Designed for building air conditioning applications, this humidity and temperature transmitter is available in wall or duct versions with a long-term stable humidity sensor. Additionally, two analog outputs cover temperature and humidity, and P2A software supports parameterization, adjustment, and analysis. It suits both room and duct installations, with an optional 2-line LCD display.
Designed for building air conditioning applications, this humidity and temperature transmitter is available in wall or duct versions with a long-term stable humidity sensor. Additionally, two analog outputs cover temperature and humidity, and P2A software supports parameterization, adjustment, and analysis. It suits both room and duct installations, with an optional 2-line LCD display.
In industrial settings, compressed air is a vital energy source, though it can lead to significant costs. Accurate measurement and control technology provide transparency in compressed air usage, helping you save energy, reduce costs, and achieve effective environmental management, such as compliance with ISO 50001 or ISO 14001.
The measurement transmitter testo 6621 stands out thanks to its patented humidity sensor which guarantees highest accuracy. Particularly practical: The sensor and the analog outputs can be adjusted, analyzed and parameterized via an external interface using the P2A software. Select the suitable design according to your application in a room or a duct. The measurement transmitter testo 6621 is available in different product variations: optionally with or without display, in the housing colours grey or white.
Features
Applications
| Measurement Parameters | |
| Humidity | Range: 0 to 100% RH (>90% RH only briefly) Accuracy: ±2.0% RH (0 to 90% RH); ±4% RH (90 to 100% RH) |
| Temperature | Range: 32 to 140°F (0 to 60°C) wall version; -4 to 158°F (-20 to 70°C) duct version ±0.9°F (±0.5°C) |
| Inputs and Outputs | |
| Output Type | 4 to 20 mA (2-wire) or 0 to 1/5/10 V (4-wire) |
| Sensor | Testo humidity sensor (active output: NTC; passive output: Ni1000) |
| Voltage Supply | 20 to 30 V AC/DC |
| General Specifications | |
| Display | 2-line LCD (optional) |
| Material / Colour | ABS, pure white (RAL 9010) or light grey |
| Weight | 5.6 oz (160 g) wall version; 2.8 to 3.2 oz (80 to 90 g) duct version |
| Protection Class | IP30 (wall version); IP65 (duct version) |
| Operating Temperature (Electronics) | 32 to 140°F (0 to 60°C) wall; -4 to 158°F (-20 to 70°C) duct |
| Storage Temperature | -40 to 176°F (-40 to 70°C) |
| Interface | 1x Mini-DIN for PC connection (P2A software) |
| Measurement Parameters | |
| Humidity | Range: 0 to 100% RH (>90% RH only briefly) Accuracy: ±2.0% RH (0 to 90% RH); ±4% RH (90 to 100% RH) |
| Temperature | Range: 32 to 140°F (0 to 60°C) wall version; -4 to 158°F (-20 to 70°C) duct version ±0.9°F (±0.5°C) |
| Inputs and Outputs | |
| Output Type | 4 to 20 mA (2-wire) or 0 to 1/5/10 V (4-wire) |
| Sensor | Testo humidity sensor (active output: NTC; passive output: Ni1000) |
| Voltage Supply | 20 to 30 V AC/DC |
| General Specifications | |
| Display | 2-line LCD (optional) |
| Material / Colour | ABS, pure white (RAL 9010) or light grey |
| Weight | 5.6 oz (160 g) wall version; 2.8 to 3.2 oz (80 to 90 g) duct version |
| Protection Class | IP30 (wall version); IP65 (duct version) |
| Operating Temperature (Electronics) | 32 to 140°F (0 to 60°C) wall; -4 to 158°F (-20 to 70°C) duct |
| Storage Temperature | -40 to 176°F (-40 to 70°C) |
| Interface | 1x Mini-DIN for PC connection (P2A software) |
