1SVR730850R0300 ABB CM-ENS.31S Liquid Level Fill/Drain Monitoring Relay

Why Choose the ABB CM-ENS.31S Liquid Level Monitoring Relay?

The ABB CM-ENS.31S is a versatile liquid level filling and draining monitoring relay designed to regulate and supervise conductive fluids in tanks, reservoirs and industrial process systems. With ABB order code 1SVR730850R0300, it supports filling (UP) or draining (DOWN) control and can also provide dry-running protection, overflow protection and minimum or maximum level alarming.

The CM-ENS.31S operates from a wide 24–240 V AC/DC control supply and provides an adjustable response sensitivity of 0.1–1000 kΩ. It can control one or two liquid levels, while the operating principle and sensitivity can be selected using front-face controls to suit different conductive fluids and process requirements.

For applications where liquid movement could otherwise cause unwanted switching, the CM-ENS.31S provides a selectable ON- or OFF-delay with a time range of 0 or 0.1–30 s. Two changeover (SPDT) output contacts, screw connection technology and a compact 22.5 mm DIN-rail housing provide flexible integration into industrial control systems.

Key Advantages

• Selectable filling or draining liquid level monitoring.
• Designed for monitoring and controlling conductive fluids.
• Supports dry-running and overflow protection.
• Wide 24–240 V AC/DC control supply simplifies use across different control systems.
• Broad adjustable 0.1–1000 kΩ sensitivity range.
• Selectable ON- or OFF-delay helps prevent unwanted switching caused by temporary level fluctuations.
• Two changeover output contacts provide flexible control and signalling.
• 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) monitoring function.
• 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 for minimum/maximum supervision.
• Selectable ON- or OFF-delay.
• 0 or 0.1–30 s adjustable tripping delay.
• 2 c/o (SPDT) relay outputs.
• Three LEDs for operational status indication.
• Screw connection technology with double-chamber cage terminals.
• Tool-free mounting and removal from DIN rail.

Flexible Filling and Draining Control for Conductive Liquids

The ABB CM-ENS.31S evaluates conductive liquid levels through connected electrodes and switches its outputs according to the selected filling or draining function. Control of one or two levels enables the relay to automate tank management while also supporting applications such as pump dry-running protection, tank overflow prevention and minimum or maximum level signalling.

Its adjustable 0.1–1000 kΩ sensitivity enables adaptation to fluids with different conductivity characteristics. The selectable ON- or OFF-delay can also prevent short-term level variations or wave formation from causing unwanted switching, making the CM-ENS.31S particularly suitable for demanding industrial liquid-handling processes.

Typical Applications

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