Among the least daunting of the trucking industry’s present challenges, at least on the face of it, is the task of creating an in-cab warning light to alert the driver to a malfunction in his trailer’s antilock braking system. The U.S. National Highway Traffic Safety Administration (NHTSA) requires the light to be in place on new vehicles starting on March 1, 2001.
The issue is that the seven-pin J560 tractor-to-trailer connection is maxed out. You need a second connector to carry another signal from the trailer, or you need to be able to send multiple signals over one wire.
It was made clear that the trucking industry wouldn’t accept the expense of a second connector just to deal with the ABS fault light. Nor would truck operators tolerate complex or incompatible technologies, or a new communications protocol beyond SAE J1587 and J1939.
The bottom line for carriers, simply enough, was that a driver would have to see that fault-light shine no matter which tractor was being hooked up to which trailer.
No worries: lighting a light on a dashboard is hardly rocket science. In this case, it’s only barely telephone science. The same proven technology that allows several phone conversations to travel down the same wire-“multiplexing”-was identified many years ago as the best way to send electronic signals between trailer and tractor, because they could go through the existing J560 cable.
And because much more than just “lighting the light” could be accomplished in terms of trailer monitoring and control.
But one year from the NHTSA deadline, the road to market remains rough, marked by professional jealousies and certainly much politicking. Why?
Partly because that road is paved with potential gold-there will likely be, after all, at least 200,000 new trailers and 250,000 new tractors produced in 2001 and similar numbers in subsequent years. And partly because nothing’s ever as simple as it seems.
NHTSA’s mandate only requires that the light be lit; it doesn’t specify how the job should be done. So as time went on different solutions began to emerge: several companies and a couple of consortiums developed variations on the multiplexing theme, and there were also wireless infrared and radio-frequency solutions proposed. Some worked well, some didn’t, some might have. Some suppliers actually brought products to market, namely Grote Inc. and Truck-Lite.
One has met particular success since 1995-namely Air-Weigh’s inexpensive WireLink ($185 US each for tractor and trailer). It uses a multiplexing technology called “FSKNet,” which is also part and parcel of the Air-Weigh’s on-board weighscale systems. Some 25,000 trucks are now equipped with WireLink.
After Air-Weigh gave its multiplexing technology to the public domain, Hendrickson International entered the fray with a similar trailer-to-tractor communications product called Control Link. And lo and behold, a tiny Canadian company-Wheel Monitor Inc. of Niagara on the Lake, Ont.-joined in as well, eventually impressing the hell out of the big boys. It pursued the idea of a tool to warn drivers of impending wheel-off conditions and came up with an answer to the warning-light dilemma and much more.
Without knowing that the ABS debate was raging, it too decided on multiplexing to get a wheel-bearing sensor’s signal to the cab (see The Fabulous Bakery Boys, June 1998).
Still, through the first half of 1998, what the industry lacked was a broadly accepted standard technology to meet the NHTSA mandate. Carriers were not going to accept proprietary technology here, which led directly to the “crowning” in July 1998 of a consortium of major manufacturers called PLC4Trucks (Power Line Carrier for Trucks) as the winner in this protracted sweepstakes. Its generic “spread spectrum” power-line carrier version of multiplexing technology would be the standard, the industry agreed, using the P-485 interface chipset made by Intellon Corp. of Florida.
“The result will be an SAE J1708/J1587 network that operates seamlessly over the DC power bus instead of its typical twisted pair network,” said the consortium at the time. “The industry will benefit from a low-cost, highly reliable, and SAE J1708/J1587-compatible solution that enables new applications to emerge for increasing safety and improving efficiency, while reducing overall costs.”
Spread-spectrum PLC technology is in use today, the consortium pointed out, in various residential, commercial, and industrial environments for critical applications such as environmental controls, security, remote telemetry, load control, and substation automation on both AC and DC power networks.
Led by Freightliner Corp. and chaired by the company’s director of electrical/electronic engineering, Paul Menig, the jointly funded consortium eventually came to include several major OEMs and first-tier suppliers, as well as many lesser players and, of course, all five of the industry’s ABS makers.
The group’s power-line carrier technology is still being tested, Menig explains, but he also says all ABS manufacturers will be ready in time for the March 1, 2001, deadline. Some will have their PLC products on the market before the end of the year.
But the target is to do no more than illuminate that warning lamp. And progress toward even that limited goal hasn’t been entirely smooth, by all accounts.
