CN114006835B - RS485 communication interface on-line self-diagnosis system based on specific code element identification technology - Google Patents
RS485 communication interface on-line self-diagnosis system based on specific code element identification technology Download PDFInfo
- Publication number
- CN114006835B CN114006835B CN202111283074.7A CN202111283074A CN114006835B CN 114006835 B CN114006835 B CN 114006835B CN 202111283074 A CN202111283074 A CN 202111283074A CN 114006835 B CN114006835 B CN 114006835B
- Authority
- CN
- China
- Prior art keywords
- self
- discharge
- communication interface
- loop
- code element
- 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.)
- Active
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L43/00—Arrangements for monitoring or testing data switching networks
- H04L43/08—Monitoring or testing based on specific metrics, e.g. QoS, energy consumption or environmental parameters
- H04L43/0805—Monitoring or testing based on specific metrics, e.g. QoS, energy consumption or environmental parameters by checking availability
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L41/00—Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
- H04L41/06—Management of faults, events, alarms or notifications
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Environmental & Geological Engineering (AREA)
- Maintenance And Management Of Digital Transmission (AREA)
Abstract
The invention discloses an RS485 communication interface on-line self-diagnosis system based on a specific code element identification technology, and belongs to the technical field of basic electronic circuits. The processor of the local terminal sends out data of specific code elements, the on-line self-diagnosis system receives confirmation and automatically enters an RS485 self-receiving loop state, and the processor diagnoses whether the RS485 communication equipment of the local terminal is normal or not by judging whether self-checking data sent by the local terminal is received or not. The invention has the advantages of simple realization, low cost, no need of additionally adding I/O resources of a processor, realization of the online self-diagnosis function of the RS485 communication equipment at the local end and convenience for the transformation of the power distribution terminal equipment.
Description
Technical Field
The invention relates to distribution automation, in particular discloses an on-line self-diagnosis system of an RS485 communication interface based on a specific code element recognition technology, which is used for self-checking of communication interruption of distribution terminal equipment and belongs to the technical field of basic electronic circuits.
Background
The traditional power distribution terminal equipment needs to be connected with equipment with different types, different manufacturers and different qualities through a plurality of RS485 communication interfaces, and meanwhile, the field environment is complex, and the possibility of communication interruption is easy to occur. However, the power distribution terminal device is often unattended, and how to automatically determine the reason of the communication interruption, especially determine whether the power distribution terminal device works normally, so as to reduce maintenance workload, is a problem to be solved urgently, and is also a real requirement for monitoring the state of the power distribution terminal device.
The traditional RS485 communication interface online self-diagnosis method needs to occupy I/O resources of a processor, and an online self-diagnosis process is started through I/O control. The invention aims to only reform each RS485 communication interface circuit to realize the on-line self-diagnosis of the RS485 communication interface without occupying the I/O resource of a processor.
Disclosure of Invention
The invention aims to overcome the defects of the background art, provide an on-line self-diagnosis system of an RS485 communication interface based on a specific code element identification technology, realize the aim of automatically judging the reason of interruption of RS485 communication on line without occupying I/O resources of a processor, have simple scheme and low cost, and solve the technical problems that the traditional on-line self-diagnosis method of the RS485 communication interface needs to reform a communication circuit and the processor circuit, which is not beneficial to reforming and upgrading a power distribution terminal.
The invention adopts the following technical scheme for realizing the purposes of the invention:
an on-line self-diagnosis system of RS485 communication interface based on specific code element recognition technology is characterized by that a specific code element recognition and self-loop starting circuit, a starting delay exit circuit and a self-loop control circuit are added in the original RS485 communication port circuit, and the functions are implemented by matching with CPU system on-line self-diagnosis program control.
