Burkert Type 8712 - Manual (Page 37)

37
Operationandfunction
Type 8626, 8712
8.3.1. standard control mode
In this operating mode, the flow-rate is controlled to the specified
set-point value with a high dynamic.
The MFC is in this operating mode once energized, after a brief
initialization phase. The green power indicator is on.
The set-point value is specified via the analogue input or the field bus,
depending on the device version.
The controller settings are set in such a way that set-point value
changes or actuating variables are corrected as quickly as possible
without appreciable overshoot occurring.
The measured flow-rate value is available on the analogue output or
the field bus, depending on the device version.
For the MFC:
If the blue Limit (y) LED is on, this means that the control
signal of the solenoid control valve is approaching the
100% limit (see section „9.3“).
The cause may be:
• either an insufficient pressure difference over the MFC,
for example an insufficient inlet pressure,
• or a dirty inlet filter
This means that the set point cannot be achieved and a
difference between the set point and the measured value
(w-x) exists.
For the MFM:
If the blue Limit (y) LED is on, the measured mass flow is
approaching the nominal flow-rate or has even exceeded it
(see section „9.3“).
If a high exceeding of the nominal flow rate occurs, a
difference between the measured and the real flow rates
may appear.
To permit an external reaction to this gap, a binary output
is activated.
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