GREISINGER GMH 3611 User manual

H74.0.04.6C-06
GHM Messtechnik GmbH • Standort Greisinger
Hans-Sachs-Str. 26 • D-93128 Regenstauf
+49 (0) 9402 / 9383-0 +49 (0) 9402 / 9383-33 [email protected]
As of Version 1.0 Operating manual GMH 3611
Oxygen meter for dissolved oxygen
with integrated temperature and pressure measuring
Sauerstoffmessgerät für gelösten Sauerstoff
mit Temperatur und Druckmessung
Please keep for future reference!
WEEE-Reg.-Nr. DE 93889386

H74.0.04.6C-06 Operating Manual GMH 3611 page 2 of 14

Contents
1GENERAL NOTE......................................................................................................................................................2
2DESIGNATED USE...................................................................................................................................................3
3SAFETY......................................................................................................................................................................3
3.1 SAFETY SIGNS AND SYMBOLS................................................................................................................................3
3.2 SAFETY GUIDELINES..............................................................................................................................................3
4PRODUCT DESCRIPTION......................................................................................................................................4
4.1 SCOPE OF SUPPLY ..................................................................................................................................................4
4.2 OPERATION AND MAINTENANCE ADVICE..............................................................................................................4
4.3 START OF OPERATION ...........................................................................................................................................4
4.4 CONNECTIONS .......................................................................................................................................................5
4.5 DISPLAY ELEMENTS...............................................................................................................................................5
4.6 PUSHBUTTONS.......................................................................................................................................................5
4.7 POP-UP CLIP...........................................................................................................................................................6
5CONFIGURATION...................................................................................................................................................7
6THE OXYGEN SENSOR..........................................................................................................................................8
6.1 DESIGN OF SENSOR GWO 3600 ............................................................................................................................8
6.2 ELECTRODE MAINTENANCE..................................................................................................................................8
7OXYGEN MEASURING - PLEASE NOTE............................................................................................................9
7.1 AMBIENT PRESSURE AND MEASURING DEPTH OF THE ELECTRODE .......................................................................9
7.2 CORRECTION OF SALINITY ('SAL')........................................................................................................................9
8CALIBRATION OF THE SENSOR.........................................................................................................................9
8.1 HOW TO CALIBRATE..............................................................................................................................................9
8.2 EVALUATION OF SENSOR STATE (ELE[)..............................................................................................................10
8.3 CALIBRATION INTERVAL ([.INT) ..........................................................................................................................10
9INSPECTION OF THE ACCURACY / ADJUSTMENT SERVICES................................................................11
10 SERIAL INTERFACE.........................................................................................................................................11
11 ERROR AND SYSTEM MESSAGES................................................................................................................12
12 SPECIFICATION.................................................................................................................................................13
13 RESHIPMENT AND DISPOSAL.......................................................................................................................13
1 General Note
Read this document carefully and get used to the operation of the device before you use it. Keep this
document within reach for consulting in case of doubt.
If the device is stored at temperatures above 50°C the battery has to be removed from the device.
NOTE: We recommend taking out battery if device is not used for a longer period of time.
Risk of leakage!

H74.0.04.6C-06 Operating Manual GMH 3611 page 3 of 14
2 Designated Use
The GMH 3611 is measuring dissolved oxygen in Water.
The measuring is performed by means of a suitable oxygen sensor (included in supply in standard
instrument) connected to the Mini-DIN socket, the sensor measures at the membrane at the tip of the sensor.
Due to the properties of the sensor, it has to be calibrated regularly (e.g. at fresh air = 20.95%) to get precise
values. If the sensor is used up, this will be detected during the calibration, the sensor has to be regenerated
or replaced before continuing with measuring.
The safety requirements (see below) have to be observed.
The device must be used only according to its intended purpose and under suitable conditions.
Use the device carefully and according to its technical data (do not throw it, strike it, …)
Protect the device from dirt.
3 Safety
3.1 Safety signs and symbols
Warnings are labeled in this document with the followings signs:
DANGER
Caution! This symbol warns of imminent danger, death, serious injuries
and significant damage to property at non-observance.

