The Harley-Davidson Can-Bus Communications System: HDLAN

In this article we will try to explain in a simple way the latest Harley-Davidson communication system, the HDLAN.
This new technology will allow the entire H-D range to have ABS brakes, less wiring and the elimination of the ignition key, among other improvements.

Internet inside your motorcycle
One of the first questions you may ask yourself when hearing about the communications system is, why does a motorcycle need this? The answer must be found in the technological evolution to which automotive brands have been forced in recent years in order to reduce emissions and comply with increasingly demanding regulations and at the same time improve safety standards and driving quality .
With the adoption of electronic injection, it is necessary for the different sensors and actuators to communicate with the ECM or control unit of the vehicle.
This communication occurs in digital language, that is, with “zeros and ones”, just like our personal computer or a tablet does.

Let's give a simple example:
-The pilot operates the left turn signal switch.
-The handlebar button module sends the message "flashing button activated" to the network.
-The BCM (electric controller) reads this message and energizes the indicators on the indicated side, it also searches for the speedometer signal and also that of the inclination sensor, thus determining how long the indicator will remain on.
-At the same time, the speedometer also reads the message and turns on the dashboard indicator light.
All these messages are sent through a cable, called the “Data Bus”, which is a kind of Internet inside the motorcycle, which allows the modules to communicate with each other.

HDLAN
Until 2011 the communications protocol used 1 cable and was based on the J1850 standard. As of this year, a faster protocol, with 2 communication cables, the HDLAN, based on the CAN BUS automotive standard, was used in the Softail models and later in the Dyna family.

In order not to get lost in technical details, imagine that J1850 is like Internet based on the RTB telephone line, old and very slow. On the other hand, CAN BUS would be like ADSL, faster and more modern.

Using the HDLAN (Harley-Davidson Local Area Network) communication system has several advantages:
-Higher data speed
-More security against data loss
-Reduction to the minimum expression of the wiring, relays and fuses on the motorcycle

-More compact and unified modules
-Improved diagnostic ability

The heart of the system is the BCM, a module that receives power directly from the battery.

In previous models of this system, if we pressed the horn button for example, what we did was connect the battery power with the horn so that it would sound. Electricity went from the battery to the button on the handlebar running through the entire bike and then back down from the button to the horn.
With HDLAN, when we press this button, what happens is that it is “published on the Internet of the motorcycle” that we want the horn to sound, so the BCM reads the message and sends electricity directly to the horn to make it sound.

There is no more electricity going up and down the handlebars to activate it, just a message. This applied to the entire electrical system of the motorcycle means that all the modules (Speedometer, ABS, BCM, ECM or control unit, Radio ...) can communicate with each other, obtaining superior performance and reliability.

Improvements such as those that have appeared in the Sportster models such as the possibility of knowing the revolutions or the gear at which we circulate on the odometer, the introduction of ABS, the disappearance of the ignition key and the optimization of the battery compartment are possible thanks to this technology.

conclusion
It is evident that the owners of Custom models are not the biggest fans of technological sophistication, but knowing that it will inevitably involve our lives (and our motorcycle), it is at least comfortable to know that in some cases it is used to simplify complex systems, making them at the same time safer and more reliable. This magical mixture of Old School & New Technologies is produced, which will keep us rolling free and better communicated.

Frank burguera

#mecanicaharley