Truck trailer use 7 core Spiral power cord cable and socket

Trailer ABS is not easy to use? Analysis of potential safety hazard of power supply line
Trailer ABS now needs to be installed compulsorily. However, in the past two years, some surveys of MBP have found that many users feel that even if they buy a trailer with ABS, they still feel that the use effect is not good. Is this just a product quality problem or another reason?

After investigating all the new domestic products (compulsory installation of ABS system), semi trailers are equipped with international ISO 7638 standard, separate ABS system connection line socket. But in practical application, the current market price of its connecting line is more than 1000 yuan, and many of them are equipped by tractor manufacturers. As a result, users are not connected to this line when they use it, can ABS system still play a role?

According to the new regulations, the ABS system equipped with semi-trailer must be powered by iso7638 independent socket, but in fact many early tractors do not have this kind of connection plug, which leads to the hidden trouble that the system cannot work. Iso7638 socket is equipped with seven pin connection, including power supply, ignition lock ACC power supply (tractor key control on), and its independent negative circuit; in addition, it is equipped with ABS detection fault indicator signal circuit, which generally displays the status in the tractor instrument panel.

The other two pins are connected to two communication lines of can high and low. At present, there is no mandatory regulation in China. The connection between the tow car and trailer installed with these two needles is carried out for the vehicles in accordance with iso1992 standard. The function is to realize communication between the main and trailer ABS braking system, including EBS (electronic control braking system) based on ABS, through calculation, coordinate the distribution of braking force of vehicles, and further strengthen the braking stability and safety.
ISO 1185 power supply
Iso1185 plug refers to the seven hole socket for electrical connection between tractor and trailer, which is the most familiar device for all truck drivers.

There are seven hole connections inside the ISO 1185 plug:

1 white is the negative circuit of trailer;
2. Black is the left side marker lamp and the rear tail lamp;
3 yellow is the left turn signal;
4. Red is the brake light;
5 green is the right turn signal;
6 Brown is the right side light and small light;
7 blue power supply for brake control system.
In the remarks, it is clearly stipulated that the rear license plate lamp is not allowed to connect 2 and 6 at the same time. This is because it prevents the lines from being connected in series, so as to ensure that if any of the lines fails, the small and medium lamps in the rear tail lamp can work normally, which is a reminder to the rear vehicle.

Let's take a look at the detailed description of national standard GB 553 "24N connector between vehicle and trailer". Although this national standard was issued in 1985, it can be seen that the power supply line has been reserved for the trailer braking control line, which is consistent with the international iso1185 standard.

ABS needs self-test, it doesn't work in case of emergency

ABS system needs a process of self checking from start-up to normal operation, usually 3-5 seconds. In order to ensure normal operation in emergency, independent uninterruptible power supply is required.

Due to the particularity of its own circuit, semi-trailer generally does not include power supply line, that is, there is no "power supply" which is continuously powered on separately. ABS anti lock system is mandatory installed in China, but in the process of implementing the regulations, some changes have been made to the line arrangement of semi trailers.
Take off the power of the brake lamp, the power connection mode is wrong
Trailer manufacturers have a headache in the universality of their products. It is difficult for the electric circuit to adapt to all types of vehicles, because in the design of old vehicles, the tractor only provides the basic electric circuit of the trailer.

In order to ensure the effective operation of ABS system, the trailer manufacturer selects the brake lamp power supply line that all vehicles have, and reserves iso7638 plug. This kind of trailer is not consistent with the standard of tractor, there are some hidden dangers, only the brake will supply power to ABS. In the sales process, the dealer did not explain to the user.
It is not difficult to understand that when the driver presses the brake pedal, the ABS system is performing self-test and does not work in the first 3-5 seconds of the reaction time of the trailer. When braking measures are taken frequently, ABS system will restart self-test repeatedly at the moment of on-off, which goes against the original design intention. When driving on ice and snow road or encountering emergency, the abnormal operation of ABS system can cause fatal accident in 3-5 seconds.
This situation makes the special built-in counter of WABCO VCs II II Trailer ABS system unable to work. When ABS works, the mileage information cannot be recovered.
Correct power supply mode

The picture shows the VCs II Abs anti lock system of WABCO equipped with domestic trailer. The power supply system is connected in parallel with the brake light line. The original purpose of this connection is to ensure the normal operation of ABS system when the power supply of iso7638 may fail. The trailer ABS is equipped with a brake lamp power supply (24N power supply), so that the trailer ABS can use both the brake lamp power supply and the standard ISO 7638 power supply. If two power supplies are connected at the same time, the system will automatically select the highest voltage; once one power supply fails, the system will automatically switch to another power supply.

In the figure, the seven hole electrical socket of Trailer (iso11185), the power supply line of ABS system is connected in parallel with the red brake lamp line, and the negative circuit is parallel to the White main circuit circuit.
How to solve the problem of old vehicles?
At present, the main engine factory has standard configuration iso7638 cable, the user can install and connect to ensure normal power supply. In the old tractor, there is no iso7638 jack, so the power supply line of ABS system can be modified. The trailer seven hole cable (iso1185) blue reserved line is used to connect the tractor power supply (controlled by ignition lock) and the trailer ABS power supply line respectively. In case of emergency, the ABS system can monitor the operation of the vehicle all the time and keep the best safety effect by braking.
At present, there are many misunderstandings in the use of vehicles. In the process of design and manufacturing, there is an imprecise way. Manufacturers can't cater to users without principle, just because the power supply of a power supply may lead to users' complete distrust of new technology and new products. There are also problems in the formulation and implementation of national standards and regulations. If only to cope with the regulations, it may lead to problems in the promotion of new technologies.
Technology is progressing and technology is developing. With a new round of truck upgrading boom, I hope to see progress in details. We will also continue to pay attention to the application of ABS in domestic trucks.