MASS-STREAM
TM
Instruction Manual D-6300
9.17.104B
– Date of issue: 2018-12
Page 11 off 34
2.3 Operation and Maintenance
When the power is switched on a warm-up period of at least 30 sec is required allowing
the
instrument’s thermal stabilisation. Afterwards the instrument will work with an
accuracy of approximately 4% FS. It takes around 30 minutes until the optimal stability is
reached and the instrument will work with an accuracy of < 2% FS. This is supposed to be
performed with or without gas flow. To avoid creating gradients it is recommended that
gas and ambient temperature are kept at the same level
(max ΔT approx. ± 2…3 °C).
Otherwise the accuracy of this thermal measurement could be affected in an
unpredictable manner.
Be sure that the specified pressures have been applied. Pressure surges, as may occur
during the system pressurisation, must be avoided. The control valve cannot be used as a
shut-off valve. When starting up, always bring the instrument gradually up to the level of
operating conditions.
There are no regular maintenance checks
required for the instrument’s operation. It has to
be ensured that a possible mounted inline filter is checked and cleaned on a regular
basis. We recommend having the calibration checked every 24 months by the supplier or
an authorized service partner.
2.4 Functional Block Diagram
Mass flow meter DMFM
The sensor signal is digitised via ADC and processed internally. Being reconverted from
digital to analogue the signal is forwarded as reading on the analogue output by means of
current or voltage. The reading is also available as 2-byte integer at parameter 8 and can
be readout via RS232.
Mass flow controller DMFC
For mass flow controllers the setpoint is added to the above process. The setpoint is
either processed as analogue signal or as 2-byte integer via RS232 (or fieldbus).
