GTI GTI-145 Compact Digital Differential Pressure Transmitter

Overview

The GTI GTI-145 Compact Digital Differential Pressure Transmitter is an engineered solution for precise, real-time monitoring of low-differential pressure in clean gas applications. Utilizing a high-stability micro-silicon piezoresistive sensor and fully digital signal conditioning architecture, the device delivers repeatable measurements across a wide selection of calibrated ranges—from 0–50 Pa up to 0–5 kPa—with resolution down to 0.1 Pa in the most sensitive configuration. Its compact form factor (24 × 48 × 73 mm), low power consumption (≤30 mA @ 24 VDC), and dual mounting options (wall or bracket) make it suitable for integration into space-constrained environments including HVAC ductwork, biological safety cabinets, cleanroom pressure cascades, and pharmaceutical isolators. The instrument operates on a standard 12–24 VDC supply and features built-in temperature compensation, ensuring measurement integrity across its full operating range of 0–60°C.

Key Features

• High-resolution segmented LCD display with 4-digit readability—user-selectable units (Pa or kPa)
• Dual independent switch outputs (NPN or PNP open-collector, 100 mA load capacity, 30 VDC max)
• Analog output configurable as 4–20 mA or 1–5 VDC, supporting loop-powered or voltage-sourced control systems
• On-device zero adjustment via front-panel potentiometer for field calibration without external tools
• Configurable digital filtering (moving average: 0.2 s / 1 s / 2 s / 4 s) to suppress transient noise in unstable flow conditions
• Peak and valley hold functionality for diagnostic capture of transient pressure events
• Front-panel key lock to prevent accidental parameter changes during operation
• Robust PC/ABS housing rated IP40 for protection against solid ingress and light splashing—suitable for controlled indoor industrial environments
• Compliance with IEC 60664-2 Pollution Degree 2 and IEC 60529 for mechanical and environmental robustness

Sample Compatibility & Compliance

The GTI-145 is validated for use with clean, dry, non-corrosive process gases—including ambient air, medical-grade nitrogen, and instrument air—commonly encountered in regulated environments such as ISO Class 5–8 cleanrooms, GMP-compliant pharmaceutical manufacturing suites, and biosafety level 2+ containment systems. It is not rated for liquid media, aggressive chemicals (e.g., chlorine, ammonia, solvents), or humid/saturated gas streams. While the device itself does not carry CE, UKCA, or ATEX certification, its electrical design adheres to IEC 61000-6-2 (immunity) and IEC 61000-6-4 (emissions) standards for industrial environments. For validation-critical installations, users may perform IQ/OQ protocols in accordance with ISO 14644-3 and EU GMP Annex 1 requirements, leveraging its stable analog output and deterministic response time (<5 ms) for traceable pressure cascade verification.

Software & Data Management

The GTI-145 operates as a stand-alone, firmware-based transmitter with no embedded software stack or network interface. All configuration—including range selection, unit preference, output mode, and filter setting—is performed locally via tactile buttons and visual feedback on the segmented LCD. Analog output signals are inherently compatible with PLCs (e.g., Siemens S7, Allen-Bradley ControlLogix), DCS systems, and data loggers compliant with 4–20 mA or 0–5 V input specifications. For facilities requiring audit-ready records, the 4–20 mA output may be connected to a validated data acquisition system supporting 21 CFR Part 11 compliance (e.g., Emerson DeltaV, Yokogawa CENTUM VP), where timestamped pressure trends, alarm states (via discrete outputs), and calibration logs can be archived under defined electronic record governance policies.

Applications

• Room-to-room differential pressure monitoring in hospital isolation rooms and pharmaceutical cleanrooms
• Filter resistance tracking across HEPA and ULPA filtration stages in HVAC and laminar flow hoods
• Combustion air-to-fuel ratio verification in low-pressure burner management systems
• Pressure drop measurement across orifice plates, venturis, and pitot tubes in low-velocity gas lines
• Real-time negative pressure verification in mobile biocontainment units and transport isolators
• Process gas line integrity checks during sterile utility qualification (e.g., compressed air, nitrogen)
• Environmental chamber pressure stability logging for semiconductor wafer fabrication tooling

FAQ

What gases are compatible with the GTI-145?
Clean, dry, non-corrosive gases only—such as ambient air, nitrogen, argon, and carbon dioxide at dew points below −20°C. Moisture, oil aerosols, or acidic/alkaline vapors will degrade sensor performance and void warranty.
Can the GTI-145 be used in explosion-hazardous areas?
No. The GTI-145 lacks intrinsic safety (IS) or flameproof (Ex d) certification and must not be installed in Zone 0, 1, or 2 hazardous locations per IEC 60079.
Is field recalibration possible without manufacturer tools?
Yes—zero point adjustment is accessible via the front-panel potentiometer. Full span calibration requires reference-standard equipment and is recommended annually or after mechanical shock exposure.
How is overpressure protection implemented?
The GTI-145 withstands static overpressure up to 20 kPa without permanent zero shift or damage—exceeding its maximum rated range (5 kPa) by 4×, providing margin for transient surges in duct or chamber systems.
Does the device support HART or other digital communication protocols?
No. The GTI-145 provides only analog (4–20 mA / 1–5 VDC) and discrete (NPN/PNP) outputs. It does not include HART, Modbus, or IO-Link interfaces.