The Vaisala GMW90 Series provides stable wall-mounted carbon-dioxide and temperature measurement, with optional humidity, for demanding HVAC and building-automation applications.
The Vaisala GMW90 Series is designed for room-level carbon-dioxide measurement in demand-controlled ventilation, green buildings and other HVAC applications where measurement stability and maintainability are important. Every model measures CO₂ and temperature; R models add relative humidity.
Vaisala CARBOCAP® technology measures CO₂ using an internal reference, supporting stable long-term operation. Exchangeable measurement modules allow maintenance and traceability to be restored without replacing the complete installed transmitter.
| Model | Measured parameters | Output | Local indication |
|---|---|---|---|
| GMW93 | CO₂ and temperature | Three-wire voltage outputs | No display |
| GMW93D | CO₂ and temperature | Three-wire voltage outputs | Display |
| GMW94 | CO₂ and temperature | Three-wire current outputs | No display |
| GMW94D | CO₂ and temperature | Three-wire current outputs | Display |
| GMW95 | CO₂ and temperature | Modbus RTU | No display |
| GMW95D | CO₂ and temperature | Modbus RTU | Display |
| GMW93R | CO₂, temperature and relative humidity | Three-wire voltage outputs | No display |
| GMW93RD | CO₂, temperature and relative humidity | Three-wire voltage outputs | Display |
| GMW93RA | CO₂, temperature and relative humidity | Three-wire voltage outputs | Display with CO₂ LED indicator |
| GMW94R | CO₂, temperature and relative humidity | Three-wire current outputs | No display |
| GMW94RD | CO₂, temperature and relative humidity | Three-wire current outputs | Display |
| GMW95R | CO₂, temperature and relative humidity | Modbus RTU | No display |
| GMW95RD | CO₂, temperature and relative humidity | Modbus RTU | Display |
| GMW90 | CO₂ and temperature | Configurable analogue or Modbus RTU | Configuration dependent |
| GMW90R | CO₂, temperature and relative humidity | Configurable analogue or Modbus RTU | Configuration dependent |
| Requirement | Recommended model family | Selection note |
|---|---|---|
| CO₂ and temperature only | GMW93, GMW94 or GMW95 families | Avoid paying for humidity when the control or monitoring system does not require it |
| CO₂, temperature and humidity | GMW93R, GMW94R or GMW95R families | Select an R model and provide enough receiving channels or fieldbus registers |
| Voltage outputs | GMW93 family | Confirm whether the controller accepts 0–5 V or 0–10 V and check input grounding |
| Current outputs | GMW94 family | Confirm 0–20 mA or 4–20 mA scaling and available loop resistance |
| Modbus RTU | GMW95 family | Confirm RS-485 wiring, baud rate, parity, address and termination |
| Local display | Models ending in D | Useful for commissioning and occupant-facing indication |
| Visible CO₂ status | GMW93RA | Adds display and an LED indicator for CO₂ status |
| Specification | GMW90 Series |
|---|---|
| Measurement range | 0 to 5000 ppm CO₂ |
| Sensor | Vaisala CARBOCAP® GM10 |
| Accuracy from +20 to +30 °C | ±(30 ppm + 2% of reading) |
| Accuracy from +10 to +20 °C and +30 to +40 °C | ±(35 ppm + 2.7% of reading) |
| Accuracy from −5 to +10 °C and +40 to +55 °C | ±(45 ppm + 3.8% of reading) |
| Five-year stability in typical HVAC applications | Total room-temperature accuracy of approximately ±75 ppm at 600 and 1000 ppm, including five-year drift |
| Default analogue scale | 0 to 2000 ppm CO₂ |
| Calibration supplied | Traceable three-point CO₂ calibration certificate |
The sensor measures up to 5000 ppm, but the standard analogue scale may be 0 to 2000 ppm. Confirm the required output scaling when the building-management system must read concentrations above 2000 ppm.
| Parameter | Range | Best specified accuracy | Sensor |
|---|---|---|---|
| Temperature | −5 to +55 °C | ±0.5 °C from +20 to +30 °C | Digital temperature sensor |
| Relative humidity | 0 to 95 %RH | ±2.5 %RH from 0 to 60 %RH at +10 to +40 °C | Vaisala HUMICAP® 180R |
Humidity accuracy changes with humidity and temperature. Use the complete datasheet specification when assessing performance near high humidity or outside the central temperature range.