Attention! This symbol warns of possible dangers or dangerous
situations which can provoke damage to the device or environment at
non-observance.
Note! This symbol point out processes which can indirectly influence
operation or provoke unforeseen reactions at non-observance.
3.2 Safety guidelines
This device has been designed and tested in accordance with the safety regulations for electronic devices.
However, its trouble-free operation and reliability cannot be guaranteed unless the standard safety measures
and special safety advises given in this manual will be adhered to when using the device.
1. Trouble-free operation and reliability of the device can only be guaranteed if the device is not subjected
to any other climatic conditions than those stated under "Specification".
If the device is transported from a cold to a warm environment condensation may cause in a failure. In
such case make sure the device temperature has adjusted to the ambient before trying a new start-up.
2. If there is a risk whatsoever involved in running it, the device has to be switched off
immediately and to be marked accordingly to avoid re-starting.
Operator safety may be a risk if:
- there is visible damage to the device
- the device is not working as specified
- the device has been stored under unsuitable conditions for a longer time.
In case of doubt, please return device to manufacturer for repair or maintenance.
3. Do not use these products as safety or emergency stop devices or in any other application
where failure of the product could result in personal injury or material damage.
Failure to comply with these instructions could result in death or serious injury and material
damage.
4. This device must not be used at potentially explosive areas! The usage of this device at
potentially explosive areas increases danger of deflagration, explosion or fire due to
sparking.
DANGER
DANGER
DANGER

H74.0.04.6C-06 Operating Manual GMH 3611 page 4 of 14
4 Product Description
4.1 Scope of supply
The scope of supply includes:
GMH 3651 with 9V-battery
Operating Manual
The necessary oxygen sensor is chosen separately due to application.
4.2 Operation and maintenance advice
1. Battery operation
If and ‘bAt’ are shown in the lower display the battery has been used up and needs to be replaced.
However, the device will operate correctly for a certain time. If ‘bAt’ is shown in the upper display the
voltage is too low to operate the device; the battery has been completely used up.
The battery has to be taken out, when storing device above 50 °C.
We recommend taking out battery if device is not used for a longer period of time.
After recommissioning the real-time clock has to be set again.
2. Mains operation with power supply
When using a power supply please note that operating voltage has to be 10.5 to 12 V DC.
Do not apply overvoltage!! Cheap 12V-power supplies often have excessive no-load voltage.
We, therefore, recommend using regulated voltage power supplies.
Trouble-free operation is guaranteed by our power supply GNG10/3000.
Prior to connecting the power supply to the mains make sure that the operating voltage stated at the
power supply is identical to the mains voltage.
3. Treat device and sensor carefully. Use only in accordance with above specification. (do not throw, hit
against etc.). Protect plug and socket from soiling.
4.3 Start of Operation
Switch the device on with the key “ON OFF”. The instrument is performing a self diagnosis, during this time
all display segments are shown.
Afterwards the instrument signals, if it was user adjusted („[ORR“)
The device starts measurement afterwards.


H74.0.04.6C-06 Operating Manual GMH 3611 page 5 of 14
4.4 Connections
1.
Output: Operation as interface for t he connection of
galvanically isolated adapters (accessories: GRS
3100, USB 3100)
Attention: The mode of operation has to be
configured (p.r.t Chapter 5) and influences
the power consumption.
2.
Sensor connection MiniDIN
3.
Power supply: d.c.connector (internal pin Ø 1.9 mm) for external 10.5-12V direct voltage supply
4.5 Display elements
1 = Main Display:
1a = display unit:
Display of the oxygen value, please refer to
chapter 5, (H 2)
(change with -key)
2 = secondary
display:
2a = display unit:
Display of sensor temperature or absoute
pressure (alternating, please refer to Chapter
5.LcD.2)
Special elements:
3 = MIN/MAX/HLD:
Shows, if minimum/maximum/
memorized measuring value is in display
4 = ok-arrow:
Signals, if oxygen and temperature values
are stable
5 = CAL-arrow:
Signals, if automatic calibration is in
progress
6 = SAL-arrow
Signals, that the salinity correction is
aktivated
7 = Logg-arrow
No function
8 = Warning sign:
Signals weak battery or other warning
message
4.6 Pushbuttons
On / off key
Set/Menü
Press 2 sec.: (Menu): call configuration menu
Press shortly: Change the oxygen display unit
(please refer to chapter 5)
+
min/max when taking measurements:
press shortly: min. or max. measured oxygen value and
referring temperature and pressure values
will be displayed
press for 2 sec.: the min. or max. value will be deleted
Configuration: to enter values, or change settings
Store/Enter
- Measuring:
with Auto-Hold off: hold and save current measuring value (‘HLD’ is displayed)
with Auto-Hold on: start new measuring, It is finished , when “HLD’ shows in display
- Set/Menu: confirm settings, return to measuring
CAL:
press shortly: display of sensor state rating
press for 2 sec: start sensor calibration

