LLC44A4A - LLC4 Series

Series: LLC4 Questions? Contact Littelfuse Support
Littelfuse Liquid Level Controllers
The LLC4 combines resistance sensing circuitry with solid-state timing to provide single probe level maintenance. On adjustable units, the sensitivity adjustment allows accurate level sensing while ignoring foaming agents and floating debris. Isolated 12VAC is provided at the probe to prevent electrolysis. A trickle current of less than 1mA determines the presence or absence of conductive liquid between the probe and common. The LLC4 Series can be used with many types of low voltage (resistance changing) transducers to perform other control functions like temperature limit control, photo limit control, condensation sensing, and ice sensing.


Operation
Drain (Pump-Down Mode): When the liquid level rises and touches the probe, the time delay begins. This time delay prevents rapid cycling of the output relay and its load. At the end of the time delay, the output relay energize and remain energized until the liquid level falls below the probe level. The output relay de-energize and remain de-energized until the liquid rises and touches the probe.
Fill (Pump Up Mode): When the liquid level falls below the probe, the time delay begins. This time delay prevents rapid cycling of the output relay and its load. At the end of the time delay, the output relay energize and remain energized until the liquid level rises and touches the probe. The output relay then de-energize and remain de-energized until the liquid level again falls below the probe level.

Property (Mouseover for details) Value
Input Voltage (V) 120VAC
Input Tolerance (%) -0.3
Input AC Line Frequency (Hz) 50/60Hz
Output Type Electromechanical relay
Output Form Isolated SPDT
Output Load Rating (VA) 4A resistive @ 240VAC and 28VDC; 1/10hp @ 240VAC
Time Delay Range 4s fixed
Sense Voltage 12VAC at probe terminals
Sense Resistance (Ohms) Adjustable to 250kΩ
Sense Resistance Tolerance 1K ±500 Ω at low end; 250K ±25% at high end
Control Type ON/OFF (single level) resistance sensor with built-in time delay to prevent rapid cycling
Isolation Voltage (V) ≥1500V RMS between input output and probe
Surge Protection IEEE C62.41-1991 Level A
Termination Type Octal 8-pin plug-in
Mounting Method Plug-in socket
Operating Temperature -20° to 60°C (-4°F to 140°F)
Storage Temperature (F/C) -40° to 80°C (-40°F to 176°F)
Dimensions 2.91 x 2.39 x 1.78 in. (73.9 x 60.7 x 45.2mm)
Weight (lbs/g) ≅6.0oz (170g)