TW202209856A - The redundant method and system of the rs485 ring network therefor - Google Patents

Abstract

The redundant method and system of the RS485 ring network therefor are provided. The method comprises of steps: a host is connected to multiple RS485 devices in a ring network. In the initial state, a first port of the host sends the first signal. The second port receives the first signal via the ring network. The host determines whether the ring network is break at second intervals. If the ring network is interrupted, the host sends the second command to the second target device with the first port. The host sends the second command to the second target device with the second after the third interval. The second target device sends the third response message to the host according to the second command.

Description

Backup Processing Method and System of RS485 Ring Network

A method and system for redundant processing of signals, particularly related to the method and system for redundant processing of RS485 ring network.

RS485 (or EIA485) is a standard for multi-point communication of 2-wire, half-duplex, balanced transmission line whose electrical characteristics belong to the physical layer of the OSI model. It is a standard jointly issued by the Telecommunications Industry Association (TIA) and the Electronic Industries Alliance (EIA). The RS485 protocol uses the voltage difference between the two ends of the cable to represent the transmission signal. The RS485 protocol can be applied to configure inexpensive local area networks and to use single-machine transmission, and multiple machines to accept communication links. Therefore, in addition to connecting multiple devices in series, the RS485 protocol can also connect various devices through a ring network.

In the structure of the ring network, the host provides two connection interfaces, and the two connection interfaces are respectively connected to two ends of the ring network. Therefore, the host can send signals through either interface and receive signals through the other interface. The advantage of the ring network is that the host can send signals to the target device through any interface.

However, when the path of the ring network is interrupted, the master of the prior art cannot know where the path interruption point is located on the path. If the host chooses the wrong interface for sending the signal, the control signal may not be sent to the target device smoothly. In the prior art, in order to ensure that the target device can receive the signal, the signal is sent to the target device through two connection interfaces.

In addition, there is no relevant mechanism for the master to know whether the ring network is back to normal. When the ring network is restored, the host will still send signals to the target device through the two connection ports. Therefore, the target device will receive two identical signals respectively, so that the target device will repeat the action twice or reply twice to the host. The host will be affected by two sets of identical replies, causing the system to malfunction.

The invention provides a backup processing method for an RS485 ring network, which is used for backup processing when an abnormality occurs in the RS485 ring network.

The backup processing method of the RS485 ring network of the present invention includes: the main control terminal is connected to a plurality of RS485 devices in series by the ring network; when the main control terminal is in the initial stage, the first interface of the main control terminal sends out a first signal , so that the first signal is received by the second interface of the main control terminal after passing through the ring network; the first time of the first signal in the ring network is timed; An interface sends a test signal to the second interface to determine whether the ring network is interrupted; if the ring network is not interrupted, the master sends a first control command to the first target device through the first interface; the first target device After the device completes the first control command, the target device sends the first response message and the second response message to the main control terminal; if the ring network is interrupted, the main control terminal drives the first interface to send the second control command to the second target device The main control terminal drives the second interface to send another second control command to the second target device at a third time interval; the second target device returns a third response message to the main control terminal according to any second control command.

The present invention further provides a backup processing system for an RS485 ring network, which includes a ring network, an RS485 device end and a main control end. The ring network connects multiple RS485 device terminals and the main control terminal in series. The main control terminal has a processing unit, a storage unit, a path control program, a first interface and a second interface, the processing unit is electrically connected to the storage unit, the first interface and the second interface, and the processing unit runs the path control program recorded in the storage unit , the first interface and the second interface are respectively connected to the two ends of the ring network, the main control terminal sends the first signal through the first interface and calculates the first time when the first signal is transmitted in the ring network, when the ring network When the circuit is connected, the main control terminal sends a first control command to the first target device in the ring network through the first interface; wherein, the main control terminal sends a test signal from the first interface every second time interval To the second interface, it is used to determine whether the ring network is interrupted. The main control terminal monitors that the ring network is interrupted, and the main control terminal drives the first interface to send the second control command to the second target device in the ring network. The main control terminal drives the second interface to send another second control command to the second target device at a third time interval.

The backup processing method and system of the RS485 ring network of the present invention can provide the main control terminal to realize the purpose of the main control terminal under various circumstances of the ring network connection, interruption or connection recovery. access control of the target device. The backup processing method and system of the RS485 ring network of the present invention can realize the relevant measures of the backup of the main control terminal and the ring network without increasing the extra hardware cost.

With regard to the features and implementation of the present invention, the preferred embodiments are described in detail as follows in conjunction with the drawings.

