Key facts
- Brand
- Vaisala
- Model
- GMW20
- Industry
- Industrial
- Documents
- 2
- Languages
- JA · EN
- Last added
- 2012-04-06
Start here
Vaisala GMW20 Carbon Dioxide Transmitter User Guide
The GMW20 series transmitters use a silicon‑based CARBOCAP® sensor and are supplied calibrated from the factory. The guide covers basic information, mounting options, electrical connections, and power‑supply requirements for the GMW20, GMW21, and GMW22 models.
Installation steps include drilling a mounting hole, routing power and signal wires through the back plate, and securing the PCB. Electrical connections describe the 24 V supply, selectable voltage or current output, and jumper settings. Power‑supply specifications and recommendations for single‑transmitter or shared‑transformer setups are also provided.
Vaisala GMW20 specifications
| Measurement range | 0‑2000 ppm CO, 0‑5 000 ppm CO₂, 0‑10 000 ppm CO₂, 0‑20 000 ppm CO |
|---|---|
| Power supply | Nominal 24 VDC/24 VAC (18‑30 VDC range) |
| Maximum current draw | 85 mA (peak 170 mA) |
| Dimensions | 80 mm × 80 mm × 85 mm |
| Operating temperature range | -20 °C to +70 °C |
All Vaisala GMW20 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 GMW20 be calibrated?
Calibration is recommended every year for typical operating environments.
What are the power supply requirements for the GMW20?
The unit requires a nominal 24 VDC or 24 VAC supply, with an acceptable range of 18‑30 VDC.
How should the GMW20 be mounted?
The GMW20 is shipped ready for installation onto a standard wallbox or surface mounting; drill a hole, pull wiring through, open the cover, remove the PCB, route the cables, and secure the base with screws.
What power supply does the GMW20 require?
It uses a nominal 24 VAC/VDC supply with a voltage range of 18‑30 VDC or 20‑26 VAC, and a DC supply is recommended to avoid current peaks.