3
FIGURE 3 -
APPLYING: NORMAL SERVICE APPLICATION
INLET SOLENOID
RESERVOIR
DOUBLE
CHECK VALVE
EXHAUST
SUPPLY
EXHAUST
SOLENOID
The wiring connections on the 14 pin connector are as
follows:
PIN A - Power
PIN IF - Serial Link
PIN B - Retarder Disable
PIN L - Sensor
PIN C - Ground
PIN M - Sensor
PIN D - Dash Light
PIN N - Sensor
PIN E - Serial Link
PIN P - Sensor
PIN A - Vehicle power is supplied to the EC-11
™
controller
from the ignition switch, through a fuse, to pin A on
the 14 pin connector.
PIN B - The EC-11
™
controller is equipped with a retarder
disable circuit, which, when coupled with an
electrical relay, will disable the vehicle retarder
(engine or transmission) during an antilock stop.
The retarder disable function is not essential but is
highly recommended for vehicles equipped with a
retarder.Connection to pin B on the EC-11
™
controller provides this function.
PIN C - Pin C connects directly to negative vehicle ground.
PIN D - A dash light and its electrical relay are controlled
by the EC-11
™
controller through pin D. The light
advises the driver of the antilock system condition.
PIN E - The serial link allows the EC-11
™
controller to “report”
its operating PIN IF condition to a specialized
external computer in response to certain commands
it receives. The serial link configuration conforms to
S.A.E. standard J1708. Pins E and F provide serial
link connections to the EC-11
™
controller, but the
function is not essential for MC-11
™
tractor antilock
assembly operation.
PIN L - Sensors mounted at the wheel end send wheel
speed information PIN M to the EC-11
™
controller
through pins L-M and N-P. The EC-11
™
controller
receives the information at (PIN N) 100 pulses per
wheel revolution.
The MC-11
™
tractor antilock assembly “knows” what’s
happening at the wheel ends because of the signals it
receives from the wheel speed sensors. The sensors are
actually A.C. generators. They create a magnetic field; and
when the field is interrupted by an irregular surface, like a
tone ring, A.C. voltage is produced. The frequency of voltage
increases or decreases as wheel speed increases or
decreases.
During normal, non-antilock operation, the M-12
™
modulator
inlet solenoid is open, and the exhaust solenoid is closed.
In this condition, the M-12
™
modulator is a regular R-12
™
relay valve. It receives a control signal from the foot valve,
TRAILER
CONTROL
VALVE
BRAKE
VALVE
PISTON
CONTROL
DELIVERY
BRAKE
CHAMBER