| Specification | GMW90 Series |
|---|---|
| Supply voltage | 18 to 35 V DC or 24 V AC ±20%, 50/60 Hz |
| Current-output options | 0–20 mA or 4–20 mA; two- and three-channel models |
| Maximum current-output loop resistance | 600 Ω |
| Voltage-output options | 0–5 V or 0–10 V; two- and three-channel models |
| Minimum voltage-output load resistance | 10 kΩ |
| Fieldbus | Galvanically isolated RS-485 with Modbus RTU |
| Modbus address range | 0 to 247 |
| Operating temperature | −5 to +55 °C |
| Operating humidity | 0 to 95 %RH, with dew point below +30 °C |
| Enclosure rating | IP30 |
| Housing | White ABS/PC wall enclosure |
| Weight | Approximately 163 g |
| Connections | Screw terminals accepting wire up to 2 mm² / AWG 14 |
| Application | How GMW90 is used | Configuration starting point |
|---|---|---|
| Demand-controlled ventilation | Adjusts outdoor-air delivery according to occupied-space CO₂ | CO₂ and temperature with analogue or Modbus RTU output |
| Green commercial buildings | Provides stable indoor-air-quality data for the building-management system | Add humidity where comfort or moisture control is required |
| Meeting rooms and classrooms | Tracks occupancy-related CO₂ changes | Display model where occupants or facility staff need local visibility |
| Offices and public spaces | Supports ventilation optimisation and indoor-condition trending | Select output according to the installed controller |
| Museums and controlled rooms | Combines CO₂ with temperature and optional humidity | Use an R model when humidity is part of the monitoring requirement |
| Selection point | GMW90 Series | GMW80 Series | GMD110 | Origo10 |
|---|---|---|---|---|
| Installation | Room wall | Room wall | Ventilation duct | Wall, duct or remote-probe arrangement according to configuration |
| Main position | Higher-performance room CO₂, temperature and optional HUMICAP humidity measurement | Cost-effective room HVAC and demand-controlled ventilation | CO₂ measurement directly inside an air duct | Modular multi-parameter HVAC platform with replaceable probes |
| CO₂ range | 0 to 5000 ppm | Selected 0–2000 or 0–5000 ppm models | Up to 10,000 ppm measurement range | Depends on the selected compatible CO₂ probe |
| Humidity technology | Optional HUMICAP® 180R | Selected models use INTERCAP® | CO₂ only | Depends on the selected interchangeable probe |
| Outputs | Voltage, current or Modbus RTU | Depends on model; building-automation options available | Analogue and Modbus RTU options | Analogue, Modbus RTU or BACnet MS/TP according to model |
| Product information | Current product | Explore Vaisala GMW80 | Explore Vaisala GMD110 | Explore Vaisala Origo10 |
| Selection point | GMW80 Series | GMW90 Series |
|---|---|---|
| Product position | Cost-efficient transmitter family for standard demand-controlled ventilation and indoor air-quality measurement | Higher-performance transmitter family for demanding HVAC and green-building projects |
| Measured parameters | CO₂-only, CO₂ + temperature, or CO₂ + temperature + humidity depending on model | CO₂ + temperature on all models, with humidity added on R models |
| CO₂ range | 0–2000 ppm on most models; selected models support 0–5000 ppm | 0–5000 ppm |
| Best CO₂ accuracy at +20 to +30 °C | Up to ±(30 ppm + 3% of reading), depending on model | Up to ±(30 ppm + 2% of reading) |
| Humidity sensor | Vaisala INTERCAP® on humidity models | Vaisala HUMICAP® 180R on R models |
| Best humidity accuracy | Designed for standard HVAC measurement; confirm the selected model's specification | Up to ±2.5 %RH from 0 to 60 %RH at +10 to +40 °C |
| Outputs | Voltage, current, relay or Modbus RTU options depending on model | Voltage, current or galvanically isolated Modbus RTU options |
| Local indication | Display or CO₂ LED indicator available on selected models | Display available on D models; GMW93RA adds a CO₂ LED indicator |
| Field maintenance | Low-maintenance CARBOCAP® design; service arrangement depends on model | Field-exchangeable calibrated CO₂, temperature, and humidity/temperature modules |
| Choose GMW80 when | A cost-effective standard HVAC solution provides the required range, output and accuracy | — |
| Choose GMW90 when | — | The project needs a consistent 0–5000 ppm range, stronger measurement accuracy or exchangeable calibrated modules |
| Product information | Explore Vaisala GMW80 | GMW90 models are detailed on this page |
| Module | Used for | Maintenance role |
|---|---|---|
| GM10SP | CO₂ measurement | Factory-calibrated replacement CO₂ module |
| TM10SP | Temperature in CO₂ + T models | Replacement temperature module for the applicable model |
| HTM10SP | Humidity and temperature in CO₂ + T + RH models | Replacement HUMICAP humidity and temperature module |
The exchangeable modules support efficient field maintenance, but the replacement must match the transmitter model and measurement configuration. Calibration checks can also be performed with suitable reference equipment and the applicable Vaisala procedure.
