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Supported Applications

The Dwyer Series Mark Position Indicators/Transmitters provide position feedback and switching for rotary valves (direct drive) and linear control valves or gate valves (lever drive). The series covers applications requiring visual indication, discrete switch outputs, analog potentiometer signals, 4-20 mA transmitters, and HART® communication. Standard models are designed to be weatherproof, flameproof, and submersible.

Specific application configurations include:

• Direct Drive (Rotary Valves): Units utilize a magnetic coupling or through-shaft drive for 1/4-turn actuators. A stainless steel mechanical visual indicator is standard on direct drive units, providing open/closed indication and an adjustable degree scale.
• Lever Drive (Linear/Multi-Turn Valves): The Mark 3 model uses a magnetic drive designed for multi-turn applications ranging from 1 to 25 revolutions. Mounting kits are available with drive yokes or slotted lever arms for specific valve and actuator interfaces.
• Hazardous Locations: Models are offered with UL, CSA, ATEX (Directive 2014/34/EU), and IECEx certifications for Class I, Div. 1 & 2; Class II, Div. 1 & 2 locations.

Operating Conditions & Performance

The Series Mark operates across a broad ambient temperature envelope depending on the output type and hazardous location certification selected:

• Ambient Temperature Range:-58 to 176°F (-50 to 80°C) for standard configurations. Specific limits apply based on switch types (e.g., Switch Type C rated to 350°F/176°C for 600 hours; Switch Type T rated to 250°F/121°C continuous). ATEX flameproof (-B suffix) and IECEx flameproof (-IE suffix) units are rated -40 to 145°F (-40 to 63°C) or lower depending on the switch type. Intrinsically safe models (ATEX -IS, IECEx -II) have reduced ranges such as -13 to 104°F (-25 to 40°C).
• Enclosure Ratings:NEMA 1, 2, 3, 3R, 3S, 4, 4X, 6, 7, 9, 12, and 13. Units are submersible to 15 meters (IP68) when fitted with proper watertight fittings.
• Accuracy:Potentiometer outputs offer ±0.5% of FS standard or optional ±0.25% of FS. Transmitter and HART® models also provide ±0.5% of FS (optional ±0.25%).
• Operational Life:Over 10,000,000 cycles.
• Altitude:Maximum altitude is 2000 meters; extended to 5000 meters for specific Mark 1, 3 & 4 models with designated switch types (A, B, C, G, I, T, V, or W).

Configuration Options

The series is configurable across three primary model styles—Mark 1 (magnetic coupling), Mark 3 (multi-turn magnetic drive), and Mark 4 (through-shaft)—with extensive options for outputs, switches, enclosures, and hazardous location compliance.

Output Signals & Switch Types

The series supports a wide range of electrical interfaces:

• Potentiometer Outputs:Standard 1000 Ω; optional 2000, 5000, 10000, or 20000 Ω.
• Analog Transmitters:4-20 mA output with power requirements of 5-30 VDC (standard) or 8-30 VDC (HART® models).
• HART® Communication:Available on Mark 1 and 4 transmitters, supporting Rx = 500 kΩ; Cx = 2500 pF.
• Switch Outputs:Configurable for 1 to 6 switches. Available types include SPDT snap (Types A, S, V), high-temperature snap (Type C: 350°F/176°C; Type T: 250°F/121°C continuous), gold contact (Types G, W), hermetically sealed (Types H, R), inductive sensors (Type B, NAMUR Type I), and magnetic blow-out (Type M).

Enclosures & Materials

Housing options include painted aluminum (black, white epoxy with SS trim, red) or cast 316 stainless steel. Electrical connections are provided via screw terminals or optional factory-sealed leads (36"/914.4 mm of 16 AWG). Conduit entries support standard one 3/4" female NPT; optional configurations include one to two 1/2" female NPT, M25 X 1.5, or M20 X 1.5 connections.

Hazardous Location Options

Models are available with specific suffixes for compliance:

• ATEX Flameproof (-B):KEMA 03ATEX2391 X, CE 2813 II 2G Ex db IIC T6 Gb.
• ATEX Intrinsically Safe (-S/IS):KEMA 03ATEX1392 X, CE 2813 II 1G Ex ia IIC T4 Ga.
• IECEx Flameproof (-IE):IECEx DEK 11.0056X Ex db IIC T6 Gb.
• IECEx Intrinsically Safe (-I/II):IECEx DEK 11.0061X Ex ia IIC T4 Ga.

Key Product Differences

The Series Mark differentiates its three model styles by drive mechanism and application scope:

• Mark 1:Utilizes a magnetic coupling to seal the switch compartment from the atmosphere. Designed for direct or lever drive applications with rotational travel up to 360° (switch outputs) or adjustable span of 50–300°/8.5 revolutions depending on output type.
• Mark 3:Incorporates the same magnetic drive as Mark 1 but is engineered for multi-turn applications, supporting 1 to 25 revolutions (gate valves). Span adjustment ranges from 1.5 to 8.5 revolutions for transmitter outputs.
• Mark 4:Features a through-shaft drive mechanism, offering a cost-effective alternative to the Mark 1 for less demanding applications where magnetic sealing is not required.

Junction packages (Options J1/J2) combine visual indication, solenoids, switches, and transmitters in a single assembly with prelabeled terminal strips. These are available on painted aluminum or stainless steel housings but are excluded from six-switch models and specific switch types (A, D, G, H, T).