Series-MBLT

Supported Applications

The Dwyer Series MBLT Miniature Submersible Level Transmitter is a submersible pressure transmitter designed for level monitoring in well and borehole applications. The unit measures the height of liquid above its position referenced to atmospheric pressure, making it suitable for compatible liquids where space constraints require a compact profile.

Key application contexts documented include:

• Boreholes and Wells: Designed specifically for monitoring in narrow-diameter wells due to the 0.63" (16 mm) diameter housing.
• Battery-Powered Telemetry Systems: Voltage output models operate with power requirements as low as 8 VDC, supporting remote or battery-operated installations.

Operating Conditions & Performance

The Series MBLT operates within a process temperature range of -4 to 176°F (-20 to 80°C). Accuracy specifications vary by model configuration and compensated temperature limits:

• Accuracy Options: ±0.25% or ±0.10% FS; configured ranges from 4.3 to 4.9 psi (10 to 11.54 in w.c.) offer ±0.30% FS accuracy.
• Compensated Temperature Limits: For the ±0.25% model, limits are 32 to 158°F (0 to 70°C); for the ±0.10% FS model, limits are 32 to 140°F (0 to 60°C).
• Thermal Effect: The thermal effect is specified as ±0.45% FS TEB for the 0.25% accuracy class and ±0.30% FS TEB for the 0.10% accuracy class.

The transmitter features a response time of < 50 ms and includes surge/lightning protection per EN61000-4-5, Class 5. The pressure limit is rated at 2X FS (full scale).

Power Requirements

• Current Output: 10 to 33 VDC.
• Voltage Output: 8 to 33 VDC; maximum current draw is 5 mA (no load).

Configuration Options

The Series MBLT offers a configurable envelope for circuit options, body materials, accuracy classes, output signals, reference types, cable materials, range units, and lengths. The transmitter consists of a piezoresistive sensing element encased in a 316 SS housing with a welded nose cap.

Output Signals

The series supports multiple electrical outputs depending on the model configuration:

• Current Output: 4 to 20 mA DC, 2-wire. Max loop resistance is 1000 Ω @ 30 VDC.
• Voltage Outputs: Standard options include 0 to 5 V; additional voltage outputs (0 to 2 V, 0 to 2.5 V, 0 to 3 V, 0 to 4 V, and 1 to 5 V) are available per model.
• Voltage Output Impedance: 10 Ω + 4.4 Ω / 100' cable.

Cable Materials & Construction

The electrical connection is provided via a wire pigtail with selectable jacket materials to suit the environment:

• Polyether Polyurethane (P): Standard option for general service.
• ETFE (E): Available as an alternative cable material.

Cable lengths are configurable in feet for ranges expressed in feet or psi, and in meters for meter-based range units. The overall body length is 6-3/4" [171.45 mm] with a diameter of 0.63" (16 mm).

Wetted Materials

• Body and Nose: 316 SS.
• Cable: Polyether polyurethane or ETFE.
• Seals: Fluoroelastomer.
• Label: Polyolefin.

Options & Accessories

• NIST Traceable Certificate: Available as an option for calibration verification.
• A-297 Desiccant Filter: A filter for the vent tube that removes humidity to protect the sensor. It changes color to indicate saturation.

Circuit Protection

The series includes circuit options with lightning surge protection (designated by '2' in model codes). This incorporates protection circuitry intended to reduce the likelihood of damage from lightning-induced transients on interconnection wiring. The product may not operate within specification during a transient but is designed to recover afterwards.

Key Product Differences

Variants within the Series MBLT are distinguished by accuracy class, output type, and range units. Model numbers follow the format: MBLT - [Circuit Options] - [Body Material] - [Accuracy] - [Output] - [Reference] - [Range Units] - [Range Value] - [Cable Length] - [Options].

• Accuracy Class: Models are available with ±0.25% FS or ±0.10% FS accuracy, impacting the compensated temperature limits and thermal effect specifications.
• Output Type: Selection between 4 to 20 mA DC (current) and various voltage outputs determines power supply requirements; current output requires a minimum of 10 VDC, while voltage output models can operate down to 8 VDC.
• Cable Material: Variants specify either Polyether polyurethane or ETFE cable jackets based on environmental needs.