I have been asked by the editorial staff of this stellar publication to talk about non-military VME applications in this missive. While about 45 percent of all VME shipments go into the military/Commercial-Off-the-Shelf (COTS) environment these days, there are many other interesting and exciting applications where VME is found today.
As a technology, VME really grew up and developed its rugged, reliable, and real-time characteristics in the industrial controls markets. Many of the attributes needed in military applications mirror the requirements in demanding industrial environments. Consequently, many of the customers outside the military are found in basic industrial markets.
Lumber industry
When a log enters the sawmill, it must be X-rayed to find any nails or spikes or metal inside the tree that could damage the expensive saw blades. The X-ray analysis also tells us where the knots are located. At that point, a VME-based computer defines the optimum yield of the log: that is, how many boards of what standard dimensions can it be cut into while avoiding the knots. The VME computer then positions the log and the saw blade to make those cuts and achieve the optimum yield. Once those boards are cut, they are hurled through the air, into special chutes for that particular board dimension, and each chute leads to the stacking and drying operation. It is amazing to see the incredible real-time performance of this operation. Very large, heavy boards and beams are flying through the air, with chute gates opening and closing in fractions of a second.
Plywood industry
If a log is headed to a plywood making process, VME is there again. The log must be peeled of bark and rounded without wasting too much of the good wood. Once the log is on a spindle, a cutter blade then starts peeling the log in a long, thin continuous sheet of wood. The density of the wood is different in different parts of the tree, and it is imperative that the thickness of the sheet be maintained. In order to do that, thickness measurements of the sheet being peeled are sampled constantly. The cutter blade is being adjusted in hundredths of a second, a real-time application. Once again, a VME system does all the work, and guarantees an optimum yield of wood from the log within the required specifications for laminating those sheets into plywood.
Transportation
The railroads have tremendous overhead costs maintaining their tracks. After years of use by heavily-loaded trains, the ties become rotten, the rails are stretched apart, and the railroad bed becomes pliable. To pull up the spikes, remove the rails, take out the old ties, reinstall a fresh bed of gravel, and then reinstall the ties, rails and spikes is very labor intensive.
A company in Utah makes an integrated track-maintenance machine, powered by five VME chassis. It looks like a small train with an engine, and cars full of ties, rails, gravel, and spikes all feeding into the maintenance car that does all the work. This car pulls up the spikes, lifts up the rails, pulls out the old ties, and discards them on the siding. In addition, it clears out the trackbed, tamps it down, reinstalls new gravel, puts in new ties, reinstalls the rails, and shoots the spikes in to hold the rails in place. It has many sensors to position the ties and spikes in the right places, and uses laser measuring and guiding devices to insure the spacing between the rails is always exact and consistent. This track-maintenance machine can completely rebuild miles of track in a single day, many times more than a labor crew could accomplish, and much more cost effectively. When this machine is running, the railroad personnel on board just need to watch their supply of ties, spikes, and gravel. It is amazing to watch this machine at work.
Semiconductor manufacturing
There are numerous applications where VME is used in semiconductor processing. They range from wafer saws, cutting silicon wafers from crystal ingots into perfectly polished and shaped wafers, to loading and controlling the annealing ovens powered by hydrogen gas and oxygen.
To me, the annealing ovens are the most interesting application. Once large silicon crystals are grown and shaped with crystal pullers, they are cut into wafers much like slicing loaves of bread. Unfortunately, the wafers still have contaminates in them, and they are not pure silicon. In order to purify the wafers, they must be annealed or heated at a high temperature in a pure environment to drive out the contaminants.
The wafers are vertically mounted on trays. The ovens are automatically loaded with the racks of wafers and the doors closed and sealed. The inside of the oven is purged of air and a pure gaseous mixture is introduced. Then, the hydrogen is introduced and ignited in the oxygen atmosphere. The heat drives the impurities from the silicon wafers over the high-temperature cycle of the ovens.
As we all know, hydrogen and oxygen are very volatile. A VME system monitors and manages the purging of the ovens, introduces the pure gaseous mixture, and slowly introduces the hydrogen, and ignites it in a very balanced non-explosive environment. Then, the VME boards control the heat cycle, cool the oven back down, and unload the annealed wafers. As you can see, there are many chemical sensors involved, and a lot of mechanical control work performed by the VME equipment in real time.
Automotive
Every carmaker in the world life tests their cars (and the cars manufactured by their competitors). This requires a dynamometer. The top two major American carmakers use VME systems to control and monitor the testing of cars.
First, a new car is mounted on the dynamometer, the gas tank removed, and a fuel line from a very large gasoline storage tank is installed. The VME computers are hooked up to all the engine, body sensors and controllers, and actuators are attached to the accelerators, brakes, and transmission. The computer starts the car, puts it in gear, and accelerates the automobile (it is running on stationary rollers on the dynamometer). They may run that particular car for 50,000 miles before they stop. Once they reach a specific test mileage, they remove the car from the dynamometer, tear it down to the last nut and bolt, and measure the wear on engine, transmission, and drivetrain parts.
They can also simulate stop-and-go driving with the VME systems attached to the cars. The VME system is controlling the actuators to the accelerator, brakes, transmission, and other elements. At the same time, the VME boards are sampling data from the engine, especially coolant temperature, oil pressure, RPM, and many other data-acquisition points. All that data is captured by the VME equipment, formatted, and sent into a large database for statistical quality control analysis Again, I am amazed by this application. I have seen brand new cars that have run 100,000 miles on a dynamometer without their tires ever rolling down a street or highway.
There are other VME applications in medical, scientific, transportation, and industrial control, but space does not allow me to get to them all in this time. Applications for VME outside the military spectrum seem to share similar characteristics. These are: real-time operation, being rugged enough to withstand tortuous environments of temperature, shock, vibration, surviving airborne contaminates and corrosives, and be reliable enough for critical applications.
I think the reason VME continues to grow and prosper while other architectures come and go is due to the three “Rs.” Real-time, Rugged, and Reliable are the primary reasons VME is used in the military and in many other applications.
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Ray Alderman is Executive Director of VITA. Previously, he was CEO of PEP Modular Computers, Technical Director of VITA, and founder and partner at Matrix Corporation.
VITA – the VMEbus International Trade Association – was formed in 1984 to promote and enhance the VME standards, and to champion open standards in the embedded computing industry. VITA received accreditation as an ANSI-certifiedstandards developer in 1993, and further received accreditation as an IEC-ITA certified standards developer in 2000.
For further information, contact Ray at:
VITA
PO Box 19658
Fountain Hills, AZ 85269
Tel: 480-837-7486
E-mail: [email protected]
Website: www.vita.com