Alpha Technologies ECM - Manual (Page 23)

23 TM 744-862-C0-003 Rev.C
Engine Control Module (ECM)
2.2 Control Functions
Refer to Figure 2-2 on the following page:
The three positions of the rocker switch (7) are RUN - AUTO - STOP (RAS).
The RAS switch is normally left in the center, AUTO, position so that the ECM
has control of the generator set. A minor alarm is indicated when the RAS
switch is not in the AUTO position. The STOP ("down") position is used to
stop or prevent APU operation during maintenance. Placing the RAS switch
in the STOP position for three (3) seconds, then switching back to AUTO
will clear any latched alarms and start the generator if the cause of the
alarm has been corrected. Placing the RAS switch in the RUN ("up") position
will cause the engine to start and run until this switch is released to AUTO.
The engine may not shut down immediately when the switch is returned to
AUTO from RUN, because the ECM’s shutdown criteria must be met in order to
shutdown the engine. Also, each time the RAS switch is placed in the AUTO
position (from the STOP position), the ECM will start and run the APU for one
minute after a short delay.
The service reset push-button switch (8) has two purposes. It resets the
engine service timer when depressed for 5 seconds and can be used to
determine which alarms are active (see "Alarms" section 3.3). The service
interval is a programmable counter within the ECM that defaults to 100 hours
after the initial 25-hour break-in period. When 100 hours of engine run time
elapses, the Service Required notification is set and the notification LED
illuminates. After the engine has been serviced, pressing and holding the
service reset switch for 5 seconds will reset the 100-hour service counter. All
of the LEDs flash, while the switch is depressed, until a five-second timer
elapses at which time all of the LEDs remain on solid until the switch is
released. This provides feedback to the technician, indicating the effective
resetting of the engine service counter.