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Table 1 Software options for evaluating digital Mass Flow Controllers
2.2.
Analog interface
To operate a Mass Flow Controller with an analog interface (SFC54XX), you need:
•
a tuneable power supply as setpoint source, being able to deliver 0-5V, 0-10V or 4-20mA, depending on the
version of the analog Mass Flow Controller
•
a DB9 cable to connect the Mass Flow Controller to a 15-24V power supply
•
a multimeter or an oscilloscope to measure the flow signal
3.
Testing recommendations
It is recommended to start by testing the communication with the device, using the EK-F5x Evaluation Kit and the Viewer
software. The baud rate and address of the device with the viewer software can easily be changed if necessary.
As a second step, connect the device to a gas supply (or a source of vacuum). For best accuracy, mount the Mass Flow
Controller horizontally and use the same pressure as during factory-calibration (specified in the datasheet, by default for
most products 3 bar inlet vs outlet).
If the Mass Flow Controller is mounted vertically, the chimney effect can adversely impact the accuracy at low flows and
especially at zero flow. It is possible to use Sensirion recalibration software to compensate for that effect. The
“R
ecalibration
software”
can be downloaded from the Sensirion website
and is also linked in the “Useful resources”
. In this
case, you will have to calibrate the mass flow controller yourself in the chosen orientation.
Try using different setpoint steps to test the Mass Flow Controller. If the chosen
setpoint can’t be
reached, try increasing
the supply pressure, removing fluidic resistances like filters, or using tubes with a larger diameter. If the supply pressure
used is significantly lower than the calibration pressure, the controller can be slower than expected. On the other hand, if
the supply pressure is significantly larger than the calibration pressure, the Mass Flow Controller may become unstable. In
these cases, lowering or increasing the user gain to adapt the controller accordingly. This can be done conveniently with
the Viewer Software. For detailed instructions, see the
“
Viewer Software Manual
”, linked in “Useful resources”
SFC5xxx/SFM5xxx Viewer software
L
C/C#/Python library
for quick evaluation
plug-and-play software
no coding required
no custom cabling required
for more flexible testing and prototyping
custom coding required
custom cabling recommended for
C/C#/Python
Figure 1 Different options for evaluating digital Mass Flow Controllers