The method comprises the steps that a local end processor sends real-time data to an RS485 communication interface, a specific code element identification and self-loop starting circuit detects specific code elements in the data sent by the local end processor and then sends a self-loop starting signal, a self-loop delay exit circuit detects the duration of a self-diagnosis program after receiving the self-loop starting signal, a self-loop delay exit circuit sends a self-loop state entering instruction to a self-loop control circuit after receiving the self-loop starting signal, the self-loop control circuit cuts off an RS485 external connection wire and enables the RS485 communication interface to send and receive the self-loop so that the RS485 communication interface enters an online self-diagnosis state, then the local end processor sends self-diagnosis data to the RS485 communication interface and receives self-check data fed back by the RS485 communication interface after self-loop, the local end processor compares the self-diagnosis data with the self-check data and obtains an evaluation result, the self-loop delay exit circuit sends a self-loop exit state exiting instruction to the self-loop control circuit after delay after detecting the self-diagnosis program is finished, and the self-loop exit state exiting control circuit recovers connection of the RS485 communication interface and an external line after receiving the self-loop exit state instruction.
The frame structure of the asynchronous communication is a one-bit start bit, 8-9 data bits, 1-bit or multi-bit stop bit, wherein the start bit is 0, and the stop bit is 1. By utilizing the characteristic that the continuous time of 0 code of one frame is less than the long time of one frame, and considering the practical application of a distribution network terminal, the baud rate of an RS485 serial port is generally more than 600, the invention selects 0x00 under the 300 baud rate as a specific code element, and the specific code element cannot appear in normal communication. The expression for a particular symbol time is hereby: equal to or greater than 9 x 1000/300=30ms.
When the CPU sets 300 baud rate and sends out 0x00, the specific code element identification and self-loop starting circuit continuously discharges through a discharge circuit consisting of a first discharge resistor, a discharge diode and a first discharge capacitor and is detected by a first voltage comparator, and sends out a self-loop starting signal, namely, the output of the first voltage comparator is turned from low level to high level. The discharge circuit continues to discharge and is detected for a time expression: t1= -r1×c1×ln ((Vfb 1-Vd 2)/(V1 max-Vd 2)), taking T1 as 70% of the specific symbol time, where Vfb1 is the comparison reference voltage of the non-inverting input terminal of the first voltage comparator U4, V1max is the start discharge voltage, and Vd2 is the turn-on voltage of the discharge diode D2. Parameters of the first discharging resistor R1 and the first discharging capacitor C1 are determined according to an expression of T1.
The self-loop delay exit circuit outputs a high level after receiving a self-loop start signal, sends a self-loop state entering instruction to the self-loop control circuit, discharges through a discharge circuit formed by a second discharge capacitor and a second discharge resistor until being detected by a second voltage comparator, the output of the second voltage comparator turns to be low level, sends an online self-diagnosis (self-loop) exiting instruction to the self-loop control circuit through T2, and the self-loop delay exit time is larger than the sum of a specific code element and self-diagnosis data time sent by a local processor and smaller than the sum of the specific code element and self-diagnosis data time sent by the local processor and 2 frame code lengths. The specific code element and the self-diagnosis data are respectively 1 and 3 frame codes, namely the self-loop delay exit time is between 4 and 6 frame code duration, and the time expression of discharging and being detected is as follows: taking into consideration that specific code elements and self-diagnosis data are respectively 1 and 3 frame codes, taking T2 as 5 frame codes for a long time, wherein Vfb2 is a comparison reference voltage of an inverting input end of a second voltage comparator U5, V2max is an initial discharge voltage, and parameters of a second discharge capacitor C2 and a second discharge resistor R2 are determined according to an expression of T2.
