Liquid Level Control LLC4 Series Single Probe Description 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. Transformer isolated 12 V AC is provided at the probe to prevent electrolysis. A trickle current of less than 1 mA determines the presence or absence of 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 Connection Drain (Pump Down Mode): When the liquid level rises and touches the probe, a fixed 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 Single Probe Level relay energizes and remains energized until the liquid Control for Conductive level falls below the probe. The output relay then de- Liquids energizes and remains de-energized until the liquid Adjustable or Fixed again touches the probe. Sensing up to 250KΩ Fill (Pump Up Mode): When the liquid level falls below Fill or Drain Operation the probe, a fixed time delay begins. This time delay Available prevents rapid cycling of the output relay and its load. 24, 120, or 230 V AC At the end of the time delay, the output relay energizes Relay contacts are isolated. Dashed lines are Models are Available and remains energized until the liquid level rises and internal connections. Isolated AC Voltage on touches the probe. The output relay then de-energizes the Probes and remains de-energized until the liquid level again Connect common to conductive tank. Additional 4 A Resistive SPDT falls below the probe. probe is necessary for non-conductive or insu- Isolated Contacts lated tanks. P = Probe C = Probe Common V = Voltage Approvals: Accessories Panel mount kit P/N: BZ1 Octal 8 pin socket P/N: NDS-8 Hold down clips P/N: PSC8 Ordering Table Electrode X X X X LLC4 P/N: PHST-38QTN Series Input Operation Time Delay Sense Resistance (Seconds) –2 - 24 V AC –A - Drain –A - Adjustable –Specify fixed delay Level probe P/N: LLP-24 –4 - 120 V AC –B - Fill (1 ... 60) secs. in –F - Fixed –6 - 230 V AC 1 s increments Specify fixed resistance (1 ... 250) in 1K Ω increments See accessory pages for specifications. Example P/N: LLC44A1A Fixed – LLC46B5F50 9.6 Low Voltage Products & Systems 1TRC 001 009 C0202 ABB Inc. • 888-385-1221 • Technical assistance 800-377-7722 • www.ssac.com Liquid level controls LLC42B01 03.18.08 LLC42B01 05.03.04 Liquid level controls Liquid Level Control LLC4 Series Single Probe Technical Data Control Type ON/OFF (Single Level) Resistance sensor with built-in time delay to prevent rapid cycling Sense Voltage 12 V AC at probe terminals Sense Resistance Factory fixed or adjustable to 250K Ω Sense Resistance Tolerance Adjustable - guaranteed range Factory fixed +/-10% Input Voltage 24, 120, or 230 V AC Tolerance 24 V AC -15% ... +20% 120 & 230 V AC -20% ... +10% Frequency 50 ... 60 Hz Output Type Electromechanical relay Form Isolated single pole double throw (SPDT) contacts Rating 4 A resistive at 240 V AC; 1/10 hp at 240 V AC Protection Surge IEEE C62.41-1991 Level A Isolation Voltage ≥ 1500 V RMS between input, output, & probe Mechanical Mounting Plug-in socket Termination 8 Pin plug-in Package 2.91 x 2.39 x 1.78 in. (73.9 x 60.7 x 45.2 mm) Environmental Operating Temperature -20°C ... +60°C Storage Temperature -40°C ... +80°C Weight ≅ 6 oz (170 g) Mechanical View Inches (Millimeters) Low Voltage Products & Systems 9.7 ABB Inc. • 888-385-1221 • Technical assistance 800-377-7722 • www.ssac.com 1TRC 001 009 C0202