CN108508876B - Daisy chain RS485 control circuit and short circuit solving method - Google Patents
Daisy chain RS485 control circuit and short circuit solving method Download PDFInfo
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- CN108508876B CN108508876B CN201810474969.0A CN201810474969A CN108508876B CN 108508876 B CN108508876 B CN 108508876B CN 201810474969 A CN201810474969 A CN 201810474969A CN 108508876 B CN108508876 B CN 108508876B
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- 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
- G05B23/00—Testing or monitoring of control systems or parts thereof
- G05B23/02—Electric testing or monitoring
- G05B23/0205—Electric testing or monitoring by means of a monitoring system capable of detecting and responding to faults
- G05B23/0259—Electric testing or monitoring by means of a monitoring system capable of detecting and responding to faults characterized by the response to fault detection
- G05B23/0286—Modifications to the monitored process, e.g. stopping operation or adapting control
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- 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
- G05B2219/24065—Real time diagnostics
Abstract
The invention belongs to the field of RS485 wiring control circuits, and particularly relates to a daisy chain RS485 control circuit which comprises a plurality of control boards connected end to end, wherein an MCU control module, an RS485 input module R1, a double-pole double-throw relay S2, a double-pole double-throw relay S1, an RS485 output module R2, a double-pole double-throw relay S5, a double-pole double-throw relay S6, a standby RS485 input module R3 and a standby RS485 output and input module R4 are arranged on each control board, and the double-pole double-throw relay S1 and the double-pole double-throw relay S6 can be directly communicated. Through adopting 6 double-pole double-throw switches and respectively setting up spare modules for RS485 input module and RS485 input module, for daisy chain RS485 control circuit's short circuit provides the solution guarantee, through the switching operation of double-pole double-throw switch, can realize short circuit position judgement and overcome in the control circuit.
Description
Technical Field
The invention belongs to the field of RS485 wiring control circuits, and particularly relates to a daisy chain RS485 control circuit and a short circuit solving method.
Background
Due to the characteristics of long distance, multiple nodes and low transmission cost of the RS485, the RS485 becomes the first choice for data transmission. The daisy chain RS485 control communication mode has the advantages that a plurality of devices are connected by using limited signal transmission lines, the same service is shared, and the problems of bus competition, blocking and the like do not exist.
However, if a short circuit occurs in a certain RS485 chip in the daisy chain RS485 control circuit, the whole system will not be controlled after the short circuit, which will affect the performance of the whole communication circuit.
Disclosure of Invention
The invention provides a daisy chain RS485 control circuit and a short circuit solving method aiming at the defects of the daisy chain RS485 control circuit, which can effectively solve the short circuit problem of the daisy chain RS485 control circuit and ensure the normal communication control of the daisy chain RS485 control circuit.
The technical scheme adopted by the invention is as follows:
the utility model provides a daisy chain RS485 control circuit, includes a plurality of end to end's control panel which characterized in that: the control panel is provided with an MCU control module, an RS485 input module R1 connected with the input end of the MCU control module through a double-pole double-throw relay S3, a double-pole double-throw relay S2 connected with the input end of the RS485 input module R1, a double-pole double-throw relay S1 connected with the double-pole double-throw relay S2 and used for controlling the signal input of the adjacent control panel, an RS485 output module R2 connected with the output end of the MCU control module through a double-pole double-throw relay S4, the double-pole double-throw relay S5 is connected with the output end of the RS485 output module R2, the double-pole double-throw relay S6 is connected with the double-pole double-throw relay S5 and used for controlling signals to be output to an adjacent control board, the standby RS485 input module R3 is arranged between the double-pole double-throw relay S2 and the double-pole double-throw relay S3, the standby RS485 output module R4 is arranged between the double-pole double-throw relay S4 and the double-pole double-throw relay S5, and the double-pole double-throw relay S1 and the double-pole double-throw relay S6 can be directly communicated.
The MCU control module adopts a PIC18FXXX chip.
Furthermore, the control panels connected end to end are n +1 control panels, one control panel is selected as a main control panel, the rest n are slave control panels, each slave control panel is labeled according to the sequence of the connection relation, the control panel directly connected with the output end of the main control panel is a slave control panel 1, and the control panel directly connected with the input end of the main control panel is a slave control panel n.
