Evoqua Wallace & Tiernan SFC-SC, Manual, Page: 56 / 83

WT.050.590.002.UA.IM.0614 42
SFC ANALYZER / CONTROLLER
EVOQUA W3T109634
3.4.4 2-point pulse frequency Controller for pulse pumps
Pulse pumps are controlled with 0 to max. pulse rate per minute, depending
on the specification of the connected pump. The SFC-SC supports pumps with
100, 120, 140, 160 and 180 pulses per minute.
The pump is switched on for at least 0.15 s. The length of pauses between
operation is calculated on the basis of the dosing capacity.
Example for a solenoid pump with 120 pulses/min.:
yout
in %
100... 84... 72... 56 50... 33... 25... 10... 5...
pulses/
min
120... 101... 86... 67 60... 40... 30... 12... 6...
3.4.5 Analog Output Controller 2-point
The SFC-SC has an analog mA output. This can optionally be assigned either
as a monitor output or a controller output.
If "Analog output 2p" is selected, the mA output is permanently set as the
controller output, no monitoring signal is available.
At a controller output of 0%, the output current is 0 or 4 mA; at higher Yout
values, the output current can can be as high as 20 mA. Pumps with current
input, VFD and SCR drives 3-phase pumps or analog control valves can be used
as actuators.
3.5 parameters and Settings
Control parameters are settings used to specify the operating mode of the
SFC-SC. Different parameters apply, depending on the settings. The exact menu
displayed is dependant on the controller type selected.
NOTE: The control parameters are listed alphabetically.
flow Rate Direction
This parameter determines the direction of the flow rate signal directly
proportional to the actuator output:
Direct = flow rate input signal directly
proportional to positioner output
(factory setting).
Inverse = 1 flow rate input signal