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1SVR740850R0200 ABB CM-ENS.21P Liquid Level Fill/Drain Monitoring Relay 24–240 V AC/DC
ABB CM-ENS.21P (1SVR740850R0200) liquid level monitoring relay with 24–240 V AC/DC supply, adjustable 0.1–1000 kΩ sensitivity, selectable filling and draining functions, one changeover output and push-in terminals for industrial pump and tank level control.
£84.01
Why Choose the ABB CM-ENS.21P Liquid Level Fill/Drain Monitoring Relay?
The ABB CM-ENS.21P (order code 1SVR740850R0200) is a versatile and reliable liquid level monitoring relay designed for automatic filling and draining control of tanks, reservoirs and industrial liquid handling systems. As part of the ABB CM-ENS measuring and monitoring relay series, it provides dependable monitoring of electrically conductive liquids, helping protect pumps against dry running and storage vessels against overflow.
The CM-ENS.21P uses conductive electrode sensing to detect liquid levels and control connected equipment according to the selected operating mode. Its adjustable sensitivity range of 0.1–1000 kΩ enables adaptation to liquids with different electrical conductivities, while selectable Fill (UP) and Drain (DOWN) functions provide flexibility for automatic liquid level regulation.
With a wide 24–240 V AC/DC control supply, a single changeover relay output and maintenance-free push-in connection terminals, the ABB CM-ENS.21P is suitable for integration into industrial control panels and pump automation systems. Its compact 22.5 mm DIN rail-mounted housing, front-mounted adjustment controls and LED status indicators simplify installation, commissioning and operational monitoring.
Key Advantages
- Reliable automatic liquid level monitoring and control for conductive fluids.
- Selectable filling and draining operating modes for flexible pump control.
- Wide 24–240 V AC/DC supply voltage for compatibility with industrial control systems.
- Adjustable 0.1–1000 kΩ sensitivity accommodates different liquid conductivities.
- Supports pump dry-running protection and tank overflow prevention.
- Easy Connect Technology with push-in terminals enables fast, maintenance-free electrical connections.
- Compact 22.5 mm housing width saves valuable control cabinet space.
- Integrated LED indicators provide convenient visual operating status information.
- Adjustable operating characteristics allow straightforward configuration for different applications.
Key Features
- ABB CM-ENS liquid level monitoring relay series.
- Fill (UP) and Drain (DOWN) operation selectable using a front-face potentiometer.
- 24–240 V AC/DC rated control supply voltage.
- 0.1–1000 kΩ adjustable response sensitivity.
- 1 changeover (SPDT) relay contact for switching external control circuits.
- 250 V AC / 4 A relay contact rating.
- Conductive liquid detection using electrode-based measurement.
- Monitoring of minimum and maximum liquid levels using suitable electrodes.
- Three integrated LEDs for operating status indication.
- Push-in connection technology for efficient control wiring.
- High electromagnetic compatibility for industrial environments.
- Tool-free mounting and removal from standard DIN rails.
- Optional electrode accessories and sealable transparent adjustment cover.
- Compact housing manufactured using flame-retardant material classified UL 94 V-0.
Technical Specifications
- Manufacturer: ABB
- Series: CM-ENS Measuring and Monitoring Relays
- Model: CM-ENS.21P
- ABB order code: 1SVR740850R0200
- Product group: 310921 – Measuring & Monitoring Relays
- Product type: Liquid level fill/drain monitoring relay
- Monitoring function: Conductive liquid level monitoring
- Operating modes: Filling (UP) / Draining (DOWN)
- Rated control supply voltage: 24–240 V AC/DC
- Rated AC supply frequency: 50 / 60 Hz
- Measuring principle: Conductive electrode sensing
- Adjustable sensitivity: 0.1–1000 kΩ
- Liquid level control: Minimum / maximum level monitoring
- Relay output: 1 changeover contact (SPDT)
- Output contact rating: 250 V AC / 4 A
- Terminal technology: Push-in, ABB Easy Connect Technology
- Operating indication: 3 LED status indicators
- Adjustment: Front-face potentiometers
- Housing width: 22.5 mm
- Mounting type: DIN rail mounting
- Protection rating: IP50 housing / IP20 terminals
- Operating ambient temperature: −25 to +60 °C
- Storage temperature: −40 to +85 °C
- Housing flammability classification: UL 94 V-0
- Approximate product weight: 0.117 kg
- GTIN / EAN: 4013614502866
Reliable Liquid Level Control for Industrial Pumping Systems
Liquid level monitoring relays such as the ABB CM-ENS.21P provide automatic control of pumps and liquid handling equipment by measuring the electrical conductivity between electrodes installed at defined liquid levels. When the liquid reaches or falls below the selected electrode positions, the relay changes its output state according to the configured operating mode. This allows connected control equipment to start or stop pumps without requiring continuous manual intervention.
