MULTICAL®
403
84
Kamstrup
A/S
∙
Technical
description
∙
5512
‐
1689_B1_GB_03.2017
7.6
Temperature
measurement
Inlet
and
outlet
temperatures
are
measured
by
means
of
an
accurately
matched
Pt500
or
Pt100
sensor
pair.
During
each
temperature
measurement
MULTICAL
403
sends
measuring
current
through
each
sensor.
The
current
is
approx.
0.5
mA
for
Pt500
and
approx.
2.5
mA
for
Pt100.
Two
measurements
are
carried
out
in
order
to
suppress
possible
50
Hz
(or
60
Hz)
low
‐
frequency
noise
picked
up
via
the
sensor
cables.
Furthermore,
current
measurements
are
made
by
internal
reference
resistors
in
order
to
secure
optimum
measuring
stability.
The
display
presents
inlet
and
outlet
temperatures
as
well
as
temperature
difference
in
range
0.00
C
to
185.00
C.
Inlet
or
outlet
temperatures
below
0
C
and
above
185
C
are
indicated
as
lines
in
the
display,
but
serial
reading
includes
0.00
C
and
185.00
C
respectively.
If
one
or
both
temperature
sensors
are
outside
measuring
range,
the
info
code
is
set
as
shown
in
the
next
paragraph.
At
negative
temperature
difference
(inlet
outlet)
the
temperature
difference
is
displayed
with
a
negative
sign
and
cooling
energy
is
calculated.
It
depends
on
the
selected
DDD
‐
code
whether
this
appears
from
the
reading
in
the
display.
Measuring
current
and
power
Measuring
current
is
only
sent
through
the
temperature
sensors
during
the
short
duration
of
the
temperature
measurement.
The
effective
power
that
is
deposited
in
the
sensor
elements
is
thus
very
small,
and
its
influence
on
self
‐
heating
of
the
temperature
sensors
is
typically
less
than
1/1000
K.
Pt100
Pt500
Measuring
current
2.5
mA
0.5
mA
Peak
power
1.0
mW
0.2
mW
RMS
influence
(fast
mode)
10
W
2
W
RMS
influence
(normal
mode)
2
W
0.4
W
Average
temperatures
MULTICAL
403
currently
calculates
the
average
temperatures
of
inlet
and
outlet
(t1
and
t2)
in
C
without
decimals,
and
background
calculations
E8
and
E9
(m
3
x
t1
and
m
3
x
t2)
are
carried
out
with
every
volume
calculation
(e.g.
with
every
0.01
m
3
if
the
meter
size
is
qp
1.5),
whereas
the
display
is
updated
with
every
integration
(depending
on
L
‐
code).
The
average
calculations
are
thus
volume
weighted
and
can
be
used
directly
for
checking
purposes.
