EAAM057608EN
GC250 Technical Manual 103
windows of supply (see par. 9.3), once the delay set in P.0218 has expired, the controller
commands the load switching.
It is possible, through parameter P.0248 to define when the MCB circuit breaker must be open:
▪
0 (default): MCB is only opened when the generator is ready to supply.
▪
1: MCB is opened immediately after the “mains failure delay”, still before starting
the engine. It is useful as protection for the loads in case the mains is not totally
absent, but simply out of tolerance.
9.6.4.1
Change-over switch.
Only for SSB plant type (single genset in emergency to the mains)
: the controller is able
to command a switch instead of breakers. To do so, it is enough not to configure any output
for MCB command. Use the “GCB Stable Close Command” (DOF.2034) to command the
switch.
In addition, it is possible to configure a minimum time before which it is not possible (not in
manual mode, nor in automatic) to invert the command of the switch (P.0220
“Time of
maintenance switch command”). This is useful because if the command is inverted during the
movement phase, with some type of power switches it is possible that they lock themselves,
and a manual action will be required to unlock them.
9.6.4.2
Switching management with circuit breakers
In case the controller commands both the MCB and GCB circuit breaker, the device, if there
are adequate conditions on mains and generator, opens the other breaker first and then closes
the desired breaker. In this case, it is possible to configure the duration of the pause with both
switches open, by means of P.0219
parameter (“contactors controls exchange time”).
9.6.5
MAN or TEST management logic
With operation in
MAN
, the switching is manually commanded through a digital input
configured with function
•
DIF.2041
“”Request of load taken in manual”
To which a selector or a switch NO must be connected, with position of steady
opening/closing. Activating and keeping the input active, the opening of MCB and the
subsequent closure of GCB is commanded to supply the generator loads; deactivating the
input, the opening of GCB and the closure of MCB are commanded.
Alternatively, it is also possible to connect some external buttons NO of breakers
opening/closing to the digital inputs of the controller. The controller will use these inputs (only
in
MAN
) exactly as:
DIF.1001 -
“GCB close command”.
DIF.1002 -
“GCB open command”.
DIF.1031 -
“MCB close command”.
DIF.1032 -
“MCB open command”.
It is possible to command the circuit breakers with only two NO buttons on the outputs
configured with the two closure commands IF.1001 and DIF1031; by pressing the button, you
command the closure of the responding breaker (and the opening of the other, if closed). If
you press it once again, you command the opening of it (but never the closure of the other
breaker). The logic of the controller impedes to have both the breakers closed.
It is possible to manage the breakers using Modbus commands via USB. To send the
commands you need to write in sequence (within 5 seconds):
▪
HOLDING REGISTER 101: write the password configured with the parameter
P.0004.
