Bendix Commercial Vehicle Systems EC-16 ANTILOCK CONTROLLER 4/08 - Manual (Page 5)

5
EC-16 ™ 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-16
™ 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-16
™ controller is able to simultaneously receive, and
individually interpret, speed signals from six wheel speed
sensors. Vehicle drive configuration and whether the traction
control feature is in use determines the number of speed
sensors that must be used. A vehicle with a single rear axle
drive (4 x 2, 4 x 4 or 6 x 2) requires 4 speed sensors for both
antilock and traction operation. A vehicle with two rear drive
axles (6 x 4) requires 4 speed sensors for antilock only
operation, but have the option to use 6 speed sensors for
enhanced performance of both antilock and traction operation.
- Vehicle power is supplied to the EC-16 ™ controller from
the ignition switch through a fuse or circuit breaker. (30 amp.)
The electrical ground for the EC-16
™ controller is the vehicle
chassis.
- A connection for a traction enable switch is provided,
but not always used. The switch allows traction to be turned
on or off manually.
OUTPUTS
- Modulators, like the Bendix ® M-21 ™ or M-22 ™ modulator,
are the means by which the EC-16 ™ controller modifies driver
applied air pressure to the service brakes. The modulator is
an electrically controlled air valve located near the service
actuator(s) it controls. It is the last valve that air passes
through on its way to the brake actuator. A wiring harness
connects the modulator to the EC-16
™ antilock controller.
Solenoid valves contained in the modulator provide the
electrical interface between the EC-16
™ controller electronics
and the air brake system. The EC-16 ™ controller is able to
simultaneously and independently control four individual
modulator assemblies.
- An antilock dash light and its electrical relay are
connected to, and controlled by, the EC-16
™ controller and
serve as a means of advising the driver of the condition of
the antilock system.
- A connection to the engine or transmission retarder and
its relay is provided on the EC-16
™ controller, which allows
the EC-16 ™ controller to temporarily disable the retarder
during certain modes of operation. While the EC-16 ™
controller is capable of this function, and connections are
provided, it is not always used. Use of the retarder disable
function is not essential but highly recommended for vehicles
equipped with a retarder.
Note: The EC-16 ™ controller can also disable the retarder
using the same J1922 protocol it uses to control
the traction control, engine torque limiting feature.
For this redundant retarder disable to function, the
EC-16
™ controller must be connected to the engine
control module (as would be the case if the EC-16 ™
controller is programmed for the traction control,
torque limiting feature).
- The data link enables the EC-16 ™ controller to "report"
its operating condition to a specialized, external computer
in response to certain commands it receives. The EC-16
™
controller diagnostic data link hardware conforms to S.A.E.
standard J1708. The protocol, or coded language used,
conforms to S.A.E. standard J1587. There are two
connections to the EC-16
™ controller devoted to the data
link. While connections are provided for this function, it is
not always used. The data link is not essential for the
EC-16
™ controller to be functional.
WS-20 ™ STRAIGHT
SPEED SENSOR
WS-20 ™ 90
DEGREE SPEED
SENSOR
FIGURE 5 - WS-20 ™ SPEED SENSORS
ELECTRICAL
CONNECTOR
DELIVERY
PORT
SUPPLY
PORT
EXHAUST
PORT
SUPPLY
PORT
DELIVERY
PORT
ELECTRICAL
CONNECTOR
M-21 ™
MODULATOR
EXHAUST
PORT
M-22 ™
MODULATOR
FIGURE 6 - MODULATORS