Industrial systems have come a long way since the days of PLCs using analogue 4-20mA control loops. Whether it be communications or internal architecture, the evolution of industrial electronics has been one towards increased digitisation and integration.
Along with the need for plant-floor-to-boardroom visibility, the shift towards industrial computer systems has been driven by the need for improved performance and speed, while still delivering rugged reliability and long-term availability.
Industrial processors, as the critical “brains” of these systems, are changing too – and not just to keep up with new application demands. In some cases, new processor technologies are driving new ways of working, leading to reduced downtime, increased safety, and quick returns on investment.
Electronics News talked to Cameron Swen, Strategic Marketing Manager for Industrial Controls and Automation, AMD Embedded Solutions Division, and Christian Eder, Director of Marketing at congatec, for their insiders’ view on the latest industrial processing technology.
Long term availability
Given the potential cost of downtime, industrial clients are understandably risk-averse. Unlike the IT and consumer spaces, where fast-paced technological upgrades are a fact of life, the industrial sector values mature technologies proven to deliver reliable operation.
As such, industrial systems are characterised by longevity – unlike consumer desktop computers which tend to be upgraded or replaced every 4.5 years, typical lifecycles for industrial computers start from a minimum of five years, and can range up to 15 years or more.
Because industrial and embedded computers tend to be highly customised for their applications, the ability to quickly replace faulty processors with the exact model is paramount. Consumer grade processors, which tend to see rapid obsolescence and ever-shifting socket form factors, are unsuited for such uses.
Processor manufacturers like AMD cater for these longer lifecycles, by guaranteeing supplies of its embedded and industrial lines of processors for at least seven years. Others, like Freescale, guarantee their system on chips (SoCs) to be available for a minimum of 10 years, ensuring ongoing support and parts for industrial customers.
Interconnected stability
Minimising or avoiding downtime on a day-to-day basis is another key focus for industrial customers. It is not surprising that in any discussion of industrial computers, the question of ruggedness is raised.
According to AMD’s Cameron Swen, the features of industrial processors contribute to and enable the reliability and ruggedness of systems built around them.
“Ensuring maximum reliability in mission critical systems is a very complex topic that encompasses the design and manufacturing processes at the silicon, board and system levels and starts with the size, weight and power (SWaP) fundamentals,” Swen explained.
Talking to system integrators and processor manufacturers, it quickly becomes clear that factors like shock and vibration resistance, power consumption and thermal management are interconnected pieces of the same puzzle.
Power consumption affects thermal output, which in turn determines the size and types of required cooling options, which has direct consequences for the ruggedness and ingress protection capabilities of the entire system.
Many industrial computers operate in vehicle or factory environments where they are subject to shock and/or constant vibration. The need for ingress protection also limits the airflow available for cooling.
As such, the conventional approach to cooling with big and heavy heatsinks and fans is out of the question – the constant movement would make short work of such systems.
To combat vibration and shock, processor manufacturers like AMD provide solutions in small footprint form factors like ball grid array (BGA) surface-mount packaging, which are soldered directly on the board for extra security.
To minimise the size of the cooling solutions required in the end solution, chip makers combine two general approaches: extend the operational temperature range of their processors; and reduce power consumption while boosting efficiency in order to reduce the heat generated by the processor.
“Managing thermals is essential for these types of systems and delivering full featured processing solutions that are able to meet the performance requirements while still operating with modest power consumption ensures that the processor doesn’t impose thermal stress on the rest of the system,” Swen said.
Like other processor manufacturers, AMD is developing its low power Embedded APUs, SoCs and discrete graphics processors to deliver maximum performance per watt, without radiating a lot of power.
Of course, power consumption can be a pressing priority in some applications, such as equipment used in remote areas, or equipment which needs to be truly wireless – the reduced energy requirements of these processors increases their suitability for such uses.
Integration and performance
Whether it be in consumer electronics or industrial applications, the trend towards increased integration is one which is continuing.
Having a single box responsible for a whole raft of functions is not just cheaper, but also reduces overall system complexity, and makes maintenance simpler.
According to congatec’s Christian Eder, the traditional configuration which required programmable logic controllers (PLCs) another system with the human machine interface (HMI) is giving way to industrial PCs.
“The functionality can be melded into one single box quite easily,” Eder explained. “With multi-core platforms, if you can separate the cores.”
Utilising virtualisation solutions such as the Real Time Hypervisor from Real Time Systems, one core can take on the function of the PLC, running a real-time operating system, while another core can run an embedded operating system and serve as the user interface. These systems can run the same software as traditional PLCs and HMIs.
These two completely separate systems exist in the one industrial PC, and are connected to each other by a virtual Ethernet controller.
Integration is also apparent on the chip level: notably, AMD’s merger with ATI in 2006 allowed the semiconductor company to merge the central processing unit (CPU) and a graphics processing unit (GPU) into one chip, which the firm dubbed an accelerated processing unit (APU). The GPU is also integrated into AMD’s SoC offerings.
As a result, Eder says even some of the low power AMD processors which have computing performance akin to Intel’s Atom processors come equipped with very high performance graphics engines, which provides additional advantages for 3D graphics applications.
According to Cameron Swen from AMD, the integrated GPU can also be used to accelerate applications which support multi-threaded processing.
“The GPU in the heterogeneous architecture of the AMD APUs and SoCs can be programmed through OpenCL for a variety of compute intensive functions to deliver excellent performance per watt,” Swen explained. “For applications like PC-based machine vision cameras, a fan-less design can be created that delivers excellent image processing performance.”
