Industrial Communications With CompactRIO: The Ultimate Multipurpose Controller


This white paper is part of a series describing the capabilities of the CompactRIO platform.  Read additional papers in this series to learn how you can use CompactRIO to simplify the design of advanced control systems.




With native support for common industrial protocols such as PROFINET, OPC UA, and EtherCAT, CompactRIO can connect to a variety of devices, equipment, and infrastructure.  Have a brownfield application that requires support for numerous protocols?  CompactRIO is an ideal industrial gateway that can act as the translator between any of the nearly 20 supported protocols, and even custom communication protocols through the FPGA.  Below is a list of industrial communication protocols that CompactRIO supports.


Connectivity at a Glace

Use the Quick Chart to find the form factor and protocol for your application.







Actuator-Sensor-Interface (AS-I) is primarily used with binary on/off devices. The AS-I protocol allows cleaner wiring by replacing 1:1 connections with a single bus that supports 31 or 62 A/B nodes. Nodes can be a single device or an I/O module.
Learn more about the BW 3023, 1-channel, AS-i Master interface for CompactRIO.




Automotive Standards

In automotive and other transportation-related industries, several standards have been developed to ensure effective communication protocols, database formats, file formats, and so on. NI offers tools specifically designed to comply with these standards and significantly reduce development time.  
Review some of the most common transportation-related standards, such as J1939, and how NI software tools address them.



Controller Area Network (CAN) includes two data link layer protocols and several physical layer options. CAN is a multimaster serial bus system with multidrop capabilities primarily used in the automotive industry.
Learn more about CAN.






The CAN with Flexible Data-Rate (CAN FD) data link layer protocol was created to meet industry and consumer demands with the constantly growing amount of electronics and data communication within modern-day vehicles.
Learn more about CAN FD.





CANopen is the application layer that sits on top of the CAN physical layer often used for industrial automation applications. It supports up to 127 slave devices and is often used with Service Data Objects (SDO) for reading data and Process Data Objects (PDO) for configuration using an object dictionary.
Learn more about the details of this protocol.





DeviceNet is a more mature industrial protocol that the Open DeviceNet Vendors Association (ODVA) manages and is commonly found in Rockwell Automation (Allen-Bradley) programmable logic controllers (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.
See PXI, PCI, and C Series DeviceNet interfaces offered by NI.




The Experimental Physics and Industrial Control System (EPICS) protocol is a set of open source software tools, libraries, and applications developed collaboratively and used worldwide to create distributed soft real-time control systems for scientific instruments such as particle accelerators, telescopes, and other large scientific experiments.
Read the Introduction to EPICS white-paper,which guides you through the basics of working with this protocol and LabVIEW software.




Ethernet for Control Automation Technology (EtherCAT) is a 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.
Learn how to use the NI 9144 chassis to add I/O to NI hardware or third-party EtherCAT systems.




EtherNet/IP is a real-time Ethernet protocol that ODVA manages and is commonly found in Rockwell Automation (Allen-Bradley) programmable logic controllers (PLCs). It communicates over standard Ethernet using TCP/IP and UDP/IP using a master (scanner) and slave (adapter) network architecture.
Checkout the NI-Industrial Communication for EtherNet/IP Product Page.





The HART protocol is often seen in plants where 4 mA to 20 mA signals were previously being used. By replacing the controller and sensor with a HART gateway and HART smart sensors, additional information can be captured. The superimposed digital HART signal on top of the typical 4 mA to 20 mA analog signal provides additional information such as device status, diagnostic data, and measured values.
Learn more about the AM 9898 4-channel HART Master interface for CompactRIO




The Local Interconnect Network (LIN) bus was developed to create a standard for low-cost, low-end multiplexed communication in automotive networks. LIN provides cost-efficient communication in applications where the bandwidth and versatility of CAN are not required.  
See a more in-depth overview of LIN.



Modbus is a common protocol used by countless devices for simple, reliable, and efficient communication across a variety of modern networks. 
Read the Modbus Protocol Reference Guide for a comprehensive explanation of the protocol and details on how you can implement it through LabVIEW software along with commonly used high-level design patterns.





OPC UA is the interoperability standard for the secure and reliable exchange of data in the industrial automation space and in other industries. It is platform independent and ensures the seamless flow of information among devices from multiple vendors.
Visit to learn more about the OPC UA technology.




Power Utility Protocols

  • IEC 61850
  • IEC 60870-5
  • DNP3


The IEC 61850 standard is a set of open protocols based on Ethernet communications commonly used in electrical utilities. SCADA systems use IEC 61850 to communicate between a master station, remote terminal units (RTUs), and intelligent electronic devices (IEDs). Real-time targets may be programmed as IEC 61850 outstation devices with advanced functionality such as power quality monitoring, phasor measurement, and other analysis related to the smart grid. The DNP3 protocol has been historically used in these types of applications, and is a simpler protocol more similar to Modbus that engineers are replacing with IEC 61850 and, to a lesser extent, IEC 60870-5
Learn how engineers are using NI in smart grid applications.



PROFIBUS was initially created by Siemens and is now managed by PROFIBUS International. The physical layer for PROFIBUS DP is based on RS485 and this sets the boundaries for the number of slaves, which can be up to 124.
See an overview of the PROFIBUS protocol.





PROFINET is a protocol that Siemens created to communicate with Siemens devices. The main differences between PROFINET and PROFIBUS are the number of slaves that can be connected to the network and the physical layer, which is Ethernet. There are three types of PROFINET networks: NRT, RT, and IRT. PROFINET IRT is used for high-speed low-latency motion control and cannot interface to PCs because it is a closed network.
See PROFINET modules for CompactRIO.




Serial covers RS232, RS485, and RS422. Often used for instrument control, RS232 can cover distances up to 50 ft. RS422 implements differential communication, which provides longer communication distances and greater noise immunity. RS485 is a superset of RS422, and also increases the number of slave devices from 10 to 32.   
Learn about the three types of serial interfaces and then check out the Quick Chart for the right product interface!



The Transmission Control Protocol (TCP) is a reliable point-to-point communication protocol; data is delivered in an ordered, lossless manner. It is a connection-based protocol, which means that a connection between the client and the server must be established before transferring data.  
Read the Basic TCP/IP Communication in LabVIEW whitepaper to get started.



The User Datagram Protocol (UDP) is a transport layer protocol used in low-latency and loss tolerating connections between devices or applications. 
Learn more about the use of the protocol in the UDP Communication in LabVIEW tutorial.



Next Steps

Improve the integration and performance of your next industrial communication application with CompactRIO:  The Ultimate Multipurpose Controller.  Learn more about the CompactRIO platform, or read additional papers in this series.

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