Technical principle: Point to point ISO 11992 connection between two successive vehicles in the combination

M. Adam (CLEPA – WABCO) presented the 1st part of his document MVC-05-02. ISO 7638 connector, with 7 pins, 2 of them belong to the CAN communication network, according to ISO11992. Point-to-point communication between 2 nodes. If man adds an additional vehicle, then there is an additional node. Mr. Adam was of the opinion that ISO contains all the necessary information for the interest of the MVC group. No need for additional requirement into UN R13.

Mr. Manz (CLEPA/BPW) pointed out:
Naming: the towing trailer is not understood as a node according to UN R13
The router should be identified as the node in the chain.
These two comments may lead a TAA to refuse an approval due to a strict reading of the regulation.

The experts found opportune to change along the text of the regulation, the word “motor vehicle” or “tractor” into “towing vehicle”.
It was clarified that the router permits to extend the number of vehicles (additional nodes) while the amplifier permits to extend the size of the vehicles (long wires). The router function is necessary for any trailer capable of towing a vehicle. There is the necessity of a router on each towing vehicles.

The question was raised about a combination with several trailers, each with a router, and where the 1st router would fail. Would the 2nd trailer receive the number 1?
N Norway, 18 to 80 meters are acceptable. The question was whether there is a possibility that the text is interpreted such that a repeater is allowed, with the current texts of the regulation. An explanatory drawing was edited on the white board:
Bus topology
Router
Amplifier
Functionality

According to M. Adam, there must be an electronic control line in every towing vehicle in a MVC.
A debate took place on the point-to-point communication.
Industry committed to prepare a presentation on the state of the art of the point2point communication.

Conclusion:
There must be an electronic control line in every towing vehicle/trailer (tbd) in an MVC.
Industry to prepare a presentation on p2p communication, routing, repeating, etc. and special requirements for towing trailers (PT and CA as pilots).
Draft text amending UN R13, from 11992, for a routing function for towing trailer (requirement to transmit forward and backward) (SM and CA as pilots) in which conditions a repeater is requested. (SM and CA as pilots)

Does any potential / practical issue exist with ISO 7638 dimensioning (UN R13 paragraph 5.2.2.17.2. also to be reviewed)?

Mr. Adam presented the Part 2 of his contribution per document MVC-05-02.

The experts had a debate on the trends of power consumptions: EBS decreased the levels of current, while the forthcoming electric steering function may increase the necessary power. Need to note that the draft amendments to take into account ACS connectors (7638).

There was a debate on whether to limit the current generated to the other vehicles. It was suggested to inspire from what was adopted by the task-force on trailer electric steering system.
Other approach: any trailer intended for MVC should benefit of a certain amount of current, hence in-use requirements that depending the level of current available at tractor, a certain number of trailers is permitted.

What consumes the most current: self-check, braking on slippery surface, number of valves?

Proposal to put labels on the vehicles about compatibility of different vehicles. Yet it was recalled that this solution should be avoided due to the poor durability of the labels.

Conclusion:
CLEPA to collect real-world data on the levels of electricity consumers (how many amps necessary for one average trailer).
Volvo to investigate internally (seems to be 25 Amps available to the trailer)