Evoqua WALLACE & TIERNAN SFC, Original Instruction Manual

Page: 72 / 288

72
WT.050.590.000.DE.IM.0719
Functions
SFC
4.
Please note
If the measuring range end value of the flow meter is not identical
with the actual maximum flow rate, a factor for adjusting the flow
rate signal should be input in the menu „Inputs/Outputs“ - „Flow
Wq“.
For example:
Measuring range flow meter = 5000 l/h / max. flow rate = 2500 l/h
=> factor = 5000: 2500 = 2,0
The ratio between control variable and dosing output is
determined by the internal dosing factor (control
„Dos.Fact.Source“ = internal), or it can also be set by an external
mA/V input signal (Dos.Fact.Source = external).
You can switch between internal and external dosing factor (DF)
via the digital input ("Dos.Fact.Source" = "external with DI2" or
"internal with DI2").
It is possible that a second control variable „Measured Value X“
(measured value from module 1) will have a proportional or inverse
proportional influence on the single feed forward ("X-direction" =
direct / inverse variable).
The second control variable X is activated, if the parameter
“Control Variable2“ is set to "Measured Value X" (second control
variable deactivated by the „Off“ setting (factory setting).
The amplification factor for this parameter is defined by the X-
factor input parameter.
The controller output is calculated in this operating mode as
follows:
Yout = Wq x DF x (X-measured value x X-factor) x Yout-factor
Wq Control variable 1 flow rate in %
DF set dosing factor in %
X-measured value Control variable 2 measured value sensor measuring
module 1 in %
X factor Amplification factor for X measured value
Yout Determined controller output value %
Yout factor This factor gives the option of increasing the dosing
output by a dosing factor DF of 100 % when the
setpoint value is not reached, increase the dosing
output.
Setting range: 1.0– 4.0
Factory setting: 1.0
Please note
If this factor is increased, there is a danger that the setpoint value
will also not be reached with a higher flow rate value, because the
Yout value takes the value 100 % prematurely.