H74.0.04.6C-06 Operating Manual GMH 3611 page 6 of 14
4.7 Pop-up clip
Handling:
•Pull at label “open” in order to swing open the pop-up clip.
•Pull at label “open” again to swing open the pop-up clip further.
Pop-up clip closed
Pop-up clip at position 90°
Pop-up clip at position 180°
Function:
• The device with a closed pop-up clip can be plainly laid onto a table or attached to a belt, etc.
• The device with pop-up clip at position 90° can be set up on a table, etc.
• The device with pop-up clip at position 180° can be suspended from a screw or the magnetic holder
GMH 1300.
Device attached to a belt
Device set up on a table
Device suspended from
magnetic holder
GMH 1300

H74.0.04.6C-06 Operating Manual GMH 3611 page 7 of 14
5 Configuration
Some menu points depend on current device settings.
To change device settings, press „Menu“ for 2 seconds. This will activate the configuration menu (main
display: “Set”). Pressing „Menu“ changes between the menus points, pressing jumps to the
referring parameters, which can be selected with key .
The parameters can be changed with or . Pressing „Menu“ again jumps back to the main
configuration menu and saves the settings. "Quit" finishes the configuration and returns to standard
measuring operation.
Menu
Parameter
Value
Description
key Menu
key
keyor 
p.r.t
SET
(ONF
Set Configuration: General configurations
U N,T
(ONC
(ONC ppm
Display unit of O2- concentration ppm (identical values like mg/l)
*
(ONC mg/l
Display unit of O2- concentration mg/l (identical values like ppm)
[H 2
SAT %O2
Main display shows O2- concentration (mg/l or ppm) or O2-Saturation in %
(ex works setting)
P 02 hPa
Main display shows O2- concentration or O2-partial pressure in hPa
P 02 mmHg
Main display shows O2- concentration or O2- partial pressure in mmHg
RES
K ,
Best O2resolutions
LO
Low O2resolution, calm value display (standard)
SAL
OFF
Salinity correction deactivated (ex works setting)
0.1 …70.0
Salinity correction activated, Unit ‰ = PSU
LCD.2
T
Second. display always temperature
P
Second. display always absolute pressure
P T
Second. display alternates between temperature and abs. pressure
U N,T
T
°C
All temperatures in degree Celsius (ex works setting)
°F
All temperatures in degree Fahrenheit
[. INT
1 …365
Calibration reminder period (in days)
OFF
No calibration reminder
A VTO
HLD
ON
Auto measuring value identification Auto Hold (when logger = off)
OFF
Standard hold function on key press (when logger = off)
P.OFF
1 …120
Power-off delay in minutes. Device will be automatically switched off as
soon as this time has elapsed if no key is pressed/no interface
communication takes place. (ex works setting 20min)
OFF
Automatic power-off function deactivated (continuous operation)
ADR
0 1,1 1,2 1,…9 1
Base address for serial interface communication (ex works setting 01)
SET
(ORR
Set Corr: Input adjustment
0FFS
°C or °F
-5.0 °C .. 5.0 °C
or
-9.0 °F .. 9.0 °F
The zero point of the temperature measuring is shifted for the entered
value.
This can be used to compensate sensor and instrument deviations
OFF
No zero adjustment for temperature measurement (=0.0°)
S[AL
°C or °F
-5.00 ... 5.00 %
The slope of the temperature measurement is corrected by this value.
This can be used to compensate sensor and instrument deviations
OFF
No slope adjustment for temperature measurement (=0.00)
0FFS
hPa
-20 .. 20 hPa
The zero point of the pressure measuring is shifted for the entered value.
This can be used to compensate sensor deviations
OFF
No zero adjustment for pressure measurement (=0.0°)
Pressing “menu” and “store” at the same time for more than 2 seconds will reset the device
to factory defaults
If no key is pressed for more than 2 minutes the configuration will be aborted.
All changes will not be saved!
1 2 3
4 5 6
ON
OFF max
Store
CAL
min
Set
Menu Quit
1 2 3
4 5 6
ON
OFF max
Store
CAL
min
Set
Menu Quit
1 2 3
4 5 6
ON
OFF max
Store
CAL
min
Set
Menu Quit
1 2 3
4 5 6
ON
OFF max
Store
CAL
min
Set
Menu Quit
1 2 3
4 5 6
ON
OFF max
Store
CAL
min
Set
Menu Quit
1 2 3
4 5 6
ON
OFF max
Store
CAL
min
Set
Menu Quit
1 2 3
4 5 6
ON
OFF max
Store
CAL
min
Set
Menu Quit
1 2 3
4 5 6
ON
OFF max
Store
CAL
min
Set
Menu Quit

