Why Modbus Matters: An Introduction

您可能听说过Modbus（广泛使用的通信协议），但您是否知道为什么它通常与Campbell Scientific Data Logger一起使用？您是否知道如何在数据记录器和其他功能的设备之间使用Modbus进行通信？Modbus只是您可以与坎贝尔科学数据记录器一起使用的通信协议之一。在本文中，我们将介绍Modbus协议，并简要说明如何在网络中使用它。

Why Modbus Has Become Popular

Modbus可能是工业监督控制和数据采集（SCADA）系统领域最广泛使用的开放式通信协议。例如，SCADA系统通常使用Modbus将远程终端单元（RTU）与监控计算机连接到中继测量数据，设备状态，控制命令和配置信息。

Over the last 35 years, because of its popularity and the ease with which Modbus can be implemented, the protocol has been used by many devices and adapted to many communication link types. You will find many devices, including those offered by Campbell Scientific, which support or facilitate Modbus communication over wired or wireless connections. Not only can intelligent devices such as microcontrollers and programmable logic controllers (PLCs) communicate with Modbus, but many intelligent sensors have a Modbus interface that enables them to send their data to host systems.

Modbus的普及已经生长，因为其消息传递结构与所使用的物理接口或连接的类型无关。Modbus可以同时在同一物理接口处与其他类型的连接共存。您可以通过多个数据链接和物理图层操作协议。

How Modbus Communication Works

在标准Modbus网络中，设备之间存在客户端 - 服务器关系。单个Modbus客户端设备启动用于信息的请求，将请求发送到同一网络上的一个或多个Modbus服务器设备。只有Modbus客户端可以启动通信。反过来，Modbus服务器又只在响应Modbus客户端的请求时进行通信。当Modbus客户端没有Modbus地址时，共享网络上的每个Modbus服务器都有1到247的唯一地址。（最多247个服务器设备可以连接到相同的Modbus网络。）由于这些原因，Modbus是非常擅长为您提供投票和争用的网络。

We have incorporated the Modbus protocol in the operating systems for the majority of our data loggers. Campbell Scientific data loggers can function as Modbus clients and Modbus servers–or even both at the same time! This proves particularly helpful when your data logger needs to use Modbus to query data (as a client) from localized sensors or other data sources, and then serve that data up to another Modbus client on a wider area network.

How You Can Use Modbus

Many of our customers leverage Modbus communication to provide environmental data to SCADA systems, grid operators, and utilities.

This capability enables you to acquire and transfer data from sensors or other devices that are compatible with Modbus.

You can use the Modbus protocol with Campbell Scientific data loggers for a variety of purposes. Some practical examples include the following:

• To interface data loggers and Modbus-enabled sensors
• To send and retrieve data between data loggers and other industrial devices
• To deliver environmental data to SCADA systems
• 将Modbus数据集成到Pakbus *网络，或Pakbus数据到Modbus网络中
  
  * PakBus is Campbell Scientific'spacket-based communications protocol.

Conclusion

We hope this brief introductory article has helped you better understand what the Modbus protocol is, how it works, and how you can leverage it with your Campbell Scientific data loggers. Future blog articles will offer more details on the communications protocols that you can use with your Campbell Scientific data loggers.

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