Why Choose the ABB CM-ENS.23S Liquid Level Monitoring Relay?
The ABB CM-ENS.23S (1SVR730850R2200) is a versatile liquid level monitoring relay designed for automatic filling and draining control in industrial electrical systems. Part of the ABB CM-ENS measuring and monitoring relay range, it monitors the level of electrically conductive liquids using electrodes, helping protect pumps against dry running and tanks against overflow.
The CM-ENS.23S provides selectable filling (UP) and draining (DOWN) functions, allowing one relay to support different liquid level control applications. It can monitor minimum and maximum liquid levels using suitable conductive electrodes, with an adjustable response sensitivity of 0.1–1000 kΩ to accommodate liquids with different electrical conductivities.
Designed for 110–130 V AC or 220–240 V AC control supplies, the relay features one changeover (SPDT) output contact rated at 250 V / 4 A. Its compact 22.5 mm DIN rail housing, screw terminal connections and front-mounted adjustment controls make it suitable for water treatment installations, pumping stations, industrial tanks and automated liquid handling systems.
Key Advantages
- Reliable automatic liquid level monitoring for conductive fluids.
- Selectable filling and draining control using a front-mounted adjustment control.
- 110–130 V AC or 220–240 V AC control supply for industrial electrical installations.
- Adjustable sensitivity from 0.1–1000 kΩ to accommodate different conductive liquids.
- Supports minimum and maximum liquid level monitoring for automatic tank control.
- Helps protect pumps against dry running and tanks against overflow.
- One changeover (SPDT) output contact rated at 250 V / 4 A.
- Uses conductive electrode measurement without requiring mechanical float switches.
- Three LED indicators provide clear operating and relay status information.
- Front-mounted controls simplify configuration and commissioning.
- Compact 22.5 mm housing width saves space in electrical control panels.
- DIN rail mounting and screw terminals support straightforward installation.
- Suitable for integration with pump contactors, PLCs and industrial alarm systems.
Key Features
- ABB CM-ENS.23S liquid level monitoring relay.
- Manufacturer part number: 1SVR730850R2200.
- Rated control supply: 110–130 V AC or 220–240 V AC.
- Rated supply frequency: 50/60 Hz.
- Monitoring medium: Electrically conductive liquids.
- Selectable operating modes: Filling (UP) or draining (DOWN).
- Liquid level monitoring: Minimum and maximum levels.
- Adjustable response sensitivity: 0.1–1000 kΩ.
- Electrode configuration: Three electrodes for two-level monitoring.
- Output: One changeover (SPDT) relay contact.
- Contact rating: 250 V / 4 A.
- Status indication: Three LEDs.
- Terminal technology: Screw connections with double-chamber cage terminals.
- Mounting: DIN rail installation.
- Housing width: 22.5 mm.
- High electromagnetic compatibility for industrial environments.
- Cascadable design for extended liquid level control applications.
- Flame-retardant housing material classified UL 94 V-0.
- Optional compatible electrodes and sealable transparent protective cover.
Technical Specifications
- Manufacturer: ABB
- Series: CM-ENS Liquid Level Monitoring Relays
- Model: CM-ENS.23S
- ABB order code: 1SVR730850R2200
- ABB product group: 310921-Measuring & Monitoring Relays
- Product type: Liquid level filling and draining monitoring relay
- Rated control supply voltage: 110–130 V AC / 220–240 V AC
- Rated frequency: 50/60 Hz
- Monitoring function: Filling or draining
- Monitored medium: Conductive liquids
- Level monitoring: Minimum and maximum liquid levels
- Number of electrodes: 3
- Measuring range: 0.1–1000 kΩ
- Sensitivity adjustment: Front-mounted potentiometer
- Operating mode selection: Filling (UP) / draining (DOWN)
- Output contacts: 1 changeover (SPDT) contact
- Contact rating: 250 V / 4 A
- Rated operational current AC-12: 4 A at 230 V
- Rated operational current AC-15: 3 A at 230 V
- Rated operational current DC-12: 4 A at 24 V
- Rated operational current DC-13: 2 A at 24 V
- Minimum switching capacity: 12 V / 10 mA
- UL/CSA contact rating: B300
- Maximum output operating voltage (UL/CSA): 300 V AC
- Rated insulation voltage: 300 V
- Rated impulse withstand voltage: 4 kV
- Status indication: 3 LEDs
- Terminal type: Screw terminals with double-chamber cage connections
- Terminal tightening torque: 0.8 N·m
- Protection rating: IP50 housing / IP20 terminals
- Mounting type: DIN rail mounting
- Housing flammability classification: UL 94 V-0
- Operating ambient temperature: −25 to +60 °C
- Storage temperature: −40 to +85 °C
- Dimensions (H × W × D): 85.6 × 22.5 × 103.7 mm
- Net weight: 0.154 kg
- EAN: 4013614502897
- Customs tariff number: 85364900
Reliable Liquid Level Control and Pump Protection
The ABB CM-ENS.23S monitors the electrical conductivity between electrodes installed at selected liquid levels inside a tank or vessel. As the liquid rises or falls, contact with the electrodes changes the monitored electrical resistance. The relay uses this information to determine whether the liquid has reached the configured minimum or maximum level and to switch its output contact accordingly.
In filling mode (UP), the relay can be used to control a pump or inlet valve so that a tank is refilled when the liquid reaches its minimum level and filling stops when the maximum level is reached. In draining mode (DOWN), it can be used to activate a discharge pump when the liquid reaches the upper level and stop pumping once the lower level is reached. These functions support automatic tank operation without continuous manual intervention.
The adjustable sensitivity range of 0.1–1000 kΩ allows the CM-ENS.23S to accommodate different conductive liquids and electrode arrangements. This makes it suitable for applications involving water, wastewater and other electrically conductive process liquids. The relay is not intended for non-conductive liquids such as oils or fuels, and the compatibility of the electrodes with the liquid must be considered during installation.
Its single changeover output contact provides a switching signal for pump contactors, control relays, PLC inputs or alarm circuits. The relay is designed for monitoring and control rather than directly switching high-power pump motors, so an appropriately rated contactor or other switching device should be used where the load exceeds the relay contact rating.
With a compact DIN rail housing, three LED status indicators and accessible front-mounted controls, the CM-ENS.23S provides a practical solution for automated filling, draining, overflow prevention and pump dry-running protection in industrial and commercial liquid handling installations.
Typical Applications
- Automatic filling of water storage tanks and reservoirs.
- Automatic draining of collection tanks and sumps.
- Pump dry-running protection in water handling systems.
- Tank overflow protection and high-level monitoring.
- Minimum and maximum liquid level supervision.
- Water treatment and wastewater processing installations.
- Industrial pumping stations and drainage systems.
- Process tanks containing electrically conductive liquids.
- Commercial and industrial water storage systems.
- Liquid level monitoring in manufacturing and processing equipment.
- PLC-controlled pump automation and alarm signalling.
- OEM machinery incorporating automatic liquid level control.
