Winco DGC-500 - Manual (Page 44)

DGC-500 Functional Description 3-24
NOTE
When ECU support is enabled during Pre-start and Resting, the fuel solenoid is
closed.
Figure 3-14. Screens Shown Following Unsuccessful Information Update from ECU
C Pulse Cycle Time - fuel solenoid is open
C
Response Timeout - fuel solenoid is closed
C
Settling Time - fuel solenoid is closed
C Engine Shut Down - fuel solenoid is open
Display Values (ECU Support Enabled)
The ECU is able to give the DGC-500 in-depth information about the values it sends. This makes it possible
for the DGC-500 to display accurate information when metering these values from the ECU. After successfully
pulsing the unit, the last values gathered when powering-off the ECU are displayed until the next pulse. The
following is a list of display values:
C Value - the actual value is displayed if the last pulse was successful or the engine is running.
C
No Communications (abbreviated as NC) - displayed if the last pulse was unsuccessful.
C
Not Applicable (abbreviated as NA) - the ECU does not monitor this data value.
C ECU Data Not Sent (abbreviated as NS) - data was not sent in the time designated by the J1939 protocol.
C
Sender Failure (abbreviated as SF) - the ECU has determined a sender failure for that metered value.
ECUs with an External Fuel Solenoid
The DGC-500 supports ECUs that are able to cut-off fuel from the engine without powering the ECU off. The
DGC-500 requests engine run-time every minute to keep the ECU from going into a sleep mode. After the
Pulse Cycle Timer expires, the DGC-500 checks whether ECU communication exists. If so, the DGC-500 will
not pulse the ECU. The same goes for Connecting, except that the DGC-500 remembers if it skipped the
Connecting state. If it did, then the DGC-500 will also skip the Engine Shutting Down state when it stops the
engine.
For ECUs that have an external fuel solenoid, it is recommended that the Engine Shut Down timer be set to
its minimum value. This ensures that, if the DGC-500 temporarily loses power while running, the unit will go
straight into the Run state and go to the Shutting Down state when the unit goes to Off. It is also
recommended that the Response Timeout Timer be set to its minimum value in order to set the ECU
Communications Fail pre-alarm as soon as possible.
The HMI screens shown in Figure 3-14 are displayed if the last attempt to pulse the ECU for an information
update was unsuccessful.
STATE MACHINES
A state machine is any device that stores the status of something at a given time. An input change can change
the status and/or cause an action or output to occur for any given change. A finite state machine can be used
to solve problems and describe the solution for system maintainers. State machine illustration methods range
from simple tables to graphically animated illustrations.
The following paragraphs describe how the DGC-500 functions as a state machine.