after detection is delivered to AGC amplifier again and is compared and enlarged, and produces an AGC voltage.The reverse bias voltage controlling photoelectric detector (APD pipe) is removed on the one hand with this voltage, deliver to the working point that main amplifier removes to adjust main amplifier on the other hand, to control the gain of main amplifier, thus the raised cosine wave making equalizer output magnitude stable, ensure the correctness of bit decision.
Claims (2)
1. based on a field instrument data box for optical cable transmission, it is characterized in that, described field instrument data box comprises microcontroller, and this microcontroller connects the current signal input of at least one road 4 ~ 20mA,
Described field instrument data box also comprises photooptical data modulator-demodulator, and this photooptical data modulator-demodulator connects described microcontroller,
Described photooptical data modulator-demodulator connects chemical enterprise DCS system by optical cable.
2. as claimed in claim 1 based on the field instrument data box of optical cable transmission, it is characterized in that, described photooptical data modulator-demodulator connects receiving terminal by optical cable, after receiving terminal accepts light signal, then is reduced into 4 ~ 20mA signal of telecommunication.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520826076.XU CN205105221U (en) | 2015-10-21 | 2015-10-21 | On --spot instrument data case based on optical cable transmission |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520826076.XU CN205105221U (en) | 2015-10-21 | 2015-10-21 | On --spot instrument data case based on optical cable transmission |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205105221U true CN205105221U (en) | 2016-03-23 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201520826076.XU Active CN205105221U (en) | 2015-10-21 | 2015-10-21 | On --spot instrument data case based on optical cable transmission |
Country Status (1)
| Country | Link |
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| CN (1) | CN205105221U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105955081A (en) * | 2016-05-19 | 2016-09-21 | 上海新联合电气有限公司 | Industrial control system based on optical cable transmission |
-
2015
- 2015-10-21 CN CN201520826076.XU patent/CN205105221U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105955081A (en) * | 2016-05-19 | 2016-09-21 | 上海新联合电气有限公司 | Industrial control system based on optical cable transmission |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |