Evoqua Wallace & Tiernan SFC-SC, Manual, Page: 51 / 83

WT.050.590.002.UA.IM.0614 37
SFC ANALYZER / CONTROLLER
EVOQUA W3T109634
3.1.3 Safety functions
The following safety functions are integrated into the control unit if configured
accordingly:
• Safety shutdown if the feed container signal indicates it is empty
• Dosing time delay (D1)
• External stop with digital input
• “Positioner closed” function in the event of a power failure (only if posi-
tioner has external power supply)
• Password protection in one level
3.1.4 Configuration Switch-Over
The SFC-SC gives the option of either saving internally or loading all necessary
operating parameters as a configuration. A maximum of two configurations
are possible (Job1 and Job2). A digital input can be used to switch between
the two configurations.
3.2 mA Input on the IC Board
There is one integrated mA input on the IC board.
3.2.1 mA Input 1
This is used for recording the flow rate signal as 0–20 mA or 4–20 mA signal.
The input signal can be freely scaled in the menu.
3.3 Outputs
3.3.1 mA Output
The mA output of the SFC-SC is electronically isolated and can be parameter-
ized to 0–5 mA, 0–10 mA, 0–20 mA or 4–20 mA in the menu. The flow rate or
the Y
out
actuator control output can be assigned to the mA output.
3.3.2 Relay Outputs
The SFC-SC has two relays, each with a two-way switch. These switches
perform various switching tasks, depending on the selected actuator. The
relevant circuit diagrams are provided in section 2. In order to switch larger
inductive load, we recommend installing an additional contact such as a
contactor or load relay, in order to guarantee the contacts have a longer
service life.
The relay contacts are protected by RC circuits prior to shipment. These
provide radio interference suppression for inductive loads such as pumps,
motors, etc.