Caution: This document contains mixed page sizes ... - Cummins Onan

Major Controller Functions
Figure 11-2 is a block diagram of Controller functions.
Initialization: Control initialization consists of
checking memory (RAM, ROM, EEPROM) and
genset configuration.
Fuel Priming: Press and hold the control switch at
STOP (Prime) for more than 3 seconds to cause
fuel pump E2 to prime the fuel system.
Starting: Press and hold the control switch at
START (Preheat) until the genset starts. The Controller:
1. Energizes fuel lift pump E2.
2. Energizes the glow plugs (3) during pre-heat
and cranking. The duration of pre-heat prior to
cranking is engine temperature dependent, but
does not exceed 15 seconds.
3. Enables the status lamp to blink rapidly.
4. Enables some fault detection.
5. Enables cranking for up to 35 seconds.
6. Enables field flash (F1-F2).
7. Energizes governor actuator E1 (full rack).
8. Disconnects the starter at 800 rpm.
9. When operating speed is reached:
A. Enables output voltage.
B. Turns off field flash.
C. Turns on status lamp.
D. Enables Switched B+ (J1-8).
E. Enables complete fault detection.
Stopping: Touch the control switch to STOP
(Prime). The Controller:
1. Disables output voltage.
2. Deenergizes the fuel lift pump and governor actuator.
3. Turns off the status lamp.
4. Writes session data (number of cranks, minutes
of operation, last fault, etc.) to non-volatile
memory (NVM).
5. Removes processor power when idle 5 minutes.
Note: Note: Stop takes precedence over Start if both
present due to a faulty switch or other cause.
Controlling Voltage: The Controller maintains
nominal AC output voltage as load varies by varying
field voltage. In response to transient loads, it lowers
the voltage setpoint to allow engine recovery.
Field power is supplied by the quadrature windings
(Q1-Q2). See ADJUSTING VOLTAGE (p. 10-6).
Controlling Fuel: The Controller positions the fuel
rack to maintain nominal frequency as load varies
by sending a pulse-width-modulated square-wave
signal (PWM) to governor actuator E1. It determines
frequency by sensing the zero crossings of the
quadrature winding output. When the actuator is not
energized, its spring-loaded plunger holds the fuel
rack in the no-fuel position.
Fault Monitoring, Shutdown and Diagnostics:
See Section 12. Troubleshooting.
11-2