Atlas Copco QAS 275-325, Instruction Manual

Page: 48 / 114

- 48 -
Standard modes
The unit has four different running modes and one
block mode. The required mode can be selected via
the MODE puhbutton. Repeat pushing the button
until the required mode appears on the display, then
press SEL to select or BACK to cancel.
This screen appears when pressing the MODE
puhbutton.
Auto mode
In this mode the Qc4002™ controls the gen-set and
the circuit breakers (generator breaker GB and mains
breaker MB) automatically according to the
operational state.
Semi-Auto mode
In semi-auto mode the operator has to initiate all
sequences. This can be done via the pushbutton
functions, modbus commands or digital inputs. When
started in semi-automatic mode, the gen-set will run
at nominal values.
Test mode
Enables the user to test the generator on a regular
basis. The generator will follow a predefined
sequence of actions.
In this mode it is possible to perform the following
tests:
– Simple test
– Load test
– Full test
Manual mode
When manual mode is selected, the gen-set can be
controlled with digital inputs.
Block mode
When the block mode is selected, the unit is locked
for certain actions. This means that it cannot start the
gen-set or perform any breaker operations.
To change the running mode from the display, the
user will be asked for a password before the change
can be made. It is not possible to select ‘block mode’
when running feedback is present.
The purpose of the block mode is to make sure that
the gen-set does not start for instance during
maintenance work. If the digital inputs are used to
change the mode, then it is important to know that the
input configured to block mode is a constant signal.
So, when it is ON the unit is in a blocked state, and
when it is OFF, it returns to the mode it was in before
block mode was selected.
MAN mode cannot be selected,
when AUTO mode is selected. To go
from AUTO to MAN it is necessary
to go to SEMI-AUTO to make MAN
available.