Getting the most from multiplexing

INTERNATIONAL Truck & Engine used its portion of the National Truck Equipment Association Truck Product Conference to provide details of the new Diamond Logic truck electrical system that promises to give truck equipment shops a 21st century way of wiring a truck.

Bill Lawrence with the International truck marketing group and Jay Bissontz, applications engineer for the company's newly formed Truck Electronics Applications Group, provided details on the new system and how distributors and their customers can benefit from it.

“This is probably the most revolutionary system that a manufacturer of wire-to-wire, point-to-point analog electrical systems for trucks has undertaken,” Bissontz says. “But the initial system is in place, and its benefits are paying off already.”

Bissontz said the multiplex electrical system enables truck equipment distributors to integrate the electrical needs of their equipment with the chassis electrical system easily.

“This isn't just significant for International,” Bissontz said. “It's significant for this industry.”

The basic components of the International Diamond Logic multiplex system are:

  • The electronic system controller. The ESC serves as the traffic cop of the chassis and body electrical system. All the logic and programming that the system requires is contained in that processor.

  • Switch packs. The ESC performs bi-directional communication with the switch packs, which contain long-life micro switches behind traditional rocker switch actuators. All information for the switches is processed by the ESC logic programming. The results of the switch logic processing is routed to ESC outputs, to the vehicle powertrain modules, or to any of the other multiplex modules such as remote power modules or remote air solenoid modules.

  • The remote power module. This module has two connectors — one for body switch inputs and one for power outputs. The connectors have six inputs and six outputs. These inputs and outputs give the multiplex system its versatility. Three power modules are available, which provide eighteen 20-amp outputs.

  • The remote air solenoid module. The air modules provide a new way to control air operated accessories such as differential locks, suspensions, or trans-axles. An air source is routed to one input on the air module. Modular air solenoids are supplied with this one air source, and the on / off control is provided by the ESC.

With multiplex systems, components in effect conduct an electronic dialog with one another. These components include engine, transmission, antilock brake system, instrument cluster, and air solenoids.

Multiplexing makes simple

One of the biggest benefits of multiplex electrical systems is the way it greatly reduces the number of wires installed on a truck — a byproduct of the growing number of electrical widgets that need power.

“As you add components, the wire bundle gets bigger and bigger,” Bissontz said. “As demand has increased, complexity has increased. We have watched the number of wires just explode. It is getting difficult to tie into wiring and get to the correct wire. International has taken a lot of the guesswork and complexity out of the system.”

To illustrate the reduced complexity, Bissontz pointed to the instrument gauge cluster, where number of wires has decreased from 67 to seven with the new system.

Greatly improved data flow helps make multiplexing possible. The International wiring system uses four data links, each with a different set of responsibilities. One of the data links connects the engine, transmission, and ABS using J-1708 communication. J-1708 protocol has been standard in recent years.

“That was not going to be enough to use on very complex applications,” Bissontz said. “The new J-1939 protocol becomes the backbone of the architecture of a multiplex electrical system. It is roughly 26 times faster than J-1708.”

New tools for the shop

International will offer distributors new ways to integrate body and equipment electrical needs with the truck chassis electrical system. The truck manufacturer will offer a new software tool to make this task easier.

The Diamond Logic Builder development software will be launched next year. It is simply computer software that allows the distributor/bodybuilder the ability to program the truck electrical system in order to create custom electrical features or functions.

Using the Diamond Logic software, distributors also will be able to relocate the electronic gauges and rocker switches on the instrument panel. This can be accomplished by dragging and dropping images on the computer screen. An example of why someone would reprogram the instrument cluster: to add a PTO hour meter to monitor the amount of time that the power take-off is engaged when the engine is running.

Another application: computer control of windshield wipers for snowplow trucks. Windshield wipers left running while the dump body is being reloaded have been known to score the windshield. Multiplexing will enable the wipers to be programmed so that the wipers operate intermittently for a period and then park — the result of a program-triggered event, such as when the driver sets the parking brake. Once the parking brake is disengaged, the wipers operate again.

“An amazing number of variations can be created,” Bissontz said. “We now have more than 2,700 different software input and output signals. The total possible combinations are 2,700 factorial.”

Diamond Logic Builder tool is an optional program that increases the flexibility of International's chassis, but is not required for body integration. In addition, International offers a variety of body electrical options that are pre-engineered and factory installed, which simplifies integration of the body and chassis electrical system.

“But if you get into a lot of complex applications such as fire apparatus, ambulances, spreaders, and utility equipment, you probably will reach a point where the Diamond Logic Builder will be the preference,” Bissontz said.

More control for the distributor

Under the current system, truck customers tell International dealer sales personnel what they want the truck to do and how they want it configured. The dealer sends the programming requirements via modem or the Internet to International. The manufacturer's computer generates the programming file that the dealer installs on the chassis.

“The system works okay, but it can be slow sometimes,” Bissontz said. “We will do away with some of those things with the Diamond Logic Builder. The system will give you the ability to take charge of your own applications.”

International will license companies to use the Diamond Logic Builder — a CD that can be installed on a laptop computer. The software can be used to create a new programming file for the truck. To download the file, the laptop is connected to the truck through the nine-pin American Trucking Associations' connector under the dash. The software can produce custom programming files or modify existing ones.

