Evoqua WALLACE & TIERNAN SFC SC, Original Manual

Page: 25 / 82

SFC SC
Functions
4.
25
4.4 Controller outputs
Controller types
Positioner (with feedback)
By selecting the positioner it is also possible to perform chlorine
feed in combination with a positioner that operates as an actuator
in a chlorinator.
If positioner feedback is available, it must be calibrated during
commissioning. Potentiometer 1 KOhm/5 KOhm or 0 – 1 V or 0/
4 – 20 mA signals can be connected as positioner feedback (see
section 4.7 “Actuator feedback”). It is possible to linearize the
actuator using several calibration points.
2-point pulse
length controller
for dosing pumps
The dosing pump is switched on for the calculated time within an
adjustable cycle period TP (relay contact). The cycle period is
mainly determined by the reaction time of the connected system
and entered as the cycle period TP.
Controller for Type
Parameter
description
Action
Positioner with feedback 3-point Positioner with Ym Dosing

or

Motor dosing pump (pulse duration
controller) 2-point Dosing pump 2p Dosing

or

Pulse pump (pulse frequency controller) 2-point Pulse pump 2p Dosing

or

Dosing pump with mA-input 2-point Analog output 2p Dosing

or

Example: Cycle period TP = 100 s
Output value Yout = 30 %
Duty cycle 30 s
Off duty cycle 70 s