TESTO 6681 Profibus User manual

testo 6681 · Humidity transmitters
testo 6610 · Probes
P2A software · Parameterizing, adjusting and analyzing
software
Instruction manual Volume 1 en

2
Safety and the environment
Safety and the environment
Avoiding electrical hazards
►Never use the instrument and connected probes to measure on or near
live parts!
►Damaged mains cables must only be replaced by authorized personnel.
►Only have the transmitter wired and connected by authorized personnel
with the voltage disconnected.
►You must always comply with the regulations applicable in your country
to the opening and repair of electrical equipment.
Avoiding personal injury/damage to equipment
►Installation, setting and calibration work must only be carried out by
qualified and authorized personnel!
►Only open the instrument when this is expressly described in the
instruction manual for installation, maintenance or repair purposes.
►Observe the permissible storage, transport and operating temperatures.
►Never store or operate the product with solvents and do not use any
desiccants.
►Do not use the instrument for control purposes at the same time as
operating or servicing the transmitter.
►Only operate the product properly, for its intended purpose and within the
parameters specified in the technical data. Do not use force.
►Carry out only the maintenance and repair work that is described in the
documentation. Follow the prescribed steps when doing so. Use only
OEM spare parts from Testo.
Any additional work must only be carried out by authorized personnel.
Otherwise Testo will not accept any responsibility for the proper functioning of
the instrument after repair and for the validity of certifications.
Protecting the environment
►Send the product back to Testo at the end of its useful life. We will
ensure that it is disposed of in an environmentally friendly manner.

About this document
3
About this document
►Please read this documentation through carefully and familiarize yourself
with the product before putting it to use. Keep this document to hand so
that you can refer to it when necessary. Hand this documentation on to
any subsequent users of the product.
►The following conventions are followed in this document:
Character/
display:
Explanation/example
With the signal word Warning!:
Warns against hazards which could result in serious physical
injury if the precautionary measures indicated are not taken,
e.g.:
De-energize the mains connection before connecting the
transmitter!
With the signal word Caution!:
Warns against hazards which could result in minor physical
injury or damage to equipment if the precautionary
measures indicated are not taken, e.g.:
Observe the permissible operating temperature!
Important information, e.g.:
Administrator rights are required to install the program under
Windows®7, 8 and 10.

Aim of action, e.g.:
Assembling the instrument at the process
connection:

Requirement that must be met, e.g.:
USB drivers are installed.

4
About this document
1 Steps are numbered if a certain sequence of actions must
be followed, e.g.:
1Loosen and remove housing screws.
2Remove the upper part of housing.
A step is not numbered if there are no further steps or if the
step is optional, e.g.:
▪Insert probe connector into socket of testo 6681 until
it engages.
" to "
Example entries are in inverted commas, e.g.:
The value "0" results in ....
Bold type Elements of the program interface or instrument display,
e.g.:
The instrument designation appears in the
instrument/parameter file list.
Select Main Menu Channel 1 and confirm with SET.
…>… Functions/paths within a menu, e.g.:
Start > All Programmes > Testo > Transmitter Software.
[ ] Buttons which start an action, e.g.:
Confirm the software key with [OK].
CAPITAL
LETTERS Keys on the instrument or keypad, e.g.:
Press ESC.

Contents
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Contents
1TRANSMITTER............................................................................................6
1.1 Specifications...........................................................................................6
1.1.1 Functions and use.......................................................................6
1.1.2 Scope of delivery ........................................................................6
1.1.3 Accessories.................................................................................7
1.1.4 Technical Data............................................................................7
1.1.5 Dimensions .................................................................................8
1.2 Product description..................................................................................9
1.2.1 At a glance ..................................................................................9
1.2.2 Usable probes...........................................................................10
1.2.3 Display and keypad...................................................................10
1.2.4 Service interface .......................................................................10
1.2.5 Relay board (option) .................................................................10
1.2.6 Analog outputs ..........................................................................11
1.2.7 Parameters ...............................................................................12
1.2.8 Scaling ......................................................................................12
1.2.9 Alarm handling ..........................................................................15
1.3 Commissioning ......................................................................................16
1.3.1 Assembling the instrument .......................................................16
1.3.2 Connecting the instrument........................................................19
1.3.3 Adjusting the instrument ...........................................................31
1.4 Operation ...............................................................................................41
1.4.1 Relationship between user menu and mini-DIN socket is active
..................................................................................................41
1.4.2 Key cover ..................................................................................42
1.4.3 Password protection .................................................................43
1.4.4 Structure of user menu .............................................................43
1.4.5 Overview of the testo 6681 user menu ...........................................45
1.4.6 The individual main menus .......................................................47
1.5 Status, warning and error messages.....................................................59
1.5.1 Status messages ......................................................................59
1.5.2 Warning messages ...................................................................60
1.5.3 Error messages.........................................................................62
1.5.4 Handling alarm messages ........................................................63
1.5.5 Namur fault conditions ..............................................................65
1.6 Maintenance and cleaning.....................................................................66
1.6.1 Maintaining the instrument........................................................66
1.6.2 Cleaning the instrument............................................................66

