TR250Z Oxygen Transmitter – Manual
CO2Meter.com
Rev. 27 April, 2015
Pg. 10 of 13
Theory of Operation
The
zirconia
oxygen
sensor
utilizes
solid
‐
state
electrochemical
reactions
to
produce
a
voltage
proportional
to
the
current
oxygen.
This
voltage
is
then
digitalized
and
filtered
to
a
usable
value.
The
oxygen
sensor
has
also
been
factory
calibrated
to
meet
specifications.
Calibration
The
calibration
process
varies
depending
on
the
type
of
unit
and
whether
it
has
optional
data
logging
functionality
or
not.
All
units
are
factory
‐
calibrated
with
multiple
reference
points
of
gas,
and
have
been
verified
to
be
accurate
within
their
specific
functionality
before
shipment.
However,
if
the
unit
is
severely
jolted
or
otherwise
mechanically
disturbed,
the
sensor
can
drift
requiring
recalibration.
All
calibration
procedures
follow
a
single
‐
point
calibration
routine
that
effectively
shifts
the
zero
‐
point
of
the
O2
sensor.
Calibrating using MODBUS or PC Connection
You
can
Download
the
software
directly
and
free
from
this
link
in
our
website.
(http://www.co2meter.com/pages/downloads)
More
precise
calibrations
can
be
performed
using
the
PC
connection.
The
unit
can
be
attached
to
a
PC
using
an
optional
USB
to
RS
‐
485
cable,
available
on
our
website,
or
via
a
mini
‐
USB
cable
to
the
internal
USB
connection.
Calibration
of
the
Oxygen
Sensor
In
the
desktop
software
application
O2
can
be
calibrated
individually.
The
O2
sensor
can
be
calibrated
to
0%
and
then
to
20.9%.
During
normal
operation
0%
calibration
of
the
oxygen
transmitter
should
not
be
necessary.
Calibration
can
also
be
performed
over
MODBUS,
see
additional
documentation
for
MODBUS
registers.
