Testo 6651, 6681 Data sheet
Industrial Measurement Transmitters for Critical
Climate
NEW!
testo 6651
testo 6681
%RH
°C/°F
°C
td
°F
td
g/m
3
g/kg
J/g
hPa
Committing to the future
2
The basis of stability - the Testo humidity sensor
The Testo humdity sensor: the central component of
high-quality humidity measurement transmitters
For years, Testo has been the first choice when it comes
to high-quality measurement transmitters for drying
processes and critical climate.
On the basis of our years of experience, the sensor and
signal processing concept has been completely
reworked.
Whether high humidity, corrosive media or constant
cleanroom conditions: the Testo humidity measurement
transmitters testo 6651 and testo 6681 offer optimum
accuracy and long-term stability.
Inter-laboratory test
Every specialist around the world knows and values it - the Testo
inter-laboratory test. With it, Testo has impressively proven that very
different national calibration laboratories (with their widely differing test
procedures), have confirmed the Testo humidity sensor’s highest
accuracy.
What exactly happened? After five years travelling around the world,
the Testo humidity sensors, which had been exposed to very different
loads, all showed accuracies of better than ±1 %RH!
This would already be an excellent result for a single test! With regard
to a time series of five years, it testifies to a quality which is of highest
priority to all users worldwide: first class long-term stability!
Long-term stable, condensation-proof and based on
international standards (ILAC / PTB / NIST etc.): the Testo
humidity sensor
Upper electrode
Lower electrode
Carrier
Connections
Dielectric layer
Polymer, constantly alters alters
permeability with the relative
humidity
Allows moisture to
penetrate through to the
dielectric layer and protects
from contamination
Ceramic substrate for
mechanical protection
Special anti-corrosive
design
5 10721346 98
Germany
PTB
04/96
08/96
France
CETIAT
10/96
10/96
USA
NIST
12/96
05/97
Italy
IMGC
07/97
10/97
England
NPL
09/98
09/98
Spain
INTA
10/98
10/98
Japan
JQA
03/99
04/00
Korea
KRISS
05/00
09/00
China
NRCCRM
10/00
12/00
Germany
PTB
03/01
08/01
Country
Institute
Arrival
Departure
International 5-year inter-laboratory
test of the Testo humidity sensor
3
The basis of stability - the Testo humidity sensor
High humidity measurement - testo 6614
Humidity measurement in the high humidity range is
among the most difficult mesasurement tasks. Unstable
measurement values, delayed signal reaction, and
sometimes also sensor corrosion are no rarity, if a special
solution is not used
For these applications, Testo has developed a special,
heated humidity sensor with the testo 6614. A
microclimate which is 5 Kelvin above the process
conditions is thus created inside the filter. The
considerably lower humidity in the microclimate greatly
improves the sensor reaction as well as noticeably
reducing the likelihood of corrosion.
Parallel to the heated humidity sensor, the testo 6614
also has an additional temperature probe. This measures
the actual process temperature; on this basis the correct
process humidity is calculated in the microprocessor of
the measurement transmitter, and displayed.
Trace humidity measurement - testo 6615
Humidity measurement in the lowest humidity range is
also very demanding. If “normal” polymer humidity
sensors are used here, the error, measured in dewpoint
degrees, soon shows high values.
For the demanding measurement of trace humidity, Testo
has developed the testo 6615, which has an integrated
trace humidity self-adjustment. The smallest
discrepencies are corrected cyclically here, up to trace
humidities of -60° dewpoint!
Humidity measurement in corrosive media –
testo 6617
Humidity measurement in corrosive media is often
accompanied by a short useful life of the sensor. For this
problem too, Testo has developed a ground-breaking
innovation: cover electrode monitoring.
Thanks to this measure, the first signs of corrosion are
detected and reported early. This early warning allows the
measurement probe to be exchanged before the
measurement is false or even interrupted. This
guarantees optimum system availability!
4
Overview of the product series testo 6651 and 6681
The two new humidity measurement transmitters from Testo, the
series testo 6651 and testo 6681, are positioned in the middle to
upper performance range. They are designed for the monitoring of
critical climate in process engineering and also in compressed air
technology. The demanding measurement is realized with the further
developed Testo humidity sensor, with its well-known and highlyvalued long-term stability. Unmatched state-of-the-art technology in
humidity measurement, with solutions for highest accuracy as well as
for special applications (high humidity, humidity in H
2O2
, trace
humidity etc.) is provided.
