User's Manual

Illustration 4 g06105748
ECM Inputs
Keyswitch
The key start switch is also used as an input signal to
the MSS. The input from the key switch is used to
determine when the machine is on. Battery voltage is
connected to this input through the ON and START
positions of the keyswitch. When the machine is
operating and the alternator is charging, the voltage
on this input will be:
• 14.1 - 15.1V for a 12V system
• 27.6 - 29.6V for a 24V system
When the machine is not running, the voltage on this
input will be approximately 12V for a 12V system and
24V for a 24V system.
Neutral Start Input
When activated, the NEUTRAL START input supplies
power to the neutral start ON/OFF driver 5
(STARTER solenoid driver) using +BATT.
Switch to ground
These inputs allow the ECM to detect closure of
switches to the ECM ground (- BATTERY input).
ECM Outputs
Status Indicator
The status indicator displays status of the system.
The status indicator has three connections. One of
the three connections is for a ground. Another
connection is for the red LED. The third connection is
for the green LED.
Output Drivers
Two output drivers are available to control relays or
solenoids on the machine. Unless a valid “key ID”
has been identified by the system, the drivers will
remain without power. The drivers are rated at 2A.
i06222315
System Components
SMCS Code: 7631
Cat® Electronic Key
Illustration 5 g00793955
The Cat® electronic key
The Cat® key is the universal key for all Caterpillar
machines. The electronic key has an electronic chip
that is embedded inside the head of the key. The
electronic keys are gray or yellow.
Exciter Coil
The exciter coil provides communication between the
electronic key and the control module.
The exciter coil is mounted around the keyswitch.
This position allows the exciter coil to communicate
with the electronic key. Any ferrous metal between
the coil and the electronic key will interfere with the
communications. Mounting the coil in the same plane
as the top of the keyswitch will minimize the
interference.
UENR7061 15
Systems Operation Section