H74.0.04.6C-06 Operating Manual GMH 3611 page 8 of 14
6 The Oxygen Sensor
6.1 Design of Sensor GWO 3600
6.2 Electrode Maintenance
If electrode can no longer be calibrated, it needs maintenance.
Attention! The electrolyte is a corrosive.
To maintain electrode please proceed as follows:
1. Unscrew diaphragm head and wipe clean of electrolyte solution using a paper cloth. Do not touch
electrolyte. If your skin had contact with electrolyte, immediately rinse thoroughly with clear water.
2. Clean silver cathode with sand paper (grain size 240). Do not polish silver cathode, surface should stay
rough. Remove all dust.
3. Remove filling screw and top up lost electrolyte (e.g. using disposable syringe))
4. Put back and tighten filling screw.
5. Top up diaphragm head with electrolyte avoiding air bubbles and place on table (cover table with
absorbent paper first).
6. Keep electrode in a vertical position and screw diaphragm head to the electrode from the bottom.
Electrolyte will be forced out of the diaphragm head and spill over (put on disposable gloves or use
paper towel to touch diaphragm head).
7. Wipe up excess electrolyte with paper cloth.
8. Check cathode for air bubbles.
If there are large air bubbles, remove diaphragm head again and repeat process as of point 5. If O-ring
has been damaged, it has to be replaced.
When maintenance has been completed plug on protective flask. Re-connect electrode to measuring device
and wait for at least 3 hours till electrode can be calibrated.
General information
The oxygen electrode is an active electrode consisting of a silver cathode and a
lead anode with the electrolyte being potassium hydroxide (KOH). In case of
oxygen being present it will be reduced at the silver cathode, i.e. the electrode
supplies a current. No oxygen means no current either. The oxygen measurements
use up both the silver cathode as well as the lead anode. The electrode is subject
to ageing. Therefore, we recommend to maintain the electrode at monthly intervals
(p.r.t. 'Electrode maintenance')
Please note: Make it a rule to always store the electrode in a humid
environment.
- in the storage flask filled with water
- in another container filled with water
If electrode has not been used for some time, clean diaphragm with soft
cloth and remove deposits, if any (algae, bacteria etc.).
Electrode design
The electrode housing is made of PVC. With the exception of the electrode shaft all
parts need to be maintained regularly and be replaced if necessary.
o Protective flask: The protective flask is used to moisten the diaphragm. This
The prolongs service life of the electrode. The protective flask contains water.
Attention! Use water only; never use potassium chloride (KCI); this is only
required for storage of pH-electrode.
o Diaphragm head: the diaphragm head is covered with a teflon diaphragm. It
will be filled with KOH electrolyte and screwed onto the electrode shaft (no air
bubbles). Damages in the diaphragm, large air bubbles or air bubble rings in
the diaphragm head will result in erroneous measurements. This may also be
the reason for errors in the calibration. The diaphragm head is a spare part
and can be ordered individually.
o Filling hole: If the electrode is used at high temperatures or if it has been
stored without its protective flask for a longer period of time, some electrolyte
will be lost due to evaporation. During maintenance make it a rule to unscrew
diaphragm head, remove locking screws and top up electrolyte using a
syringe. Replace and tighten locking screws.
Attention when working with electrolyte! The electrolyte is corrosive!
(strong base, KOH)
Filling hole
Electrode shank
O-ring
Diaphragm cap

