Author: Srik Gurrapu, Industrial Automation Business Manager, Texas Instruments (TI)
summary
In today's increasingly competitive global market, efficient industrial production capacity typically depends on the speed, precision, and reliability of the automation systems in each factory. Even in regions with low labor costs, manufacturers are eager to improve the precision of their automation systems because they know that failure to do so would jeopardize their position in the global economy.
The heart of industrial automation is a new generation of advanced intelligent sensors that keep production lines running continuously, connected to high-performance programmable logic controllers (PLCs) and human-machine interface (HMI) systems via low-latency and real-time networks. For manufacturers, time is money. As long as the manufactured products meet specified quality levels, efficient production lines will continue running as quickly as possible. High-speed, reliable sensors must monitor or measure various states of the production line very rapidly (milliseconds or even faster). The network must then transmit this information with minimal latency and without interrupting production. A wide range of industrial communication protocols are needed to achieve the required critical communication performance, such as PROFIBUS®/PROFINET®, Ethernet/IP™, EtherCAT®, POWERLINK, and SERCOS®III. Furthermore, processing components such as PLCs must respond correctly in real time; otherwise, productivity will be affected, resulting in lost profits (see Figure 1 below).
Texas Instruments (TI) has extensive experience in providing comprehensive high-performance, efficient, and scalable technologies for industrial automation. TI's broad portfolio of analog and embedded processors helps customers design complete system-level solutions. This article highlights TI's innovative, highly differentiated solutions that make industrial communication more cost-effective and easier to access, driving automation and productivity improvements.
Figure 1. Industrial automation system with HMI + PLC + sensor + motor control.
Introduction to Industrial Automation
A typical industrial automation system generally consists of four main parts, which can communicate with each other with low latency and real-time high speed. These four parts are: sensors, human-machine interface, PLC, and motor driver.
sensor
Modern factory automation systems increasingly rely on smart sensors for information and data transmission. Previously, sensors only monitored and measured, without analysis. Now, as sensors become more intelligent, they can better evaluate what they detect and complete tasks in real time. The many functions of sensors include detecting temperature, motion, optical objects and their position, weight, acceleration, chemical composition, gases, air pressure or other pressures, liquid flow, and other aspects of the physical world.
Human-Machine Interface (HMI)
A human-machine interface (HMI) is a unit or subsystem that communicates with the operator. Using current state-of-the-art technology, most industrial automation systems integrate a graphical display subsystem into their HMIs, such as a touchscreen, because these systems are intuitive and easy to learn.
Programmable Logic Controller (PLC)
Generally, PLCs are microcontroller- or processor-based systems that receive information from various sensors distributed throughout the factory and from system operators. Based on the information from these two sources, the PLC initiates actions to control the production line process.
Motor driver
Motor drivers are machine parts that actually respond to PLC commands. For example, in an automobile assembly plant, sensors provide the PLC with information about the car's position. The PLC then responds to this information by sending commands to the motor control unit, which in turn controls a robotic arm to spot weld the car.
In industrial automation systems, these four main components are connected via a high-speed, low-latency network. This network ensures rapid response from the PLC to sensor or operator input. In summary, today's industrial automation systems are real-time, high-precision systems with decision-making capabilities, enabling precise control of high-speed production processes.
Future challenges
The fundamental challenges facing industrial automation are similar to some of those we have already overcome. To achieve better results, control systems must continue to improve their real-time responsiveness, reliability, accuracy, precision, and overall maturity. An essential condition for meeting these requirements is the continuous development of networking and other interconnected technologies.
In the industrial automation market, there are over 120 serial communication standards and 25 Ethernet-based protocols, all of which can be deployed in our factories today. The problem is not that we lack solutions, but rather their diversity and the methods to deploy them.
Each popular industrial communication protocol, such as PROFIBUS/PROFINET, EtherCAT, and Ethernet/IP, is backed by one or more major suppliers of sensors, PLCs, HMIs, and motor drives. Implementing industrial automation systems using components from multiple vendors typically requires deploying several communication protocols supported by multiple vendors. This increases the overall system complexity and drives up costs. For example, many modern automation systems generally use a central processing unit (CPU) to run the application, and then use another discrete component, such as an application-specific integrated circuit (ASIC) or a field-programmable gate array (FPGA), specifically for communication protocol processing. This is especially true in automation components where the communication protocol treats them as slave devices.
Most industrial automation communication protocols use a hierarchical master/slave architecture. Master devices are typically PLCs or intelligent control units. Slave devices are generally motor drives and sensors that do not initiate actions or control processes. To achieve the high-speed, low-latency communication required for the network of automation systems, many protocols have enhanced the Media Access (MAC) layer functionality associated with these slave devices. This places a greater burden on the local protocol processing of slave devices, ultimately leading to the use of dedicated ASICs or FPGAs for protocol processing in distributed slave devices. Since there are usually more slave devices than master devices in industrial automation systems, this significantly increases the overall system cost.
TI stands with you to meet the challenges
Overcoming these challenges in industrial automation requires advanced technologies to enable networking and rationalization of communications. TI has been committed to providing industrial automation system manufacturers with complete solutions encompassing embedded processors, sensors, software building blocks, and support tools. This technology must be simple and cost-effective to meet the needs of critical components in these systems (PLCs, HMIs, sensors, and motor drives), while simultaneously supporting the hierarchical requirements of master-slave devices. Furthermore, TI focuses on providing efficient support solutions to simplify the deployment of factory automation systems for diverse customer needs.