Seacom Process Instruments supplies and supports the Vaisala GMW90 Series CO₂, temperature and humidity transmitters in Malaysia for demand-controlled ventilation, green buildings, offices, meeting rooms, classrooms and demanding HVAC applications.
Our team can help select the measured parameters, voltage, current or Modbus RTU model, display option, analogue scaling and suitable installation location. We can also assist with commissioning, reference checks and replacement measurement modules.
Selecting a GMW90 model? Send us the room type, expected occupancy, required CO₂ range, temperature and humidity requirements, controller input, supply voltage, display preference and building-management protocol.
Download |
.
The Vaisala HMW90 Series provides high-accuracy humidity and temperature measurement for demanding indoor HVAC and controlled-environment applications.
.
The Vaisala RFL100 uses secure, long-range VaiNet wireless technology to monitor temperature, relative humidity and carbon dioxide with the AP10 Access Point and viewLinc Continuous Monitoring System.
The Vaisala Indigo300 is a rugged industrial transmitter for one Vaisala Indigo-compatible smart probe, providing local measurement display and up to three configurable analog outputs.
Its corrosion-resistant IP66 metal enclosure, flexible probe mounting and interchangeable probe design make Indigo300 suitable for humidity, temperature, dew point, CO2, moisture in oil and other demanding industrial measurements.
The Vaisala GM70 was a portable carbon-dioxide meter for diffusion measurements, pump sampling, data logging and field checking fixed CO₂ instruments.
The Vaisala GMD110 measures carbon dioxide directly inside ventilation ducts for precise HVAC control and demand-controlled ventilation.
The Vaisala MGP262 continuously measures methane slip and carbon dioxide in offgas from biomethane-upgrading processes. Its in-situ design provides direct, always-on measurement without a separate sampling system.
The Vaisala VDL200 is a secure Power-over-Ethernet data logger for monitoring temperature, relative humidity, carbon dioxide and analog or Boolean inputs in controlled and GxP-regulated environments.
Designed for the Vaisala viewLinc Continuous Monitoring System, the VDL200 combines interchangeable smart probes, onboard memory and battery backup to provide reliable, gap-free environmental monitoring.
The Vaisala GMP251 is an intelligent probe for stable percentage-level carbon-dioxide measurement in incubators, controlled-atmosphere storage and demanding industrial applications.
The Vaisala GMP231 is an OEM carbon-dioxide probe designed for accurate measurement and permanent wall installation in life-science incubators.
The Vaisala GMP343 is a rugged, high-accuracy carbon-dioxide probe for outdoor monitoring, ecological research, soil respiration, plant-growth chambers and demanding OEM applications.
The Vaisala GMW80 Series provides dependable, cost-efficient room measurement for demand-controlled ventilation and indoor air-quality applications.
The Vaisala GMD20 Series was designed for carbon-dioxide measurement inside ventilation ducts and demand-controlled ventilation systems.
The Vaisala Indigo500 Series provides flagship industrial measurement integration: choose Indigo510 for a simplified single-probe system or Indigo520 for full dual-probe capability.
The Vaisala GMW90 Series provides stable wall-mounted carbon-dioxide and temperature measurement, with optional humidity, for demanding HVAC and building-automation applications.
.png)
GMW90 catalogue
(199.76k)
