TW201514645A - Group control system and method applying Modbus communication protocol - Google Patents

Abstract

A group control system applying Modbus communication protocol comprises a central controller taken as a master node, and a plurality of control groups used as slave nodes. Each control group includes a controller and a plurality of devices. The central controller sends a command packet of the Modbus communication protocol. The content of the command packet has an address and a register address. The controller corresponding to the address receives the command packet and outputs an execution command. The device corresponding to the register address receives and executes the execution command to accomplish Modbus communications. By means of integrating a plurality of devices and a controller into a control group and by performing the Modbus communication protocol through the controller and the central controller, the number of devices centrally monitored by a central controller can be greatly increased to enhance the convenience in monitoring.

Description

Group control system and method using Modbus communication protocol

The present invention relates to a group control system and method, and more particularly to a group control system and method for applying a Modbus communication protocol.

The Modbus protocol is a serial communication protocol that is commonly used in the automation industry to communicate as a connection between various industrial electronic devices.

Referring to Figure 1, the Modbus protocol is a master/slave protocol. There is one controller 11 as the master and the other devices d1~d63 as slaves. The node has a unique address, and generally only the controller 11 acting as the master node can initiate an instruction.

As shown in Table 1 on the following page, a ModBus instruction will contain the device address (Function), the Start Address Address (Starting Address Hi/Starting Address Lo), and the temporary storage of the instruction to be executed. No. of Registers Hi/No. of Registers Lo, and Error Check.

The example shown in Table 1 is to send a read command to the device d1 with the device address 01 (function 03 represents the read command), and start from the scratchpad. The address 0001 starts to continuously read the data of the three scratchpads (the number of registers 0003).

In the Modbus protocol, when the controller 11 (master node) issues an instruction, all devices d1~d63 (servant nodes) will receive the instruction, but only the device d1 of the specified address will execute and respond to the instruction (with the exception of address 0). Address 0 represents the broadcast mode, and all devices that receive the command d1~d63 will execute the command, but will not respond.)

Since the Modbus protocol allows multiple devices d1~d63 to communicate on the same network for communication, and is relatively easy to set up, it is widely used for one-to-many device control, however The requirements for communication quality are generally in practical applications. The number of devices equipped with one controller 11 is more than 63. Therefore, when it is necessary to monitor multiple devices at the same time, such as factories, buildings and other public facilities, it is necessary. Separate monitoring using multiple controllers 11 causes great inconvenience in management.

Accordingly, a first object of the present invention is to provide a group control system for a Modbus communication protocol that solves the above problems.

Therefore, the present invention applies a group control system of the Modbus protocol, and includes a central controller and a plurality of control groups.

The central controller, as the master node in the Modbus communication protocol, issues a command packet of a Modbus protocol, and the content of the instruction packet includes an address and a scratchpad address.

The control groups respectively serve as servants of the Modbus protocol, and each control group includes a controller and a plurality of devices.

The controller is electrically connected to the central controller, receives the instruction packet, and outputs an execution instruction to the controller corresponding to the address, where the execution instruction content includes a device address corresponding to the temporary register address.

The devices are electrically coupled to the controller and the device corresponding to the device address receives and executes the execution instruction.

A second object of the present invention is to provide a group control method for a Modbus communication protocol that can solve the above problems.

The invention applies a group control method of Modbus communication protocol, and is applied to a group control system. The group control system includes a central controller as a master node and a plurality of control groups as servant nodes, and each control group has a controller electrically coupled to the central controller and a plurality of devices electrically coupled to the controller, the method comprising the steps of: causing the central controller to issue a command packet of a Modbus protocol, and the content of the command packet includes an address And the scratchpad address.

The controllers are caused to receive the instruction packet, and the controller corresponding to the address outputs an execution instruction, the execution instruction content including the device address corresponding to the temporary register address.

The execution instruction is executed by the device corresponding to the device address.

2‧‧‧Central controller

G1~G63‧‧‧Control Group

C1~C63‧‧‧ controller

D1~D63‧‧‧ equipment

51~55‧‧‧Steps

Other features and effects of the present invention will be apparent from the following description of the drawings, wherein: FIG. 1 is a schematic diagram illustrating a conventional Modbus communication protocol architecture; FIG. 2 is a schematic diagram illustrating the application of the present invention. A preferred embodiment of a group control system for a Modbus protocol; and FIG. 3 is a flow chart illustrating a preferred embodiment of a group control method for applying the Modbus protocol of the present invention.

Referring to FIG. 2, a preferred embodiment of the group control system to which the Modbus protocol is applied includes a central controller 2 and a plurality of control groups G1 to G63.

In the present embodiment, the Modbus RTU communication protocol in the Modbus protocol is used as an explanation, but is not limited thereto.

The central controller 2, as a master node in the Modbus communication protocol, issues a command packet of a Modbus protocol, and the content of the instruction packet includes an address, a function, a register address, a number of registers, and an error check code. In this embodiment, the register address corresponds to the scratchpad start address.

