测量技术中的工业以太网 测量技术中的工业以太网 | HBM

以太网发起于1970年代,并在随后的20年中成为了IT领域的通信标准。现在,以太网已成为办公通信EDP基础设施不可或缺的组成部分,许多版本和协议都是基于以太网建立。在过去的十年里,以太网也逐渐成功地应用于工业应用,这其中就包括测量技术领域。

工业应用中的通信通常包含办公通信所不强调的要求,其中包括实时性和确定性这两大关键要求。在办公环境中,电子邮件或打印订单延迟半秒送达几乎不是问题,也不会导致故障。但是在工业环境中控制机器时,这种延迟通常是无法接受的。因为,在这类情形下,任何响应的时间都必须是确定的。而正由于此,工业应用中的通信系统最常用的是现场总线,例如Profibus、CAN等,这些现场总线能够保证所需的实时性。

。现代化工厂通常提出的挑战是从过程控制层(例如包含ERP系统)到现场层的传感器和驱动器的通用通信。在过程控制层,通过以太网通信是标准通信方式,因此较低层级的通信通常也致力于使用以太网通信方式。在过去的十年里,针对机器和设备控制所需的实时性要求,有许多种关于以太网通信的方法和解决方案被提出。

工业应用中的通信系统

工业应用中的通信系统 可分为不同层级:

  • 现场层
  • 控制器层
  • 过程控制层

现代化工厂通常提出的挑战是从过程控制层(例如包含ERP系统)到现场层的传感器和驱动器的通用通信

过程控制层,通过以太网通信是标准通信方式,因此较低层级的通信通常也致力于使用以太网通信方式。在过去的十年里,针对机器和设备控制所需的实时性要求,有许多种关于以太网通信的方法和解决方案被提出。

以太网实时解决方案

现在,关于工业以太网的解决方案多种多样,例如Ethercat、Profinet、以太网/IP等,它们也能为以太网通信提供实时能力。这些不同系统由不同类别的用户组所支持,同样地,这些用户组又由相应工业自动化领域的大型供应商所支持。

然而,这些开发出的不同系统通常互不兼容,这意味着它们无法实现办公通信领域中方便的互换性和互操作性。除了提供从过程控制层到现场层的“通用”通信能力外,工业以太网还具有其他优势。首先,工业以太网的带宽高,能够高速传送更大的数据量。其次,在维护、数据备份和工程设计方面,工业以太网通常费用更低,即意味着更低的成本。另外,工业以太网配备面向未来应用的开放式通信接口,这样,通常无需对硬件进行全面修改,就可实现改进。

Even larger data volumes can be easily transferred

In addition to "universal" communication from the process control level to the field level, Industrial Ethernet has further advantages: The primary advantage is the very high bandwidth, compared to conventional field bus systems, that makes it possible to transmit even larger data volumes at high speed.

A universal system also offers great advantages with regards to maintenance, data backup and engineering, advantages that are generally linked with less outlay and therefore less costs. A system with open communication interfaces is also equipped for future applications. Enhancements can often be implemented without need for comprehensive modifications to the hardware.

The differences between Industrial Ethernet and "normal" Ethernet

Industrial Ethernet is not the same as "normal" Ethernet. What are the differences between the technologies?

The various solutions for real time-capable Ethernet use protocols, components and topologies that, in part, are significantly different from conventional Ethernet. But it is not just the different mode of functioning, due to real time capabilities, that is decisive in components used in the industrial environment, for example a switch.

All the other ambient conditions that are present, for example, during production, also have to be tolerated at the same time. The components must be designed for the sometimes significant stresses caused by dust, humidity, higher temperatures, shocks and vibrations.

Large data volumes, fast connections, secure results: Various points have to be considered in the interaction between measurement technology, industrial automation and Industrial Ethernet.

Measurement technology is frequently used – in machines and plants – during industrial production processes. The spectrum here is extremely diverse, ranging from simple signals acquired with low frequencies - for example, slowly changing temperature values - right up to complex measurement data, which need to be measured using higher measurement frequencies.

Industrial Ethernet and Measurement technology in industry

Ethernet enables fast connections

A fast connection, as offered by Ethernet, is a great advantage, especially in applications where very large data volumes occur during measurement. If the measurement technology used needs to be integrated in a higher-level control architecture, for example, based on PLC, the hardware used needs to provide the appropriate communication options.

In applications where large data volumes occur and where real time is also a necessity, then solutions based on Industrial Ethernet are suitable.

The manufacturers of measurement technology components and systems have therefore been offering interfaces to various Industrial Ethernet solutions for some time now. The general trend that can be seen here is that classic measurement technology systems on the one side and automation solutions on the other side are coming together at an increasing rate.

Measurement technology taking over automation tasks

Modern industrial measurement technology systems are now also capable of taking over automation tasks. In addition to controlling the measurement sequences, such modern systems can also control the machines. Industrial Ethernet also offers new possibilities in the sectors of remote maintenance and operation. Numerous measurement technology systems can be operated using a standard web browser. The measured data can therefore be displayed over the Internet with practically no limitations.

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