Both instrument series present many new features, among them
world innovations such as a professional bus interface in the humidity
measurement transmitter testo 6681
It is a completely newly developed generation of instruments, which in
particular offers solutions for safe and service-friendly use, meaning
high reliability and operational security for industry:
– exchangeable probes
– early warning reports
– variable possibilites for adjustment
In addition, they also continue to use already existing technology such
as the external interface for communication, for example for the
parameterization and adjustment software P2A from Testo.
The overview on the next page shows a comparison of the two
models, followed by a detailed description of the individual models.
Measurement transmitter testo 6681 with and without display
Measurement transmitter testo 6651 with and without display
Measurement transmitter series
5
Overview of the product series testo 6651 and 6681
0 to 100 %RH
(no high humidity processes)
Measuring range Humidity 0 to 100 %RH
5 mmax. cable length 10 m
4 to 20 mA, 2-wire
0/4 to 20 mA, 4-wire
0 to 1/5/10 Volt, 4-wire
Signal outputs 4 to 20 mA, 2-wire (not for testo 6614/6615)
0/4 to 20 mA, 4-wire
0 to 1/5/10 Volt, 4-wire
ABS, plastic, IP65Housing Metal, IP65
digital Testo (for P2A software or testo 400/650)Interfaces digital Testo
professional bus (optional intermediary layer
4 relays, optional
early warning system (via display or relay collective
alarm)
Special features Special probe versions for
• Temperature ranges up to +180 °C (+324 °F)
• Trace humidity testo 6615
• High humidity testo 6614
• Self-diagnosis testo 6617
4 relays, optional
early warning system (via display, relay collective alarm
or professional bus)
Wall probe testo 6601
Duct probe testo 6602/6603
Cable probe testo 6604/6605
Mounting variants Wall probe testo 6611
Duct probe testo 6612
Cable probe testo 6613/6614/6615/6617
-20 to +120 °CTemperature
(dependent on probe)
-20 to +180 °C
±(1,7 %RH + 0,007 x mv)Accuracy at
+25 °C (+77 °F)*
Humidity up to ±(1 %RH + 0,007 x mv)
Pt100 Class A
±0,2 °C / 0,38 °F
Temperature* Pt100 1/3 Class B
±0,15 °C / 0,27 °F
°C/°F, %rF/%RH, °C
td
/°F
td
Measurement parameters
°C/°F, %rF/%RH, °C
td
/°Ftd,°C
tpd
/°F
tpd
, g/m3/gr/ft3,
g/kg/gr/lb, enthalpy/°Ctw, °Ftw, inch, H
2
O, ppm(vol),
% Vol
Probe 6615 only: °C
tpd
/°F
tpd
for H2O2-applications: °Ctm/°Ftm
testo 6651 testo 6681
*Other accuracies apply for the wall probe with 70 mm length in combination with a current output (P07):
Operation: with 2 channels at 12 mA, without display illumination, relay off, additional measurement inaccuracy to above data at +25 °C (+77 °F), humidity ±2.5 %RH,
temperature ±1 °C (1.8 °F)
Price
Performance
testo 6651
testo 6681
Model
Applications
testo 6651
Climate technology and industry:
critical climate, cleanrooms
Industry:
critical climate, cleanrooms, drying processes, high humidity, trace humidity,
humidity in H
2O2
environment etc.
testo 6681
6
P2A software for testo 6651 and testo 6681
Software for parameterization, adjustment and
analysis
Optimum procedures from the point of view of the user –
that is the central idea of the new measurement
transmitter software “P2A” from Testo. The name stands
for
P – Parameterization
A – Adjustment
A – Analysis
All new (and future) Testo measurement transmitters
communicate with this software, the connection of the
PC (via external or easily accessible interfaces) being
extremely easy. The software only needs to be bought
once – all further updates are free of charge!
An additional advantage is the supply of the
measurement transmitter via USB. Parameterization or
analysis can thus be carried out without the need for
wiring – e.g. at a desk or in a workshop.
P2A software: parameterization and data
management
In the course of commissioning, the scaling of the analog
channels, the limit values of the (optional) relays, the
signal damping etc. are set. The P2A software supports
all these procedures with convenient menus which are
extensively supported graphically.
Are several measurement sites intended to have the
same parameters? No problem - the parameter sets can
be transferred by simple “drag and drop”. This saves
considerable time in larger installations.