When no fault exists initially, an RS485 signal of the control circuit starts from an RS485 output module R2 of the main control panel, goes to an RS485 input module R1 of the slave control panel 1, is processed by an MCU control module of the slave control panel 1, then starts from an RS485 output module R2 of the slave control panel 1, goes to an RS485 input module R1 of the slave control panel n, is processed by an MCU of the slave control panel n, and then is sent to an RS485 input module R1 of the main control panel from an RS485 output module R2 of the slave control panel n, so that a communication ring is formed.
When a fault occurs, the provided short circuit solution method of the daisy chain RS485 control circuit comprises the following steps:
1) the MCU control module of the master control board sends an instruction for checking whether all RS485 in the system is normal or not at intervals, the slave control board receives the instruction and then replies with a corresponding format, meanwhile, the slave control board also sends a checking instruction to the next slave control board at regular time, and if the slave control board m (m is not less than 1 and not less than n) does not receive the instruction for a long time, the RS485 input module R1 of the slave control board m or the RS485 output module R2 of the slave control board m-1 is judged to have the short circuit or open circuit problem.
2) Firstly, signals are switched to a standby RS485 input module R3 through double-pole double-throw relays S2 and S3 on a control panel m, then a checking command is sent to see whether an instruction can be received, and if the instruction is received, the problem is solved;
3) if the command cannot be received, the command is used for judging that the RS485 output module R2 of the slave control panel m-1 possibly has a problem, the input module on the slave control panel m is switched to the RS485 input module R1, then the command is sent to the slave control panel m-1, the slave control panel m-1 is required to send a signal to the standby RS485 output module R4 through switching the double-pole double-throw relays S4 and S5, then the viewing command is sent to the slave control panel m, and if the command is received from the slave control panel m, the problem is solved;
4) if the problem is not solved, the output module of the slave control board m-1 and the input module of the slave control board m simultaneously select a standby module to check whether the slave control board m can receive the instruction, and if the problem can be solved;
5) if the fault cannot be solved, the RS485 communication twisted pair between the slave control panel m-1 and the slave control panel m fails, and manual maintenance is carried out;
6) if a certain spare module on the slave control board m is used, and the problem occurs again, the RS485 signal on the slave control board m directly crosses over by switching S1 and S6, so that the slave control board m can not receive the instruction any more.
According to the invention, 6 double-pole double-throw switches are adopted, and the standby modules are respectively arranged for the RS485 input module and the RS485 input module, so that the solution and the guarantee are provided for the short circuit of the daisy chain RS485 control circuit, the judgment and the overcoming of the short circuit position in the control circuit can be realized through the switching operation of the double-pole double-throw switches, the smoothness of the RS485 control circuit is ensured, and the universality of the RS485 control circuit is improved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
fig. 1 is a block diagram of a control circuit of the present invention.
Detailed Description
As shown in FIG. 1, the daisy chain RS485 control circuit comprises a plurality of end-to-end control boards, and is characterized in that: the control panel is provided with an MCU control module, an RS485 input module R1 connected with the input end of the MCU control module through a double-pole double-throw relay S3, a double-pole double-throw relay S2 connected with the input end of the RS485 input module R1, a double-pole double-throw relay S1 connected with the double-pole double-throw relay S2 and used for controlling the signal input of the adjacent control panel, an RS485 output module R2 connected with the output end of the MCU control module through a double-pole double-throw relay S4, the double-pole double-throw relay S5 is connected with the output end of the RS485 output module R2, the double-pole double-throw relay S6 is connected with the double-pole double-throw relay S5 and used for controlling signals to be output to an adjacent control board, the standby RS485 input module R3 is arranged between the double-pole double-throw relay S2 and the double-pole double-throw relay S3, the standby RS485 output module R4 is arranged between the double-pole double-throw relay S4 and the double-pole double-throw relay S5, and the double-pole double-throw relay S1 and the double-pole double-throw relay S6 can be directly communicated.
The MCU control module adopts a PIC18FXXX chip.
Furthermore, the control panels connected end to end are n +1 control panels, one control panel is selected as a main control panel, the rest n are slave control panels, each control panel is labeled according to the sequence of connection relations, the control panel is directly connected with the output end of the main control panel and is a slave control panel 1, and the control panel is directly connected with the input end of the main control panel and is a slave control panel n.
