Series-648B-648C

Supported Applications

The Dwyer Series 648B and 648C Differential Pressure Transmitters are designed for use with clean, dry air and other non-corrosive gases. These transmitters monitor differential pressure in applications requiring a compact solution with push-button zero calibration capability.

Operating Conditions & Performance

The series offers measurement ranges from 0 to 0.1 in w.c. up to 0 to 25 in w.c. for unidirectional sensing, and bidirectional options ranging from 0 to ±0.25 in w.c. through 0 to ±5 in w.c. Accuracy is specified as ±0.8% FS* at room temperature for Series 648B models and ±0.4% FS* at room temperature for Series 648C models, where the error includes non-linearity, hysteresis, and non-repeatability (RSS). The response time is approximately 10 ms.

Operating ambient temperatures range from 0 to 170°F (-18 to 77°C), with storage limits of -65 to 185°F (-54 to 85°C). The transmitters feature a proof pressure rating of 15 psi (100 kPa) and a burst pressure limit of 30 psi (200 kPa).

Configuration Options

The Series 648B/648C provides configurable options across accuracy class, measurement range directionality, and model numbering. Key capabilities include:

• Accuracy Classes: Standard ±0.8% FS* (Series 648B) or high-precision ±0.4% FS* (Series 648C).
• Output Signal: 2-wire, short-circuit protected 4 to 20 mA output.
• Power Supply: Operates on 13 to 32 VDC with a load resistance of DC: 0 to 950 Ω.
• Zero Calibration: Push-activated zero function with an associated dual-color LED indicator for normal operation, overpressure, or calibration status.
• Housing & Connections: Flame retardant plastic top cover and stainless steel bottom plate; electrical connection via detachable euro-style terminal block. Process connections utilize a 3/16" OD barbed fitting compatible with 1/8" ID push-on tubing.
• Wetted Materials: Includes 302 SS, glass, nickel, silicon rubber, polyethylene, acrylic, ABS, and brass.

An optional NIST traceable calibration certificate is available using order code NISTCAL-PT1. The enclosure dimensions are 1-9/16 in [39.50] depth, 3-15/32 in [88.00] height, and 1-57/64 in [48.00] width.

Key Product Differences

The primary distinction between the two series is accuracy: Series 648B models provide ±0.8% FS* accuracy, while Series 648C models offer improved precision at ±0.4% FS*. Model numbers follow a specific construction where changing "B" to "C" in the model number (e.g., from 648B-01 to 648C-01) designates the higher accuracy variant.

Range codes define the measurement span and directionality. Unidirectional ranges are available for models ending in -01 through -08, covering spans up to 25 in w.c. Bidirectional (±) ranges correspond to model suffixes such as -13 through -17, offering differential sensing from ±0.25 in w.c. to ±5 in w.c.