Bendix Commercial Vehicle Systems EC-17 ANTILOCK TRACTION CONTROL4/10 - Manual (Page 3)

3
When programmed to provide traction control in addition to
antilock, the following components are added:
- One traction solenoid (incorporated into the relay valve)
- One dash mounted traction condition lamp
- Serial connection to engine control module (for vehicles
programmed for torque limiting feature)
- Traction disable wiring and switch
PHYSICAL
The EC-17 ™ controller electronics are contained in a non-
metallic housing and are environmentally protected by an
epoxy compound. The design of the digital electronics are
intended to provide a high degree of protection from radio,
electromagnetic and environmental interference.
The patented optional light emitting diode (LED) display and
magnetically actuated reset switch is incorporated in the
housing for troubleshooting and diagnostic purposes.
Two electrical connectors, located in the controller housing
opposite the diagnostic display (if so equipped), connect
the EC-17
™ controller to antilock and traction system
components: one 30 pin and one 18 pin connector. The
optional traction solenoid is linked to the 18 pin connector
using a 2 pin Deutsch connector. The optional traction
solenoid is located in the upper portion of the antilock traction
relay valve assembly. (See Figure 3.)
MOUNTING
The EC-17 ™ controller is available in two different mounting
styles. One model, shown in Figure 1, is a stand-alone. It
is intended for bracket mounting to a frame member and is
not attached to an antilock relay valve.
The other EC-17 ™ controller is designed to be mounted on
one of four different valves. All of the valves provide the relay
EC-17 ™ CONTROLLER INFORMATIONAL
INPUTS AND COMMAND OUTPUTS
GENERAL
The EC-17 ™ 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-17
™ controller both receive and deliver
commands and information. (See Figure 5.)
INPUTS
- Wheel speed information is provided to the EC-17 ™
controller via a wiring harness from individual wheel speed
sensors at the vehicle wheels (See Figure 4). Working with
an exciter or tone ring, wheel speed sensors provide
information to the EC-17
™ 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-17
™ controller is
designed to receive wheel speed information, from various
wheel speed sensor models, at the rate of 100 pulses (86
pulses if so configured) per wheel revolution. The EC-17
™
controller is able to simultaneously receive, and individually
interpret, speed signals from up to 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
2-PIN
CONNECTOR
(TO TRACTION
SOLENOID)
ANTILOCK TRACTION
ASSEMBLY EC-17 ™
CONTROLLER
TRACTION
SOLENOID
(IN HOUSING)
TRACTION
RELAY
FIGURE 3 - EC-17 ™ CONTROLLER W/ANTILOCK
TRACTION RELAY VALVE
AntiLock Added Function Vehicle Designation (Valve +
Valve Provided Application EC-17 ™ Controller)
AR-1 ™ None All CR-17 ™ Controller Relay
AR-2 ™ Bobtail Brake Tractors Only CR-18 ™ Controller Relay
Proportioning
ATR-1 ™ Traction All AT-1 ™ AntiLock Traction
ATR-2 ™ Traction & Bobtail Tractors Only AT-2 ™ AntiLock Traction
Brake Proportioning
function and replace the standard service relay on antilock
equipped vehicles. In some instances the valves also provide
specialized functions. When the EC-17
™ controller is
mounted on any of these valves, the result is a final assembly
with its own model designation. Refer to the chart below
and Figure 3.
FIGURE 4 - WS-20 ™ AND WS-24 ™ WHEEL SPEED
SENSORS
90° SPEED
SENSORS
STRAIGHT SPEED
SENSORS
WS-24 ™
SENSOR
WS-20 ™
SENSOR
WS-20 ™
SENSOR
WS-24 ™
SENSOR