When no fault exists initially, an RS485 signal of the control circuit starts from an RS485 output module R2 of the main control panel, goes to an RS485 input module R1 of the slave control panel 1, is processed by an MCU control module of the slave control panel 1, then starts from an RS485 output module R2 of the slave control panel 1, goes to an RS485 input module R1 of the slave control panel n, is processed by an MCU of the slave control panel n, and then is sent to an RS485 input module R1 of the main control panel from an RS485 output module R2 of the slave control panel n, so that a communication ring is formed.
When a fault occurs, the provided short circuit solution method of the daisy chain RS485 control circuit comprises the following steps:
1) the MCU control module of the master control board sends an instruction for checking whether all RS485 in the system is normal or not at intervals, the slave control board receives the instruction and then replies with a corresponding format, meanwhile, the slave control board also sends a checking instruction to the next slave control board at regular time, and if the slave control board m (1 ≦ m ≦ n) does not receive the instruction for a long time, the RS485 input module R1 of the slave control board m or the RS485 output module R2 of the slave control board m-1 has a short circuit or open circuit problem.
2) Firstly, signals are switched to a standby RS485 input module R3 through double-pole double-throw relays S2 and S3 on a control panel m, then a checking command is sent to see whether an instruction can be received, and if the instruction is received, the problem is solved;
3) if the command cannot be received, the RS485 output module R2 of the slave control panel m-1 is judged to have a problem, the input module on the slave control panel m is switched to the RS485 input module R1, then the command is sent to the slave control panel m-1 to request the slave control panel m-1 to send a signal to the standby RS485 output module R4 through switching the double-pole double-throw relays S4 and S5, then the view command is sent to the slave control panel m, and if the command is received from the slave control panel m, the problem is solved;
4) if the problem is not solved, the output module of the slave control board m-1 and the input module of the slave control board m simultaneously select a standby module to check whether the slave control board m can receive the instruction, and if the problem can be solved;
5) if the fault cannot be solved, the RS485 communication twisted pair between the slave control panel m-1 and the slave control panel m fails, and manual maintenance is carried out;
6) if a certain spare module on the slave control board m is used, and the problem occurs again, the RS485 signal on the slave control board m directly crosses over by switching S1 and S6, so that the slave control board m can not receive the instruction any more.
Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (2)
1. The utility model provides a daisy chain RS485 control circuit, includes a plurality of end to end's control panel which characterized in that: the control panel is provided with an MCU control module, an RS485 input module R1 connected with the input end of the MCU control module through a double-pole double-throw relay S3, a double-pole double-throw relay S2 connected with the input end of the RS485 input module R1, a double-pole double-throw relay S1 connected with the double-pole double-throw relay S2 and used for controlling the signal input of the adjacent control panel, an RS485 output module R2 connected with the output end of the MCU control module through a double-pole double-throw relay S4, the double-pole double-throw relay S5 is connected with the output end of the RS485 output module R2, the double-pole double-throw relay S6 is connected with the double-pole double-throw relay S5 and is used for controlling signals to be output to an adjacent control board, a standby RS485 input module R3 is arranged between the double-pole double-throw relay S2 and the double-pole double-throw relay S3, a standby RS485 output module R4 is arranged between the double-pole double-throw relay S4 and the double-pole double-throw relay S5, and the double-pole double-throw relay S1 is directly communicated with the double-pole double-throw relay S6;
the plurality of control panels connected end to end are n +1 control panels, one control panel is selected as a main control panel, the rest n control panels are slave control panels, each slave control panel is labeled according to the sequence of the connection relation, the slave control panel is directly connected with the output end of the main control panel and is a slave control panel 1, and the slave control panel is directly connected with the input end of the main control panel and is a slave control panel n;
the short circuit solving method of the daisy chain RS485 control circuit comprises the following steps:
