TWM608805U - Backup processing system of RS485 ring network - Google Patents

Abstract

A backup processing system for an RS485 ring network is characterized by backup processing when the RS485 ring network is abnormal. This model includes: ring network, RS485 equipment terminal and main control terminal. The ring network connects multiple RS485 device terminals and the master terminal in series. The processing unit of the main control terminal 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 the two ends of the ring network. The control terminal sends the first signal and calculates the first time when the first signal is transmitted in the ring network; the control terminal sends a test signal to the second interface every second time interval, which is used to identify the ring network Whether it is interrupted, the host monitors that the ring network is interrupted, and the host drives the second interface to send another second control command to the second target device at a third interval.

Description

Backup processing system of RS485 ring network

A signal backup processing system, especially related to the backup processing system of the RS485 ring network.

RS485 (or EIA485) is a standard for 2-wire, half-duplex, balanced transmission line multi-point communication that belongs to the electrical characteristics of 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 used to configure cheap local area networks and use a single machine to transmit, 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 ring network architecture, the host provides two connection interfaces and the two connection interfaces are respectively connected to the two ends of the ring network. Therefore, the host can send signals through any interface and receive signals through another interface. The advantage of a ring network is that the host can send signals to the target device through any interface.

However, when the path of the loop network is interrupted, the master of the conventional technology cannot know where the path interruption point is located on the path. If the host selects the wrong interface to send the signal, the control signal may not be sent to the target device smoothly. In order to ensure that the target device can receive the signal, the conventional technology sends a signal to the target device through two connection interfaces.

In addition, the host has no relevant mechanism 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 the same two sets of replies, causing the system to malfunction.

The model provides a backup processing system for an RS485 ring network, which is used for backup processing when the RS485 ring network is abnormal.

The backup processing system of the new RS485 ring network includes a ring network, an RS485 device terminal and a master control terminal. The ring network connects multiple RS485 device terminals and the master 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. 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, and the host sends the first signal through the first interface and calculates the first time when the first signal is transmitted in the ring network. During the connection, the host sends the first control command to the first target device in the ring network through the first interface; among them, the host 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 host monitors that the ring network is interrupted, and the host drives the first interface to send a 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 interval.

The new RS485 ring network backup processing system can provide the master control terminal to realize the access control of the target device to the target device in various situations of ring network connection, interruption or connection recovery. The new type of RS485 ring network backup processing method and system can realize the related measures of the host and ring network backup without adding additional hardware costs.

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

100: Redundant Processing System

110: Master

111: Processing Unit

112: storage unit

113: Path Control Program

114: first interface

115: second interface

120: RS485 device side

130: ring network

140: target device

510: first target device

520: second target device

Figure 1 is a schematic diagram of the redundant processing system architecture of the new RS485 ring network.

Figure 2 is a schematic diagram of the new ring network architecture.

Figure 3 is a schematic diagram of the operation flow of the new model.

Figure 4 is a timing diagram of signal transmission between each interface of the new model and the target device.

FIG. 5A is a schematic diagram of the first target device, the first response message, and the second response message of the new type.

Figure 5B is a timing diagram of signal transmission between each interface of the new model and the target device.

Figure 5C is a timing diagram of signal transmission when an interrupt occurs in the new model.

Please refer to Fig. 1 and Fig. 2, which are schematic diagrams of the redundant processing system architecture of the new RS485 ring network. 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 a plurality of RS485 device terminals 120. The host 110 can be, but is not limited to, a personal computer or a server, and can 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 the processing unit 111 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 terminal 120 in series. In other words, the first interface 114 connects the cable to the first RS485 device terminal 120, from the first RS485 device terminal 120 to the second RS485 device terminal 120, and then connects to the next RS485 device terminal 120 to the second RS485 device terminal 120 in sequence. The second interface is 115. In the present invention, for the convenience of explaining the designated RS485 device terminal 120, the designated RS485 device terminal 120 is defined as the target device 140. The target device in Figure 2 is only for illustration, and is not limited to the RS485 device terminal 120 at this location. According to different transmission purposes, the host 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 the target device under different conditions, the first target device and the second target device are defined. When the ring network 130 is normally connected, the master The target device to be controlled by 110 is the first target device 510. If the ring network 130 is abnormal, the host 110 defines the device to be controlled as the second target device 520. The abnormal situation generally refers to situations such as interruption of network signal transmission or excessive network delay.

In order to further explain the operation mode of the present invention, please cooperate with Figure 3, which is a schematic diagram of the operation process of the present invention. The backup processing method of the RS485 ring network of the present invention includes the following steps: Step S310: The main control terminal is connected to multiple RS485 devices in a ring network in series; Step S320: When the main control terminal is in the initial stage, the main control The first interface of the terminal sends out the first signal, so that the first signal passes through the ring network and then is received via the second interface of the master terminal; step S330: confirm the connection of the ring network and time the first signal in the ring network The first time elapsed; Step S340: The master control terminal 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 The path is not interrupted, the host 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 has elapsed; step S360: the first target device completes the first control After the command, the target device sends a first response message and a second response message to the host; step S370: if the ring network is interrupted, the host drives the first interface to send a 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 host drives the second interface at a third interval Send another set of second control commands to the second target device; 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 according to any second control command To the host.

