TT
Series
LR
Manual
Page
04
DISPLAY
Auto
Zero
.
.
.
Whenever
the
auto
zero
sequence
is
initiated
manually
or
at
preset
‘Auto
Zero
.
.
.’
will
be
displayed
until
the
cycle
is
complete.
Being
an
auto
ranging
instrument,
the
resolution
and
decimal
points
will
change
according
to
the
pressure
being
applied.
Slow4
Shows
which
mode
the
instrument
is
in.
Press
the
FAST
SLOW
key
to
change
the
mode.
7.7
m/s
Shows
the
unit
of
measurement.
Press
UNITS
to
toggle
between
units
of
measurement.
AvgVel
4.5
Shows
the average
velocity
of
the
readings
stored.
Store
10
Shows
the
number
of
readings
stored.
Up
to
2500
readings
can
be
stored.
TT
Series
LR
Manual
Page
04
PRESSURE
CONNECTIONS
Gauge
/
Duct
Static
Measurement:
Connect
to
Signal
In. Leave
Reference
open
to
atmosphere.
Readings
may
be
positive
or
negative
depending
on
whether
the
system
under
test
is
above
or
below
atmosphere
pressure.
Orifice
Plates:
Connect
upstream
tapping
to
Signal
In
and
downstream
tapping
to
Reference.
Pressure
readings
should
always
be
positive.
Flow
Grids:
Connect
+Ve
tapping
to
Signal
In
and
‐
Ve
tapping
to
Reference.
Pressure
readings
should
always
be
positive.
Inlet
Cones:
Connect
tapping
to
Signal
In
using
‘T’
pieces
to
join
the
annular
tapping
together.
Leave
Reference
open
to
atmosphere,
ensuring
that
the
open
port
is
shielded
against
significant
air
movement
from
the
ingoing
airstream.
Pressure
readings
should
always
be
negative.
Total
Head
Probe:
Connect
to
Signal
In.
Leave
Reference
open.
Readings
should
always
be
positive
dpm
‐
i
Pitot
Tube:
Input
the
Pitot
Tube
factor
0.838.
Connect
clear
tubing
to
Signal
In
and
black
tubing
to
Reference.
Use
UNITS
to
toggle
to
m/s
or
ft/min
depending
upon
model.
Readings
should
always
be
positive.
Ellipsoidal
Pitot
Tube:
Input
the
Pitot
Tube
factor
1.000.
Connect
clear
tubing
to
Signal
In
and
black
tubing
to
Reference.
Use
UNITS
to
toggle
to
m/s
or
ft/min
depending
upon
model.
Readings
should
always
be
positive.
Auto
Zero
.
.
.
Slow4
7.7
m/s
AvgVel
Store
4.5
10
