Bendix Commercial Vehicle Systems EC-13 TRAILER ANTILOCK CONTROL 8/07 - Manual (Page 2)

2
WS-20 ™
WHEEL SPEED SENSOR
Reservoir Reservoir
SPRING
BRAKE
SUPPLY (EMERGENCY) LINE
CONTROL (SERVICE) LINE
TO TRAILER ELECTRICAL
CONNECTOR
SPRING BRAKE
M-12R ™
MODULATOR
TRAILER ANTILOCK
WIRING HARNESS
EC-13 ™ CONTROLLER INFORMATION
INPUTS AND COMMAND OUTPUTS
GENERAL
The EC-13 ™ controller receives information from several
components in the antilock system and, based on these
inputs, issues commands or delivers information. Some
portions of the EC-13
™ controller both receive and deliver
commands and information.
INPUTS
Wheel speed information is provided to the EC-13 ™
controller via a wiring harness from individual speed sensors
located in the trailer wheels or axle housing. Working in
conjunction with an exciter or tone ring, the speed sensors
provide information to the EC-13
™ controller in the form of
an AC signal which varies in voltage and frequency as the
speed of the wheel increases or decreases. The EC-13
™
controller is designed to receive wheel speed information,
from various wheel speed sensor models, at the rate of 100
pulses per wheel revolution. The EC-13
™ controller is able
to simultaneously receive, and individually interpret, speed
signals from four wheel speed sensors (2 axles).
Vehicle power is supplied to the EC-13 ™ controller
from the stop light switch. The electrical ground for the
EC-13
™ controller is from the 7 pin trailer connector and
trailer chassis.
OUTPUTS
Modulators, like the Bendix ® M-12 ™ and M-12R ™
modulators, are the means by which the EC-13 ™ antilock
controller is able to modify driver applied air pressure
to the service brakes. The EC-13
™ controller is able to
simultaneously and independently control two modulators
assemblies. The M-12
™ and M-12R ™ modulators are
combination valves consisting of a standard relay valve
and solenoid assembly. They replace the standard relay
valves used to speed up the application and release of the
trailer’s rear axle brakes. An external, three pin, wiring
harness connects the EC-13
™ controller to the M-12 ™ or
M-12R ™ modulator solenoid assembly. For additional
information and service procedures see Bendix Service
Data Sheet SD-13-4772.
As stated previously, the EC-13 ™ controller is designed to
control two modulators. It can be mounted directly on an
M-12
™ modulator relay valve assembly and control a separate
M-12R ™ modulator or the EC-13 ™ controller can itself be
remote mounted to the trailer and control two M-12R ™
modulators. When mounted directly on a modulator, the
two separate components (EC-13
™ controller and M-12 ™
modulator) become a single assembly called the MC-13 ™
modulator controller.
EC-13 ™
CONTROLLER
FIGURE 2 - TYPICAL EC-13 ™ TRAILER ANTILOCK SYSTEM
30 PIN CONTROLLER
CONNECTOR
WS-20 ™
WHEEL SPEED
SENSOR
SR-5 ™
SPRING BRAKE VALVE
M-12R ™
MODULATOR