Ahlborn ALMEMO 2690-8A User manual

____________________________
Operating Instructions
Data Logger
ALMEMO® 2690-8A
V4.7
20.10.2021
www.ahlborn.com

2
1. OPERATING CONTROLS
(1) Meas. inputs M0 to M4
M0 ... M4 for all ALMEMO-Sensors
M10...M34 15 additional channels
(2) Output sockets A1, A2
A1 Interfaces USB(ZA1919-DKU)
Interface V24 (ZA 1909-DK5)
Fiber optics V24 (ZA 1909-DKL)
Ethernet (ZA 1945-DK)
RS 422 (ZA 5099-NVL/NVB)
Analog output 2 (ZA 1601-RK)
A2 Network cable (ZA1999-NK5/NKL)
SD card connector (ZA 1904-SD)
Trigger input (ZA 1000-ET/EK)
Relay outputs (ZA 1000-EGK)
Analog output 1 (ZA 1601-RK)
(3) Connector socket DC 12V
Mainsadapter(ZA1312-NAx,12V, 1,5A)
USB Cable (ZA1919-DKU5, 5V 0.4A)
DC-Cable isolat. (ZA2690-UKx, 10-30V)
(4) Sleep-LED
(5) LCD display
Status line:
CCont. measuring point scan
© , ll Measurement Start, Stop
REC Memory record
COM Output of meas. values
l©,©l Meas. start, end programmed
R01 Alarm relay status
* , * Light on, pause
Battery operation/charge status
13 lines for functions
Function of keys F1, F2, F3, F4
(6) Control keys
ON ,<POFF> Switch device on, off
 ,  ,  Function selection
F1 ... F4 Function keys (soft keys)
PROG Programming
 ,  ,  Data input
<ESC> Function abort
 Last measuring menu
(7) Rubber shock absorber
Back of unit:
(8) Battery box
3 Mignon Alkaline Batteries
or 3 Mignon NiCd/NiMH Accumulators
(9) Stand for stand and hang up
(for opening out from 90° to 180°
please press the stand together!)

3
2. TABLE OF CONTENTS
1. Operating Controls .....................................................................................2
2. Table of Contents........................................................................................3
3. General.......................................................................................................8
3.1 Guaranteed ........................................................................................8
3.2 Extent of the Delivery.........................................................................8
3.3Waste disposal...................................................................................9
4. Safety instructions ....................................................................................10
4.1 Special notes on use ....................................................................... 11
4.2 Handling batteries / rechargeable batteries correctly ...................... 11
5. Introduction...............................................................................................12
5.1 Functions .........................................................................................12
5.1.1 Sensor Programming ...................................................................13
5.1.2 Measurement ...............................................................................14
5.1.3 Process flow control.....................................................................15
6. Initial Operation ........................................................................................17
7. Power supply ............................................................................................18
7.1 Rechargeable battery operation voltage monitoring........................18
7.2 Battery operating mode ...................................................................18
7.3 Mains operation ...............................................................................19
7.4 External DC voltage supply .............................................................19
7.5 Sensor Supply..................................................................................19
7.6 Switch On/Off, Reinitialisation .........................................................19
7.7 Data buffering ..................................................................................20
8. Connection of the Transducers ................................................................21
8.1 Transducers .....................................................................................21
8.2 Measuring inputs and Additional Channels .....................................21
8.3 Isolation............................................................................................22
9. Display and Keypad..................................................................................24
9.1 Display and Menu Selection ............................................................24
9.2 Function Keys ..................................................................................25
9.3 Control Symbols...............................................................................25

2. Table of Contents
4
9.4 Function Selection ...........................................................................26
9.5 Data Entry ........................................................................................26
10. Measuring using Measuring-Menus.....................................................27
10.1 Measuring with one Measuring Point...............................................28
10.1.1 Selecting the Measuring Point .................................................28
10.1.2 Peak Value Memory with Time and Date.................................28
10.2 Correction of the Meas. Value and Compensation .........................29
10.2.1 Setting the Meas. Value to Zero ..............................................29
10.2.2 Zero Point Adjustment..............................................................30
10.2.3 Sensor Adjustment in the case of chemical sensors ...............30
10.2.4 Two-point Adjustment with Setpoint Entry ...............................31
10.2.5 Temperature Compensation ....................................................32
10.2.6 Atmospheric Pressure Compensation .....................................32
10.2.7 Cold Junction Compensation...................................................33
10.3 Measuring point scans and Output ..................................................34
10.3.1 Single Output / Storage of all Measuring Points......................34
10.3.2 Cyclic Output / Storage of all Measuring Points ......................34
10.3.3 Memory space, Memory Output, Clearing the Memory...........35
10.3.4 Output of Menu Functions .......................................................35
10.3.5 Displaying Measured Values as a Line Diagram .....................36
10.4 Averaging.........................................................................................37
10.4.1 Damping of Meas. values by a Sliding averag. window ..........38
10.4.2 Averaging Mode.......................................................................38
10.4.3 Averaging over Manual Single Measurements ........................38
10.4.4 Array Measurement .................................................................39
10.4.5 Averaging over the Measuring Time ........................................40
10.4.6 Measurement Time, Measuring duration, Timer ......................40
10.4.7 Averaging over the Cycle.........................................................41
10.4.8 Averaging over several Measuring Points ...............................42
10.4.9 Volume Flow Measurement .....................................................43
10.5 Display of Several Measuring Points ...............................................44

