Trailer ABS System Passes Test,But Hurdles Still Remain in Path

NASHVILLE, Tenn. — The PLC4Trucks powerline protocol that will warn a driver of a faulty trailer antilock brake system was effective in tests and is expected to work on the road. But not all issues are resolved.

A consortium of 27 suppliers developed multiplexing for the standard tractor-trailer link to accommodate the trailer ABS warning, but a rival commercial system is still the source of interference, technically and figuratively.

Also, users of the PLC4Trucks system may have to pay licensing fees if an inventor is granted a patent.

A demonstration at The Maintenance Council’s annual meeting in mid-March showed that the single-cable technology is compatible among trailer and tractor ABS supplied by Allied Signal/Bendix, Eaton Corp., Meritor Wabco and Haldex.

The four ABS sets, mounted on a wooden board, sent warning signals when malfunctions were induced. No matter how they were electrically linked on the test board, each sent the proper signal to the cab light.

Multiplexing works well on the common seven-wire tractor-trailer circuitry — it will “light the light,” said Paul Menig of Freightliner Corp., who has led the consortium since its formation in 1997.

A second cable between the tractor and trailer was initially proposed by the National Highway Traffic Safety Administration. But NHTSA dropped it when fleet managers showed the malfunction warning could be done by multiplexing the existing single cable.

For the full story, see the March 29 print edition of Transport Topics. Subscribe today.