DE-18 USER MANUAL SECTION 5
54
controller will enable outputs at the appropriate times
for starting, running, stopping and controlling the load
as measured by the discharge pressure. The engine
speed will be varied in order to maintain the
discharge pressure. Set points and other adjustable
factors are stored in non-volatile EPROM memory.
At any time there is a shutdown or alarm condition,
the reset button must be pressed to reset the system.
In the case of an alarm, when the reset push button
is pressed, if the alarm condition has already cleared
itself, then the alarm display and compressor
warning I shutdown light will be cleared. If the alarm
condition is still present, then the alarm display and
the compressor warning I shutdown light will remain
on. In the case of a shutdown, the unit will be locked
out from running or being restarted until the reset
push button is pressed. Once the reset push button
is pressed, and the shutdown condition has been
cleared, the compressor warning I shutdown light will
be turned off, and the unit will go into standby mode
to be ready to start. Note: The reset push button
does not reset the MDDM.
The engine warning and engine shutdown /
diagnostics lights are controlled by the CAT ECM.
The Emergency Stop push button must be pulled out
to power the controller.
The maintained discharge pressure setpoint is stored
when a normal stop takes place. When powered up,
the controller will reset the setpoint pressure to the
last stored maintained discharge pressure setpoint.
After installing a new chip, before starting for the first
time, the maintained discharge pressure setpoint
should be inspected on the front display of the
EMS547. (Its factory default is 125 psi)
There is a 10-second delay when the unit is started
up, during this time the program name and the "MAX
PRS@xPSI" is displayed. When the 10 seconds
expires it goes to the top of the front displays,
displaying the P2 pressure and the current set
pressure. At this point the user may navigate freely.
When changing the MAX PRS@ (P-64 adjustment)
to a different mode nothing happens until the user
presses the enter key once. If a change was made
the unit will do a factory default with the new
pressure mode defaults and then it will reboot. Do
not keep the enter key depressed.
STARTING SEQUENCE
If no class A shutdown conditions exist, then the
controller will be in the STANDBY state. 10 seconds
later the Cat ECM power relay will be energized. The
controller must be in the STANDBY state before the
engine can be started. The controller will wait for a
start signal from the start push button while in the
STANDBY state.
When the controller receives the signal to start from
the push button, the following will occur:
The crank relays are energized. When the engine
RPM rises above the Crank Disconnect setpoint the
cranking cycle will cease, the controller will enter the
RUNNING state. The Air Intake Valve relay and the
Blowdown relay are energized when the engine rpm
reaches the MIN RPM setpoint and the Discharge
Pressure P2 is less than the Setpoint Pressure.
The Crank Cycle begins by energizing the Crank
Output for the Crank Delay time period P-8
adjustment). Then it will de-energize the Crank
Output for the Rest Delay time period (P-9
adjustment). This Crank Cycle will repeat for Crank
Attempts times (P-3 adjustment). If the engine fails to
start, the controller will shutdown on an
OVERCRANK Failure.
RUNNING SEQUENCE
The Internal Hourmeter begins to record engine
running hours. The Class B lockout time delay (P-6
adjustment) will begin. A warm-up timer (P-10
adjustment) starts.
When the adjustable preset Class B lockout delay
expires, all class B shutdowns and alarms become
activated. When the warm-up timer expires, or the
engine temperature is read to be greater than the
warm-up setpoint (P-11 adjustment), the unit is ready
for loading.
When the compressor first loads, the throttle will stay
at Minimum RPM until the discharge pressure stops
increasing. The increase is measured by the
discharge pressure increasing by the amount of the
Increase Pressure Setpoint (P-48 adjustment) within
the Increase Pressure Delay Setpoint (P-47
adjustment) time. This adjustment combination
allows us the most flexibility for detecting the
pressure increase.
Once the discharge pressure stops increasing, the
pressure will then throttle the engine between the
minimum RPM setpoint (P-13 adjustment) and the
maximum RPM setpoint (P-14 adjustment) of the
Caterpillar Engine.
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