The control groups G1 G G63 are respectively used as servant nodes of the Modbus communication protocol, and each control group G1 G G63 includes: a controller C1~C63 And multiple devices D1~D63.

The controllers C1 - C63 are electrically connected to the central controller 2, receive the instruction packet, and output an execution instruction to the controllers C1 - C63 corresponding to the address, the execution instruction content including the corresponding register address Device address.

The devices D1~D63 are electrically connected to the controllers C1~C63, and the devices D1~D63 corresponding to the device addresses receive and execute the execution instruction. When the function is read, the device D1 corresponding to the device address is used. ~D63 executes the execution command and outputs a read signal, and the corresponding controller C1~C63 receives the read signal and outputs it to the central controller 2.

Each controller C1~C63 has a specific address, and in each control group G1~G63, the device address of each device D1~D63 corresponds to a specific register address range.

table 3

Referring to FIG. 2, Table 2 and Table 3, in this embodiment, a central controller 2 is combined with 63 control groups G1 G G63, and each control group G1 G G63 has one controller C1 C C63 and 63 The devices D1~D63 are described as descriptions, wherein each controller C1~C63 corresponds to the address of 00~3F, and in each control group G1~G63, each device D1~D63 corresponds to 000X~03FX respectively. The address range of the scratchpad, but this is for convenience only and is not limited to this.

Referring to FIG. 2, Table 3 and Table 4, an example of the instruction packet is shown in Table 4, wherein the instruction packet includes: Address, Function, and Scratch Start Address (Starting) Address Hi/Starting Address Lo), No. of Registers Hi/No. of Registers Lo, and Error Check.

In this embodiment, the error check code uses a Cyclic redundancy check (CRC), and the function uses a commonly used read (corresponding to the instruction 03) and a single write (corresponding to the command 06). , multiple writes (corresponding to instruction 10), etc., and when the address bar is 00, broadcast is performed, but is not limited thereto.

In general use, when the central controller 2 issues the instruction packet of the Modbus protocol, the controllers C1~C63 receive the instruction packet, but only the controllers C1~C63 corresponding to the address output the execution instruction, and The device D1~D63 corresponding to the device address is received and executed.

As shown in Table 4, the function performed by the instruction packet is to read the third device D3 in the second control group G2, and the reading range is to continuously read five pieces of information from the first pen. As follows: the address field 02 corresponds to the controller C2, that is, to the control group G2, so after the central controller 2 issues the instruction packet, only the controller C2 will react to the instruction packet, the controller C2 It will judge the devices D1~D63 corresponding to the start address of the scratchpad (in this example, referring to Table 3, it can be seen that the scratchpad start address 0020 will correspond to device D3, and it is the temporary storage corresponding to device D3. The first pen in the address range, and output the execution instruction, the device D3 receives the execution instruction, and continuously reads 5 pieces of data from the register address 0020 according to the execution instruction (the number of registers is 0005) In order to output the read signal, the controller C2 receives the read signal and outputs it to the central controller 2.

It is worth mentioning that when the controller C2 responds, the device address of the default device or the device D3 can be taken in the read signal or other response signals for the central controller 2 to discriminate the label.

Referring to Figure 2, Table 3 and Table 5, when the function is write (function is 06 or 10), the instruction packet will also include at least one data.

As shown in Table 5, the function performed by the instruction packet is to perform multiple writings on the first device D1 in the fifth control group G5, and the writing range is to continuously write two pieces of information from the third pen. The data written are data one and two data respectively, which are described in detail as follows: the address field 05 corresponds to the controller C5, that is, to the control group G5, so after the central controller 2 issues the instruction packet, Only controller C5 will react to the instruction packet, and controller C5 will determine the devices D1~D63 corresponding to the start address of the scratchpad (in this example, refer to Table 3, the register start address is known. 0002 corresponds to device D1 and is the third pen in the register address range corresponding to device D1, and outputs the execution instruction, and device D1 receives the execution instruction, and is started by the temporary register according to the execution instruction. The start address 0002 starts two consecutive data writes (the number of scratchpads is 0002), and the data written is data one (000A) and data two (0005).

Through the above description, the advantages of the embodiment can be summarized as follows under:

1. By integrating the plurality of devices D1~D63 and one controller C1~C63 into one control group G1~G63, and performing Modbus communication agreement with the central controller 2 through the controllers C1~C63, a large increase can be made. The number of devices that can be uniformly monitored by the central controller 2, for example, without affecting the communication quality, the conventional technology is generally a central controller 2 with 63 devices, but in this embodiment, it can be increased to one The central controller 2 is equipped with 63x63 devices, so it can monitor a large number of devices at the same time, improving the convenience of monitoring.

