Specifications: Model: 685 Level Controller Measurement Principle: Buoyancy / Torque Tube Output Signals: Pneumatic: 20 to 100 kPa (3 to 15 psig) Electronic: 4 to 20 mA DC, HART protocol Enclosure Rating: NEMA 4 (Weatherproof), NEMA 7 (Explosion-Proof for electronic versions) Process Connection & Capacity: Chamber Size: Standard displacer lengths available from 14 in to 120 in (355 mm to 3048 mm). Process Connection: Typically 2-inch or 3-inch NPT or flanged cage connections. Displacer Size: Various diameters available to match specific buoyancy force requirements and density. Process Conditions (Dependent on Model & Materials): Pressure Rating: Standard: Up to ANSI Class 600 (1440 psig @ 100°F) High-Performance: Up to ANSI Class 2500 (6000 psig @ 100°F) Temperature Range: Standard: -20° to 400°F (-29° to 204°C) High-Performance: -20° to 800°F (-29° to 427°C) Performance: Accuracy: Typically ±1% of span. Dead Band: Typically less than 0.5% of span. Span Adjustment: Field-adjustable. Materials of Construction: Cage / Chamber: Carbon Steel (standard), Stainless Steel, Alloy Steel. Displacer: 316 Stainless Steel (standard), other alloys available. Torque Tube: 316 Stainless Steel, Inconel, or other high-strength alloys for high-temperature service. Control Capability (with Integral Pilot): Control Actions: Direct or Reverse acting (configurable). Proportional Band: Field adjustable.