Maximising capabilities
While chipmakers continue to bake features into their processors that present compelling capabilities for industrial applications, the role of the engineers who build the industrial PCs and boards on which the processors reside remains key.
According to Eder, it is the engineers at companies like congatec who ensure that the advantages provided by the processors are translated into useable features in the final solution.
“Processors themselves are quite general purpose,” Eder said. “Our systems are tailored for industrial functions through the features we provide on the modules.”
These include BIOS/UEFI features, microcontrollers which handle battery management or watchdog timers (critical for detecting and recovering from faults), and implementing support within the firmware for remote management capabilities such as Intel’s Active Management Technology.
When working with ARM-based processors, such as the Freescale i.MX 6 SoC, which do not have BIOS or UEFI for the initialisation functions, the onus is on congatec and other system manufacturers to provide the software support systems, such as bootloaders in addition to the drivers which support the embedded features provided by the processor.
Security is also a focus for congatec, and keeping up with the changes in technology is an important part of the job.
“Today we equip our modules with an external security chip,” said Eder, “But upcoming processor generations will have enhanced security features like Trusted Platform Module (TPM) built in.”
But perhaps the most complicated issue that engineers have to deal with is power management. The demand for reduced power consumption and thermal output means many industrial processors run in low-power states most of the time, which necessitates careful power management.
“Parts of the processors are switched off when not needed,” Eder explained. “This brings the most power use improvements, but this also means a high change of load on the power supplies.”
For a high-performance CPU, the electrical load can drop from 50A down to almost zero within microseconds, depending on the application. Software with repeated cycles of high processing demands and idle times can aggravate the situation, and special knowhow on the part of the board engineers is needed to avoid destabilising voltage swings caused by this high change in loads.
Hot and cold
Even with on-chip power/thermal management measures, cooling is still very important.
“The cooler the chips stay, the longer the life expectancy,” Eder said. “The mean time between failures (MTBF) numbers can double if you cool it down additionally 5 degrees, for example.”
But optimised cooling is not just about reliability. Intel’s Turbo Boost functionality, for instance, provides greater computer performance by dynamically overclocking the processor, but the feature limited by temperature constraints.
By providing better cooling within the constraints of the application, the processor can run at higher clock speeds for longer. To address this, congatec engineered a new COM Express-compliant heat-spreader and heat-piped-based cooling solution.
The new cooler improved cooling by 14 degrees compared to previous coolers. This yielded a calculated eight-fold increase in MTBF figures, and 30 to 40 percent more performance due to the ability to run on Turbo Boost mode for a longer period of time.
According to Eder, completed modules undergo intensive testing to ensure they can stand up to the rigours of industrial applications.
“Temperature is always an issue, even for extended CPUs where our module is specified for 0 to 60 degrees Celcius,” explained Eder.
“We do the tests down to -40 degrees, and up to 90-100 degrees, just to make sure that the design is rugged, even if we do not end up exceeding chip maker specifications.”
Where the module is specified as an extended temperature version, congatec will ensure all other components also perform under the extended temperature range, and test the systems to ensure they meet specifications.
Future directions
In the short term at least, according to Eder, the trend towards increasing numbers of cores will continue, as will influence from the mobile and smartphone markets.
“Scaling will happen with additional processors, and with slight improvements from single processors. We will get many more processors in parallel onto the chips,” he said.
“I am also looking forward to the next ARM developments. Right now we see the Cortex A9 coming out. With ARM targeting the server market, and I am curious to see what emerges from there.”
On AMD’s part, increased integration is the way forward, with a strong push towards Heterogeneous System Architectures, beyond its current integration of CPUs and GPUs, or SoC approaches which also integrate DSP and FPGA functionality to boost performance and system flexibility.
Currently, in order to use the GPU to process data, a program running on the CPU queues work for the GPU using system calls through a device driver stack managed by a completely separate scheduler.
According to AMD, this introduces significant dispatch latency, with overhead that makes the process worthwhile only when the application requires a very large amount of parallel computation.
The aim for Heterogeneous System Architectures is to even more closely integrate different processing elements, unify their memory space, and reduce additional data handling and transfer – in short, to make the sum greater than its parts.
Applications will be able to create data structures in a single unified address space and initiate work items on the hardware most appropriate for a given task. Data sharing between the various compute elements will be simple.
Multiple compute tasks will be able to work on the same coherent memory regions, utilising barriers and atomic memory operations as needed to maintain data synchronisation.
“Heterogeneous architectures are still in their infancy, with new solutions coming down the line that will make them easily programmable you will start to see interesting combinations of processing solutions, that people may have not considered yet,” Swen told Electronics News.
For starters, heterogeneous architectures are expected to yield drastic improvements in the size, weight and power fundamentals for industrial and embedded applications.
Standards and compatibility
But even as chip makers continue looking into the future, legacy support is still of utmost importance.
“Industrial applications are generally slow to adopt new technologies,” Swen said. “This helps to ensure that the technology, and products offering it, are mature enough to deliver reliable operation.”
“For this reason it is important that solutions offer a migration path between existing and new technology.”
Compatibility and standards are thus a focus for both AMD and congatec. In pushing to improve the adoption of heterogeneous architectures, AMD is working with partners like ARM, Samsung and Qualcomm to unify approaches to the issue.
On its part, congatec sits on and advises a number of standards committees, with the aim of promoting competition and inter-vendor compatibility, which keeps prices down and encourages technological innovation.
“We are trying to stabilise and enhance standards, to make sure customers are not tied to one or another vendor. When we talk about standards, it must be exchangeable between vendors, which is very important,” Eder said.