Version: TCM_0450_E80_M_EN_150209_E007
33
Manual Operation
4.1.1.
Using the Magnet
The explosion-proof variants with the blue Ex d housings provide a magnet to be able to operate the
pushbuttons without opening the display cover.
In hazardous, wet and dusty areas the display cover must not be opened to operate the pushbuttons.
Beside every pushbutton there is a hall sensor which can be operated via the magnet attached to the housing.
For operating the pushbuttons hold the magnet to the glass.
The best positions for operating the keys are:
Pushbutton
Position
P
left upper edge of the yellow area
Reset
lower edge of the yellow area
Display
lower edge of the yellow area
Info
lower edge of the yellow area
NOTE:
The P button cannot be operated with the magnet with the
“Custody Transfer” option!
4.2.
Setup Guidelines
Ex factory the TRICOR Mass Flow Meters come with a setup optimized for normal applications. In more than
90% of the applications no further optimization except a regular offset adjustment is required.
The different possibilities for optimizing the settings are described below.
4.2.1.
Offset Adjustment
In contrast to a positive displacement meter, a Coriolis Mass Flow Meter does not have a
“natural” zero. At no
flow the measured time shift is nearly zero, but not exactly. The offset adjustment determines this offset and
corrects the measured value correspondingly.
As the offset depends slightly upon the temperature, the density of the medium and the operating pressure, it is
strongly recommended to make the offset procedure under working conditions, i.e. with the medium to be
measured and at operating pressure and temperature.
To execute an offset adjustment, please refer to chapter 4.4 and 4.5.3.
4.2.2.
Flow Filter
The raw data of a mass flow meter is relatively noisy. To get a stable reading a filtering of the calculated flow is
required.
The filters in the TCE 8000 are set by means of the time constant
t
. The time constant is the time the output
needs, after a jump from a value
x
to 0, to go to
x
/
e
=
x
/2.72. A higher time constant means more stable
reading, but also a slower reaction to changing flows.
A rough relation between the time and the filtered flow value after a jump is:
