Bendix Commercial Vehicle Systems EC-30 ABS/ATC CONTROLLER 2/08 - Manual (Page 4)

4
FIGURE 5 - BENDIX ® WS-20 ™ AND WS-24 ™ WHEEL SPEED
SENSORS
EC-30 ™ CONTROLLER INPUTS
Power and Ground
Power is supplied to the EC-30 ™ controller from the ignition
circuit through a 30 Amp fuse. The EC-30 ™ controller is
grounded to the vehicle chassis. For EC-30 ™ controller
power and ground connector pin locations, see EC-30 ™
controller system schematic, Figure 14.
Wheel Speed Sensors
Wheel speed data is provided to the EC-30 ™ controller from
the Bendix ® WS-20 ™ or WS-24 ™ wheel speed sensors.
See fi gure 5 for wheel speed sensor illustrations. Working
with an exciter ring, wheel speed sensors provide the
EC-30
™ controller with an AC signal, which varies in voltage
and frequency in relation to the speed of the wheel. The
EC-30
™ controller can be confi gured to receive wheel
speed information from 100 or 86 tooth exciter rings.
Vehicle axle confi gurations and ATC features determine
the number of speed sensors that must be used. A vehicle
with a single rear drive axle (4x2, 4x4 or 6x2) requires four
speed sensors for both ABS and ATC operation. A vehicle
with two rear drive axles (6x4) can utilize six speed sensors
for optimal ABS and ATC performance. For wheel speed
sensor connector pin locations, see the EC-30
™ controller
system schematic, Figure 14.
Blink Code Switch
The EC-30 ™ controller can be confi gured to support an
optional diagnostic blink code switch to ground, which can
be used to activate several functions available through
blink code diagnostics. Pin F3, of the 30-pin connector, is
the blink code switch input.
Three Position Switch for ATC and Blink Codes
The EC-30 ™ controller can be confi gured to receive both
the ATC enable/disable signal and the blink code activation
signal from a single three-position switch. In this case, the
common position of the switch is connected to pin F2 of
the 30-pin connector. The normally-open switch position
is connected to +12 VDC to disable ATC. The normally-
open (momentary) switch position is connected to ground
to activate blink codes. When confi gured in this manner,
there is no wire installed in pin F3 of the 30-pin connector,
which is normally used for the blink code switch input.
Brake Switch Input
The EC-30 ™ controller can be confi gured to support an
optional brake switch input. The brake switch input can be
used in accordance with ABS and ATC performance. Pin
A2, of the 18-pin connector, is the brake switch input.
EC-30 ™ CONTROLLER OUTPUTS
ABS Modulators
Bendix ® ABS modulators (M-21 ™ , M-22 ™ , M-30 ™ or
M-32 ™ ) are controlled by the EC-30 ™ controller to modify
driver applied air pressure to the service brakes during
ABS or ATC activation. See fi gure 6 for illustration. The
ABS modulator, an electro-pneumatic control valve, is the
last valve that air passes through on its way to the brake
chamber. The modulator hold and exhaust solenoids are
activated to precisely modify the brake pressure during
ABS. The hold solenoid is normally open and the exhaust
solenoid is normally closed. The EC-30
™ controller is
able to control four individual modulator assemblies. For
ABS modulator connector pin locations see the EC-30
™
controller system schematic, fi gure 13.
ATC Enable/Disable Switch
Premium EC-30 ™ controller models, confi gured for ATC,
monitor an ATC enable/disable switch to +12 VDC, which
allows ATC to be manually deactivated. The ATC active/
warning lamp will be on while the ATC is disabled. Pin F2,
of the 30-pin connector is the ATC enable/disable switch
input.
J1939 - ATC Enable/Disable Switch
The EC-30 ™ controller can be confi gured to receive the
status of the ATC enable/disable switch over the SAE J1939
serial communications link. A vehicle controller will monitor
the position of the ATC enable/disable switch directly, and
broadcast a J1939 message indicating its status. When
confi gured in this manner, there will be no wire installed in
pin F2 of the 30-pin ECU connector. In the event that J1939
communications is lost between the EC-30
™ controller and
the vehicle controller, the EC-30 ™ controller will disable the
ATC function.
90° Speed
Sensors
Straight Speed
Sensors
WS-24 ™
Sensor
WS-20 ™
Sensor
WS-20 ™
Sensor
WS-24 ™
Sensor
FIGURE 6 - M-30 ™ , M-32 ™ , AND M-32QR ™ MODULATORS
Delivery
(Port 2)
Supply
(Port 1)
Exhaust
(Port 3)
Electrical
Connector
M-30 ™
Modulator
M-32QR ™
Modulator
M-32 ™
Modulator