The self-loop control circuit receives a self-loop state entering instruction, the RS485 outlet is disconnected through a normally closed relay U2 switch, and meanwhile, the receiver of the RS485 communication interface is forced through a NOR gate U3, so that RS485 communication receives and transmits a self-loop through the receiver enabling end of the RS485 communication interface U1, and then the on-line self-diagnosis state is achieved. And then the local processor sends out self-diagnosis data, compares the self-diagnosis data with self-detection data returned in a self-loop state through receiving and transmitting by the RS485 communication interface to obtain an evaluation result, and exits for a long time by delaying at least 2 frame codes. The self-diagnosis data are 0xFF, 0x55 and 0xAA (the sending sequence is from left to right), and the received last two data are normally 0x55 and 0xAA, namely the device RS485 communication circuit is normal, otherwise faults are judged, and the self-detection data corresponding to the first self-diagnosis data are required to be changed when the self-loop control circuit is switched.
The invention adopts the technical scheme and has the following beneficial effects: the invention provides a system capable of diagnosing an RS485 communication state on line without occupying I/O resources of a power distribution terminal processor, which is characterized in that a 0 code continuous time is detected by a specific code element identification and self-loop starting circuit, the 0 code continuous time is slowly discharged when the 0 code is detected, the self-loop starting signal is generated when the 1 code continuous time is detected, the 0 code continuous time is detected after the self-loop starting signal is received by a self-loop delay exit circuit, the self-loop state entering instruction is generated when the 1 code is detected by the self-loop delay exit circuit, the self-loop state exiting instruction is generated after the self-loop state entering instruction is reasonably delayed by a slow discharging and 1 code quick charging timing self-diagnostic program, the self-loop control circuit is used for realizing the disconnection and the access of RS485 external line by a normally closed relay, the self-loop communication interface is forced to enter the self-loop receiving state by simple logic operation of a NOR gate, the whole scheme is simple and low in cost, the self-diagnosis of the self-loop communication interface can be realized without modifying the communication circuit and the processor circuit, and the improvement of the RS485 communication interface is facilitated, and the improvement cost of the power distribution terminal equipment can be reduced.
Drawings
Fig. 1 is a circuit diagram of an RS485 communication interface on-line self-diagnosis system of the present invention.
Fig. 2 is a flowchart of an on-line self-diagnosis procedure of the RS485 communication interface of the invention.
The reference numerals in the figures illustrate: u1 is RS485 communication interface, U2 is normally closed relay, U3 is the nor gate, U4 is first voltage comparator, U5 is second voltage comparator, R1 is first discharge resistance, R2 is second discharge resistance, C1 is first discharge capacitance, C2 is second discharge capacitance, D1 is first quick charge diode, D2 is discharge diode, D3 is second quick charge diode.
Detailed Description
The technical scheme of the invention is described in detail below with reference to the accompanying drawings.
The invention discloses an RS485 communication interface on-line self-diagnosis system based on specific code element recognition technology, as shown in figure 1, comprising: a specific code element identification and self-loop starting circuit consisting of a first quick charge diode D1, a discharge diode D2, a first discharge resistor R1, a first discharge capacitor C1 and a first voltage comparator U4; the self-loop delay exit circuit consists of a second quick charge diode D3, a second discharge resistor R2, a second discharge capacitor C3 and a second voltage comparator U5; a self-loop control circuit consisting of a normally closed relay U2 and an or-gate U3; the device comprises a local end processor, a D end (namely a transmitter input end) of an RS485 communication interface U1, a R end (namely a receiver output end) of the RS485 communication interface U1, a receiving end and a driver output enabling end, wherein the local end processor is used for sending data to the RS485 communication interface, transmitting enabling signals and receiving self-checking data fed back by the RS485 communication interface after self-loop, the D end (namely the transmitter input end) of the RS485 communication interface U1 receives TXD sent by the local end processor, the R end (namely the receiver output end) of the RS485 communication interface U1 outputs RXD to the local end processor, and the local end processor outputs TXE (namely the transmitting enabling signals) to a DE end (namely the driver output enabling end) of the RS485 communication interface U1. The self-loop delay exit circuit cuts off RS485 external lines to enable the RS485 communication interface to receive and send self-loop, and the self-loop control circuit closes RS485 external lines when receiving the self-loop exit state command.
