PROFIBUS接口

ØCompactRIO、PXI和PCI单端口接口适用于PROFIBUS DP工业网络

Ø连接LabVIEW和LabVIEW实时系统并将其作为PROFIBUS网络上的主站或从站

Ø包含的配置器工具用以设置PROFIBUS网络

HYPERLINK "http://sine.ni.com/nips/cds/view/p/lang/zhs/nid/20

PROFIBUS PCI和PXI单端口接口，可将基于PC的控制器作为功能强大的主站或从站，连至PROFIBUS工业网络。PROFIBUS C系列模块，可将NI CompactRIO和NI Single-Board RIO等嵌入式实时可编程自动化控制器(PAC)作为主站或从站，连至PROFIBUS工业网络。NI PROFIBUS接口包含的NI LabVIEW驱动软件，适合人机对话界面(HMI)和SCADA应用。用户可通过这些接口，进行PROFIBUS设备自动化测试。

LabVIEW实时(Real-Time)支持可帮助用户，将CompactRIO、PXI或PC系统作为主站或从站节点，加入PROFIBUS工业网络。装有超过2000万个节点的PROFIBUS作为一款尖端工业网络，能够在工业环境中，以可靠的方式，远程连接可编程逻辑控制器(PLC)、I/O、传感器、驱动器。

ØNI连接针对工业通信

NI Connectivity to Industrial Communications

Overview

National Instruments programmable automation controllers (PACs) and LabVIEW software can add a wide variety of functionality to existing programmable logic controllers (PLCs) and industrial systems. Machine condition monitoring, high-speed analog measurements, and custom vision applications are a few examples of typical PAC applications. Communication between the PLC and PAC systems is extremely important and must be simple, effective, and often times deterministic. Common methods include using basic analog and digital I/O, as well as the widespread standard, OLE for Process Control (OPC). For more complex fieldbus systems, there exists a large number of industrial protocols used in process automation, machine building, and other such markets. This white paper explains how you can use industrial communications to connect to your existing networks with LabVIEW and PACs.

1. Industrial Communications Platforms

This table shows the complete spread of NI industrial communications products and their platforms:

Below is a brief summary of each protocol and the related NI software and hardware product offerings.

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2. Modbus TCP and Modbus Serial

Modbus TCP and Modbus Serial are two of the most commonly used industrial protocols on the market. The LabVIEW Real-Time and LabVIEW Datalogging and Supervisory Control (DSC) Modules allow you to create a Modbus TCP or Modbus Serial I/O server through a graphical configuration assistant. With just a few clicks of the mouse, you can create a Modbus master or slave and specify the different registers to read and write.

Figure 1. Create a Modbus I/O server using the LabVIEW Real-Time or LabVIEW DSC Modules.

In LabVIEW 2014 and later, this functionality is extended with the inclusion of Modbus VIs for you to establish Modbus communication in LabVIEW. The new Modbus palette, available on the Data Communication palette, provides VIs to control the requests that Modbus masters generate, determine when to send these requests, and operate on the responses that Modbus slaves send.

Figure 2. The LabVIEW Modbus Library provides low-level functions for greater flexibility and performance.

For more information on differences between Modbus I/O servers and Modbus VIs, review the LabVIEW help topic on Choosing Between Modbus I/O Servers and Modbus VIs.

Modbus Serial and TCP based communications are also available as a Third-Party Add-On on the LabVIEW Tools Network, titled ModBusVIEW over TCP.

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3. OPC Data Access (DA)

OPC DA is a standard interface defined by the OPC Foundation that allows communication between numerous data sources, including devices on a factory floor, laboratory equipment, test system fixtures, and databases. Most suppliers of industrial data acquisition and control devices, such as Programmable Logic Controllers (PLCs) and Programmable Automation Controllers (PACs), work with the OPC Foundation standard. LabVIEW allows developers to integrate with OPC systems as well. You can connect both OPC clients and servers to LabVIEW applications to share data.

Figure 3. LabVIEW can connect to both OPC clients and servers to share data.

Additionally, National Instruments provides an OPC Server solution with NI OPC Servers that contains a list of drivers for many of the industry’s PLCs. For a list of supported PLCs, refer to the NI Developer Zone article Supported Device & Driver Plug-in List for NI-OPC Server.

Figure 4. OPC servers allow connectivity to hundreds of third-party PLCs.

To know more about OPC connectivity, please visit ni.com/opc.