We’ve been told that in testing the PLC4Trucks/Intellon signal has been weak and susceptible to interference from other ECUs, which has in turn created a problem with multiple-trailer vehicles in moving the signal along the whole length of the rig.
Early tests at Air-Weigh, a member of the PLC4Trucks consortium, showed that the Intellon P-485 did not work when other technologies-specifically, WireLink, Air-Weigh on-board scales, Hendrickson Control Link, and Qualcomm’s TrailerTracs-were also operating on the seven-pin connector’s blue wire. The products worked, but the P-485 chips couldn’t move their information.
The consortium originally suggested that Air-Weigh solve the compatibility problem by dropping its existing technology in favor of the unproven P-485 chip. Nope, said Air-Weigh president Martin Ambros.
“The problem is that PLC4Trucks is not a very robust technology as it’s presently implemented,” he says. “For us, using the PLC4Trucks technology was not an option. It’s not robust enough to handle on-board weighing.”
However, Wheel Monitor president John Mantini had praise for the P-485. “The Intellon chip sends a powerful signal,” says Mantini. “It’s a cannon. We’ve got it working fine on five trailers. The industry’s saying it can’t be done, but it works.”
But Wheel Monitor, too, was swept up in the do-it-our-way politics of the consortium. Very reluctantly, despite having developed its own successful technology, Wheel Monitor changed over to Intellon P-485 integrated circuits last year.
“We saw the writing on the wall,” Mantini says. “We had to join with PLC4Trucks to get anywhere.” So Wheel Monitor took the Intellon chip and improved on it. And Mantini is doing much more with it than making the warning light shine. His full-blown Early Warning System will light the light, warn of impending wheel failures (by sensing wheel and axle heat and vibration abnormalities on all axles), and send signals to and from as many as 14 other trailer sensors. It can communicate other data such as brake adjustment and almost anything else that can be sensed electronically. Cost will be in the $1200 to $1400 range when it hits market in a couple of months.
The basic $200 Wheel Monitor system will power the ABS fault light, handle a lift axle, and provide either a horn or radar to be used when reversing the truck.
In fact, Intellon invited Mantini to give a presentation at the recent Truck Trailer Manufacturers Association conference in Florida. Says Mantini: “The phone hasn’t stopped ringing since.”
As for Air-Weigh’s Martin Ambros, some of his concerns about compatibility seemed to be addressed when Menig recommended that FSKNet multiplexing products be used to light the in-dash trailer ABS fault light in those applications where Air-Weigh on-board scales, WireLink, and Hendrickson Control Link products are operating, and for specialty/multi-trailer operations.
That cleared the way for the Intellon P-485 chipset to be integrated into ABS control units without expensive filtering to make it co-exist with Air-Weigh and Hendrickson technologies.
With WireLink or Control Link, customers make a simple connection to the trailer ABS ECU fault-lamp circuit. Air-Weigh’s fault-lamp signal then over-rides the weaker PLC4Trucks signal on the power line.
After Menig’s announcement, Ambros said that users of the blue auxiliary wire could discard their second tractor/trailer connectors and cables. This would guarantee that the Intellon signal would successfully transmit over the distance and use WireLink or Control Link to control trailer functions, as well as comply with the March 2001 NHTSA deadline for an in-cab trailer ABS fault light.
In order to assure the industry of compliance, Ambros announced that all multiplexing devices from Air-Weigh and its strategic partners would include ABS fault-light capability at no extra charge.
“It’s not a beautiful, seamless solution,” Ambros tells us. “There will still be throughput problems for the PLC4Trucks signal.”
And the co-existence issue-a matter of available bandwidth-led Ambros to urge SAE or The Maintenance Council of the American Trucking Associations to step forward on the issues of PLC bandwidth allocation and co-existence compliance.
He figures the consortium’s efforts to transmit trailer ABS status and diagnostic information to the cab will succeed just fine.
“But we also recognize that the current P-485 device under development is not co-existent and, once completed, will still not meet the needs for vehicle control functions,” Ambros says.
“It’s apparent that with future changes to size-and-weight regulations, driver-controlled functions will become increasingly important to all fleets.”
Obviously, there’s more to come.
For more information, visit the PLC4Trucks Web site at www.plc4trucks.com, or contact TMC about ordering Recommended Practice 137A, 141, and 144.
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