Series-GSTA

Supported Applications

The Dwyer Series GSTA Carbon Monoxide (CO) and Nitrogen Dioxide (NO₂) Gas Transmitters monitor gas concentration in underground parking garages and loading docks. The CO transmitter measures exhaust from gasoline engines, while the NO₂ transmitter is designed for diesel engine applications.

Operating Conditions & Performance

The Series GSTA operates within an ambient temperature range of -4 to 122°F (-20 to 50°C). For best sensor life, storage should be maintained between 32 to 68°F (0 to 20°C). The unit is rated for humidity levels of 15 to 90% RH constant and 0 to 99% RH intermittent. Performance specifications include:

• Accuracy: CO: ±2% FS; NO₂: ±3% FS, at the time of calibration.
• Resolution: CO: 1 PPM; NO₂: 0.1 PPM.
• Response Time: <45 s to 90% CO; <25 s to 90% NO₂.
• Sensor Lifespan: Field replaceable electrochemical sensors with a typical lifespan of 4 years.
• Coverage Area: 5,000 to 7,500 sq ft typical.

The housing is constructed from UV resistant glass filled polycarbonate and carries an IP64 enclosure rating. The unit weighs 1 lb (0.45 kg).

Configuration Options

The Series GSTA offers configurable measurement ranges, output signals, and calibration options to accommodate specific installation needs.

• Measurement Ranges:
  • CO: Switch selectable 200 or 500 PPM; adjustable from 0 to 50 PPM up to 0 to 599 PPM.
  • NO₂: Standard range of 10 PPM (0 to 10 PPM).
• Output Signals: Switch selectable options include:
  • 4-20 mA (loop powered)
  • 0-5 V @ 5 mA or 0-10 V @ 5 mA
  • Switch selectable 0-5 V/1-5 V or 0-10 V/2-10 V
  • Normal or reverse output configuration.
• Power Requirements:
  • Current output: 10-35 VDC
  • Voltage output: 15-35 VDC or 15-29 VAC
• Electrical Connection: Removable terminal block with knockouts for conduit fitting.
• Calibration & Display Options:
  • Span and zero adjustments via onboard push-buttons (LCD model only) or using the optional A-449 remote LCD display.
  • The A-449 display indicates when a sensor needs replacement.

Key Product Differences

Dwyer Series GSTA models are distinguished by the gas sensed and available options:

• Gas Type: Models are designated for Carbon Monoxide (CO) or Nitrogen Dioxide (NO₂). CO units feature switch-selectable ranges, while NO₂ units utilize a standard 10 PPM range.
• LCD Display Option: Variants with the "-LCD" suffix include an onboard display for calibration and status monitoring. Non-LCD models require the optional A-449 remote LCD display for these functions.
• Duct Mounting: Models designated with a "-D" option are configured for duct mounting, utilizing a kit that includes an air flow pitot tube, air filter with barbed connections, and tubing components. Wall mount dimensions differ from duct mount configurations (Wall: 3-45/64 x 3-1/8 x 4-17/32 inches; Duct: 2-15/64 x 2-55/64 x 3-59/64 inches).
• Field Calibration: Models with the "-FC" suffix indicate field calibration capabilities or configurations.