DM-LF120 Capacitive Level Switch for Liquids and Powders

Overview

The DM-LF120 detects the presence or absence of material at a single point. A rod probe forms one plate of a capacitor and the vessel wall the other, so when product covers the rod the capacitance changes and the output switches. There are no moving parts and nothing to jam, which is why capacitive switches are used on powders and sticky media where a float would fail.

Sensitivity is adjustable to compensate for a low dielectric constant or for build-up on the probe. The standard output is PNP, with relay and NAMUR versions available for interlock circuits and hazardous areas.

Key features

• Point-level detection for liquids, granules and powders
• Adjustable sensitivity for media with low dielectric constant
• PNP, relay or NAMUR output
• Stainless steel or PTFE-coated rod, lengths 100-1,000 mm
• Build-up compensation via sensitivity adjustment
• IP67 with M12 connector

Typical applications

• High-level alarm on tanks and silos
• Dry-run protection on pumps and dosing systems
• Powder and granule presence in hoppers
• Interface detection between two liquids

Selection note

Capacitive switching depends on the dielectric constant of the medium. Water at 80 is easy; oils at 2.2 and plastic pellets at 2.0 are marginal and need a coated probe or a different technology. State the medium when ordering so the probe length and sensitivity are set at the factory.