Key facts
- Brand
- Vaisala
- Model
- GMD20
- Industry
- Industrial
- Documents
- 4
- Languages
- JA · EN · FI
- Last added
- 2012-04-06
Start here
Vaisala GMD20 Operating Instructions
The GMD20 series CO₂ transmitter uses Vaisala's CARBOCAPS sensor technology for high stability and repeatability, suitable for ventilation control and other applications. The manual provides guidance on duct mounting, electrical connections, and optional relay or LonWorks interfaces.
Key sections include installation steps, power supply requirements, wiring diagrams, technical specifications, and service/maintenance recommendations, including yearly calibration and safety warnings. This manual is written in Japanese.
Vaisala GMD20 specifications
| Measurement range | 0‑2 000 ppm CO, 0‑5 000 ppm CO₂, 0‑10 000 ppm CO₂, 0‑20 000 ppm CO₂ |
|---|---|
| Resolution (analog output) | 0.596 %FS |
| Response time (63 % rise) | 1 min |
| Operating temperature range | -5 °C to +45 °C |
| Operating humidity range | 0‑85 % RH |
| Analog output options | 0‑20 mA or 4‑20 mA, 0‑10 V |
| Current output max | 500 µA |
| Voltage output min | 1 kΩ |
| Relay contact rating | 50 V 0.5 A |
| Power consumption | < 2.5 W average |
| Storage temperature range | -20 °C to +70 °C |
| Weight | 140 g (typical) / 170 g (max) |
All Vaisala GMD20 documents by type
Day-to-day operation, settings and troubleshooting. Start here if the product is already set up.
Questions answered in these manuals
How often should the GMD20 be calibrated?
Calibration is recommended once a year under normal operating conditions.
What power supply voltage is required for the GMD20?
The device is designed for a nominal 24 V AC or DC supply, with acceptable ranges of 18‑30 V DC or 20‑26 V AC.
What is the recommended calibration interval for the GMD20?
The recommended calibration interval is five years for HVAC and related benign applications.
How should the GMD20 be mounted?
The GMD20 is duct‑mounted using a mounting plate fastened with four screws, allowing the probe distance to be adjusted.
How often should the GMD20/D be calibrated?
The recommended calibration interval is five years under normal indoor conditions.
How often should the GMD20/D transmitter be calibrated?
The recommended calibration interval is five years.