The testo 6321 differential pressure transmitter offers an optimal balance between price and operational characteristics; it is ideally suited for application in ventilation and air conditioning systems. Equipment for complex building automation requires high-precision monitoring, which is why special demands are placed on the measurement technologies used. The testo 6321 will support the optimization of microclimate conditions and energy saving.

The transmitter is used for monitoring in industrial and commercial, office and administrative buildings, in exhibition halls, museums, and libraries, as well as in cleanrooms. Learn more about the testo 6321.

Order Number 0555 6321

The testo 6381 measures differential pressure, flow velocity, and volumetric flow; optionally: humidity and temperature measurement. Automatic zero point adjustment guarantees high, temperature-independent accuracy and long-term stability. The measuring range down to 10 Pa ensures high accuracy when measuring low pressures. Ethernet, relay, and analog outputs allow for optimal integration of the transmitters into individual automated systems.

The transmitter has a wide range of applications (cleanrooms, drying processes, bottling and dosing processes – in spray painting systems).

Order Number 0555 6381

The testo 6621 transmitter for air conditioning systems is specially designed for application in this field, which includes the regulation and monitoring of air conditioning in buildings such as office buildings, museums, hotels, hospitals, as well as in storage and production rooms. Commissioning and maintenance performed via the external interface (mini-DIN) and Testo P2A software significantly save your time.

The instrument is not suitable for use in drying processes and conditions of high humidity (**relative humidity exceeds 90%**).

Order Number 0555 6621

The testo 6681 transmitter fully meets the professional instrument requirements for the industrial sector and has a robust metal housing. In addition to the features and characteristics of the testo 6651, it possesses a range of other advantages. The transmitter is chosen for use in cleanrooms, drying systems, compressed air systems with residual moisture, and complex air conditioning technology.

Features:

• Highest accuracy and long-term stability
• **Replaceable pre-calibrated** testo 6610 series probes
• Special probe versions for measuring **residual moisture**, in **H2O2** atmospheres, and in **polluted environments**.
• **Robust metal housing**
• Optional **ProfiBus DP** bus interface
• Optimal adjustment and calibration capabilities **on-site**
• Optional **Ethernet** interface
• Early warning protocols / **self-monitoring**
• Configuration via **P2A** adjustment and parameterization software or via the instrument menu
• Saving adjustment history/reports in the instrument memory
• All the most common instrument configurations can be ordered via **user configuration**

The most suitable application areas for these measuring solutions are:

• Process control
• Cleanrooms
• Test benches
• Drying processes
• Air quality in production and warehouses
• Relevant applications for ventilation and air conditioning systems

Order Number 0555 6681

The testo 6742 instrument was specifically designed for measuring residual moisture in compressed or dry air (adsorption dryers). This type of measurement is successfully carried out thanks to the Testo humidity sensor and its proven and well-established long-term stability. The sensor’s effectiveness has been repeatedly confirmed through tests in international calibration laboratories (PTB, NIST, etc.), where the error limit of ± 1% RH was not exceeded for 5 years without sensor readjustment. Optimal accuracy is achieved due to special tuning in the residual moisture range.

The results of the testo 6742 development: the possibility of measurement in the range of -45 °Ctd to +30 °Ctd and an accuracy of ±1 K (dew point) at 0 °Ctd.

For the configuration of output parameters such as pressure dew point, relative humidity, temperature, ppmvol. (parts per million by volume), absolute humidity, and atmospheric dew point, you can use the freely adjustable analog output—optionally with a signal module connector for monitoring maximum values.

Additionally, the testo 6742 features a compact and convenient design with a 350° rotatable housing function for the most optimal display positioning.

Order Number 0555 6742

The testo 6744 instrument was specifically designed for measuring residual moisture in compressed or dry air (adsorption dryers). This type of measurement is successfully carried out thanks to the Testo humidity sensor and its proven and well-established long-term stability. The sensor’s effectiveness has been repeatedly confirmed through tests in international calibration laboratories (PTB, NIST, etc.), where the error limit of ± 1% RH was not exceeded for 5 years without sensor readjustment. Optimal accuracy is achieved due to special tuning in the residual moisture range.

The results of the testo 6744 development: the possibility of measurement in the range of -45 °Ctd to +30 °Ctd and an accuracy of ±1 K (dew point) at 0 °Ctd.

For the configuration of output parameters such as pressure dew point, relative humidity, temperature, ppmvol. (parts per million by volume), absolute humidity, and atmospheric dew point, you can use the freely adjustable analog output—optionally with a signal module connector for monitoring maximum values.

Additionally, the testo 6744 features a compact and convenient design with a 350° rotatable housing function for the most optimal display positioning.

Order Number 055

testo 6383 for cleanroom applications, with optional humidity and temperature measurement, selectable measuring ranges from 10 Pa to 10 hPa, selectable analog signal outputs, and optional display (depending on configuration)

• The flat housing allows for flush mounting on the cleanroom wall
• The low measuring range from 10 Pa ensures the highest accuracy for low pressure measurement
• Transmitter for measuring differential pressure, as well as, optionally, humidity and temperature
• Automatic zero point adjustment guarantees high accuracy independent of temperature and long-term stability

testo 6383 differential pressure transmitter for cleanroom applications (panel mounting), optionally with temperature/humidity measurement function, accuracy ±0.3% of measuring range, automatic “zero point” adjustment, selectable measuring ranges from 10 Pa to 10 hPa, selectable analog signal outputs, external digital interface for adjustment and parameterization, display, data output in all pressure and humidity units.

The testo 6651 transmitter is suitable for stationary measurements in air conditioning systems for rooms (comfort level monitoring, museums, storage of hygroscopic materials, storage of electronic components) and for stationary measurements of industrial climate conditions (drying processes, food products, cheese ripening, fruit maturation, pasta drying, bio-research, mushroom cultivation).
System components are monitored using the instrument; commissioning, adjustment, and analysis are possible directly without the use of software (optional display/operation menu). Measured parameters, settings, and reports are stored in the device’s memory—with an hourly operation counter. The transmitter performs continuous self-monitoring.
Order Number 0555 6651

The results of the testo 6741 development: the possibility of measurement in the range of -45 °Ctd to +30 °Ctd and an accuracy of ±1 K (dew point) at 0 °Ctd. For the configuration of output parameters such as pressure dew point, relative humidity, temperature, ppmvol. (parts per million by volume), absolute humidity, and atmospheric dew point, you can use the freely adjustable analog output—optionally with a signal module connector for monitoring maximum values. Additionally, the testo 6741 features a compact and convenient design with a 350° rotatable housing function for the most optimal display positioning.

Order Number 0555 6741

The testo 6743 instrument was specifically designed for measuring residual moisture in compressed or dry air (adsorption dryers). This type of measurement is successfully carried out thanks to the Testo humidity sensor and its proven and well-established long-term stability. The sensor’s effectiveness has been repeatedly confirmed through tests in international calibration laboratories (PTB, NIST, etc.), where the error limit of ± 1% RH was not exceeded for 5 years without sensor readjustment. Optimal accuracy is achieved due to special tuning in the residual moisture range. The results of the testo 6743 development: the possibility of measurement in the range of -45 °Ctd to +30 °Ctd and an accuracy of ±1 K (dew point) at 0 °Ctd. For the configuration of output parameters such as pressure dew point, relative humidity, temperature, ppmvol. (parts per million by volume), absolute humidity, and atmospheric dew point, you can use the freely adjustable analog output—optionally with a signal module connector for monitoring maximum values. Additionally, the testo 6743 features a compact and convenient design with a 350° rotatable housing function for the most optimal display positioning. Order Number 0555 6743