In the specific code element identification and self-loop starting circuit, the anode of a first quick charge diode D1 and one end of a first discharge resistor R1 receive TXD sent by a local end processor, the other end of the first discharge resistor R1 is connected with the cathode of a discharge diode D2, the cathode of the first quick charge diode D1 is connected with the anode of the discharge diode D2, one pole of a first discharge capacitor C1 and the inverting input end of a first voltage comparator U4, the other pole of the first discharge capacitor C1 is grounded, the non-inverting input end of the first voltage comparator U4 is connected with a comparison reference voltage Vfb1, and the output end of the first voltage comparator U4 is connected with the input end of a self-loop delay exiting circuit.
In the self-loop delay exit circuit, the anode of the second fast charge diode D3 is used as the input end of the self-loop delay exit circuit to be connected with the output end of the specific code element identification and self-loop starting circuit, namely the output end of the first voltage comparator U4, the cathode of the second fast charge diode D3 is connected with one pole of the second discharge capacitor C2, one end of the second discharge resistor R2 and the non-inverting input end of the second voltage comparator U5, the other pole of the second discharge capacitor C2 and the other end of the second discharge resistor R2 are grounded, and the inverting input end of the second voltage comparator U5 is connected with the comparison reference voltage Vfb2.
In the self-loop control circuit, the output end of the second voltage comparator U5 is connected with one input end of the NOR gate U3, the other input end of the NOR gate U3 receives TXE (namely transmitting an enabling signal) sent by the local processor, the output end of the NOR gate U3 is connected with an nRE end (namely receiving an enabling end) of U1 of the RS485 communication interface, the contacts J1-2 and J2-2 of the normally closed relay U2 are respectively connected with RS485 external lines XOA and XOB, one contact J1-1 of the normally closed relay U2 is connected with an OA end (namely a driver in-phase output end or a receiver in-phase input end) of the RS485 communication interface U1, one contact J1-2 of the normally closed relay U2 is connected with an OB end (namely a driver in-phase output end or a receiver in-phase input end) of the RS485 communication interface U1, and the J-CT end (namely a control end of the normally closed relay) of the normally closed relay U2 is connected with the output end of the second voltage comparator U5.
The parameter design method of the RS485 communication on-line self-diagnosis circuit based on the specific code element identification technology comprises the following steps:
step 1, determining the code value and time of a specific code element: the code value of the specific symbol is 0x00, and the specific symbol time expression at 300 baud rate is: greater than or equal to 9 x 1000/300 = 30mS;
step 2, in combination with step 1, the conclusion that the specific symbol time is not less than 30mS, the specific symbol identification and the discharge from the loop starting circuit and detected time takes 70% (21 mS) of the specific symbol time, expression: t1= -R1 x C1 x LN ((Vfb 1-Vd 2)/(V1 max-Vd 2))=21 mS, wherein V1max expression: VDD-Vd1, VDD is the supply voltage of the signal TXD, vd1 and Vd2 are the forward voltages of the first fast charge diode and the discharge diode, vfb1 is 2×vd, vd is the diode forward voltage of the online self-diagnosis system, and the expression of T1 can be simplified to t1= -r1×c1×ln (Vd/(VDD-2×vd))=21 mS;
step 3, determining the self-diagnosis data code value, the self-diagnosis judgment basis and the time parameter of delayed exit sent by the local processor: the self-diagnosis data code values sent by the local end processor are 0xFF, 0x55 and 0xAA (the sending sequence is from left to right), the self-diagnosis judgment basis is that the last two data of the received three code values are normally 0x55 and 0xAA, namely the device RS485 communication circuit is normal, otherwise, the fault is judged, and the first received code value is not judged.
