User's Manual

Sensors provide an electrical signal to the ECM that
constantly changes. The sensor input to the ECM
can be one of several different types of electrical
signals such as: pulse width modulated (PWM)
signals, voltage signals and frequency input signals.
Refer to the correct pilot machine schematic to verify
each input to the ECM.
Outputs
The ECM sends electrical signals through the
outputs. The outputs can create an action or the
outputs can provide information to the ECM. The
ECM can send output signals to the system
components in one of several different electrical
signal types such as: driver outputs, sinking driver
outputs, sensor power supply outputs and data link
outputs. Refer to the correct pilot machine schematic
to verify each output to the ECM.
Input/Output
Communication between the ECM and the other
control modules on the machine is conducted over
data link circuits. The data link circuits allow the
sharing of information with other electronic control
modules. The data link circuits are bidirectional. The
data link circuit allows the ECM to send information
and to receive information.
The ECM supports two types of data link systems.
• Cat
®
Data Link
• SAE J1939 Data Link
The two types of data links are the main structure for
communication between all of the control modules on
the machine. More than one CAN data link system
can be present on a machine. Dedicated CAN data
link circuits can be used for communication between
specific controls on the machine.
Communication between the ECM and the other
control modules on the machine are conducted over
the J1939 Data Link circuit. The J1939 Data Link
circuit is connected to each control module. The
ECMs use the Cat Data Link to send and receive
information from the Cat
®
Electronic Technician (Cat
ET) Service Tool.
A module identifier (MID) is assigned to each ECM
on a machine. For example, the MID for the Machine
ECM is 299.
60 UENR7061
Service