Graphical displays and virtual interfaces will allow the technician to test the new program to verify that it is working as intended. This will enable the technician to work on the program without having the truck in the shop. The program can be developed and then downloaded to a vehicle(s) at another location.

Virtual installation

Under International's standard software configuration, aftermarket equipment can be powered by either a rocker switch in the cab or by running one wire into a remote switch input. Connecting the remote switch input to battery voltage will tell the microprocessor to send 12-volt power to the respective remote power module output. Biasing the switch to ground turns off the flow of electricity.

The new system will give distributors a range of flexibility to reprogram the International electrical system. A wide range of features can be added to the truck simply by checking boxes on a computer screen or by dragging and dropping graphics on an electronic wiring diagram.

“The only thing International requires is that at some point in time — the end of the day or the end of the work week — you reconnect with International and download the file(s) that you created or modified,” Bissontz said. The purpose is to make the modified file available to other technicians should the truck require service in a remote location.

International also is experimenting with global positioning systems to deliver data generated by the multiplex system. The objective is to enhance asset tracking and to monitor what is going on with the chassis.

Learning about it

International plans to communicate the finer points of the new electrical system several ways, including:

  • The body builders book. The current body builders book was written as the company's new generation of medium-duty trucks was being developed. As a result, some of the contents are out of date. The company will revise the book, adding to it entire sections dedicated to the system — particularly on how to use the Diamond Logic Tool.

  • Training classes at local International dealers. “This is probably the best way to get the fear of new stuff out of the way,” Lawrence said. “Contact your local dealer and request the training for your organization. It takes less than a day. We will walk through the electrical system, point out on the chassis where you can splice and where you can't splice.

  • Telephone assistance from the International service organization.

“Things like the Diamond Logic Builder and PTO combinations can be perceived as being rather technical,” Bissontz said. “They are not super tough after you have done them once or twice, but there will be a learning curve. Our tech central people are coming up to speed and will be able to walk people through the process over the telephone. With the vehicle identification number, I can call up the truck information and look at the exact screens that they are looking at.”

If all else fails, there is nothing to prevent the trucks from being hardwired in the traditional way.

“We don't like doing that, though, because we have a more reliable and more cost effective way of doing it now,” Lawrence said.

Among the questions NTEA members asked following the formal presentation:

Question: What about using the system to activate electronic trailer brake controllers?

Bissontz: We have an option to prewire the truck for an inertia-type brake controller. It includes loomed 18-inch wires tied to the steering column bracket. A 30-amp wire runs to the end of the frame plus an additional two feet so that you can build whatever type of socket you need without splicing the wire that we give you. All of the software is programmed, and the wiring is in place. You have to order it upfront from the factory — it is not standard on every vehicle.

Question: How does this system affect PTO installation?

Bissontz: PTOs come down to five general configurations — clutch-type, electro-shift, solenoid, pneumatic engagement, and cable-lever type. At International, we developed five feature codes. Our code for clutch-type PTOs, for example, gives you 46 programmable parameters — rules regarding PTO engagement, disengagement, re-engagement, and warning methods.

Question: Will the system monitor engine torque?

Lawrence: International Engines will have a significant engine upgrade in 2004. Engine torque limiting in PTO operation is something we plan to make available.

Question: If we develop some sophisticated programming for International trucks, what is to keep others from copying it?

Bissontz: The code will be proprietary. Maybe the integration file could be cracked, but it probably would take an experienced programmer 80-120 hours to do it. By that time, the hacker would be better off doing his own code. Plus, this code is for just one truck. He would have to start over for another truck.

So what else is new?

International Truck and Engine has more than multiplexing to talk about this year. Changes include:

  • The new International 4200. The “200” signifies that the chassis has the new International VT-365 engine replacing the T-444E. The 6.0-liter engine is similar to the engine International sells to Ford as the Powerstroke. However, the International version has a proprietary ECM which allows for programmable engine features such as idle shutdown, PTO set speeds, and engine protection.

  • The new International 7600 model, which replaces the International 2000 Series, is now available. It offers the new cab style and amenities now packaged with the Cummins ISM and Caterpillar C10 and C12 engines up to 430 horsepower.

  • Changes in some exhaust systems as a result of the Environmental Protection Agency's diesel emission regulations that became effective October 1.

Caterpillar is going to use a larger diameter muffler as part of its interim action to reduce diesel emissions until its ACERT solution to emissions regulations comes on stream next year. As a result, exhaust packaging problems will force International to discontinue horizontal mufflers with horizontal tailpipe exhaust configurations on chassis powered by Caterpillar engines.

International will continue to offer an under-cab muffler with frame mounted vertical tailpipe and clean CA configuration on the 7600 models. The vertical muffler configuration, however, will reduce usable CA by three inches from the pre- 02 emissions engines.

“This will be a one-year deal,” Lawrence said. “When the Cat ACERT system becomes available next year, we will revisit the possibilities.”

Distributors will notice little if any changes to exhaust systems for those chassis equipped with International and Cummins engines.

“Cummins engines will be EGR cooled. This just means a little more packaging under the hood,” Lawrence said. “No major changes to the exhaust packaging — everything happens under the hood.”

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