TESTO 6681 Profibus User manual

testo 6681 Ethernet · Humidity transmitte
r
with Ethernet module
testo 6610 · Probes
P2A software · Parameterizing, adjusting and analyzing
software
Instruction manual Volume 1 en

Safety and the environment 3
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.

4 About this document
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®2000, XP and Vista.
Aim of action, e.g.:
Assembling the instrument at the process
connection:
Requirement that must be met, e.g.:
USB drivers are installed.

About this document 5
Character/
display:
Explanation/example
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 > P2A 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.

6 Contents
Contents
SAFETY AND THE ENVIRONMENT ......................................................................... 3
ABOUT THIS DOCUMENT ..................................................................................... 4
CONTENTS......................................................................................................... 6
1TRANSMITTER............................................................................................ 8
1.1 Specifications........................................................................................... 8
1.1.1 Functions and use....................................................................... 8
1.1.2 Scope of delivery ........................................................................ 8
1.1.3 Accessories................................................................................. 9
1.1.4 Technical Data ............................................................................ 9
1.1.5 Dimensions ............................................................................... 11
1.2 Product description................................................................................ 12
1.2.1 At a glance ................................................................................ 12
1.2.2 Usable probes ........................................................................... 13
1.2.3 Display and keypad................................................................... 14
1.2.4 Service interface ....................................................................... 14
1.2.5 Relay board (option) ................................................................. 14
1.2.6 Analog outputs .......................................................................... 15
1.2.7 Parameters................................................................................ 15
1.2.8 Scaling ...................................................................................... 16
1.2.9 Alarm handling .......................................................................... 18
1.3 Commissioning ...................................................................................... 19
1.3.1 Insert Ethernet module (Order no. 0554 6656)......................... 19
1.3.2 Assembling the instrument........................................................ 21
1.3.3 Connecting the instrument ........................................................ 24
1.3.4 Ethernet communication ........................................................... 38
1.3.5 Adjusting the instrument ........................................................... 57
1.4 Operation ............................................................................................... 68
1.4.1 Relationship between user menu and mini-DIN socket is active
.................................................................................................. 68
1.4.2 Key cover .................................................................................. 69
1.4.3 Password protection ................................................................. 70
1.4.4 Structure of user menu .............................................................70
1.4.5 Overview of the testo 6681 user menu............................................ 72
1.4.6 The individual main menus ....................................................... 74
1.5 Status, warning and error messages..................................................... 87
1.5.1 Status messages ...................................................................... 87
1.5.2 Warning messages ................................................................... 88

Contents 7
1.5.3 Transmitter error messages......................................................90
1.5.4 Status codes in cyclical service ................................................91
1.5.5 Handling alarm messages ........................................................91
1.5.6 Namur fault conditions ..............................................................93
1.6 Maintenance and cleaning.....................................................................94
1.6.1 Maintaining the instrument........................................................ 94
1.6.2 Cleaning the instrument ............................................................94

8 testo 6681 Ethernet - 1.1 Specifications
1 Transmitter
1.1 Specifications
1.1.1 Functions and use
The testo 6681 humidity transmitter with Ethernet module is used in
conjunction with plug-in, adjusted probes from the testo 6610 range.
Please refer to volume 2, chapter 2, page 103 for information
about commissioning, operating and maintaining the
testo 6610 probe.
The testo 6681 humidity transmitter is suitable for the following applications
with Ethernet networking, for example:
Process instrumentation
Clean rooms
Test benches
Drying processes
Production and storage air quality
Complex room climate applications.
In addition to the signal transmission of the readings to a control unit via
analog outputs, the measurement data can simultaneously be recorded,
documented and visualized via Ethernet. Furthermore, it is possible to issue
an alarm for those responsible for the process, if necessary.
1.1.2 Scope of delivery
The scope of delivery of the testo 6681 humidity transmitter includes the
following:
Key cover
Rear panel bracket
Ethernet module

testo 6681 Ethernet - 1.1 Specifications 9
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, page 179 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) and handheld testo
400/650
Voltage supply
-4-wire (separate signal and supply
lines):
20 - 30 V AC/DC,
300 mA power consumption
Maximum load
- 4-wire: 500 Ω(power output)
Analogue output*
-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)

