Burkert Type 8741 - Manual (Page 27)

27
Operationandfunction
Type 8741
9.6 functions
9.6.1 AUTOTUNE function
Function optimisation of the MFC control parameters.
For the MFC, the AUTOTUNE function is conducted at the
factory. This is done at the operating pressure and with the
calibration medium specified in the calibration protocol.
A re-run of this function is not normally necessary.
However, a re-run of the
AUTOTUNE function is required in
the following cases:
• If the pressure conditions in the installation have changed.
• If the operating medium is not the same as the calibration
medium.
description:
With the
AUTOTUNE function, the control parameters for the device
which are dependent on the conditions of the installation, are calcu-
lated and optimised.
The proportional valve is activated according to a pre-defined scheme,
by which the mass flow changes. Certain control parameters are then
adapted to local conditions. Optimisation is carried out according to
the criteria for as short a recovery time as possible, without overshoot.
Warning!
danger from flowing gas.
While the
AUTOTUNE function is running, the gas flow may be
greater than the nominal flow.
▶ Before running AUTOTUNE, check whether a hazard could arise
through an increased gas flow and take appropriate measures
to ensure safety.
during the AUTOTUNE:
→
Do not interrupt the power supply to the MFC.
→
Keep the supply pressure constant.
The AUTOTUNE function is triggered via the fieldbus. (See
operating instructions "Digital Communication, Type 8741").
• During the running of the AUTOTUNE function, the LED on the
device is lit green.
• The flow control of the MFC is suspended.
• After completion of the
AUTOTUNE, the device returns to its previous
operating state.
• After successful running of AUTOTUNE, the optimised control set-
tings are transferred to the hard memory of the device.
English