Our panel of seven industry experts tackle the tough questions about the future of enclosures and how industrial PCs are affecting machine design.
The plant-floor HMI function is often performed using an industrial PC, typically one that's been placed inside an industrial enclosure. What sorts of considerations do machine builders need to make for this type of configuration when enclosure space is at a premium?
Steve Sullivan, Rittal: Facility managers want to fit the maximum amount of equipment in the smallest amount of space possible. It’s important to take into account limiting factors, such as machine locations, aisles, maintenance needs, ceilings and walls, line of sight, modular enclosure designs to ensure greater access and doors.
Modular enclosures provide optimum cable management, which can save up to 50% of space within an enclosure because cables can enter from all sides—roof, sides, base—while keeping maximum protection. In addition, cooling systems can be mounted on any roof or side to maximize space efficiency.
Steve Sullivan is training supervisor at Rittal
Tim Stone, Advantech: First and foremost is the CPU speed—applications that consume horsepower—and the temperature rating. Faster CPUs generate more heat, so temperature range in a limited-size enclosure becomes a balancing act. More and more, the physical size of depth has become important. We are seeing, with the increased use of widescreen HMIs, that depth is sacrificed as the front panel space is consumed by the HMI. Also with 16:9 aspect ratio, front panel rigidity becomes a factor. With the advent of sealed units front and rear, sometimes the necessity for a panel mount is overcome by pendant or VESA-mounted options. Ergonomics has also become a factor, even in panel-mounted configurations having the ability for the operator to adjust either by allowing the operator to adjust by view angle or by height.
More and more customization drives the final configuration, also the change from manual buttons to software applications pushing the productivity up overall. That recovers valuable panel space once reserved for manual buttons and switches.
Tim Stone is HMI product sales manager at Advantech
Eric Reiner, Beckhoff Automation: Tacking more functionality and performance into ever smaller spaces remains the most basic driver in all technology areas, both for the industrial and consumer markets. This trend has really taken an especially significant leap forward in plant-floor operations as PC-based control makes further inroads into a wide range of application areas.
One of the foremost considerations for machine builders when choosing an industrial PC (IPC) is form factor. Devices such as DIN-rail-mounted embedded PCs and panel PCs that combine a high-performance IPC for automation with an industrial display for HMI can offer attractive options when space is at a premium. One might think that moving to a smaller footprint would require a sacrifice in performance, but this is certainly not the case. If a machine builder seeks the means to remove the cabinet altogether, panel PCs offer another attractive benefit by providing PC-based control with the display in a streamlined package. Panel PC models with protection ratings up to IP65 make them suitable for highly demanding applications.
Eric Reiner is industrial PC market specialist at Beckhoff Automation
John Kowal, B&R Industrial Automation: We have so many form factors. It really becomes a matter of defining what you need to do and then comparing your options.
The first enclosure consideration is whether you want a standalone IPC in the cabinet, an integrated IPC/HMI/automation controller with mounted flush on the machine frame or cabinet face with the electronics behind, or a sealed, arm-mounted HMI with or without attached IPC/controller.
If the priority consideration is cabinet space, it’s logical to go with the second or third choice. Since you can also mount motor/drives, drives and I/O outside the cabinet, it’s possible to shrink the cabinet substantially. But there is an inherent space saving just having a single box that can serve multiple control functions, as well as IPC even if it is inside the cabinet.
And they are all getting smaller. CFast cards and internal solid-state memory are highly compact. Fanless IPCs are now commonplace.
Consolidating the cabling used between a cabinet-mounted IPC and display can also make a difference in space. And that includes replacing hardwired safety with networked safety cabling.
Using the minimum number of slots to get the job done will also save cabinet space, while adding slots to a single, powerful IPC can also reduce cabinet size by replacing multiple standalone devices. Swing arm mounted panels can be used as IPC/HMI or remote HMI only.
John Kowal is director of business development at B&R Industrial Automation
Chris Mason, Rockwell Automation: Take into account the temperature inside the enclosure. Small spaces often mean elevated temperatures, and it’s not always easy to determine how hot the panel will get. While there is a wide range of PCs on the market, not all are suitable for use in these elevated temperatures due to the components used in the design. It all boils down to reliability and preventing unplanned downtime.
Chris Mason is product manager, industrial computers, at Rockwell Automation
Joe Bastulli, Dell: There are many things to consider under these circumstances, such as panel size and thickness; computer, storage and connectivity; touch type IP class and safety certifications; and mounting, power inputs, reliability and ease-of-use software. But I’ll share my top three.
First and foremost, machine builders must evaluate airflow—can you use a fanless PC? And, if so, how does the fanless PC live up to its full temperature range when installed in a static environment without air flow? Some embedded PC manufacturers take liberties with their rating specs and take into consideration some nominal amount of airflow to achieve the spec.
Second, it’s important the enclosure is rated for the environment. If used in a hazardous location, all entry and exit points need to either be in conduit or use special types of cables rated for no conduit use. Energy and power traveling through cables, and not in a conduit, need to meet another set of controlled specifications.
Third, due to the advancement of electronics in terms of compute power and efficiency, it is possible now, more than ever, to achieve higher levels of performance in these environments. With the shrinking size and smaller footprint of today’s compute engines, it can be tempting to simply throw more things into the enclosure along with the computer. However, careful attention should be paid to the devices installed along with the computer as they can lead to excess heat buildup or even electronic noise in the enclosure.
Joe Bastulli is business development manager, embedded computing, at Dell
Mark Lovell, Pepperl+Fuchs: Consider heat dissipation of the PC/enclosure. Most small PCs are only rated for 40 °C (104 °F). If the internal temperature of the enclosure rises above this, then the reliability and performance of the PC will be affected.
Many of the small industrial PCs will come with a standard brick-style power supply—19.1 Vdc. It may be advantageous to find a PC that uses standard power found in industrial control cabinets—12 or 24 Vdc.
If modularity is not required, then panel PCs provide a good alternative in saving space, while at the same time having internal connections to what may have had to be wired in the cabinet.
Mark Lovell is proposals manager at Pepperl+Fuchs
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