And 4, combining the step 3, wherein the delay exit time required for starting the delay exit circuit is larger than the sum of the specific code element and the self-diagnosis data sent by the CPU and smaller than the sum of the specific code element, the self-diagnosis data and the time delayed by 2 frame code lengths, and considering that the specific code element and the self-diagnosis data are respectively 1 and 3 frame codes, namely the delay exit time required for starting the delay exit current is between 4 and 6 frame code lengths, and 5 frame code lengths are taken. The time expression of which discharges and is detected: t2= -r2×c2×ln (Vfb 2/V2 max) =150 mS (5×30 mS), where V2max expression: VDD2-Vd3, VDD2 is the power supply voltage of the first voltage comparator U4, vd3 is the forward voltage of the second fast charge diode D3, vfb2 takes 2×vd, and the expression of T2 can be simplified to t2= -r2×c2×ln (2 Vd/(VDD 2-Vd))=150 mS.
The on-line self-diagnosis flow of the RS485 communication interface based on specific code element identification disclosed by the invention is shown in figure 2, and comprises the following steps:
setting the serial port baud rate as 300, and initializing specific code element time;
the local end processor sends out 0x00 at 300 baud rate as a specific code element;
after a specific code element time, the local end processor sends out self-diagnosis data and receives self-checking data fed back by RS 485;
a conclusion on whether the RS485 communication is normal is given by comparing the self-diagnosis data with the received self-detection data;
and recovering the original serial port configuration and delaying 2 frames with 300 baud rate for a long time.
Claims (6)
1. The RS485 communication interface on-line self-diagnosis system based on specific code element identification technology is characterized by comprising:
a specific code element identification and self-loop starting circuit, which receives a specific code element sent by a local terminal processor, and sends a self-loop starting signal to a self-loop delay exit circuit after identifying the specific code element, wherein the specific code element is 0x00 under 300 baud rate, and the specific code element time is more than or equal to 30mS;
the self-loop delay exit circuit sends an entering self-loop state instruction to the self-loop control circuit after receiving a self-loop starting signal, counts the self-diagnosis program, and sends an exiting self-loop state instruction to the self-loop control circuit after the self-diagnosis program is ended and the self-loop state instruction is delayed, wherein the delay experienced by the self-loop delay exit circuit after the self-diagnosis program is ended is greater than the sum of specific code element time and self-diagnosis data time sent by the local processor and less than the sum of specific code element time and self-diagnosis data time sent by the local processor and 2 frame code lengths;
the self-loop control circuit cuts off the RS485 external line after receiving the self-loop state command and enables a receiver of the RS485 communication interface, and resumes connection between the RS485 communication interface and the RS485 external line after receiving the self-loop state command; the method comprises the steps of,
the local end processor sends a specific code element, executes a self-diagnosis program after the specific code element time is passed, sends at least three self-diagnosis data to the RS485 communication interface, receives self-detection data fed back by the RS485 communication interface, and obtains a diagnosis result of normal communication of the RS485 communication interface when the second to last self-detection data fed back by the RS485 communication interface corresponds to the second to last self-diagnosis data one by one.
2. The RS485 communication interface on-line self-diagnosis system based on specific symbol recognition technology according to claim 1, wherein the specific symbol recognition and self-loop start-up circuit comprises: the device comprises a first quick charge diode, a first discharge resistor, a discharge diode, a first discharge capacitor and a first voltage comparator, wherein the anode of the first quick charge diode and one end of the first discharge resistor receive data sent by a local processor, the other end of the first discharge resistor is connected with the cathode of the discharge diode, the cathode of the first quick charge diode is connected with the anode of the discharge diode, one pole of the first discharge capacitor and the inverting input end of the first voltage comparator, the other pole of the first discharge capacitor is grounded, the non-inverting input end of the first voltage comparator is connected with a comparison reference voltage, and the output end of the first voltage comparator is connected with the input end of a self-loop delay exit circuit.
