01
Differentiate coating from medium
Impedance spectroscopy allows the sensor to evaluate the electrical signature of the actual medium rather than react only to deposits.
ifm · Level sensors
ifm LMT Point-Level Sensors
Use impedance spectroscopy for reliable point-level detection in hygienic and demanding processes where residue, foam, splash or changing media can challenge conventional switches. Current LMT variants are programmable through IO-Link and are available with media-specific factory settings.
Impedance spectroscopyIO-LinkResidue suppressionMedia differentiationHygienic process
PrincipleImpedanceMulti-frequency media signature
Probe lengths11–253 mmCurrent LMT selection
ConfigurationIO-LinkAll current LMT variants programmable
Primary rolePoint levelHigh / low / run-dry
Process reliability
Reliable detection even with buildup, foam and residue
The LMT is strongest when the application needs to distinguish actual medium contact from process disturbances that can cause false switching in simpler point-level technologies.
02
Reduce false switching
Suitable LMT applications can ignore common foam and splashing conditions that would otherwise mimic a level event.
03
Process value output
IO-Link process values can help distinguish product, cleaning media and buildup where the media signatures are sufficiently different.
04
Media-specific defaults
Current variants are factory-set for water-based, oil/powder or high sugar/salt media groups and remain programmable through IO-Link.
Application routes
LMT point-level sensors in the system architecture
High- & low-level detection
Use LMT as an independent switching point for overflow prevention, minimum level or process interlocks.
Run-dry protection
Confirm that product is present at the pump inlet or critical pipe point before permitting operation.
Product / media differentiation
Use IO-Link process values where the application needs to distinguish product, cleaning medium or residue.
Impedance spectroscopy
Multiple frequencies create a characteristic electrical signature of the medium
LMT evaluates how the medium affects an electrical field across several frequencies. Conductance, permittivity and attenuation contribute to the resulting signature, allowing the sensor to separate actual medium contact from many deposits and disturbances.
ConductanceHow readily the medium carries electrical current.
PermittivityHow strongly the medium interacts with the electric field.
AttenuationHow the signal changes as the medium influences the measurement.
Frequency responseThe combined response across frequencies forms the useful process signature.
IO-Link value
IO-Link adds beyond a simple level switch
01
Tune the application
Adjust the sensor when the factory media preset is not the final process setting.
02
Continuous measurement beyond ON/OFF
Read the impedance-derived process value to support media differentiation and troubleshooting.
03
Digital integration
Use device identification and digital parameter access within an IO-Link architecture.
Current LMT models
Select probe length, connection and factory media preset together
| Model | Probe length | Process connection | Factory setting |
|---|---|---|---|
| LMT100 | 11 mm | G1/2 sanitary cone | Water-based liquids |
| LMT102 | 38 mm | G1/2 sanitary cone | Water-based liquids |
| LMT104 | 153 mm | G1/2 sanitary cone | Water-based liquids |
| LMT105 | 253 mm | G1/2 sanitary cone | Water-based liquids |
| LMT110 | 11 mm | G1/2 sanitary cone | Oil-based liquids / powders |
| LMT121 | 11 mm | G1/2 sanitary cone | High sugar / salt liquids |
| LMT202 | 28 mm | G3/4 BSPP | Water-based liquids; tuning-fork retrofit |
| LMT302 | 38 mm | G1 BSPP | Water-based liquids; tuning-fork retrofit |
Selection note: current IFM guidance states that all LMT products can be programmed using IO-Link. Choosing the closest factory preset still simplifies commissioning.
Technology selection
LMT or another ifm level technology?
| Requirement | Technology route | Reason |
|---|---|---|
| Hygienic point-level with residue / foam challenges | LMT | Primary fit Impedance spectroscopy and media differentiation |
| Continuous tank level | LR / radar / other continuous family | LMT provides a switching point, not a continuous level profile |
| Simple standard point level | LMC / capacitive / other point-level route | May be more appropriate when hygienic/media-differentiation capability is not needed |
| Non-contact measurement | Radar / ultrasonic route | No wetted point-level probe |
Requirement capture
Inputs required to select the LMT sensor
MediumWater-based, oil, powder, high sugar/salt, cleaning media or product mix.
FunctionHigh level, low level, overflow, run-dry or media differentiation.
TemperatureNormal and cleaning/process temperature range.
ConnectionExisting hygienic fitting / retrofit connection.
Insertion lengthRequired probe reach into the vessel or line.
IO-LinkSwitch-only use or process-value / parameter access.