100: Backup Processing System

110: main control terminal

111: Processing unit

112: storage unit

113: Path Control Program

114: The first interface

115: Second interface

120: RS485 device side

130: Ring network

140: target device

510: First target device

520: Second target device

FIG. 1 is a schematic diagram of the structure of the redundant processing system of the RS485 ring network of the present invention.

FIG. 2 is a schematic diagram of the ring network architecture of the present invention.

FIG. 3 is a schematic diagram of the operation flow of the present invention.

FIG. 4 is a signal transmission timing diagram of each interface and the target device of the present invention.

FIG. 5A is a schematic diagram of the first target device, the first response message and the second response message according to the present invention.

FIG. 5B is a signal transmission timing diagram of each interface and the target device of the present invention.

FIG. 5C is a timing diagram of signal transmission when an interruption occurs according to the present invention.

Please refer to FIG. 1 and FIG. 2, which are schematic diagrams of the redundant processing system of the RS485 ring network of the present invention, respectively. The backup processing system 100 of the RS485 ring network of the present invention includes a main control terminal 110 , an RS485 device terminal 120 and a ring network 130 . The ring network 130 is respectively connected to the main control terminal 110 and the plurality of RS485 device terminals 120 . The main control terminal 110 may be, but is not limited to, a personal computer or a server, and may also be an electronic device with independent communication and computing capabilities.

The main control terminal 110 has a processing unit 111 , a storage unit 112 , a path control program 113 , a first interface 114 and a second interface 115 . The processing unit 111 is electrically connected to the storage unit 112 , the first interface 114 and the second interface 115 . The storage unit 112 stores the path control program 113 . In addition to executing the path control program 113, the processing unit 111 also drives the first interface 114 and the second interface 115 to transmit commands or messages. In the present invention, both the first interface 114 and the second interface 115 can transmit commands or messages arbitrarily, and are not limited to the transmission direction described in the present invention.

The first interface 114 and the second interface 115 are respectively connected to two ends of the ring network 130 . In Figures 1 and 2, the ring network 130 is represented by a thick black line. The connection mode of the ring network 130 is formed by connecting the RS485 device terminals 120 in series. In other words, the first interface 114 connects the cable to the RS485 device end 120 of the first set, and then the first RS485 device end 120 is cabled to the second RS485 device end 120, and then connected to the next RS485 device end 120 in sequence until the first RS485 device end 120. up to the second interface 115 . In the present invention, for the convenience of describing the designated RS485 device end 120 , the designated RS485 device end 120 is defined as the target device 140 . The target device in Figure 2 is for illustration only, and is not limited to the RS485 device terminal 120 at this position. In addition, according to different transmission purposes, the main control terminal 110 can send control commands and test signals to the target device 140 to drive the target device 140 or confirm the connection status of the ring network 130 .

In the present invention, in order to facilitate the description of target devices under different conditions, a first target device and a second target device are defined. When the ring network 130 is normally connected, the target device to be controlled by the main control terminal 110 is the first target device 510 . If the ring network 130 is abnormal, the main control terminal 110 defines the device to be controlled as the second target device 520 . The abnormal conditions generally refer to the interruption of network signal transmission or the excessively long network delay.

To further illustrate the operation of the present invention, please refer to FIG. 3 , which is a schematic diagram of the operation flow of the present invention. The backup processing method of the RS485 ring network of the present invention comprises the following steps:

Step S310: the main control terminal is connected in series with a plurality of RS485 devices through a ring network;

Step S320: when the main control terminal is in the initial stage, the first interface of the main control terminal sends out a first signal, so that the first signal is received through the second interface of the main control terminal after passing through the ring network;

Step S330: confirming the connection of the ring network and timing the first time elapsed by the first signal in the ring network;

Step S340: the main control end sends a test signal from the first interface to the second interface every second time interval to determine whether the ring network is interrupted;

Step S350: if the ring network is not interrupted, the main control terminal sends the first control command to the first target device through the first interface, and the second interface receives the first control command after the first time;

Step S360: After the first target device completes the first control command, the target device sends the first response message and the second response message to the host;

Step S370: if the ring network is interrupted, the main control terminal drives the first interface to send the second control command to the second target device;

Step S380: Determine whether the second target device completes the second control command within the first time;

Step S381: If the second target device does not complete the second control command within the first time, the main control driving the second interface to send another group of second control commands to the second target device at a third time interval; and

Step S382 : If the second target device completes the second control command within the first time, the second target device returns a third response message to the master according to any second control command.

The main control terminal 110 of the present invention is connected to a plurality of RS485 devices in a serial manner, thereby forming a ring network 130, as shown in FIG. 2 . In the initial stage of the ring network 130 , the master terminal 110 starts to run the path control program 113 . The path control program 113 sends a first signal to the ring network 130 through the first interface 114, as shown in FIG.

