1SVR730850R0200 ABB CM-ENS.21S Liquid Level Fill/Drain Monitoring Relay

Why Choose the ABB CM-ENS.21S Liquid Level Monitoring Relay?

The ABB CM-ENS.21S is a compact liquid level filling and draining monitoring relay designed to regulate and supervise the level of conductive fluids. With ABB order code 1SVR730850R0200, it can be configured for filling (UP) or draining (DOWN) applications and can also help protect pumps against dry running and tanks against overflow.

The CM-ENS.21S operates from a wide 24–240 V AC/DC control supply and offers an adjustable response sensitivity of 0.1–1000 kΩ. The operating function and sensitivity are selectable using front-face controls, enabling the relay to be adapted to liquids with different conductivity characteristics and to different tank-control requirements.

A single changeover (SPDT) output contact rated at 250 V / 4 A provides straightforward interfacing with pumps, contactors, alarms and control systems. Screw connection technology, three status LEDs and a compact 22.5 mm DIN-rail housing make the CM-ENS.21S suitable for industrial control-panel installations.

Key Advantages

• Selectable filling or draining liquid level monitoring.
• Suitable for monitoring and controlling conductive fluids.
• Helps protect pumps against dry running and tanks against overflow.
• Wide 24–240 V AC/DC control supply supports varied industrial control systems.
• Broad adjustable 0.1–1000 kΩ sensitivity range.
• Supports control of one or two liquid levels for minimum/maximum supervision.
• 1 c/o (SPDT) output contact for switching, signalling and control functions.
• Compact 22.5 mm-wide housing conserves DIN-rail space.

Key Features

• ABB CM-ENS liquid level monitoring relay series.
• Filling (UP) or draining (DOWN) function selectable from the front face.
• 24–240 V AC/DC rated control supply voltage.
• 0.1–1000 kΩ adjustable response sensitivity.
• Designed for conductive fluid level monitoring.
• Control of one or two liquid levels.
• Suitable for minimum and maximum level supervision.
• 1 c/o (SPDT) relay output.
• Output contact rated at 250 V / 4 A.
• Three LEDs indicate operational states.
• Screw connection technology with double-chamber cage terminals.
• Tool-free mounting and removal from DIN rail.

Reliable Filling and Draining Control for Conductive Liquids

The ABB CM-ENS.21S detects liquid levels through electrodes immersed in the conductive fluid. Depending on the selected operating mode, the relay can control filling or draining equipment as the monitored liquid reaches the defined electrode levels, providing an effective method of automating tank and reservoir management without mechanical float mechanisms.

Its wide 0.1–1000 kΩ sensitivity adjustment allows the monitoring circuit to be matched to different conductive fluids. The CM-ENS.21S can therefore be used for automatic level control as well as dry-running protection, overflow protection and minimum or maximum level signalling in industrial processes.

Typical Applications

• Automatic tank filling systems.
• Automatic tank draining systems.
• Pump dry-running protection.
• Tank overflow protection.
• Minimum and maximum level signalling.
• Water and wastewater systems.
• Industrial tanks and process reservoirs.
• Pump control and process automation panels.