28 GC250 Technical Manual
EAAM057608EN
5.5
INFORMATION!
To configure the T.09 for the +D connection at recharge alternator
energizing you need to configure the parameter P.4041 with the value AIF.1300
– “Signal
D+”. To use the T.09 for functions not correlated to D+ refer to par. 5.6.1, 5.5.2, 5.7.2 and
correlated. The output is configured by default as AIF.0000
– “Unused”.
When the controller starts the engine, the
T.09
terminal supplies the necessary power for
energizing the battery recharge alternator.
With engine and alternator are idle, the D+ terminal of the alternator is practically a short circuit
to the battery minus and the voltage at its ends is close to 0V. During and after engine starting,
as well as under normal operating conditions, with the revolution of the recharge alternator,
the +D voltage rises up to the value of the battery voltage. When the engine stops, or even if
only the recharge alternator stops because of the breakage of the drive belt, the +D voltage
returns to 0V. The same thing happens in case of malfunction of the alternator.
The power supplied with the alternator idle is internally limited and it is around 200mA for 12V
systems and around 100mA for 24V systems; the selection of the current level is automatic.
The energizing command is activated on the engine start command.
During the engine start cycle, up to when the engine is no longer acknowledged as started
with a method whatsoever (voltage, frequency, rpm, D+ voltage, oil pressure), the command
is kept active for 30s continuously and then is deactivated/activated every 5s (5s ON followed
by 5s OFF) until the starting sequence ends. When the engine is acknowledged as started,
the command is kept active for 5 more seconds and then released.
Still through
T.09
, the controller measures the +D voltage of the recharge alternator, both
during engine start and during its operation. It is displayed in the S.15 menu, under item D+.
The voltage measure can be used for two purposes:
Engine running/stop detection
Usually the recharge alternator is driven by the drive shaft through a drive belt.
Normally, the drive belt also drives other mechanical components of the engine, for
example the cooling fan of the radiator. If during engine operation the +D voltage of
the recharge alternator drops below 0V or if it does not rise after start, once the P.0349
time is up, it is assumed that the belt is broken or at least that there is a malfunction
and the controller activates the anomaly AL.005 (“A005 – Broken belt”) that can be
configured with the parameter P.0357 (as warning, deactivation or lock) to protect the
engine from the lack of operation of the mechanical parts driven by the belt.
Using parameters P.0230 and P.0231 it is possible to enable/disable the acknowledgement of
engine started by D+ signal; by using the parameter P.0349 it is possible to disable the AL.005
anomaly(“A005 – Broken belt”) (see document [1]).