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4. OPC Unified Architecture (UA)

The LabVIEW Datalogging and Supervisory Control (DSC) Module and the LabVIEW Real-Time (Real-Time) Module include the OPC UA VIs for exchanging data between OPC UA servers and clients and for creating certificates that protect data. You need the DSC Module to use the OPC UA VIs on Windows targets, and you need the Real-Time Module to use the OPC UA VIs on LabVIEW Real-Time targets.

Figure 5. The OPC UA VIs support both non-secure connections and secure connections between an OPC UA server and an OPC UA client.

To know more about the OPC UA standard, please read the white-paper Why OPC UA Matters.

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5. PROFIBUS

PROFIBUS is an industrial RS485 serial protocol that was originally developed in Europe and has now become one of the world’s most popular types of fieldbus. With more than 20,000,000 installed nodes, PROFIBUS is the communication standard for Siemens Automation PLCs, smart sensors, actuators, and I/O. There are two variations of PROFIBUS: the more commonly used DP (Distributed Peripherals), which NI supports, and the lesser used PA (Process Automation).

Figure 6. NI offers PCI, PXI and CompactRIO PROFIBUS DP interfaces for master and slave support.

NI PROFIBUS PCI, PXI, and CompactRIO one-port interfaces connect PC-based controllers to PROFIBUS industrial networks as powerful masters or slaves. NI PROFIBUS interfaces include a stand-alone configurator and an NI LabVIEW driver for human machine interface (HMI) and SCADA applications. You can perform PROFIBUS device automated test using these interfaces. The programming API works with LabVIEW and LabVIEW Real-Time Module, and includes pre-made examples.

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6. EtherCAT

EtherCAT (Ethernet for Control Automation Technology) is a high-performance, industrial communication protocol for deterministic Ethernet, popularly known in Europe. Published as part of the IEC 61158, this open standard implements a master and slave architecture daisy chained over standard Ethernet cabling, typically in a line topology. As a control bus, it focuses on deterministic, high-speed I/O for single-point applications, such as machine control and motion.

Figure 7. The CompactRIO controller connects with the NI 9144 modular EtherCAT slave chassis.

To program the NI master controller, LabVIEW Real-Time accesses the slaves’ physical channels with the simple click-and-drag I/O variable. You can also use the LabVIEW FPGA Module to program logic on the FPGA of the NI 9144 chassis, allowing you to reduce response time by making decisions at the node. Plus, these intelligent distributed devices can offload processing from the controller with onboard analysis, custom timing, and signal manipulation before sending the results back to the master. One of the advantages that LabVIEW provides is the ability to programmatically discover and access both slave devices and their attached modules through the use of the programmatic shared variable API. This ability was added in LabVIEW 2010, and is discussed in the help documentation for IO and PSP Variables. A full tutorial on programmatic EtherCAT discovery is covered by KnowledgeBase 5P1FIB7F: How Can I Programmatically Discover and Access EtherCAT I/O Items?

Figure 8. LabVIEW provides easy graphical programming tools for the NI EtherCAT master controller and the NI 9144 FPGA chip.

For more information on EtherCAT, view this Introduction to EtherCAT. EtherCAT connectivity requires the NI-Industrial Communications for EtherCAT driver.

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7. EtherNet/IP

Figure 9. The EtherNet/IP Driver for Industrial Communication provides explicit messaging and adapter communication from LabVIEW.

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8. DeviceNet

DeviceNet is another, more mature industrial protocol that ODVA manages, and is commonly found in Rockwell Automation (Allen-Bradley) PLCs. Unlike Ethernet/IP, which is based on the Ethernet physical layer, DeviceNet is based on the CAN physical layer and increases strength and interconnectivity by specifying various parameters, such as the required cable length, connectors, and baud rates.

NI offers two interface platforms, DeviceNet for Control and DeviceNet for Test.  DeviceNet for Control provides PCI and PXI master (scanner) interfaces designed to easily manage and control a network full of DeviceNet slaves. Included with these interfaces is the NI-Industrial Communications for DeviceNet software, which offers a high-level API that supports drag-and-drop I/O variables and explicit messaging function blocks. DeviceNet for Test interfaces for PCI, PXI, and PCMCIA have master (scanner) and slave (adapter) support, best used for testing DeviceNet products. The included software consists of a configurator, analyzer, and the NI-DNET driver, which provides low-level functions for creating custom DeviceNet applications.

Figure 10. The NI plug-in DeviceNet interfaces are designed for both control and test applications.

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9. CANopen

CANopen is a higher-level protocol also based on the CAN physical layer and was developed as a standardized embedded network with highly flexible configuration capabilities. Originally designed for motion control applications, the CANopen protocol is common in many industry segments including medical equipment, off-road vehicles, public transportation, and building automation.