The strong performance of Sitara™ ARM® processors in industrial automation applications demonstrates the success of TI's solutions. The Sitara AM18xARM9™ (and the latest AM335xARMCortex™-A8 System-on-Chip (SoC)) integrates multiple processing cores and real-time communication accelerators for multi-protocol processing, real-time and advanced operating systems, graphics processing, and a host of other resource processing tasks to overcome the challenges facing industrial automation in the coming years.
In particular, the AM335x ARM Cortex-A8 SoC exemplifies TI's industrial automation strategy. Utilizing processing speeds ranging from 275GHz to 1GHz, the AM335x SoC can meet the processing requirements of smart sensors, PLCs, and other automation components in between. Furthermore, its low power consumption allows the AM335x processor to handle even the most stringent power budgets.
Figure 2. Sitara ARM AM335x processor architecture diagram
The AM335x solution features multi-protocol communication capabilities, eliminating the need for dedicated discrete ASICs or FPGAs for protocol processing. This essentially reduces the bill of materials (BOM) cost of slave devices by 40%. Integrating support for many popular protocols (such as PROFIBUS and EtherCAT) into the AM335x processor significantly simplifies networking AM335x processor-based devices. For example, connecting AM335x processor-based sensors to a factory automation system typically requires programming a typical PHY or UART interface—a task already familiar to most industrial programmers. This elimination of arduous learning reduces deployment time and lowers costs.
The key to the success of the AM335x embedded processor in industrial control systems lies in its Programmable Real-Time Unit-based Industrial Communication Subsystem (PRU-ICSS), which implements on-chip multi-protocol processing and ensures the necessary latency communication between master and slave devices. The PRU-ICSS consists of two 32-bit RISC processing cores running at 200MHz. It is capable of single-cycle execution, and its direct I/O interface samples at 5 nanoseconds, ensuring the high throughput required for real-time communication. The PRU-ICSS also features a complete memory subsystem consisting of core-specified shared memory and a 32-bit interrupt controller. These features, along with its logic, control, and algorithms, make the PRU-ICSS ideal for supporting real-time slave communication interfaces for all popular industrial automation protocols, including PROFIBUS/PROFINET, EtherCAT, and Ethernet/IP. Due to its programmability, the PRU-ICSS can also implement custom intellectual property (IP) or custom underlying buses.
Figure 3 PRU-ICSS Structure Diagram
The AM335x processor is a general-purpose SoC that effectively implements the vast majority of functions in industrial automation networks. For example, its optional support for 2D and 3D graphics makes it particularly well-suited for HMI units. Furthermore, its support for advanced operating systems (HLOS), such as Linux™, Windows® Embedded CE, and Android™, allows operators to easily interact with HMIs and other applications when using the AM335x SoC. Many real-time operating systems (RTOS), including TI's SYS/BIOS™ and numerous other third-party RTOS, provide developers with efficient sensor and motor driver solutions that do not require memory-intensive HLOS but demand low-latency real-time performance.
Component reliability and lifespan are another critical criterion for industrial automation systems. These systems are often used in harsh environments, posing a significant challenge. Due to their deployment time and cost, factory automation systems typically have long expected lifecycles. The AM335x processor proves to be a highly reliable SoC. It operates over a wide temperature range and can remain powered on for over 100,000 hours. TI also guarantees a product lifespan of over 10 years for AM335x solutions.
Figure 4. Sitara AM335x Scalable Platform
Seize the market opportunity
TI's factory automation solutions are widely supported by numerous software and hardware development tools, enabling automation vendors to quickly implement their system designs with the most advanced features on the market. In particular, the AM335x processor is supported by the Industrial Communication Engine (ICE), a simple yet powerful development tool that provides automation vendors with a cost-effective platform for developing, testing, and optimizing communication functions. ICE provides developers with quick connectivity to several popular industrial automation protocols, such as PROFIBUS/PROFINET, Ethernet/IP, and EtherCAT. Numerous signal LED combinations are available for each protocol, including tri-color LEDs from Sercos3. Eight digital outputs connect to onboard LEDs and a 24V output driver. Additionally, eight 24V digital inputs and a temperature sensor are available for simple I/O applications. Developers can expand I/O functionality via Serial Peripheral Interface (SPI) communication and signals on the pulse width modulation (PWM) driver pin headers. An isolated transceiver is used, based on serial CAN and PROFIBUS fieldbus. The module boots from external flash memory, supporting serial flash, parallel flash, and MMC. The ICE software environment includes TI's SYS/BIOSOS, the CodeComposerStudio™ integrated development environment, and StarterWare (a development environment similar to that familiar to most microcontroller developers). Application kits and sample applications combined with ICE give developers a significant head start in their industrial automation applications. Utilizing the on-chip USB emulator interface, customers can begin developing their own applications directly without purchasing an external JTAG emulator.
Figure 5 SitaraICE
A fiercely competitive future
To meet the demands of global product manufacturing and materials handling, industrial automation systems are constantly improving in speed, accuracy, reliability, and precision. More and more manufacturers are turning to automation to increase efficiency, reduce costs, and gain a competitive edge and larger market share. Furthermore, manufacturing companies are striving to tightly integrate their production systems with their business systems, including supply chain and demand monitoring systems. As a result, communication protocol environments are becoming more diverse, highlighting the importance of multi-protocol support for factory automation systems and other business systems within an enterprise. Manufacturers aim to become flexible, agile, and highly efficient producers of product materials. Leading technologies such as TI's AM335xSoC, complemented by a broad analog product line and supported by numerous tools including the ICE platform, will ensure that industrial automation vendors have the capabilities they need to meet the demands of evolving markets.
—This article is selected from the September 2003 issue of Elecfans.com's special technical issue, "Intelligent Industry Special Issue".
