O
PERATION
M
ANUAL
P
ROMO
®
2000
P
ALAS
®
G
MB
H,
M
ARCH
2010,
V
ERSION
V001032010
19
4.2
Calibration
of
the
velocity:
The
objective
that
has
to
be
achieved
hereby
is
to
change
the
velocity
(preset
velocity)
to
the
measured
velocity.
You
measure
the
velocity
by
moving
the
red
cross
into
the
right
maximum
within
the
time
chart.
If
the
gas
density
of
your
measured
aerosol
doesn't
change
you
do
not
have
to
calibrate
the
velocity.
However,
during
a
calibration
procedure
one
should
always
compare
the
old
particle
velocity
with
the
new
particle
velocity
as
a
large
deviation
gives
also
an
indication
for
a
leakage
in
your
suction
tubes
or
a
problem
with
your
suction
pump.
In
case
you
have
a
pressure
‐
resistant
sensor,
e.g.
welas®
sensor
2070
P,
or
a
pressure
‐
resistant
and
heatable
sensor,
e.g.
we
‐
las®
sensor
2070
HP,
and
if
the
pressure
or
temperature
conditions
change,
you
have
to
calibrate
and
adjust
the
particle
velocity
as
well.
Always
try
to
calibrate
your
sensor
with
CalDust
1100
at
the
same
pressure
and
temperature
conditions
as
your
subsequent
measurements.
However,
sometimes
it
is
not
possible
to
calibrate
your
sensor
with
a
calibration
dust
at
the
same
thermo
‐
dynamic
conditions.
For
this
reason,
you
can
also
adjust
the
velocity
without
re
‐
adjusting
the
pho
‐
tomultiplier
amplification
and
without
using
a
calibration
dust.
However,
the
particles
have
to
be
larger
than
0.4
µm.
If
you
adjust
the
PM
amplification,
the
velocity
should
not
change.
Alternative
‐
ly
you
can
activate
the
automated
gas
density
correction.