In Fill (UP) mode, the relay can control a filling pump to maintain the liquid between minimum and maximum levels. In Drain (DOWN) mode, it can control an emptying pump to remove liquid when the upper level is reached and stop when the lower level is detected. These functions support reliable tank level regulation while helping prevent overflow and unnecessary pump operation.
The adjustable sensitivity makes the CM-ENS.21P suitable for different electrically conductive liquids, while its wide supply voltage range and push-in terminals simplify integration into existing automation installations. Its compact DIN rail design and clear LED indications make it a practical solution for industrial maintenance engineers, control panel builders and pump system integrators. Suitable sensing electrodes are selected separately according to the liquid and installation conditions.
Typical Applications
- Automatic filling and draining of industrial storage tanks.
- Water reservoir and liquid storage level control.
- Industrial pump control and dry-running protection.
- Tank overflow prevention and high-level monitoring.
- Wastewater collection and drainage systems.
- Sump pump and liquid transfer installations.
- Water treatment and filtration equipment.
- Process tanks containing electrically conductive liquids.
- Industrial machinery requiring automatic liquid level regulation.
- OEM control panels and automated pumping systems.
Technical Specifications
Tick the specs you need, then view products that match.
| Monitoring Function | Liquid level |
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Frequently Asked Questions
What is the ABB CM-ENS.21P used for?
The ABB CM-ENS.21P is a liquid level monitoring relay used to automatically control the filling and draining of tanks containing electrically conductive liquids. It also supports pump dry-running protection and tank overflow prevention.
What supply voltage does the ABB CM-ENS.21P require?
The CM-ENS.21P operates with a wide 24–240 V AC/DC control supply, making it suitable for a variety of industrial automation and electrical control systems.
Can the CM-ENS.21P control both filling and draining operations?
Yes. The relay supports selectable Fill (UP) and Drain (DOWN) operating modes. These allow automatic control of pumps used to fill or empty tanks between defined liquid levels.
What is the adjustable sensitivity range of this liquid level relay?
The ABB CM-ENS.21P provides an adjustable sensitivity range of 0.1–1000 kΩ, allowing it to monitor liquids with different electrical conductivity characteristics.
What type of output does the CM-ENS.21P provide?
The relay features one changeover (SPDT) output contact rated at 250 V AC / 4 A. This output can be used to control external contactors, pump control circuits or automation equipment within the specified contact ratings.
Does the ABB CM-ENS.21P require liquid level electrodes?
Yes. The CM-ENS.21P uses conductive electrodes to detect liquid levels. Suitable electrodes are available as accessories and should be selected according to the liquid, tank configuration and required monitoring levels.
What type of electrical terminals does this model use?
The CM-ENS.21P uses ABB Easy Connect push-in terminals, allowing convenient, maintenance-free wiring connections. The P suffix identifies the push-in terminal version.
Where is the ABB CM-ENS.21P typically installed?
The relay is designed for DIN rail mounting inside electrical control panels. Its compact 22.5 mm housing makes it suitable for industrial pump controllers, automation cabinets and liquid level management systems.
Can the CM-ENS.21P detect non-conductive liquids?
No. The CM-ENS.21P uses an electrical conductivity measurement principle and is intended for electrically conductive liquids. Non-conductive liquids generally require a different sensing technology.
Trusted by Industrial Automation and Pump Control Professionals
ABB CM-ENS liquid level monitoring relays provide dependable conductive liquid detection and flexible filling and draining control for industrial pumping installations. With adjustable sensitivity, convenient push-in terminals and compact DIN rail mounting, the CM-ENS.21P is a practical choice for engineers and system integrators seeking reliable liquid level automation.
