York Instruments DM9700 Cold Mirror Dew Point Meter
| Brand | York Instruments |
|---|---|
| Origin | Beijing, China |
| Manufacturer Type | Manufacturer |
| Product Type | Portable Dew Point Meter |
| Measurement Principle | Chilled-Mirror Hygrometry |
| Operating Temperature | -20 °C to +40 °C |
| Accuracy | ±0.1 °C |
| Repeatability | ±0.05 °C |
| Dew Point Range | -70 °C to +20 °C |
| Resolution | 0.01 °C |
| Response Time | ≤60 s (for 10 °C step change) |
| Mirror Material | Chromium-Plated Copper |
| Flow Rate Range | 0–2 L/min (accuracy ±5%) |
| Pressure Sensor Range | 0–200 kPa (abs), accuracy ±0.25% FS |
| Remote Temperature Sensor | 4-wire PT100, accuracy ±0.1 °C, cable length <2 m |
| Power Supply | 80–264 VAC, 47–63 Hz, 400 W |
| Analog Outputs | 4–20 mA / 0–20 mA / 0–24 mA / 0–5 V / 0–10 V (3-channel, user-configurable) |
| Alarm Outputs | 2 programmable SPDT relays (250 VAC/5 A, 30 VDC/5 A, resistive load) |
| Communication | USB, RS-485, Modbus RTU protocol |
| Data Storage | SD card (FAT32, up to 32 GB) |
| Display | 7" LCD touch screen, 1024×600 RGB WVGA, 16:9 aspect ratio |
| Supported Units | °C, °F, ppmv, ppmw, %RH, g/kg, mg/m³ |
| Sample Gas Temp | -20 °C to +40 °C |
| Sample Gas Pressure | 0–200 kPa (abs) |
| Sample Flow Rate | 0.3–1 L/min |
| Environmental Humidity Limit | <80% RH |
| Storage Temperature | -20 °C to +50 °C (optimal at 20 °C) |
| Dimensions | 190 mm (H) × 483 mm (W) × 498 mm (D) |
| Weight | 15 kg |
| Gas Inlet Fitting | 1/4" stainless steel compression fitting |
| Enclosure Material | Aluminum alloy |
| Gas Path Materials | 316L stainless steel |
Overview
The York Instruments DM9700 Cold Mirror Dew Point Meter is a high-precision, microprocessor-controlled hygrometer engineered for trace moisture analysis in compressed air, industrial gases, natural gas transmission, semiconductor process lines, and pharmaceutical dry-air systems. It operates on the fundamental physical principle of chilled-mirror hygrometry: a polished, temperature-controlled mirror surface is cooled until condensation forms; the corresponding mirror temperature—measured with a calibrated platinum resistance thermometer (PT100)—is defined as the dew point temperature. This primary measurement method provides direct, absolute humidity quantification without calibration drift, making the DM9700 suitable for reference-grade applications and metrological traceability. Its chromium-plated copper mirror ensures rapid thermal response and long-term stability under repeated condensation cycles, while integrated digital fuzzy logic control enables autonomous mirror cooling, condensate detection, and dynamic equilibrium stabilization—minimizing operator intervention and maximizing measurement reproducibility.
Key Features
- Chilled-mirror sensor with chromium-plated copper substrate for enhanced thermal conductivity, corrosion resistance, and optical reflectivity
- 7-inch capacitive touchscreen LCD (1024×600 WVGA) with intuitive, icon-driven UI supporting English and Chinese language switching
- Dual-mode operation: standalone field measurement or rack-mounted integration (19″, 4U standard chassis)
- Triple-sensor fusion architecture: dew point mirror, inline flow meter (0–2 L/min), absolute pressure transducer (0–200 kPa abs), and remote 4-wire PT100 temperature probe
- Intelligent mirror maintenance system: automated condensate detection, periodic self-cleaning sequence, and real-time mirror contamination assessment
- Configurable analog outputs (3 channels) supporting 4–20 mA, 0–10 V, and other industrial signal standards for PLC/SCADA interfacing
- Two programmable SPDT relay outputs with configurable alarm thresholds for process interlock or maintenance notification
- Fat32-formatted SD card logging (up to 32 GB) with timestamped, multi-parameter records compliant with GLP audit requirements
Sample Compatibility & Compliance
The DM9700 is validated for continuous monitoring of non-corrosive, particle-free gas streams including compressed air (ISO 8573-1 Class 0–4), nitrogen, argon, hydrogen, CO₂, and natural gas. Sample conditioning is required for gases containing oil aerosols, particulates >0.1 µm, or condensable hydrocarbons. The instrument meets IEC 61000-6-2 (immunity) and IEC 61000-6-3 (emissions) standards. Its pressure and temperature compensation algorithms align with ISO 6245 and ASTM D1142 for water vapor content calculation. While not intrinsically safe, optional ATEX/IECEx-certified enclosures are available upon request. All firmware and data handling protocols support 21 CFR Part 11-compliant electronic records when used with validated PC software and access-controlled user roles.
Software & Data Management
York Instruments provides a Windows-based desktop application for configuration, real-time visualization, historical trend analysis, and report generation (PDF/CSV). The software implements full audit-trail functionality—including user login logs, parameter change history, and calibration event timestamps—meeting GLP and GMP documentation requirements. Data export supports SI units and industry-standard moisture metrics (ppmv, ppmw, g/kg, mg/m³). Firmware updates are delivered via encrypted USB stick or secure HTTPS download, with SHA-256 checksum verification. The embedded Modbus RTU interface enables seamless integration into distributed control systems (DCS) and MES platforms without proprietary drivers.
Applications
- Compressed air quality validation per ISO 8573-1 for food, beverage, and pharmaceutical manufacturing
- Moisture monitoring in SF₆-insulated high-voltage switchgear (IEC 60480 compliance)
- Process gas drying verification in petrochemical refining and LNG dehydration units
- Environmental chamber and glovebox humidity control in R&D laboratories
- Calibration transfer standard for capacitance and aluminum oxide hygrometers
- On-site verification of desiccant dryer performance and regenerative cycle efficiency
FAQ
What is the recommended calibration interval for the DM9700?
York Instruments recommends annual calibration using NIST-traceable chilled-mirror reference standards; however, interval may be extended to 18 months under documented stable operating conditions and successful interim verification checks.
Can the DM9700 measure dew point below -70 °C?
No—the certified measurement range is strictly -70 °C to +20 °C. Operation outside this range risks mirror icing, thermal stress damage, and invalid readings.
Is the flow sensor mandatory for accurate dew point measurement?
Yes. Accurate dew point determination requires known sample flow rate (0.3–1 L/min optimal) to ensure laminar, thermally stabilized conditions at the mirror surface; unregulated flow introduces convective heat loss and measurement uncertainty.
Does the DM9700 support HART communication?
No—it features RS-485/Modbus RTU and USB only. HART compatibility requires external protocol converters.
How is mirror contamination detected and reported?
The system continuously analyzes reflected light intensity and cooling dynamics; deviations exceeding factory-set thresholds trigger “Mirror Dirty” status, logged event, and on-screen advisory—prompting manual cleaning or service.
