MVI56-MCM PROSOFT 通讯模块

MVI56-MCM (“Modbus 通讯模块”) 产品可以让 Allen-Bradley ControlLogix I/O 兼容处理器
轻松的和其它 Modbus 协议兼容设备取得通讯。兼容的设备不仅包括 Modicon PLC (都支
持 Modbus 协议)，还包括类别广阔的终端设备。
MVI56-MCM 模块是 Modbus 网络和 Allen-Bradley backplane 之间的一个网关。来自于
ControlLogix 处理器的数据传送异步于 Modbus 网络上的数据活动。模块内部具有 5000 个
字的寄存器，用于处理器和 Modbus 网络之间的数据交换。
以下讨论包括一些概念，这些概念对于理解 MVI56-MCM 模块的运作是十分重要的。
上电时，模块开始执行以下逻辑功能：
1. 初始化硬件组件
a. 初始化 ControlLogix 背板驱动
b. 测试并复位所有 RAM
c. 初始化串行通讯端口
2. 等待来自于 ControlLogix 处理器的模块配置
3. 初始化模块寄存器空间
4. 在所选端口上，启动从站驱动
5. 在所选端口上，启动主站驱动

MVI56-MCM

当模块已经接收来自处理器的模块配置后，模块会根据配置和网络上的其它节点开始通
讯。
MVI56-MCM 模块对 ControlLogix 背板使用方式是非常独特的。通过背板，模块使用自身
的输入和输出镜像以分页的方式，接收数据和发送数据到处理器。镜像刷新的频率取决于
用户为模块定义的计划扫描频率（scheduled scan rate）和模块的通讯负荷。典型的刷新
频率在 2 到 10 毫秒之间。
双向的数据传送是这样实现的，模块在其输入镜像中填充数据，再发送到处理器。梯形逻
辑程序把输入镜像中的数据放置在处理器的控制器标签（Controller Tags）中。模块的输
入镜像是 250 个字。这个大型数据区让数据在模块和处理器之间快速的交换。

需要传送到模块的数据被处理器插放到模块的输出镜像。模块程序会把这些数据提取出
来，放置在模块的内部数据库。模块的输出镜像共有 248 个字。这个大型数据区让数据在
模块和处理器之间快速的交换。
下面的示意图描述了在 ControlLogix 处理器，MVI56-MCM 模块和 Modbus 网络之间数据
移动的方式。

MVI56-MCM

The MVI56-MCM (” Modbus Communication Module “) product enables Allen-Bradley ControlLogix I/O compatible processors
Easily communicate with other Modbus protocol compatible devices. Compatible devices include not only Modicon PLC (all branches
With Modbus protocol), also includes a broad category of terminal devices.
The MVI56-MCM module is a gateway between the Modbus network and the Allen-Bradley backplane. Be from
The data transfer of the ControlLogix processor is asynchronous to data activity on the Modbus network. There are 5000 modules inside the module
Word register for data exchange between processor and Modbus network.
The following discussion includes some concepts that are important to understanding the operation of the MVI56-MCM module.
When the module is powered on, the following logical functions are performed:
1. Initialize hardware components
a. Initialize the ControlLogix backplane driver
b. Test and reset all RAM
c. Initialize the serial communication port
2. Wait for the module configuration from the ControlLogix processor
3. Initialize the module register space
4. Enable the slave driver on the selected port
5. On the selected port, start the primary station driver
When the module has received the module configuration from the processor, the module will start to communicate with other nodes on the network according to the configuration
Message.
The MVI56-MCM module is unique in its use of the ControlLogix backplane. Through the backplane, the module uses itself
The input and output mirrors in a paging manner, receiving data and sending data to the processor. The frequency of image refresh depends on
The scheduled scan rate defined by the user for the module and the communication load of the module. Typical refresh
The frequency is between 2 and 10 milliseconds.
Bidirectional data transfer is implemented in such a way that the module fills the data in its input image and sends it to the processor. Trapezoidal logic
The assembler places the data in the input image in the Controller Tags of the processor. Module output
It’s like 250 words. This large data area allows data to be exchanged quickly between modules and processors.

The data that needs to be sent to the module is plugged into the output image of the module by the processor. The module program will extract the data
To place in the module’s internal database. The output image of the module contains 248 characters. This large data area keeps the data in
Fast exchange between modules and processors.
The following diagram depicts data between the ControlLogix processor, the MVI56-MCM module, and the Modbus network
The way it moves.

MVI56-MCM