Operating Modes; Normal Control Mode - Burkert 8626 Instructions De Service

è Make sure the inlet pressure does not exceed the maximum value stated on
the rating plate.
è On running up the installation, raise the pressure as continuously as possible
to the operating value and avoid abrupt pressure impulses.
è Make the electrical connections according to the scheme given in
Section 2.3.
è Always connect the PE terminal with an earthing point in the interest of
protecting the equipment from interference.
After switching on the power supply, the MFC Type 8626 is ready for operation after
a few seconds.
NOTE After switching on the supply voltage, the MFC works correctly after
approximately 5 seconds. With high flow rates there may be, due to
thermal equilibration processes, drifts in the resulting flow within a
few parts per thousand within the first 10 minutes of operation.
3.4

Operating modes

3.4.1 Normal control mode

This is the mode in which the MFC Type 8626 operates immediately after switching
on. In the LED display area on the front panel, only the green power LED lights.
The flow rate is adjusted to the preset value with a high dynamic ratio. Disturbances,
e.g. as a result of pressure variations, are rapidly compensated by a corresponding
adjustment of the control valve position.
NOTE At set values < 2% Q
correcting variable limits determined by the autotune function,
transmit a pulse-duty factor of zero to the valve, in order to assure
tight closure.
The responsiveness of the MFC Type 8626 with small changes in set value is
determined by the responsiveness of the valve and the resolution of the A/D
converter. Under normal operating conditions, it amounts to a few tenths of a
percent.
Operating Instructions-No. 801 147
, the control electronics, independent of the
nom
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