H74.0.04.6C-06 Operating Manual GMH 3611 page 9 of 14
7 Oxygen Measuring - please note
Please observe the following points when measuring dissolved oxygen:
- For measuring remove the protective flask.
- Do not disconnect electrode from device.
If electrode has been disconnected, wait 2 - 3 hours till the final electrode signal has settled
before carrying out measurements or a calibration.
- Electrode needs to be calibrated (p.r.t. 'How to calibrate oxygen electrode')
- The temperatures of the electrode and of the liquid to be measured have to be identical
(if necessary, wait till temperatures match)
- The Electrode has to be submerged at least 3 cm into the liquid to being measured
- The measured liquid has to stream along the electrode membrane with at least 30 cm/sec
for measurements to be sufficiently accurate: either stir continuously or use agitator.
- The electrode measurement is sensitive against shocks!
By stirring of the electrode in the measured liquid be careful that the electrode does not hit the
container. A vibration of the electrode has a effect to the measured value.
-The optimum operation position is: with the sensor inlet pointing downwards
The instrument calculates the oxygen concentration [mg/l], the oxygen saturation [%] and the oxygen partial
pressure [hPa] from the electrode signal and the temperature. According to DIN38408-C22 all
measurements refer to steam saturated air.
7.1 Ambient pressure and measuring depth of the electrode
The pressure at the sensor membrane is important for:
The calculation oft he oxygen saturation (%sat).
At air water can get 100% saturation. Assumed that there are no oxygen consuming processes
(biological degradation, chemical effects) and that there are no oxygen enriching processes (e.g.
excessive ventilation or photosynthesis)
The calculation of oxygen concentration (mg/l or ppm)
The electrode evaluation at calibration
Therefore it is necessary to compensate the pressure influence via integrated sensor or, like practised with
more primitive instruments via tables and manual input of pressure or Elevation above sea level values.
7.2 Correction of salinity ('SAL')
The higher the salinity (salt content) the lower the solubility of oxygen in water, i.e. although the partial
oxygen pressure is the same, the quantity of oxygen dissolved in water (mg/l) is lower. Therefore,
determination of the oxygen concentration requires entering the salinity of the medium (p.r.t. 'Configuration').
The correction of salinity is based on media on a water basis, whose chemical content is similar to sea water.
The corrections are based on the 'International Oceanographic Tables' (IOT).
8 Calibration of the Sensor
In order to compensate for ageing of the sensor, the sensor has to be calibrated at regular intervals.
The device is equipped with a easy-to-use calibration function.
We recommend to calibrate the sensor at least all 7 days, or to get maximum precision, before each
measuring series.
If the electrode was dry for one or more days it has to be 'watered' for at least 30 minutes before carrying out
a new calibration.
8.1 How to Calibrate
The calibration adjusts the sensor to the oxygen content of the atmosphere (20.95%). Remove protective
flask prior to calibration and wipe diaphragm with a soft piece
of cloth. You can choose between three modes of calibration for which the electrode has to
be prepared accordingly.