3. The RS485 communication interface on-line self-diagnosis system based on specific symbol recognition technology according to claim 1, wherein the self-loop delay exit circuit comprises: the positive electrode of the second quick charge diode is used as the input end of the self-loop delay exit circuit to be connected with the output end of the specific code element identification and self-loop starting circuit, the negative electrode of the second quick charge diode is connected with one electrode of the second discharge capacitor, one end of the second discharge resistor and the non-inverting input end of the second voltage comparator, the other electrode of the second discharge capacitor and the other end of the second discharge resistor are grounded, and the inverting input end of the second voltage comparator is connected with the comparison reference voltage.
4. The RS485 communication interface on-line self-diagnosis system based on specific symbol recognition technology according to claim 1, wherein the self-loop control circuit comprises: the device comprises a normally closed relay and a NOR gate, wherein one input end of the NOR gate is connected with the output end of a self-loop delay exit circuit, the other input end of the NOR gate receives an enabling signal transmitted by a local processor, the output end of the NOR gate is connected with the receiving enabling end of an RS485 communication interface, one side contact of the normally closed relay is connected with RS485 external rays, the other side contact of the normally closed relay is connected with the in-phase output end and the anti-phase output end of a driver of the RS485 communication interface, and the control end of the normally closed relay is connected with the output end of a second voltage comparator.
5. The RS485 communication interface on-line self-diagnosis system according to claim 2, wherein the resistance of the first discharge resistor and the capacitance of the first discharge capacitor are determined according to t1= -r1×c1×ln ((Vfb 1-Vd 2)/(V1 max-Vd 2)), T1 is the duration of discharge of the discharge circuit consisting of the first discharge resistor, the discharge diode, and the first discharge capacitor, T1 is 70% of the specific symbol time, R1 is the resistance of the first discharge resistor, C1 is the capacitance of the first discharge capacitor, vfb1 is the comparison reference voltage input from the non-inverting input terminal of the first voltage comparator, vd2 is the turn-on voltage of the discharge diode, and V1max is the initial discharge voltage of the discharge circuit.
6. The RS485 communication interface on-line self-diagnosis system based on specific symbol recognition technology according to claim 3, wherein the capacitance value of the second discharge capacitor and the resistance value of the second discharge resistor are determined according to t2= -r2×c2×ln (Vfb 2/V2 max), T2 is the duration of continuous discharge of the discharge circuit formed by the second discharge capacitor and the second discharge resistor, T2 is greater than the sum of specific symbol time and self-diagnosis data time sent by the local processor and less than the sum of specific symbol time and self-diagnosis data time and 2 frame code lengths sent by the local processor, R2 is the resistance value of the second discharge resistor, C2 is the capacitance value of the second discharge capacitor, vfb2 is the comparison reference voltage input by the inverting input terminal of the second voltage comparator, and V2max is the initial discharge voltage of the discharge circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111283074.7A CN114006835B (en) | 2021-11-01 | 2021-11-01 | RS485 communication interface on-line self-diagnosis system based on specific code element identification technology |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111283074.7A CN114006835B (en) | 2021-11-01 | 2021-11-01 | RS485 communication interface on-line self-diagnosis system based on specific code element identification technology |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114006835A CN114006835A (en) | 2022-02-01 |
| CN114006835B true CN114006835B (en) | 2023-10-20 |
Family
ID=79926219
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111283074.7A Active CN114006835B (en) | 2021-11-01 | 2021-11-01 | RS485 communication interface on-line self-diagnosis system based on specific code element identification technology |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114006835B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR200432811Y1 (en) * | 2006-09-29 | 2006-12-07 | 엘에스산전 주식회사 | A communication line test apparatus of communication node for rs-485 serial communication network |