The main control terminal 110 of the present invention connects multiple RS485 devices in a serial manner to form a ring network 130, as shown in FIG. 2. In the initial stage of the ring network 130, the host 110 will start to run the path control program 113. The path control program 113 will pass through the first interface 114 sends the first signal to the ring network 130, as shown in FIG. 4, which is a timing diagram of signal transmission between each interface of the new model and the target device 140.

Figure 4 is divided into two parts, the upper part and the lower part, respectively showing the initial stage and operation stage of the network connection. The initial stage is the stage in which the host 110 is connected to the ring network 130 after booting. The host 110 will count 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 side 110 restarts, the host side 110 will load the first time of the previous time as the judgment benchmark for the new round in the initial stage. For example, the master 110 will multiply the multiple m according to the first time T _{n -1 of the} previous time, where 0<m≦5 and m is any number; n is the number of restart rounds of the master 110, if When n is 1, m is not included in the calculation. m * T _{n -1 is} used to determine 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 * T _{n -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. For a time. Conversely, if the second interface 115 does not receive the first signal within the time of m * T _{n -1} , it means that the ring network 130 is interrupted. The host 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 host 110 will send a test signal from the first interface 114 to the second interface 115 every second time interval. The main control terminal 110 uses whether the second interface 115 receives the test signal as a basis for interruption of the ring network 130. Among them, the length of the second time can be set by the user.

During the operation phase, the host 110 determines whether the ring network 130 is interrupted. The following are commands that can be sent in different situations. Therefore, the control command sent without interruption is the first control command, and the control command sent during interruption is the second control command.

If the ring network 130 is not interrupted, the host 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 receives 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 gap in the packet transmission time. Therefore, in order to avoid repeated reception of response messages, the present invention sets a set of threshold intervals 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 host 110 will start timing the threshold interval. If it is in the threshold interval and the host 110 receives another response message, the host 110 will discard the second set of response messages.

In this stage, the RS485 device terminal 120 to be operated is defined as the first target device 510. In addition to executing the first control command by the first target device 510, the first target device 510 will also send a group 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 defined as the first response message and the second response message, respectively. The content of the first response message and the second response message are the same, and the receiving destinations 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 determines whether the time difference between the first response message and the second response message exceeds the first preset threshold according to the first time interval, 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 preset threshold is Δ T. Duration of the first predetermined threshold Δ T is proportional to the first time. When | T ₁ - T ₂ | is less than Δ T , the path control program 113 will continue to record the ring network as 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 Figure 5B, the first target device 510 is drawn at intervals for the convenience of illustration, but In fact, it is not sent in time-sharing.

The host 110 can determine whether the ring network 130 is interrupted based on the ΔT and the test signal described above. In fact, the breakpoint of 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 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 after the third time interval. 520, as shown in Figure 5C. In other words, the main control terminal 110 will respectively issue the second control commands to the first interface 114 and the second interface 115 at different time points. 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 after the first time has elapsed, the host 110 will regard the ring network 130 as being interrupted. However, 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 host 110 detects that the ring network 130 is interrupted, the host 110 detects that the second target device 520 completes the second control command and responds to the first interface 114 within the fourth time. Then the host 110 will stop the second interface 115 to issue the second control command again. The fourth time is the sum of the processing time Ta for the second target device 520 to complete the second control command and twice the transmission time Tb*2 from the first interface 114 to the second target device 520 (meaning Ta+2 *Tb). If the host 110 receives the third response message within the fourth time.

The new RS485 ring network backup processing method and system can provide the host terminal to realize the access control of the host terminal to the target device in various situations of ring network connection, interruption or connection recovery. The new type of RS485 ring network backup processing method and system can realize the related measures of the host and ring network backup without adding additional hardware costs.

Although the present invention is disclosed in the foregoing preferred embodiments as above, it is not intended to limit the present invention. Anyone familiar with similar art can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of patent protection for new models shall be determined by the scope of patent applications attached to this specification.

100: Redundant Processing System

110: Master

111: Processing Unit

112: storage unit

113: Path Control Program

114: first interface

115: second interface

120: RS485 device side

130: ring network

140: target device

Claims (5)

A backup processing system for RS485 ring network, which is characterized by backup processing when an RS485 ring network is abnormal. The backup processing system for RS485 ring network includes: a ring network with multiple connections in series An RS485 device terminal; and a master control terminal, having 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 and the first interface With 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 both ends of the ring network, and the master terminal passes through the first interface Send a first signal 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 through the first interface To a first target device in the ring network; wherein, every second time interval between the master terminal, the master terminal sends a test signal from the first interface to the second interface for judging the Whether the ring network is interrupted, the host monitors that the ring network is interrupted, the host drives the first interface to send a second control command to a second target device in the ring network, the The main control terminal drives the second interface to send another second control command to the second target device at a third interval. The RS485 ring network backup processing system described in claim 1, wherein the first target device receives the first control command and 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 of the RS485 ring network as described in claim 1, wherein the master control terminal determines the second time according to the number of the RS485 devices. The backup processing system for an RS485 ring network according to claim 1, wherein the ring network is serially connected to the RS485 devices and the second interface through the first interface. The backup processing system of the RS485 ring network described in claim 1, wherein if the ring network is interrupted, the master drives the second interface to send another second control command at intervals of the third time To the second target device.

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