Operating Modes Of The Mfc; Standard Control Operation; Autotune Routine - Burkert 8626 Instructions De Service

Operating modes of the MFC

Standard control operation

This is the operating mode in which the MFC finds itself after being switched on
and after a short initialization phase. In the LED group, only the green Power LED
lights.
The flow rate is controlled to the setpoint with high sensitivity. Disturbances such
as those resulting from pressure variations are rapidly corrected by suitable
adjustment to the aperture of the control valve.
In this mode, the setpoint is set via the analog input (standard signal input) or the
field bus, depending on the version of the device.
The controller parameters are set such that changes in the process value or
distrubances are corrected as fast as possible without significant overswing being
caused.
NOTE
When the driving signal of the control valve approaches the
100 % limit, the LIMIT (y) LED lights. The cause is usually that
the pressure difference over the MFC is too small, e.g. because
the pressure supply is insufficient or the filter is heavily
contaminated. This can lead to non-achievement of the setpoint
and an enduring positive actuating signal (w-x). To enable an
external reaction to be made to this situation, a relay output is
actuated in addition.

Autotune routine

A prerequisiste for the automatic adaptation of the controller to the conditions in
the system is that the typical pressure conditions pertain.
Initiate the Autotune routine by operating the binary input 1.
The Autotune routine runs automatically. During this operation, the green POWER
LED flashes.
ATTENTION!
Observe the following points while the Autotune routine runs:
Various changes in flow occur.
The power supply of the MFC must not be switched off.
The supply pressure should be kept constant.
While the Autotune routine runs, the MFC does not control. The control valve is
driven according to an internally specified scheme. This leads to flow changes,
whereby some of the control parameters are adapted to the conditions pertaining
in the system. At the end of the Autotune routine, these parameters are stored in
the non-volatile memory of the device.
After completion of the Autotune routine, the MFC returns to the previous
operating mode.
MFC/MFM - 41