Figure 4 is divided into upper and lower parts, which respectively represent the initial stage and the operation stage of network connection. The initial stage is the stage in which the main control terminal 110 is connected to the ring network 130 after being powered on. The main control terminal 110 will time the time when the first signal will pass through the first interface 114 , the ring network 130 and the second interface 115 , and this time is the first time. If the host terminal 110 is restarted, the host terminal 110 will load the previous first time in the initial stage as a judgment criterion for a new round. For example, the main control terminal 110 will multiply the multiple m according to the previous first time T _{n -1} , where 0<m≦5 and m is an arbitrary number; n is the number of restart rounds of the main control terminal 110, if When n is 1, m is not included in the calculation. m * T _{n -1 is} used to judge whether the ring network in this initial stage is interrupted.

In other words, if the second interface 115 receives the first signal within the time of m * Tn _{- 1} , the second interface 115 can consider that the ring network is connected and the elapsed time of the first signal is the new first signal. a time. On the contrary, if the second interface 115 does not receive the first signal within the time of m * Tn _{- 1} , it means that the ring network 130 is interrupted. The main control terminal 110 will issue a warning signal to remind the user that the ring network 130 is abnormal.

After confirming that the ring network 130 is normal, the main control terminal 110 will send a test signal to the second interface 115 through the first interface 114 every second time interval. The main control terminal 110 uses whether the second interface 115 receives the test signal as the basis for the interruption of the ring network 130 . The length of the second time can be set by the user.

In the operation phase, the main control terminal 110 determines whether the ring network 130 is interrupted. The following commands are sent to distinguish different situations, so the control command sent when not interrupted is the first control command, and the control command sent when interrupted is the second control command.

If the ring network 130 is not interrupted, the master terminal 110 sends the first control command to the first target device 510 and the second interface 115 through the first interface 114 . Since the ring network 130 is not interrupted, the first control command will not only flow through the first target device 150 but also be transmitted to the second interface 115 . Therefore, after the first control command is sent from the first interface 114, the second interface 115 should also receive the first control command after the first time has elapsed. The path control program 113 can determine whether the ring network 130 is interrupted through whether the second interface 115 has received the first control command.

Since the connection distance between the first target device 510 and the first interface 114 and the second interface 115 is different, there will also be a difference in the packet transmission time. Therefore, in the present invention, in order to avoid the situation of repeatedly receiving the response message, a set of threshold intervals is set when the response message is first received. Regardless of whether the first interface 114 receives the response message first or the second interface 115 receives the response message first, the main control terminal 110 will start timing the threshold interval. If the main control terminal 110 receives another response message within the threshold interval, the main control terminal 110 will discard the second group of response messages.

In this stage, the RS485 device 120 to be operated is defined as the first target device 510 . In addition to executing the first control command, the first target device 510 also sends a set of response messages after completion. Since the first target device 510 sends the response message to the first interface 114 and the second interface 115, the response message is respectively defined as the first response message and the second response message. The contents of the first response message and the second response message are the same, and the receiving ends of the first response message and the second response message are different, as shown in FIG. 5A .

The host 110 will receive the first response message through the first interface 114, and the second interface 115 will receive the second response message. The path control program 113 according to the first time interval It is determined whether the time difference between the first response message and the second response message exceeds a first preset threshold, so as to determine whether the transmission path of the ring network 130 is abnormal.

For example, the time when the first interface 114 receives the first response message is T ₁ , the time when the second interface 115 receives the second response message is T ₂ , and the time length of the first predetermined threshold is ΔT . The time length of the first preset threshold ΔT is proportional to the first time. When | T ₁ - T ₂ | is smaller than ΔT , the path control program 113 will continue to record that the ring network is in a normal connection state, as shown in FIG. 5B . The first target device 510 sends the first response message and the second response message to the first interface 114 and the second interface 115 at the same time. In FIG. 5B, the first target device 510 is drawn at intervals for convenience, but Not actually time-sharing.

The main control terminal 110 can determine whether the ring network 130 is interrupted according to the aforementioned ΔT and the test signal. In fact, the location of the breakpoint in the ring network 130 may be between the first interface 114 and the second target device 520 , or the breakpoint may be between the second target device 520 and the second interface 115 . If the breakpoint is in the former case, the second target device 520 will not receive any message. Therefore, after the first time has elapsed, the second interface 115 will not receive the second control command. Therefore, the main control terminal 110 drives the second interface 115 to send the second control command to the second target device 520 after a third time interval, as shown in FIG. 5C . In other words, the main control terminal 110 sends the second control command to the first interface 114 and the second interface 115 at different time points respectively. When the ring network 130 is interrupted, the second target device 520 returns a third response message according to the second control command.

