Table 8.13 Engine start flowchart*
Genset
start command
Start
conditions
OK
No
Yes
Crank output
activated
Crank on
timer
expired
No
Yes
Running
detection
ON
No
Yes
Max start
attempts
Yes
No
Genset
started
Command
and mode
match
No
Yes
Crank output
deactivated
Genset stop
sequence
Info message
Info message
Alarm
1. Command and mode match: The controller checks that the
command source and the controller mode match:
• In AUTO mode, the power management system must send the
command to start the genset. The controller ignores all other
external commands.
• In SEMI mode, the command to start the genset can come from
the following:
◦ The operator can press the push-button Start on the
display unit.
◦ The operator can use PICUS to send a genset start
command.
◦ The command can come from an external source, for
example, a relay output from a PLC.
2. Start conditions OK: The controller checks whether the start
conditions are OK:
• For a power management command, the controller is in AUTO
mode.
• If configured, the Start enable digital input is activated.
• There are no active or unacknowledged alarms to prevent the
genset start. These alarm actions prevent a genset start:
◦ Block
◦ PMS-controlled stop
◦ Trip generator breaker and stop engine
◦ Trip generator breaker and shutdown engine
3. Crank output activated: If all the start conditions are OK, the
controller activates the Crank output and a timer.
4. Running detection ON: While the start timer runs, the controller
checks whether Running detection is ON.
• When the controller detects that the genset is running, the genset
start is complete.
5. Crank on timer expired: If Running detection is OFF after the
Crank on timer runs out, the controller checks the number of start
attempts:
• If the maximum number of start attempts has not been reached,
the controller attempts to start the genset again.
• If the maximum number of start attempts has been reached, the
controller activates the Start failure alarm and stops the engine.
*Note: The optional Start prepare function is not shown here.
More information
See GENSET controller, Engine start, Engine start sequence for more information about these functions.
8.3.3 Engine start sequence
These sequence diagrams show the engine start sequence.
Engine start sequence for a stop coil system
In this example, the Engine > Start sequence > Stop coil > During crank off parameter is Activated. The engine speed (RPM
measurement) and/or the Remove start (release crank relay) digital input do not disengage the crank before there is Running
detection.
DESIGNER'S HANDBOOK 4189340911K UK Page 292 of 521
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