01
Coolant tank level
Continuously monitor coolant inventory and use switch points to prevent overfill or low-level operation.
ifm · Level sensors
ifm LK Continuous Level Sensors
Continuous capacitive level measurement for industrial tanks containing suitable water- or oil-based media. LK provides top-down level monitoring without floats or other moving parts, with model-dependent switching, analogue and IO-Link functions.
Capacitive continuous level264–728 mmTop-down mountingIndependent overflow protectionIO-Link
MeasurementContinuousLevel across the active probe zone
TechnologyCapacitive16 stacked sensing cells
Probe length264–728 mmThree principal rod lengths
ProtectionIndependentSeparate overflow-monitoring algorithm
Industrial tank monitoring
LK continuous level sensors in the system architecture
LK is aimed at industrial tank applications such as coolants, cleaning agents, lubricants and hydraulic oils where a contact probe is acceptable.
02
HPU reservoir
Track oil level without mechanical floats and expose the level to control logic.
03
Oil reservoir
Monitor process and lubrication tanks where the selected LK variant is compatible with the medium and temperature.
04
Independent protection
LK/LT architecture includes a separate overflow-monitoring function independent of the general level calculation.
Measuring principle
Sixteen capacitive cells determine how much of the probe is covered
The LK/LT probe contains 16 individual capacitive sensing elements arranged along the probe. Each cell evaluates whether it is covered by the medium; the microprocessor combines those states into a continuous level value.
No floatNo mechanical moving element to stick or wear.
Continuous valueLevel is evaluated across the active measuring range.
Overflow layerIndependent monitoring is designed to force outputs if the level keeps rising.
LT alternativeLT variants add temperature output in addition to level.
Current LK model routes
Probe length and output architecture selection
Current documentation shows LK families in 264, 472 and 728 mm lengths. The exact active range and media behaviour depend on the selected model.
| Family | 264 mm | 472 mm | 728 mm | Output route |
|---|---|---|---|---|
| LK10 | LK1022 | LK1023 | LK1024 | 2 switching outputs |
| LK70 | LK7022 | LK7023 | LK7024 | 2 switching outputs; automatic media-detection route |
| LK31 | LK3122 | LK3123 | LK3124 | 1 switching + 1 analogue output |
| LK81 | LK8122 | LK8123 | LK8124 | 4 switching outputs |
| LK12 | LK1222 | LK1223 | LK1224 | Overflow-protection / WHG route; confirm local applicability |
Model check: output functions, approvals, active measuring length, temperature limits and medium suitability must be confirmed from the current order-number datasheet before quotation.
Installation
Top-down mounting is the normal LK route
The probe is inserted into the tank from above. Tank geometry, mounting distance, process connection and medium properties must be reviewed before final selection.
01
Match the usable tank range
Choose 264, 472 or 728 mm family length, then confirm the active measurement zone for the exact model.
02
Water or oil based
Current ifm selection guides position LK/LT for suitable water- and oil-based industrial media.
03
Review exact limits
Oil temperature and process conditions vary by variant; do not copy one limit across all LK models.
Technology alternatives
LK or another ifm level technology?
Choose according to tank access, medium, range, sanitation and whether contact measurement is acceptable.
| Requirement | Review | Why |
|---|---|---|
| Industrial water/oil tank, 264–728 mm | LK / LT | Capacitive continuous level with top-down probe |
| Longer probe / flexible cut-to-length | LR guided wave radar | Current LR ranges extend well beyond LK |
| Non-contact measurement | LW / ultrasonic / optical | No probe in the medium; choose by tank and environment |
| Single high/low point | LMC / LMT / LI | Point-level technology may be simpler |
| Level + temperature | LT | Current LT family adds temperature output |
Requirement capture
Inputs required to select the correct LK
A photograph of the tank plus dimensions usually eliminates several selection mistakes.
MediumCoolant, water, hydraulic oil, lubricant, cleaning solution or other.
Tank depthRequired measuring range and available probe insertion.
TemperatureNormal and maximum medium temperature.
OutputSwitching, analogue, IO-Link or multiple setpoints.
MountingTop opening, process connection, clearance and tank material.
Overflow needWhether independent overflow protection or a specific approval is required.