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6.6.8 Protective Functions
・ In a multi-system with two or more inverter units, if any one of the inverter enters an alarm state due to some
reason, continuing operation with the remaining unit(s) may not be able to provide sufficient torque and normal
operation of the system may not be possible. To prevent this situation, the multi-system puts all inverters linked
via the high-speed serial communication-capable terminal block in the alarm state in a moment (within several
milliseconds). You also need to design a sequence to stop all the inverters using 30X (Batch alarm output).
・ After the inverter protective function has acted and the cause has been removed, giving the alarm reset signal
with the operation command ON (closed) will start the inverters. To prevent an injury, check that the operation
command is OFF (open) before giving the alarm reset signal.
・ If the optical cable connecting the inverters get broken during operation, correct operation becomes impossible
and the inverters are forced to enter the alarm state (inter-inverter link error
erb
). The motors will coast to
stop. This alarm does not act while the inverter is stopped.
6.6.8.1 Process in Protective Operation
(1) Batch alarm process
When the master inverter unit enters the alarm state, the alarm is indicated on all stations via the
optical link, the 30X operation is executed, and the inverters are shut down.
* "
o
" (other station) is shown for alarm indication on the slave inverters.
Example: Inter-Inverter Link Error (
erb
)
Master inverter unit alarm indication :
er6
Slave inverter unit alarm indication :
oer6
When a slave inverter unit enters the alarm state, the alarm is indicated on all stations via the optical
link, the 30X operation is executed, and the inverters are shut down.
* "
o
" (other station) is shown for alarm indication on the master inverter.
Example: Inter-Inverter Link Error (
erb
)
Master inverter unit alarm indication :
oer6
Slave inverter unit alarm indication :
er6
(2) Reset process
When giving the reset command from the master, all stations are batch reset if the alarm cause has
been removed.
When giving the reset command from a slave, all stations are batch reset if the alarm cause has been
removed.
(3) Disabling disconnection detection
The slave inverter unit does not require feedback of the PG and NTC signals. Therefore, on an
inverter configured as a slave in a multi-system, PG and NTC disconnection detection is disabled.
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