PREVOST X3-45 Multiplex, Maintenance Manual

Page: 578 / 1422

4
REVISED 5/31/05
FIGURE 7 - POWER LINE WITH PLC SIGNAL
PLC SIGNAL
An oscilloscope can be used to measure or identify the
presence of a PLC signal on the power line. The PLC
signal is an amplitude and frequency modulated signal.
Depending on the filtering and load on the power line, the
PLC signal amplitude can range from 5.0mVp-p to 7.0
Vp-p. Suggested oscilloscope settings are AC coupling, 1
volt/div, 100 µsec/div. The signal should be measured at
the ignition power input of the EC-60
™
controller.
Note: An ABS trailer equipped with PLC, or a PLC diagnostic
tool, must be connected to the vehicle in order to generate
a PLC signal on the power line.
EC-60
™
CONTROLLER INPUTS
Battery and Ignition Inputs
The ECU operates at a nominal supply voltage of 12 volts.
The battery input is connected through a 30 amp fuse
directly to the battery.
The ignition input is applied by the ignition switch circuit
through a 5 amp fuse.
Ground Input
The EC-60
™
controller supports one ground input. See page
42 for a system schematic.
ABS Indicator Lamp Ground Input
Advanced EC-60
™
cab ECUs require a second ground input
(X1-12) for the ABS indicator lamp. The X1 wire harness
connector contains an ABS indicator lamp interlock (X1-15),
which shorts the ABS indicator lamp circuit (X1-18) to
ground if the connector is removed from the ECU.
Bendix
®
WS-24
™
Wheel Speed Sensors
Wheel speed data is provided to the EC-60
™
controller from
the WS-24
™
wheel speed sensor (see Figure 2). Vehicles
have an exciter ring (or “tone ring”) as part of the wheel
assembly, and as the wheel turns, the teeth of the exciter
ring pass the wheel speed sensor, generating an AC signal.
The EC-60
™
controller receives the AC signal, which varies
in voltage and frequency as the wheel speed changes.
Vehicle axle configurations determine the number of
WS-24
™
wheel speed sensors that must be used. A vehicle
with a single rear axle requires four wheel speed sensors.
Vehicles with two rear axles can utilize six wheel speed
sensors for optimal performance.
Diagnostic Blink Code Switch
A momentary switch that grounds the ABS Indicator Lamp
output is used to place the ECU into the diagnostic blink
code mode and is typically located on the vehicle’s dash
panel.
Optional ABS Off-Road Switch and Indicator
Lamp Operation
Advanced EC-60
™
controllers use an optional dash-
mounted switch for the operator to place the ECU into the
ABS off-road mode. See "Optional ABS Off-Road Mode"
on page 7 for further details. In some cases, ECUs may
also be put into the ABS off-road mode by one of the other
vehicle control modules, using a J1939 message to the
EC-60
™
controller.
(If you need to know if this EC-60
™
controller uses a J1939
message to operate the lamp, e-mail ABS@bendix.com,
specifying the ECU part number, or call 1-800-AIR-BRAKE
and speak to the Bendix TechTeam.)
WARNING: The ABS off-road mode should not be used on
normal, paved road surfaces because vehicle stability and
steerability may be affected. When the ECU is placed in
the ABS off-road mode, the ABS Indicator Lamp will flash
constantly (at a rate of once per 2.5 seconds) to notify the
vehicle operator that the off-road mode is active.
Optional ATC Mud/Snow (Off-Road) Switch and
Indicator Lamp Operation
(see also page 8.)
Advanced controllers use a dash-mounted switch for
the operator to place the ECU into the ATC Mud/Snow
mode.
Stop Lamp Switch (SLS)
The Advanced EC-60
™
controller monitors the vehicle stop
lamp status. Certain vehicle functions, such as ATC and
All-Wheel Drive (AWD), use the status of the stop lamp to
determine when the driver makes a brake application. This
can be provided to the ECU via J1939 communications,
or hardware input.
Brake Demand Sensors
The brake demand sensors provide the controller with an
indication of driver-applied brake pressure. One is installed
in the primary air brake circuit, and another is installed in
the secondary air brake circuit.
Load Sensor
The load sensor provides the controller with an indication
of the vehicle load. It is typically installed in one of the
suspension air bags.
Bendix
®
SAS-60
™
Steering Angle Sensor
The Steering Angle Sensor (SAS) is used to provide driver
steering input to the controller. It reports the steering
wheel position to the controller utilizing a dedicated serial
communications link that is shared with the YAS-60
™
sensor. The controller supplies the power and ground inputs
to the SAS-60
™
sensor.
The SAS-60 sensor is available with two different styles of
wire harness connectors. (See Figure 4)