Burkert 8626 - Page 46

46 - MFC/MFM
english
Problem Possible cause Remedy
Process value varies No porper FE connection Connect the FE to the earthing
point (as short as possible,
wires min. 2.5 mm²).
Controller must
continuously correct
disturbances in an unstable
pressure supply.
Install a suitable pressure
regulator upstream.
Residual ripple of supply
voltage too high.
Select a suitable voltage
source.
Controller tends to
oscillate
Operating pressure lies far
above that at which the last
Autotune was executed.
Execute an Autotune to adapt
to the operating conditions.
Control parameters do not
correspond to the section
behaviour.
Adapt the control dynamics
with the PC software
MassFlowCommunicator.
A medium is being used
other than that intended on
calibration.
Return the device to the
manufacturer for recalibration
for the operating medium.
Residual ripple of supply
voltage too high.
Select a suitable voltage
source.
Setpoint value w = 0,
flow still present after
a few seconds
Operating pressure above
the leak-tight pressure of
the proportional valve.
Lower the operating pressure.
Setpoint value w = 0,
valve closed, no flow;
but process value
output shows a small
flow
Operating pressure
significantly higher than
that used for calibration
(→ increased intrinsic con-
vection, only with 8716 and
8626)
Execute an Autotune to adapt
to the operating conditions.
Incorrect installation
position
(→ increased intrinsic con-
vection, only with 8716 and
8626)
Install the MFC in the position
calibrated or execute an
Autotune to adapt to the
operating conditions.
A medium is being used
other than that intended on
calibration.
Return the device to the
manufacturer for recalibration
for the operating medium.
Controller shows
strong overswing
starting after a step
in the setpoint of 0%.
On using an aditional
isolation valve, the drive
sequence was not adhered
to.
See Section Operation with an
Additional Isolation Valve.
In the case of flame
control, the flame
extinguishes after a
step in the setpoint.
Flame is starved of oxygen
because medium
concentration too high.
Activate the ramp function with
the PC software
MassFlowCommunicator.