H74.0.04.6C-06 Operating Manual GMH 3611 page 10 of 14
Air calibration without accessories ('Cal Air')
The electrode will be exposed to ambient air. To protect it
from draughts, wrap electrode in a paper towel. (before
calibration, expose sensor at least 15 minutes to the
ambient air, to let the temperature adjust and to dry
membrane)
Depending on the rel. atmospheric humidity [%] and the
temperature [°C] a small calibration error cannot be
avoided and will have to be accepted. The cooler the air is,
the smaller the deviation.
Recommended temperature: < 25°C.
For error compensation please refer to the opposite table.
Note: A correctly calibrated electrode shows 106 - 108% at air and at room temperature.
Air calibration for highly accurate measurements ('Cal Air')
The electrode is exposed to air with a relative atmospheric humidity of 100%.
Proceed as follows: Put some distilled water in a bottle. Close bottle and generate a water steam saturation
(100% rel. atmospheric humidity) in the remaining air by shaking it vigorously for approx. 3 minutes. Both
water and air temperatures should be identical. Open bottle and insert electrode so that the diaphragm is in
the air chamber.
Attention: By no means must the diaphragm get wet or be immersed in water. The bottle neck opening
should only be slightly larger than the electrode diameter; make sure to avoid over pressure in the container.
Note: A correctly calibrated electrode shows 106 - 108% at air and at room temperature.
Calibration in air saturated water (configuration: 'Cal AqUA')
This mode of calibration is more difficult than the ones already described. As water is easily oversaturated it
quickly results in calibration errors. In order to generate air saturated water, pure water (25-30°C) is poured
into another container from a height of 50 cm. This process is repeated 20 times. In order to let an
oversaturation evaporate, wait approx. 5 min. before carrying out the calibration (do not forget to stir).
Start calibration: press -key for 2 seconds
The display will show 'A,R , and as soon the values for oxygen and temperature are stable, the
calibration will be finished.
Then the electrode state resulting of the successful calibration will be shown for a short time (evaluation in
10% steps: xx% ELE[).
In case of error messages being displayed during the calibration process, please refer to our notes
at the end of this manual! If a calibration cannot be carried out after an extended period of time, at
least one of the measuring values is unstable (oxygen partial pressure, temperature).
Please check your measuring arrangements!
8.2 Evaluation of Sensor State (ELE[)
Watch sensor state: press key "CAL" shortly oncedisplay show for a short time xx% ELE[.
It will show the electrode state resulting of the last successful calibration carried out.
The valuation is displayed in 10 percent steps: 100% means optimal sensor condition. Lower values are
indicating that the sensor life time will be reached soon.
Remark: But also a erroneous pressure may be the cause of low valuation values.
8.3 Calibration Interval ([.INT)
You can enter the interval after which the device reminds you to recalibrate in the configuration.
The interval times should be chosen according to the application and the stability of the sensor.
“CAL” flashes on the display as soon as the interval has expired.
20%
40%
60%
80%
100%
5 °C
1.007
1.005
1.003
1.002
1.00
10 °C
1.01
1.007
1.005
1.002
1.00
15 °C
1.014
1.01
1.007
1.003
1.00
20 °C
1.019
1.014
1.009
1.005
1.00
25 °C
1.026
1.019
1.013
1.006
1.00
30 °C
1.035
1.026
1.017
1.009
1.00
35 °C
1.047
1.035
1.023
1.012
1.00
40 °C
1.063
1.047
1.031
1.016
1.00
Deviations when carrying out an air calibration
without accessories,
O2-saturation= display value*corr. factor