10 testo 6681 Ethernet - 1.1 Specifications
Housing operating temperature
--40 to +70 °C/-40 to +158 °F, with
display from 0 to 50 °C/+32 to +122 °F
-With integrated relay: -40 - +60 °C
Operating humidity
-0...100 %rF
Storage temperature
-- 40 to 80 °C/-40 to +176 °F
Housing, weight
-Metal: 1.960 kg
-Ethernet module: 0.610 kg
Protection class
-IP 65 only if the transmitter is
wired properly (closed cable
entries), Ethernet connector,
Harting PushPull connector and
humidity probe are inserted and/or
sealing plug is inserted.
Directives, standards and tests
-EC Directive: 2004/108/EC
-DIN 14644-4
-EN 61000-6-2 interference
immunity
-EN 61000-6-3 interference
emission
-EN 61326-1+A1+A2
Ethernet module
-Interface:
1 x mini DIN
1 x RJ45 (Ethernet 10 BatesT/100
BaseTX
-LED:
2 x green
Warranty
-Duration: 2 years
-Warranty conditions: See web page
www.testo.com/warranty

testo 6681 Ethernet - 1.1 Specifications 11
1.1.5 Dimensions
Dimensions in mm a b
With M 20 cable couplings 144 147
With NPT cable couplings 144 144
With M plug-in connections 143

12 testo 6681 Ethernet - 1.2 Product description
1.2 Product description
1.2.1 At a glance
1 Keys (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 Eyelet for measuring point
panel
8 M 20 x 1.5 screw connection*,
e.g. relay R 3 and R 4
9 Earthing/PE connection
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
A
Ethernet module
13 DIP switch
14 Ethernet port
15 LED: LAN connection status
16 LED: Supply

testo 6681 Ethernet - 1.2 Product description 13
17 Housing screws (4x)
18 Socket for probe connector
19 Hole for fastening to rear
panel bracket (M3 x 6 screw)
20 Plastic bracket for assembly
on rear panel
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,
plug-on sensor
testo 6612 0555 6610-L12 Duct probe version; accuracy to ± 1 % RH;
temperature range -30 °C to 150 °C/-22 to +302 °F,
sensor soldered/optionally plugged
testo 6613 0555 6610-L13 Cable probe version; accuracy to ± 1 % RH;
temperature range -70 °C to +180 °C/-94 to
+356 °F, sensor soldered/optionally plugged
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, sensor soldered

14 testo 6681 Ethernet - 1.2 Product description
Probe Article no. Characteristic
testo 6615 0555 6610-L15 Trace humidity cable probe version;
accuracy ± 6 K at -60 °Ctd;
temperature range -40 °C to +120 °C/-40 to
+248 °F, sensor soldered
testo 6617 0555 6610-L17 Cable with cover electrode monitoring probe
version; accuracy to ± 1.2 % RH; temperature range
-40 °C to +180 °C/-40 to +356 °F, sensor soldered
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 or Testo handheld instrument
(testo 400/testo 650).
1.2.5 Relay board (option)
This has a floating switch capacity of 250 V AC/3 A. The switching limits and
hysteresis can be set via the display or the P2A software. Further features
include:
Function of changeover contacts (NC/NO contacts) freely selectable
12 terminals for a total of 4 relays.
If no relays are available, settings for monitoring limit values
or alarms can still be controlled via the display. The alarm
status will be shown on the display.
Only have the transmitter wired and connected by authorized
personnel with the voltage disconnected.

testo 6681 Ethernet - 1.2 Product description 15
1.2.6 Analog outputs
For analog outputs, the testo 6681 has either
2 or optionally 3 current outputs of 4 to 20 mA/0 to 20 mA (4-wire) or
2 or optionally 3 voltage outputs of 0 to 1 V/0 to 5 V/0 to 10 V (4-wire).
The transmitter can be ordered with a third analog output as an option.
1.2.7 Parameters
The following parameters are displayed:
Relative humidity in %RH (technical)
Relative humidity in % WMO* (calculation according to the WMO
standard)
Temperature °C and °F
Dewpoint in °Ctd and °Ftd
Absolute humidity in g/m³ and gr/ft³
Degree of humidity in g/kg and gr/lb
Enthalpy in kJ/kg and BTU/lb
Psychrometer temperature in °Ctw and °Ftw
Water vapour partial pressure in hPa and "H2O (inch H2O)
Water content in ppmvol and % vol
Dewpoint of H2O2mixture in °Ctm and °Ftm
Mixture humidity H2O2in %RHm
*It is possible that condensation appears as of a displayed humidity
starting from 70 % and is shown on the display. This unit is used in
meteorology, for example. According to the WMO, the Magnus
coefficient is used for sub-cooled water in the calculation of relative
humidity.
Calculated humidity variables correspond to the medium of
air. With other gases/gas compositions, deviations may
occur, e.g. with the enthalpy

