The testo 521-3 differential pressure measuring instrument is designed for high-precision differential pressure measurements in air conditioning and ventilation technology. It can be used, for example, for measurements in clean rooms and for flue inspections – thanks to a high level of accuracy and outstanding resolution. In conjunction with a Pitot tube (optional), the integrated pressure sensor measures flow velocities of +1 to +20 m/s.
The integrated temperature-compensated differential pressure sensor performs measurements to an accuracy of up to ± 0.5 Pa. In addition, you can attach up to 2 further optional probes to the measuring instrument. This means you can flexibly adapt the differential pressure measuring instrument to your application. You have the choice of the following probes:
Differential pressure probes
Absolute pressure probes
Relative pressure probes
Temperature probes (e.g. surface probes or immersion and penetration probes)
The practical features of the testo 521-3 differential pressure measuring instrument
The integrated differential pressure sensor enables the testo 521-3 measuring instrument to calculate flow velocity and volume flow using a Pitot tube (which can be ordered separately). The differential pressure measuring instrument also offers timed and multi-point mean calculation.
The optional ComSoft software enables you to save the measurement data so that it is linked to the measuring location and analyze it on the PC. You can use the optional testo fast printer to print out measurement data directly at the measuring location.
You can choose between the following units for pressure measurement: mbar, hPa, bar, Pa, kPa, inH2O, mmH2O, torr and psi. The mean value, the last measured value and the min./max. values can be displayed at the press of a button.
testo 521-3 differential pressure measuring instrument, including calibration protocol and batteries.
| General technical data | |
| Weight | 300 g |
| Dimensions | 219 x 68 x 50 mm |
| Operating temperature | 0 to +50 °C |
| Protection Housing | ABS |
| Product Channels | 2; 1 |
| Measuring rate | 0.04 s |
| Connection | Hose: inner Ø 4 mm outer Ø 6 mm |
| Battery type | 9 V (6LR61) |
| Battery life | Continuous operation w/ internal pressure sensor: 30 h; With rech. battery: 10 h; With carbon battery: 18 h |
| Display function | 7 segment display and point matrix |
| Display update | 2x per second, in fast measurement 4x per second |
| Power supply | Battery/Rechargeable battery,Mains unit 12 V |
| Interface | RS232 |
| Memory | 100 kB; 25,000 measuring values |
| Storage temperature | -20 to +70 °C |
| Temperature – NTC | |
| Measuring range | -40 to +150 °C |
| Accuracy | ±0.2 °C (-10 to +50 °C)* ±0.4 °C (Remaining Range)* |
| Resolution | 0.1 °C *Accuracy information applies only to instrument without probes connected |
| Temperature – TC Type K (NiCr-Ni) | |
| Measuring range | -200 to +1370 °C |
| Accuracy | ±0.4 °C (-100 to +200 °C)* ±1 °C (Remaining Range)* |
| Resolution | 0.1 °C *Accuracy information applies only to instrument without probes connected |
| Differential pressure (internal sensor) – Piezoresistive | |
| Measuring range | 0 to 2.5 hPa** |
| Accuracy | ±0.5 Pa (0 to 20 Pa) ±(0.5 Pa ±0.5 % of mv) (20.1 to 250 Pa) |
| Resolution | 0.1 Pa |
| Static pressure | 1000 hPa |
| Overload | 50 hPa |
| Zeroing | to 0.5 hPa **Sensor is not suitable for long-term measurements |
| Differential pressure (external probe) – Piezoresistive | |
| Measuring range | 0 to 2000 hPa |
| Accuracy | ±0.1 % of mv* |
| Resolution | 0.1 Pa (0638 1347) 0.01 hPa (0638 1547) 0.001 hPa (0638 1447) 0.1 hPa (0638 1847 / 0638 1647) *Accuracy information applies only to instrument without probes connected |
| Differential pressure (external probe) – Ceramic | |
| Measuring range | -1 to 400 bar |
| Accuracy | ±0.2 % of fsv* |
| Resolution | 0.01 bar *Accuracy information applies only to instrument without probes connected |
