15 Base Load Sequencing (BLS) (Optional)
Gardner Denver
62
In the event of a line pressure sensor fault (Fault E406),
the master can no longer control the group and shuts
off the BLS until the fault is removed and reset.
Note
If the master compressor shuts down because of a fault
other than a line pressure sensor fault, or if it is shut
down manually, the master will continue to control the
sequencing.
Once the line pressure exceeds the defined maximum
line pressure, the compressor at the far right in the
sequence will be shut down. As long as the maximum
line pressure is exceeded, the system will continue to
shut down further compressors consecutively in short
time intervals.
If the line pressure drops below the defined minimum
line pressure, the next available compressor will be
started up immediately, followed by more compressors
in a set period of time (Start Delay) if the line pressure
remains low.
: The rotational speed regulated compressor(s)
regulate(s) the line pressure within the available
rotational speed range, to be exactly between the
minimum and the maximum line pressure. If the
pressure band limits are reached, compressors are
started up and shut down as described above.
Several
compressors: Speed-regulated compressors
will run approximately at the same rotational speed and
load if their size is approximately the same. After a
manual restart of a compressor (e.g. after service), the
rotational speed may be asynchronous until the
compressor has achieved its minimum or maximum
rotational speed limit.
15.11.2 Establishing a new Sequence based on
Operating Hours (BLS)
Whenever the transfer interval period has elapsed, the
BLS master establishes a new sequence order on the
basis of the operating hours (BLS) of the compressors.
The compressor with the lowest operating hour count
(BLS) is placed in first position in the sequence and so
on.
Single
compressor: For economic reasons, the
speed-regulated compressor will always stay in first
position, whereas the fixed-speed slaves will have their
sequence order changed periodically.
The freely adjustable operating hour (BLS) counters
can be used to manipulate the sequence if necessary,
for example if a new compressor is installed alongside
older ones.
Example 1
Example 1
Compressor 1
Compressor 2
Operating hours
(actual)
1000 h
1 h
Operating hours
(BLS)
1000 h
1 h
Operating hours (BLS) are set to the same figure as the
actual operating hours. The new Compressor 2 will run
on base load position for about 1000 h, as it has the
lowest running hour (BLS) count. Afterwards, both
compressors alternate in sequence.
Example 2
Example 2
Compressor 1
Compressor 2
Operating hours
(actual)
1000 h
1 h
Operating hours
(BLS)
1000 h
1000 h
Operating hours (BLS) were modified to integrate
Compressor 2 and the alternating sequence for the two
compressors starts immediately.
15.12 BLS Trend and Statistic Graphs
If the Base Load Sequencing feature is activated, two
other pages can be viewed in the “Trends” tab
:
Total delivered volume flow (BLS) of the group
Statistical weekly profile (BLS) of the group
VS
VS
VS