(1) the MCU control module of the main control panel sends a checking instruction for checking whether all RS485 in the system is normal or not at intervals, the slave control panel receives the instruction and then replies with a corresponding format, meanwhile, the slave control panel also sends the checking instruction to the next slave control panel at regular time, and if the slave control panel m does not receive the instruction for a long time, the RS485 input module R1 of the slave control panel m or the RS485 output module R2 of the slave control panel m-1 is judged to have short circuit or open circuit problems;
(2) the signals are switched to a standby RS485 input module R3 through double-pole double-throw relays S2 and S3 on the slave control panel m, then the MCU control module of the master control panel sends a checking command to see whether the slave control panel m can receive the command, and if the slave control panel m receives the command, the problem is solved;
(3) if the slave control board m cannot receive the instruction, the RS485 output module R2 of the slave control board m-1 is judged to have a problem, the input module on the slave control board m is switched to the RS485 input module R1, then the instruction is sent to the slave control board m-1 to request the slave control board m-1 to send a signal to the standby RS485 output module R4 through switching the double-pole double-throw relays S4 and S5, the master control board sends a viewing instruction to the slave control board m, and if the slave control board m receives the instruction, the problem is solved;
(4) if the problem is not solved, the output module of the slave control panel m-1 and the input module of the slave control panel m simultaneously select a standby module to check whether the control panel m can receive the instruction, and if the problem can be solved;
(5) if the fault can not be solved, manually maintaining the slave control panel m-1 and the slave control panel m if the fault is judged to occur in the RS485 communication twisted pair;
(6) if the standby RS485 input module or the standby RS485 output module on the slave control board m is used, when problems occur again, the communication of the double-pole double-throw relays S1 and S6 on the slave control board m is switched, so that the RS485 signal on the slave control board m directly crosses.
2. The daisy chain RS485 control circuit of claim 1 wherein: the MCU control module adopts a series chip with the model number of PIC 18F.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201810474969.0A CN108508876B (en) | 2018-05-17 | 2018-05-17 | Daisy chain RS485 control circuit and short circuit solving method |
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| CN201810474969.0A CN108508876B (en) | 2018-05-17 | 2018-05-17 | Daisy chain RS485 control circuit and short circuit solving method |
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| CN108508876A CN108508876A (en) | 2018-09-07 |
| CN108508876B true CN108508876B (en) | 2021-08-20 |
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| US11585835B2 (en) | 2021-01-15 | 2023-02-21 | Red Lion Controls, Inc. | System of determining the sequence and positioning of pluggable modules |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1469595A (en) * | 2002-05-31 | 2004-01-21 | 日本电气株式会社 | Loop network system |
| CN103326911A (en) * | 2013-07-03 | 2013-09-25 | 富盛科技股份有限公司 | Self healing ring RS485 bus structure with short circuit and circuit break prevention |
| CN104767633A (en) * | 2014-01-07 | 2015-07-08 | 艾默生网络能源有限公司 | Industrial Ethernet system |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4760504B2 (en) * | 2006-04-12 | 2011-08-31 | 株式会社日立製作所 | Network system and communication device |
| CN101989932B (en) * | 2009-08-07 | 2012-12-12 | 巨尔(上海)光电照明有限公司 | RS485-based automatic error detection method |
| US9143398B2 (en) * | 2012-12-27 | 2015-09-22 | Futurewei Technologies, Inc. | System and method for spare capacity allocation for shared backup path protection for dual link failures using successive survivable routing |
| US9946675B2 (en) * | 2013-03-13 | 2018-04-17 | Atieva, Inc. | Fault-tolerant loop for a communication bus |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1469595A (en) * | 2002-05-31 | 2004-01-21 | 日本电气株式会社 | Loop network system |
| CN103326911A (en) * | 2013-07-03 | 2013-09-25 | 富盛科技股份有限公司 | Self healing ring RS485 bus structure with short circuit and circuit break prevention |
| CN104767633A (en) * | 2014-01-07 | 2015-07-08 | 艾默生网络能源有限公司 | Industrial Ethernet system |
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Effective date of registration: 20221219 Address after: 233000 Chaoyang Industrial Park, the intersection of Middle Ring Road and Guxing Road, Longzihu District, Bengbu City, Anhui Province Patentee after: Anhui Weidi Intelligent Glass Co.,Ltd. Address before: 230012 no.1399 wulishan Road, Xinzhan District, Hefei City, Anhui Province Patentee before: Hefei Wedi Color Glass Co.,Ltd. |