2. By performing Modbus communication protocol with the central controller 2 through the controllers C1~C63, only a small number of change packet formats can be required, and the Modbus communication protocol can be similarly implemented. Referring to Table 6, the Modbus communication protocol in the prior art is known. Comparing the instruction packet with the instruction packet in this embodiment, it can be seen that the difference in format between the two is extremely low, the only difference is that the address corresponding to the device D1~D63 is changed to correspond to the controller C1~C63, and By using the scratchpad start address corresponding to the device address, since the packet format is less dynamic, it can be modified not only by the original Modbus protocol architecture, but also for the original Modbus protocol domain. Get started, greatly increase the convenience of use and promotion.

3. In the control system using the Modbus protocol, since each device D1~D63 must have a specific address for identification, for example, the devices in the same building but in different floors may be numbered sequentially. Addresses 1~20 are on the first floor, and 21~40 are on the second floor... not only when the system is set up, it is easy to confuse the location of the floor where each device is located, but also to test the user's memory, and this embodiment can be used by One floor is merged into one control group. For example, the equipment D1~D63 on the first floor are combined in the control group G1, and the devices D1~D63 on the second floor are combined in the control group G2..., if they will have the same The equipment of the equipment address is set at the corresponding position on different floors, so that as long as the number of the control group and the corresponding equipment address are seen, the floor and location of the equipment can be immediately known, which greatly increases the intuitiveness and use of the system. Convenience.

Referring to FIG. 2 and FIG. 3, a preferred embodiment of the group control method using the Modbus protocol of the present invention is applied to the above group control system applying the Modbus protocol, and the method comprises the following steps: Step 51: Making the central control The device 2 sends a command packet of a Modbus protocol, and the content of the instruction packet includes an address and a scratchpad address.

Step 52: The controllers C1~C63 receive the instruction packet, and output an execution instruction to the controllers C1~C63 corresponding to the address. The execution instruction content includes the device address corresponding to the scratchpad address.

Step 53: The execution instruction is executed by the devices D1 to D63 corresponding to the device address.

Among them, when the function is read, the following steps are also included: Step 54: Output a read signal to the devices D1~D63 corresponding to the device address.

Step 55: The corresponding controller C1~C63 receives the read signal and outputs it to the central controller 2.

In summary, the group control system and method using the Modbus communication protocol described above can not only monitor a large number of devices at the same time, but also improve the convenience of monitoring, and can also increase the convenience of use, so that the present invention can be achieved. The purpose.

The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the patent application scope and patent specification content of the present invention, All remain within the scope of the invention patent.

2‧‧‧Central controller

G1~G63‧‧‧Control Group

C1~C63‧‧‧ controller

D1~D63‧‧‧ equipment

Claims (10)

A group control system applying a Modbus communication protocol, comprising: a central controller, as a master node in a Modbus communication protocol, issuing a command packet of a Modbus protocol, and the content of the instruction packet includes an address and a scratchpad address And a plurality of control groups respectively serving as servant nodes of the Modbus communication protocol, each control group comprising: a controller electrically connected to the central controller, receiving the instruction packet, and outputting a controller corresponding to the address Executing an instruction, the execution instruction content includes a device address corresponding to the scratchpad address, and a plurality of devices electrically connected to the controller, and the device corresponding to the device address receives and executes the execution instruction. The group control system applying the Modbus protocol according to claim 1, wherein each controller has a specific address, and in each control group, the device address of each device corresponds to a specific one. The address range of the scratchpad. The group control system for applying the Modbus protocol according to claim 2, wherein the instruction packet content further includes: a function, a number of registers, and an error check code. The group control system for applying the Modbus protocol according to claim 3, wherein, when the function is reading, the device corresponding to the device address executes the execution instruction and outputs a read signal, and the corresponding controller receives The read signal is output to the central controller. The group control system for applying the Modbus protocol according to claim 4, wherein the controller receives the read signal and encloses a device address of the corresponding device in the read signal for the central controller to discriminate use. A group control method applying a Modbus communication protocol is applied to a group control system, the group control system includes a central controller as a master node and a plurality of control groups as servant nodes, each control group having one a controller electrically coupled to the central controller and a plurality of devices electrically coupled to the controller, the method comprising the steps of: (A) causing the central controller to issue a command packet of a Modbus protocol, and the instruction packet includes a address and a scratchpad address; (B) causing the controllers to receive the instruction packet and outputting an execution instruction to the controller corresponding to the address, the execution instruction content including the device bit corresponding to the temporary register address And (C) cause the execution instruction to be executed by the device corresponding to the device address. The group control method for applying a Modbus protocol according to claim 6, wherein each controller has a specific address, and in each control group, a device address of each device corresponds to a specific one. The address range of the scratchpad. The group control method for applying the Modbus protocol according to claim 7, wherein the instruction packet content further includes: a function, a number of registers, and an error check code. The group control method for applying a Modbus protocol according to claim 8, wherein when the function is read, the following steps are further included: (D) outputting a read signal to the device corresponding to the device address; and (E) causing the corresponding controller to receive the read signal and output to the central controller. The group control method for applying a Modbus protocol according to claim 9, wherein the controller receives the read signal and encloses a device address of the corresponding device in the read signal for the central controller to determine use.