Series-608

Supported Applications

The Dwyer Series 608 Differential Pressure Transmitter converts positive, negative (vacuum), or differential pressures of clean, dry air and other non-conductive, non-corrosive gases into a standard 4-20 mA DC output signal. The series is designed for industrial and process plant environments where precision measurement of very low differential pressures is required while withstanding high static working pressure.

Key application constraints include:

• Media Compatibility: Clean/dry air and compatible gases; not for use with liquids.
• Hazardous Locations: FM approved intrinsically safe for Class I, Div. 1 (Groups A, B, C, D); Class II, Div. 1 (Groups E, F, G); and Class III, Div. 1 when wired with an approved intrinsic safety barrier.
• Housing Environment: NEMA 4X (IP65) enclosure supports indoor and outdoor installations.

Operating Conditions & Performance

The Series 608 employs a variable capacitance transducer with a micro-machined, ultra-thin silicon diaphragm. This design enables precision measurement across ranges from 0-0.1 in w.c. (0-2.5 mm) up to 0-25 in w.c. (0-634.4 mm). The transducer withstands a static working pressure of 100 psig (6.89 bar) and a differential pressure limit of 15 psid (1.03 bar).

Performance specifications include:

• Accuracy: ±0.5% or ±0.25% of full scale, depending on the model.
• Stability: ±0.5% F.S./year.
• Response Time: 250 ms.
• Ambient Temperature Limits: -20 to 185°F (-28 to 85°C).
• Compensated Temperature Range: 0 to 160°F (-18 to 71°C).
• Thermal Effect: ±0.02% F.S./°F for the 0.5% accuracy models; ±0.01% F.S./°F for the 0.25% accuracy models.

The transmitter is not position sensitive and operates on a 12-36 VDC (2-wire) power supply with a maximum loop resistance of 0-1045 Ω.

Configuration Options

The series offers multiple factory-calibrated models covering specific differential pressure ranges. The model number guide follows the format 608-<RANGE>, with examples including 608-02 through 608-07 for unidirectional ranges and 608-01B, 608-13B*, and 608-04B for bidirectional (±) ranges.

Configuration options include:

• Housing Material: Stainless steel with a NEMA 4X (IP65) rating. Overall dimensions are approximately 3 in [76.20 mm] depth, 4-1/2 in [107.95 mm] height, and 2-11/16 in [68.26 mm] width.
• Process Connections: Two 1/4" female NPT ports.
• Electrical Connections: Screw terminal with two 1/2" female NPT conduit entries.
• Adjustments: Potentiometers for zero and span adjustments are provided on the unit.

Wetted materials include aluminum, titanium, PBT, buna, silicone, glass, gold, silicone RTV, and stainless steel. Specific wetted material compatibility should be confirmed by consulting the factory.

Key Product Differences

Variants within the Series 608 are distinguished primarily by their measurement range and accuracy class:

• Unidirectional Models (e.g., 608-02 to 608-07): Cover ranges from 0 to 0.5 in w.c. up to 0 to 25.0 in w.c.
• Bidirectional Models (suffix B, e.g., 608-01B, 608-13B*, 608-04B): Cover ranges such as 0 to ±0.25 in w.c., 0 to ±1.0 in w.c., and 0 to ±2.0 in w.c.
• Accuracy Class: Models marked with an asterisk (*) feature a higher accuracy of ±0.25% FS, while standard models typically offer ±0.5% FS.

Optional accessories include the NISTCAL-PT1 for a NIST traceable calibration certificate and intrinsically safe barriers such as the MTL5541 galvanic isolator or MTL7706 zener barrier, required for hazardous location installations. New units are supplied with a data report/calibration report.