Another situation is that the ring network 130 between the second target device 520 and the second interface 115 is interrupted. Generally speaking, if the second interface 115 does not receive the second control command within the first time, the host 110 will regard the ring network 130 as being interrupted. But there is an exception, the second target device 520 may complete the second control command within the first time. Because the content types of the second control commands are different, or the second target device 520 is adjacent to the first interface 114, the command processing time is too short. Therefore, it may happen that the second target device 520 completes the second control command within the first time.

If the main control terminal 110 detects that the ring network 130 is interrupted, the main control terminal 110 detects that the second target device 520 completes the second control command and returns a third response message to the first interface 114 within the fourth time. Then, the main control terminal 110 will stop the second interface 115 from issuing the second control command again. The fourth time is when the second target device 520 completes the processing of the second control command The sum of the time Ta and twice the transmission time Tb*2 from the first interface 114 to the second target device 520 (meaning Ta+2*Tb). If the main control terminal 110 receives the third response message within the fourth time

The backup processing method and system of the RS485 ring network of the present invention can provide the main control terminal to realize the access control of the target device by the main control terminal under various conditions of connection, interruption or connection recovery of the ring network. The backup processing method and system of the RS485 ring network of the present invention can realize the relevant measures of the backup of the main control terminal and the ring network without increasing the extra hardware cost.

Although the present invention is disclosed by the above-mentioned preferred embodiments, it is not intended to limit the present invention. Anyone who is familiar with the similar arts can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, this The scope of patent protection of the invention shall be determined by the scope of the patent application attached to this specification.

100: Backup Processing System

110: main control terminal

111: Processing unit

112: storage unit

113: Path Control Program

114: The first interface

115: Second interface

120: RS485 device side

130: Ring network

140: target device

Claims (7)

A backup processing method for an RS485 ring network is characterized in that the backup processing when an abnormality occurs in the RS485 ring network, and the backup processing method for the RS485 ring network comprises: A main control terminal is connected to multiple RS485 devices in series with a ring network; In an initial stage, the main control terminal sends a first signal from a first interface of the main control terminal, so that the first signal is received through a second interface of the main control terminal after passing through the ring network; timing a first time of the first signal in the ring network; The main control end sends a test signal from the first interface to the second interface at every second time interval for judging whether the ring network is interrupted; If the ring network is not interrupted, the host sends a first control command to a first target device through the first interface, and the second interface receives the first control command after the first time ; After the first target device completes the first control command, the target device sends a first response message and a second response message to the host; If the ring network is interrupted, the main control terminal drives the first interface to send a second control command to a second target device; The host computer drives the second interface to send another second control command to the second target device at a third time interval; and The second target device returns a third response message and a fourth response message to the host according to any of the second control commands. The backup processing method for an RS485 ring network according to claim 1, wherein connecting the main control terminal to the ring network comprises: connecting the ring network to the RS485 devices in series through the first interface with this second interface. The backup processing method for an RS485 ring network according to claim 1, wherein the main control terminal determines the second time according to the first time and the number of the RS485 devices. A backup processing system for an RS485 ring network is characterized in that the backup processing when an abnormality occurs in the RS485 ring network, the backup processing system for the RS485 ring network comprises: A ring network, connecting multiple RS485 devices in series; and A main control terminal has a processing unit, a storage unit, a path control program, a first interface and a second interface, the processing unit is electrically connected to the storage unit, the first interface and the second interface, The processing unit runs the path control program recorded in the storage unit, the first interface and the second interface are respectively connected to two ends of the ring network, the master sends a first signal through the first interface and Calculate a first time when the first signal is transmitted in the ring network, when the ring network is connected, the host sends a first control command to the ring network through the first interface a first target device in; Wherein, the main control end sends a test signal from the first interface to the second interface every second time interval to determine whether the ring network is interrupted, and the main control end monitors the ring When the ring network is interrupted, the main control terminal drives the first interface to send a second control command to a second target device in the ring network, and the main control terminal drives the second interface to send a third time interval. Another of the second control commands to the second target device. The backup processing system for an RS485 ring network according to claim 4, wherein after receiving the first control command, the first target device sends a first response signal and a first response signal to the first interface and the second interface respectively. The second response signal. The backup processing system for an RS485 ring network according to claim 4, wherein the main control terminal determines the second time according to the number of the RS485 devices. The backup processing system for an RS485 ring network as claimed in claim 4, wherein if the ring network is interrupted, the host computer drives the second interface to send another second control command at the third time interval to the second target device.

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