| CN102355507A (en) * | 2011-09-29 | 2012-02-15 | 南京国电南自轨道交通工程有限公司 | Novel serial communication interface with functions of self-detection and conflict detection |
| CN105656656A (en) * | 2014-11-26 | 2016-06-08 | 上海协同科技股份有限公司 | RS485 communication circuit and fault detection method of nodes applying the circuit |
| CN208636683U (en) * | 2018-07-31 | 2019-03-22 | 深圳职业技术学院 | RS485 electrical level transferring chip |
| CN113422599A (en) * | 2021-06-25 | 2021-09-21 | 厦门科灿信息技术有限公司 | RS485 automatic receiving and transmitting control device and communication equipment |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102298550A (en) * | 2010-06-23 | 2011-12-28 | 鸿富锦精密工业（深圳）有限公司 | Test device for recommended standard 485 (RS 485) port |
-
2021
- 2021-11-01 CN CN202111283074.7A patent/CN114006835B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR200432811Y1 (en) * | 2006-09-29 | 2006-12-07 | 엘에스산전 주식회사 | A communication line test apparatus of communication node for rs-485 serial communication network |
| CN102355507A (en) * | 2011-09-29 | 2012-02-15 | 南京国电南自轨道交通工程有限公司 | Novel serial communication interface with functions of self-detection and conflict detection |
| CN105656656A (en) * | 2014-11-26 | 2016-06-08 | 上海协同科技股份有限公司 | RS485 communication circuit and fault detection method of nodes applying the circuit |
| CN208636683U (en) * | 2018-07-31 | 2019-03-22 | 深圳职业技术学院 | RS485 electrical level transferring chip |
| CN113422599A (en) * | 2021-06-25 | 2021-09-21 | 厦门科灿信息技术有限公司 | RS485 automatic receiving and transmitting control device and communication equipment |
Non-Patent Citations (2)
| Title |
|---|
| 基于RS-485总线的设备分布检测系统的研究;李革梅 等;计算机与现代化(第03期);第56-59页 * |
| 电能表RS485通信压力测试方法与应用研究;赵永辉 等;中国新技术新产品(第23期);第22-24页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114006835A (en) | 2022-02-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101304568B (en) | Apparatus and method for charging mobile terminal | |
| CN108958106A (en) | A kind of electric vehicle controller dormancy awakening system and control method | |
| CN112543717A (en) | Low-voltage storage battery charging system and method | |
| CN109992464B (en) | VCU automatic test method for integrated application layer software refreshing | |
| CN107306043A (en) | The control method of charging Rouser and the Rouser that charges | |
| CN107547210B (en) | Non-standard power supply equipment, powered equipment and system | |
| CN110416974A (en) | A kind of protective circuit of switch power source, Switching Power Supply and Switching Power Supply guard method | |
| CN105291875A (en) | Electromobile quick charge method | |
| CN106300501A (en) | A kind of adapter recognition methods and intelligent mobile terminal | |
| CN112014701A (en) | Direct current arc detection method of direct current system | |
| CN109991535A (en) | A kind of flash on-off control system and its input flash detection circuit | |
| CN114006835B (en) | RS485 communication interface on-line self-diagnosis system based on specific code element identification technology | |
| CN111211596A (en) | Method and device for monitoring power utilization state of charging cabinet | |
| CN109660006A (en) | A kind of charging method for the method and robot whether detection rechargeable battery accesses | |
| CN115473204A (en) | Double-component series connection input micro-inverse control device and control method thereof | |
| CN111257742A (en) | Fault diagnosis method and device for relay and vehicle | |
| CN114156844A (en) | On-site reclosing type feeder automatic protection device with residual voltage locking function | |
| CN105843126B (en) | A kind of intelligent type frequency-conversion device DC support controller and its control method | |
| CN113541603A (en) | Photovoltaic module control method and device | |
| CN112162201A (en) | Detection system and method for battery module | |
| CN201203801Y (en) | Self-diagnosis system for equipment operation failure | |
| CN114244440B (en) | Method, device and storage medium for information interaction of stations in self-healing system | |
| CN103904984B (en) | A kind of voltage shock avoiding motor intelligent manager and method | |
| CN110554649B (en) | Object-oriented substation programming control device | |
| CN218343313U (en) | Battery protection device and vehicle |
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 |