H74.0.04.6C-06 Operating Manual GMH 3611 page 11 of 14
9 Inspection of the accuracy / Adjustment Services
The instrument can be sent to the manufacturer for adjustment and function test.
Only the manufacturer can check all systems on correct them if necessary.
Calibration certificates –DKD-certificates –other certificates:
If device should be certificated for its accuracy, this is not possible for dissolved oxygen measuring, only for
abs. Pressure and temperature.
10 Serial Interface
With an electrically isolated interface converter USB3100, GRS3100 or GRS3105 (accessory) the device can
be connected to a PC.
With the GRS3105 it is possible to connect up to 5 instruments of the GMH3000 family to a single interface
(please also refer to GRS3105-manual). As a precondition the base addresses of all devices must not be
identical, make sure to configure the base addresses accordingly (refer menu point “Adr.” in chapter 5).
In order to avoid transmission errors, there are several security checks implemented (e.g. CRC).
The following standard software packages are available for data transfer:
GSOFT3050: Operating and evaluation software for instruments with integrated logger function
EBS20M/ -60M: 20- / 60-channel software to record and display the measuring values
GMHKonfig: Software for a comfortable configuration of the device (e.g. freeware)
In case you want to develop your own software we offer a GMH3000-development package including
- an universally applicable 32bit Windows functions library ('GMH3000.DLL') with documentation that can
be used by all 'serious' programming languages.
- Programming examples for Visual Studio 2010 (C#, C++), Visual Basic 6.0™, Delphi 1.0™, Testpoint™,
Labview™
The Device has 4 Channels:
- oxygen concentration in mg/l or ppm
- oxygen saturation in percent or partial pressure in hPa or mmHg
- temperature value at the time of recording in °C or °F
- absolute pressure in hPa abs or mmHg abs or depth in m
Supported Interface-functions:
1
2
3
4
Code
Name/Function
1
2
3
4
Code
Name/Function
x
x
x
x
0
read nominal value
x
x
x
x
199
read measuring type in display
x
x
x
x
3
read system status
x
x
x
x
200
read min. display range
x
12
read ID-no.
x
x
x
x
201
read max. display range
x
x
x
22
read min alarm limit
x
x
x
x
202
read unit of display
x
x
x
23
read max alarm limit
x
x
x
x
204
read decimal point of display
x
208
read channel count
x
222
read turn-off-delay
x
x
x
x
178
read measuring range unit
x
223
Set turn-off-delay
x
x
x
x
179
read measuring range decimal point
x
240
Reset
x
x
x
x
180
read measuring type
x
254
read program identification
The measuring and range values read via interface are always in the selected display
unit!

H74.0.04.6C-06 Operating Manual GMH 3611 page 12 of 14
11 Error and System Messages
Display
Meaning
Remedy
low battery voltage, device will continue to work
for a short time
replace battery
If mains operation: wrong voltage
replace power supply, if fault continues to
exist: device damaged
low battery voltage
replace battery
If mains operation: wrong voltage
Check/replace power supply, if fault
continues to exist: device damaged
No display
or
weird display
Device does not
react on keys
low battery voltage
replace battery
If mains operation: wrong voltage
check/replace power supply, if fault
continues to exist: device damaged
system error
disconnect battery or power supply, wait
some time, re-connect
device defective
return to manufacturer for repair
SENS
ERRO
sensor error: no sensor cable connected
connect suitable sensor
Sensor, cable or instrument defect
return to manufacturer for repair
ERR.1
Value exceeding measuring range
Check: Is the value exceeding the
measuring range specified? ->value too
high!
Wrong sensor connected
Check sensor
Sensor, cable or instrument defect
return to manufacturer for repair
ERR.2
Value below display range
Check: Is the value below the measuring
range specified? ->value too low!
Wrong sensor connected
Check sensor
Sensor, cable or instrument defect
return to manufacturer for repair
ERR.7
system error
return to manufacturer for repair
If “BAT“ is flashing, the battery will be exhausted soon. Further measurements are possible for short time.
If “BAT“is displayed continuously the battery is ultimately exhausted and has to be replaced. Further
measurements aren’t possible any more.
Messages During Calibration/Adjustment
>CAL<
CAL flashing in
display
either preset calibration interval has expired or
last calibration is not valid
Device has to be calibrated!
[AL ERR.1
wrong reference point at air
check sensor and reference gas / solution
[AL ERR.2
slope too low
reference gas / solution wrong
check sensor and reference gas / solution
sensor is defect
replace sensor / perform maintenance
[AL ERR.3
slope too high
reference gas / solution wrong
check sensor and reference gas / solution
sensor is defect
replace sensor / perform maintenance
[AL ERR.4
incorrect calibration temperature
calibration can only be done at 0…40 °C
[AL ERR.5
Zero value to low/negative
sensor is defect
replace sensor / perform maintenance
[AL ERR.6
zero value to high
reference gas / solution wrong
check sensor and reference gas / solution
sensor is defect
replace sensor / perform maintenance
[AL ERR.7
incorrect calibration pressure
check calibration pressure
[AL ERR.8
signal not stable / timeout
check sensor and reference gas / solution
[AL ERR.9
sensor not known: cannot be calibrated
check sensor and wiring