16 testo 6681 Ethernet - 1.2 Product description
1.2.8 Scaling
There are three types of min./max. values:
1 The measuring range
The maximum sensor performance is in this range. Values outside of
the measuring range are displayed via messages, for example. Refer
to table (see below) for the measuring range.
2 Standard scaling
The output signals are assigned to this measuring range as standard:
- during delivery if no entries are made in the order code
- after exchanging the unit, the measuring range recorded in the
instrument is applied as standard.
The transmitter even retains its scaling with the voltage
disconnected.
Refer to table (see below) for the measuring range.
3 The maximum settings for the manual scaling
- the values are not expressly given in the table. The maximum limits
can be calculated as follows:
X = difference between MIN. and MAX. value of the standard scaling
(Max. value of standard) + (50 % of X)
(Min. value of standard) - (50 % of X)
- It is thus possible to scale beyond the measuring range, e.g. for the
adjustment of the scaling limits to standard values of a PLC.
However, the physical measurement range limits are the deciding
factor when defining alarms.

testo 6681 Ethernet - 1.2 Product description 17
Parameter Unit Probe
Measuring
range
Physical
at 1013 hPa
Standard
scaling
MUF
measuring
range
MIN MAX MIN MAX
Temperature °C 6611 -20 +70 -20 +70
°F 6611 -4 +158 -4 +158
°C 6612 -30 +150 -30 +150
°F 6612 -22 +302 -22 +302
°C 6613 -70 +180 -70 +180
°F 6613 -94 +356 -94 +356
°C 6614, 6617 -40 +180 -40 +180
°F 6614, 6617 -40 +356 -40 +356
°C 6615 -40 +120 -40 +120
°F 6615 -40 +248 -40 +248
relative humidity % RH 0 +100 0 +100
WMO relative humidity % RH 0 +100 0 +100
Mixture humidity H2O2% RHm0 100 0 100
Dewpoint °Ctd 6611 -20 +70 -80 +100
°Ftd 6611 -4 +158 -112 +212
°Ctd 6612, 6613, 6614,
6617 -20
+100 -80 +100
°Ftd 6612, 6613, 6614, 6617 -112
+212 -112 +212
°Ctd 6615 -60 +30 -80 +100
°Ftd 6615 -148 +212 -112 +212
Mixture dewpoint (H2O2) °Ctm -20 +100 -20 +100
°Ftm -4 +212 -4 +212
Absolute humidity g/m3 all probes 0 600 0 2000
gr/ft3 0 250 0 800
Degree of humidity g/kg all probes 0 13300 0 9500
gr/lb 0 93000 0 66500
Enthalpy kJ/kg -40 99999 -40 8000
BTU/lb -18 43000 -18 3500
Psychrometer temperature °Ctw -40 100 -40 180
°Ftw -58 210 -40 356

18 testo 6681 Ethernet - 1.2 Product description
Parameter Unit Probe
Measuring
range
Physical
at 1013 hPa
Standard
scaling
MUF
measuring
range
MIN MAX MIN MAX
Water content
ppm vol
H2O 0 99999 0 99999
% vol 0 100 0 100
Water vapour partial pressure hPa 0 1000 0 7000
inchH2O 0 400 0 2800
1.2.9 Alarm handling
For upper and lower alarm limits, individual alarms as well as collective
alarms can be specified. If the collective alarm function is activated, an alarm
is triggered as soon as the alarm limit of an alarm is exceeded, if this alarm is
assigned to the collective alarm.
The testo 6681 monitors limit values using relays. If a reading is outside the
limit values, a relay to be specified by the user is switched.
If the reading reverts to more than a specified hysteresis below or above the
limit value, the alarm is cancelled.
In addition, information about the occurrence of error/status messages can
be provided by means of a collective alarm relay, see chapter 1.5, Status,
warning and error messages, page 87.
If multiple alarm messages are activated at the same time,
the last alarm is shown. If the alarm is cancelled again, the
previous messages are no longer shown.
Example:
If the condensation of the probe begins, the "Condensation"
message appears on the display and the "Start" status
display. If the condensation is over, the status display
changes from "Start" to "End".

testo 6681 Ethernet - 1.3 Commissioning 19
1.3 Commissioning
1.3.1 Insert Ethernet module (Order no.
0554 6656)
The Ethernet module can be ordered retroactively as an accessory. It can
easily be installed in the testo 6681 humidity transmitter.
The probe connector must be disconnected.
1 Loosen screw connection (1) of service flap and open the flap.
2 Loosen and remove housing screws (2).
3 Remove upper part of housing (3) and place on a clean surface.

20 testo 6681 Ethernet - 1.3 Commissioning
4 Place Ethernet module (A) on lower part of instrument (4).
If necessary, manually set the address using the rotary
encoder switches (see chapter 1.3.3.6, page 34 before fixing
the instrument in place.
5 Set on upper part of instrument (5) and fix in place using housing
screws (2).