Testo 645 Specifications

Data sheet

testo 645

Humidity/temperature
measuring instrument

testo 645 – Highly precise
measurements for industry

Highly accurate humidity measurement up to ±1 %RH

Connection of 2 plug-in probes

Measurement of temperature, relative humidity and
pressure dewpoint

Internal measurement store (3000 measurement values)

PC software for the analysis, archiving and documentation
of the measurement values (option)

Button for Hold, min./max. values, mean value calculation

Convenient data analysis

The highly accurate thermal hygrometer testo 645 has two
probe inputs for the connection of an extensive range of
probes:

- Channel 1: temperature Type K/J/S, NTC

- Channel 2: combi probe humidity/temperature or
temperature probe Pt 100
The measuring instrument automatically displays the
measurement parameters temperature, relative humidity,
dewpoint, pressure dewpoint, absolute humidity, degree of
humidity and enthalpy, and additionally presents the current
values, the last measured values, min., max. and mean
values at the press of a button.

%RH

°C

Measurement data can be stored by measurement site
in the testo 645, and analyzed on a PC, or documented
using the Testo fast printer (option). The TopSafe (option) is
available for tough applications. The measuring instrument,
probes and accessories can be stored safely and tidily in
the transport case (option).

www.testo.com

testo 645

Technical data

General technical data

testo 645

testo 645, humidity/temperature measuring
instrument, with battery

Part no. 0560 6450

Operating temperature 0 to +50 °C

Storage temperature -20 to +70 °C

Display LCD, 4 lines

Battery type 9V block battery

Battery life 45 h

Dimensions 215 x 68 x 47 mm

Weight 255 g

Housing material ABS

Accuracy of temperature: ± 1 digit at +22°C
Ni 10000 sensor: meas. range: ...+180 °C
Typical battery lives: 9V block (Al-Mn) 20-45h.
The hour times are reduced by a factor of 5 if a 9V rech. battery is
used
Calculated humidity parameters: td, g/m³, g/kg, J/g (pressure
compensated)
Mains connection and battery recharging in instrument

Save data by measurement site
and analyze on a notebook

Connections for temperature
probes Type K/J/S, NTC and
combi probe humidity/temperature
or temperature probe Pt100

testo 645

Technical data / Accessories

Measuring rangeSensor type Accuracy ±1 digit Resolution

Testo humid. sensor,
cap.

Pt100 -200 to +800 °C ±0.1% of m.v. (+200.1 to +800 °C)

Type K (NiCr-Ni) -200 to +1370 °C ±0.5% of m.v. (-200 to -60.1 °C)

Type S (Pt10Rh-Pt) -50 to +1700 °C

Type J (Fe-CuNi) -40 to +750 °C

NTC -50 to +150 °C 0.1 °C (-50 to +150 °C)

Accessories Part no.

Transport and Protection

Transport case (plastic) for measuring instrument, probes and accessories
for safe and orderly storage

TopSafe (indestructible protection case), with bench stand and belt clip

0 to +100 %RH See probe data 0.1 %RH (0 to +100 %RH)

0.1 °C (-200 to +800 °C)

±0.2 °C (-200 to +200 °C)

0.1 °C (-200 to +1370 °C)
±0.5% of m.v. (+60.1 to +1370 °C)
±0.3 °C (-60 to +60 °C)

±0.5% of m.v. (-200 to -60.1 °C)
±0.5% of m.v. (+60.1 to +1370 °C)
±0.3 °C (-60 to +60 °C)

0516 0445

0516 0440

Printer and Accessories

Testo fast printer IrDA with wireless infrared interface; 1 roll thermal paper; 4 AA batteries

Spare thermal paper for printer (6 rolls), permanent ink
measurement data documentation legible for up to 10 years

Software and Accessories

ComSoft Professional Pro software incl. data archiving

RS232 cable connects instrument to PC (1.8 m) for data transfer

0554 0549

0554 0568

0554 1704

0409 0178