H74.0.04.6C-06 Operating Manual GMH 3611 page 13 of 14
12 Specification
Measuring ranges
Oxygen concentration
0.00 ... 70.00 mg/l or ppm
electrochemical sensor GWO 3600
Oxygen saturation
0.0 ... 600.0 % O2
Oxygen partial pressure
0 ... 1200 hPa O2 (0.0 .. 427.5 mmHg)“
Sensor temperature
-5.0 ... + 50.0 °C
NTC 10k (integrated in GWO 3600)
Absolute pressure
10 ... 1200 hPa abs.
integrated pressure sensor
Accuracy
at 25°C, 1000 hPa abs
Oxygen
±1.5 % of measured value ±0,2 mg/l (0-25 mg/l)
or ±2.5 % of measured value±0,3 mg/l (25-70 mg/l)
Sensor temperature
± 0.1 °C
Accuracy
Absolute pressure
3 hPa or 0.1% of measured value (the higher one to be applied)
Working conditions
-20 ... 50 °C; 0 ... 95 % r.H. (not condensing)
Nom. temperature
25°C
Storage temp.
-20 ... 70 °C
Connections
O2& temperature
6 pole Mini-DIN Socket
Interface /
serial, (3.5mm audio plug),via isolated adapter GRS3100, GRS3105 or
USB3100 (accessories) for PC-USB or RS232- connection
external supply
d.c. connector (diameter of internal pin 1.9 mm) for external 10.5-12V
direct voltage supply. (suitable power supply: GNG10/3000)
Oxygen sensor
GWO 3600
Working conditions
0 ... 40 °C
Operating pressure
max. 3 bar
Display
4 digit 7-segment 2 lines, additional segments
Calibration
automatic
1 -point calibration, at ambient air (20.95%)
GLP
adjustable calibration intervals (1 to 365 days, CAL warning after
expiration)
Additional functions
Min / max / hold / auto hold
Housing
Break-proof ABS housing
Protection class
Front side IP65
Dimensions L*B*H [mm]
Weight
142 x 71 x 26 mm (L x B x H)
approx 160 g (incl. battery)
Power supply
Current consumption
9V-Battery, Type IEC 6F22 (in scope of supply) or external supply
Ca. 0.6 mA (if Out = Off ca. 0.4mA)
Change battery indicator
Automatic at weak battery and ’ bAt ’
Auto-Off-Function
Device will be automatically switched off if no key is pressed/no
interface communication takes place for the time of the power-off delay.
The power-off delay can be set to values between 1and 120 min.; it can
be completely deactivated.
EMI
The device corresponds to the essential protection ratings established in
the Regulations of the Council for the Approximation of Legislation for
the member countries regarding electromagnetic compatibility
(2004/108/EG). Additional fault: <1%
13 Reshipment and Disposal
Dispense exhausted batteries at destined gathering places.
This device must not be disposed as “residual waste”. To dispose this device, please send it
directly to us (adequately stamped). We will dispose it appropriately and environmentally friendly.
DANGER
All devices returned to the manufacturer have to be free of any residual of measuring media and
other hazardous substances. Measuring residuals at housing or sensor may be a risk for persons
or environment

Use an adequate transport package for reshipment, especially for fully functional devices. Please
make sure that the device is protected in the package by enough packing materials.

H74.0.04.6C-06 Operating Manual GMH 3611 page 14 of 14