P2A software: adjustment
In addition to the 1-point adjustment (offset) and the 2point adjustment (with the help of the saline solution pots
or a humidity generator), the P2A software supports the
analog adjustment of each analog channel. Using a
precise multimeter, the entire measurement chain
(including the digital-analog converter) can thus be
adjusted. Unique: adjustment histories present in detail
who carried out which adjustment when, and at which
reference values. This provides uninterrupted
documentation, independently of whether the
adjustments were carried out with (any) P2A software, the
operating menu or the adjustment buttons.
7
P2A software for testo 6651 and testo 6681
P2A software: analysis and histories
Ideal for the localization of errors and optimization: the
analysis tools of the P2A software. They allow the analog
and relay signals to be tested, and the min./max. values
to be displayed.
How can you look into the past? With the help of an
operational hour counter, the measurement transmitter
stores occuring reoprts with a time stamp. This report
history is displayed in the P2A software and provides
important information on all events.
The P2A software has five such histories.
– Parameterization history (what was set when?)
– Report history (which errors, warnings and status
reports occured)
– History of 1-point adjustments
– History of 2-point adjustments
– History of analog adjustments
As all these procedures are stored in the measurement
transmitter (with operational hour counter), a sound
analysis can be made with the help of any P2A software.
8
Common features + benefits testo 6651 and testo 6681
Display and operating menu
The optional display has an extremely convenient
operating menu. With the help of four operating buttons,
almost all operations can be carried out which can be
conducted using the P2A software. Commissioning,
adjustment and analysis are thus possible completely
without a PC - simply on site!
The display not only presents the measurement values
and relay status clearly, but also guides the user safely
through the operating menu thanks to a clear-text line. A
password protects against unauthorized operation. A
cover for the buttons can also be installed.
And last but not least: The clear-text can be selected in
six languages - optimum for your systems at home and
abroad.
Digital probes
The humidity probe in the models testo 6651 and 6681
can be easily exchanged by hand. A readjustment with
the measurement transmitter itself is not necessary, since
the probe series testo 6600 used in the humidity
measurement transmitter testo 6651 not only has a purely
digital interface to the measurement transmitter, it is also
completely calibrated and adjusted.
Uplug probe 1, plug in probe 2 - continue measuring!
At the same time, Testo fulfils the highest demands, for
example those of the pharmaceutical industry. Each
probe has its own serial number, a store for the
adjustments carried out with it, and its own operational
hour counter. The visualizes (via the measurement
transmitter’s operating menu or the P2A software) how
long the probe has already been in use, and which
settings have been carried out on it (see also P2A
software):
Password (enter if required)
Measurement
operation
Channel 1 Unit channel 1 Select
Scale min. chan. 1 Edit
Scale max. chan. 1 Edit
Signal delay chan. 1 Select
°C
19.3
%RH
57.8
PROBE CONNECTION
9
Common features + benefits testo 6651 and testo 6681
Direct on-site adjustment with the testo 400
A regular adjustment is indispensible for all demanding
humidity measurement - although the highly stable Testo
sensors mean that a correction is often not necesary
even after three or four years.
The important thing for the user is that the process (the
air conditioning system, pasta drying etc.) is not
interrupted by the adjustment procedure. And
transporting a laptop/PC to the measurement site is not
always feasible.
For this reason, Testo has equipped the testo 6651 with
an easily accessible interface. Using the adapter 0554
6022, the reference measuring instrument test 400 or
650 (with a precision humidity probe) can be directly
connected to the measurement transmitter. In the display
of the hand instrument, the humidity and temperature
values of the two instruments are shown opposite each
other. If the discrepancies are too high, a few touches of
a button are sufficient to adjust the testo 6651 (1-point
adjustment). After only a few moments, you are ready to
carry on to the next measurement site.
Adjustment via operating menu or P2A software
In addition to the numerous possibilities for calibrating the
probe together with the measurement transmitter locally,
(cf. P2A software and operating menu), it is possible,
thanks to the digital probe series testo 6600, to leave the
measurement transmitter on site and to exchange only
the probe and calibrate it in a laboratory.
Companies with internal calibration laboratories install at
least one testo 6651 measurement transmitter in the
laboratory and use it as an adjustment basis for various
probes. After adjustment, the probes - or others of the
same design - are reconnected at the original
measurement site. Thanks to the probe serial number, it
is always possible to trace (for example with the P2A
software), which probe was connected when to a
measurement transmitter, and how it was adjusted (1 or
2-point adjustment).
Measurement transmitter and probe
Humidity generator
1-point adjustment on site with the portable instrument testo 400 or testo
650 with precision humidity probe and adjustment adapter
Adjustment via operating menu or testo P2A software
testo 400
testo 650
USB to Mini DIN
cable
Adjustment adapter
Loading...