Multiplexing increases user options, reduces diagnostic worries

May 1, 2002
INTERNATIONAL'S new multiplex electrical platform is in full use by customers across the US. The company is working diligently to ensure that dealers,

INTERNATIONAL'S new multiplex electrical platform is in full use by customers across the US. The company is working diligently to ensure that dealers, body upfitters, and end-users are familiar with the intricacies of the new system. That's the message that Bill Lawrence, vocational marketing manager from International's Severe Service Vehicle Center, Warrenville, Illinois, delivered at the NTEA convention and Work Truck Show in Orlando, Florida.

Electrical multiplexing

“International's family of trucks are running on a multiplexed electrical system,” said Lawrence. “This helps body upfitters do their job more efficiently.”

Lawrence said that multiplexing makes body building more efficient; however, he notes there is a learning curve for field service personnel.

Multiple messaging, data link, radio frequency interface, and the Society of Automotive Engineers (SAE) Recommended Language Standards are the modern catchwords in understanding International's new multiplexing electrical platform, Lawrence said. “International is helping everyone to be familiar with the new terminology by putting some useful information into the marketplace.

“Several new publications should help us to get our message out, especially publication AD-44181-F, The New International Electrical System. Several videos explain the electrical system and also the electronic control modules and data link compatibilities.

“Multiplexing reduces electrical diagnostic time by more than 20%.” The EZ Tech diagnostic tool can isolate electrical problems down to the input or output side, plus the explicit fault codes that the diagnostic tools display.

The electrical system controller (ESC) integrates or replaces many of the vehicle's former electrical circuits.

Fuses and circuit breakers for daytime running lights, flashers, wipe/wash relays are now replaced by the ESC. Instead of passing amperage through an open circuit, multiplexing platforms first check with the ESC to authorize the requested device to operate.

Body integration is now easier because the multiplexing system has fewer variables that can create problems. The multiplexing system uses milliamps in lieu of high current. Items such as turn signal switches have a longer life expectancy because of the lower amperage. Additionally, there are prewired instrument panel switches for remote mounted electrical and air modules. The dash panel provides for the installation of one or two ‘six-pack’ switch modules or as many as 24 switches with the addition of a ‘twelve-pack’ panel.

Multiplexing promotes the ease of connectability and reduces the need for the body upfitter to splice into the vehicle wiring harness. “We don't want technicians splicing directly into the multiplex system,” Lawrence said.

“Upfitters and customers are understanding how they can now use the multiplexing technology. Because of this, International is researching where we need to add more options to the multiplexing content package.”

Task automation

Task can be automated by programming the parameters or software rules into the ECS. Automation examples are:

  • Work light time outs to eliminate battery drain.
  • Automatic headlight operations when the wipers are turned on in order to comply with some state regulations and company safety directives.
  • Air suspension, dump-valve limiting devices that eliminates the potential for vehicle abuse.
  • Doors automatically locking at any chosen speed.

International is developing future software that will incorporate specific electronic control packages for the utility, ambulance, fire, rescue, and towing vocations.