MODE
OF
OPERATION
TT
Series
LR Manual
Page
03
On
/
Off:
Press
and
hold
ENABLE
then
press
ON
or
OFF
as
appropriate.
Auto
Zero:
The
cycle
will
begin
as
soon
as
the
instrument
is
switched
on.
This
is
factory
set at
a
30
second
interval
upon
switch
on
and
thereafter
at
60
second
intervals.
To
change
this
timing
see
User
Menu
page
05.
The
instrument
contains
a
miniature
solenoid
valve,
which
isolates
the
pressure
sensors
during
auto
zero.
The
valve
emits
two
clearly
audible
clicks,
which
signal
the
start
and
end
of
the
auto
zero
process.
Battery
Low:
The
battery
condition
is
monitored
every
time
the
instrument
auto
zeroes.
When
the
‘battery
low’
warning
appears,
the
battery
must
be
replaced
immediately,
otherwise
the
readings
obtained
will
be
unreliable.
If
at
any
time
the
readings
seem
suspect,
check
the
condition
of
the
battery
by
zeroing
the
instrument
manually
using
ZERO.
If
in
doubt
replace
the
battery.
For
rechargeable
instruments
charge
the
internal
battery
with
the
charger
supplied.
Units:
The
unit
of
measurement
is
shown
on
the
right
hand
side
of
the
display.
Being
an
auto
ranging
instrument,
the
correct
resolution
and
the
decimal
point
will
be
displayed
according
to
the
pressure
being
applied.
FAST
SLOW:
Some
pressurised
circuits
exhibit
pressure
and
velocity
fluctuations,
which
can
be
disconcerting;
if
unacceptable
fluctuations
occur,
press
FAST
SLOW
and
verify
that
the
slow
indication
is
displayed
on
the
screen.
Store:
Shows
the
number
of
readings
stored
on
the
instrument.
To
store
data
manually
press
STORE
while
the
instrument
is
in
Slow1,
Slow2,
Slow3
or
Slow4
mode:
the
reading
on
the
display
will
be
logged
and
the
counter
will
increase
by
one.
During
data
logging
the
counter
will
increase
by
one
every
time
the
instrument
records
a
value.
For
information
on
data
logging
see
Option
Menu
pages
08
and
09.
Audible
Feedback:
While
the
instrument
is
on,
audible
feedback
can
be
heard
every
time
a
key
is
pressed.
Signal
In
/
Reference:
Pressure
ports.
The
instrument
responds
to
positive,
negative
and
differential
pressure.
RS
232
Port:
Is
located
between
the
two
ports.