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testo 6681 - 1.1 Specifications
1 Transmitter
1.1 Specifications
1.1.1 Functions and use
The testo 6681 humidity transmitter is used in conjunction with plug-in,
adjusted probes from the testo 6610 range.
Please refer to volume 2, chapter 2for information about
commissioning, operating and maintaining the testo 6610
probe.
The testo 6681 humidity transmitter is suitable for the following applications,
for example:
•Process instrumentation
•Clean rooms
•Test benches
•Drying processes
•Production and storage air quality
•Complex room climate applications.
1.1.2 Scope of delivery
The scope of delivery of the testo 6681 humidity transmitter includes the
following:
•Key cover
•Rear panel bracket

testo 6681 - 1.1 Specifications
7
1.1.3 Accessories
The following accessories are available for the testo 6681 humidity
transmitter:
•Protection caps for probes
•Mains unit
•P2A software (parameterizing, adjusting and analyzing software)
•Assembly accessories.
Information about accessories and their order numbers can
be found in volume 2, chapter 4.2 or on the website at
www.testo.com.
1.1.4 Technical Data
Parameters
-Humidity (various variables and
units)
-Temperature (°C/°F)
Measuring range
-Depends on probe
Accuracy
-Depends on probe
Resolution
-0.1 % RH or 0.1 °C/0.1 °F
Meas. cycle
-1/s
Interface
-Mini-DIN for P2A software
(parameterizing and adjusting
software)
Voltage supply
-2-wire: 18 to 24 V DC ± 10%
-4-wire (separate signal and supply
lines):
20 - 30 V AC/DC,
300 mA power consumption
Maximum load
-2-wire: 100 to 750 Ω
- 4-wire: 500 Ω (power output)

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testo 6681 - 1.1 Specifications
Analog output
-4 to 20 mA ± 0.03 mA (2-wire) or
-0 to 1 V ± 1.5 mV (4-wire) or
-0 to 5 V ± 7.5 mV (4-wire) or
-0 to 10 V ± 15 mV (4-wire) or
-0 to 20 mA ± 0.03 mA (4-wire) or
-4 to 20 mA ± 0.03 mA (4-wire)
Resolution of analog output
-12 bit
Relay
-4 relays, 250 V AC/DC, 3 A
(optional)
Display
-2-line LCD with plain text line
(optional)
Housing operating temperature
--40 to 70 °C/-40 to +158 °F, with
-display from 0 - 50 °C/+32 to
+122 °F
-With integrated relay: -40 to +60°C
Storage temperature
-- 40 to 80 °C/-40 to +176 °F
Housing, weight
-Metal, 1.960 kg/432 lb
Protection class
-IP 65 only if the transmitter is wired
and/or seal plugs are inserted
Directives, standards and tests
-EC Directive: 2014/130/EC
1.1.5 Dimensions
Dimensions in mm
a
b
With M 20 cable couplings
144
147
With NPT cable couplings
144
144
With plug-in connections
143

testo 6681 - 1.2 Product description
9
1.2 Product description
1.2.1 At a glance
1
Keys (only with optional display)
2
Service flap screw connection
(self-locking, 2x)
3
Display (optional)
4
Service flap
5
M 16 x 1.5 screw connection*,
e.g. analog outputs
6
M 16 x 1.5 screw connection*,
e.g. voltage supply
7
Earthing/PE connection
8
M 20 x 1.5 screw connection*,
e.g. relay R 3 and R 4
9
Eyelet for measuring point panel
10
M 20 x 1.5 screw connection*,
e.g. relay R 1 and R 2
11
Probe connector (testo 6610)
12
Upper part of housing
*
Alternatively, NPT cable
couplings or M plug-in
connections are available
13 Housing screws
14 Socket for probe connector
15 Hole for fastening to rear panel
bracket (M3 x 6 screw)
16 Plastic bracket for assembly on
rear panel

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testo 6681 - 1.2 Product description
1.2.2 Usable probes
The testo 6681 humidity transmitter can be used with the following probes:
probe
Article no.
Characteristic
testo 6611 0555 6610-L11 Wall probe version; accuracy to ± 1 % RH;
temperature range -20 °C to +70 °C/-4 to +158 °F
testo 6612 0555 6610-L12 Duct probe version; accuracy to ± 1 % RH;
temperature range -30 °C to +150°C/-22 to +302 °F
testo 6613 0555 6610-L13 Cable probe version; accuracy to ± 1 % RH;
temperature range -70 bis +180 °C/-94...+356 °F
testo 6614 0555 6610-L14 Heated cable probe version; accuracy to
± 1.0 % RH; temperature range -40 °C to +180 °C/
-40 to +356 °F
testo 6615 0555 6610-L15 Trace humidity cable probe version;
dew point to -60 °Ctd;
temperature range -40 °C to +120°C/-40 to +248 °F
testo 6617 0555 6610-L17 Cable with cover electrode monitoring probe
version; temperature range -40 °C to +180 °C/-40
to +356 °F
1.2.3 Display and keypad
The display option allows the testo 6681 humidity transmitter to be operated
via the display and four keys.
The LCD display consists of two 7-segment lines for displaying readings and
units and of an information line (for status messages, for example).
The brightness and contrast of the display and the background lighting
(permanent or off) can be changed via the user menu or the P2A software.
1.2.4 Service interface
Behind the service flap is the parameterizing socket (mini-DIN) as an
interface to the P2A software.
1.2.5 Relay board (option)
This has a floating switch capacity of 250 V AC/3 A. The switching limits and
hysteresis as well as the function as relay for the collective alarm can be set
via the display or the P2A software. Further features include:
•Function of changeover contacts (NC/NO contacts) freely selectable