2. Table of Contents
5
10.5.1 Menu Multi Channel Display and Bar chart .............................44
10.5.2 Differential Measurement.........................................................44
10.5.3 Menu List of Measuring Points ................................................45
10.6 Assistant-Menus for Special Meas. Operations...............................46
10.6.1 Thermal Coefficient..................................................................46
10.6.2 Wet Bulb Globe Temperature...................................................46
10.7 User Menus......................................................................................47
10.7.1 Functions .................................................................................47
10.7.2 Configuration of the menus......................................................48
10.7.3 Function Printouts ....................................................................49
11. Programming With Programming-Menus ............................................50
11.1 Times and Cycles ............................................................................50
11.1.1 Time and Date..........................................................................50
11.1.2 Cycle with Storage Activation and Output Format ...................50
11.1.3 Conversion Rate, Continuous Measuring Point Scan .............51
11.1.4 Time and Date of Start, Time and Date of End........................52
11.2 Data Memory ...................................................................................53
11.2.1 Memory connector with SD card..............................................53
11.2.2 Data Acquisition .......................................................................54
11.2.3 Numbering of measurements ..................................................54
11.2.4 Starting and Stopping of measurements .................................55
11.2.5 Scanning mode ........................................................................55
11.2.6 Memory Output ........................................................................57
11.3 Sensor Programming .......................................................................58
11.3.1 Selecting the Input Channel.....................................................58
11.3.2 Measuring Point Designation...................................................59
11.3.3 Averaging Mode.......................................................................59
11.3.4 Locking the Programming of the Sensor .................................59
11.3.5 Limit Values..............................................................................60
11.3.6 Scaling, Decimal Point Setting.................................................60
11.3.7 Correction Values.....................................................................61

2. Table of Contents
6
11.3.8 Changing the Dimension .........................................................61
11.3.9 Selecting the Measuring Range...............................................61
11.3.10 Function Channels ...................................................................64
11.3.11 Special meas. ranges, linearization, calibration ......................65
11.4 Special Functions.............................................................................66
11.4.1 Print Cycle Factor ....................................................................66
11.4.2 Minimum Sensor Supply Voltage.............................................66
11.4.3 Limit Value Responses ............................................................67
11.4.4 Analog Output Start and End...................................................68
11.4.5 Output Function .......................................................................68
11.4.6 Reference Channel 1...............................................................69
11.4.7 Reference Channel 2 or Multiplexer ........................................69
11.4.8 Element Flags ..........................................................................69
11.5 Device Configuration .......................................................................70
11.5.1 Device Designation ..................................................................70
11.5.2 Device Address and Networking..............................................70
11.5.3 Baud Rate, Data Format..........................................................71
11.5.4 Language .................................................................................71
11.5.5 Lighting and Contrast...............................................................71
11.5.6 Atmospheric Pressure..............................................................71
11.5.7 Hysteresis ................................................................................72
11.5.8 Operating Parameters..............................................................72
11.6 Output Modules................................................................................72
11.6.1 Data cable................................................................................73
11.6.2 Relais Trigger modules ............................................................73
11.6.3 Analog Output ..........................................................................75
11.7 Menu Power Supply.........................................................................76
11.8 The locking and calibration menu (option KL) .................................77
12. Troubleshooting ...................................................................................78
13. Declaration of conformity .....................................................................80
14. Appendix ..............................................................................................81

2. Table of Contents
7
14.1 Technical Data .................................................................................81
14.2 Product overview .............................................................................82
14.3 Index ................................................................................................83
Your contact .................................................................................................88

8
3. GENERAL
Congratulations for buying this innovative ALMEMO® data logger. By means of
the patented ALMEMO® connectors the device configures itself and with the help
of menus and help windows the operation should not be too difficult. However,
the device allows the connection of a great variety of sensors and peripherals
with many special functions. For getting to know the function range of the sen-
sors and the diverse possibilities of the device, you really should read these
operating instructions and the corresponding chapters of the ALMEMO® manual.
This is the only way to avoid operating and measuring errors as well as damages
of the device. For a quick answer to all questions, a detailed keyword index is
provided at the end of the instructions and of the manual.
3.1 Guaranteed
Every device has to pass through several quality tests before leaving the works.
For a perfect function, a guarantee of two years from the delivery date is
granted. Before sending back the device, please pay attention to the indications
in chapter 12. Troubleshooting. Should there actually be a defect, please use
the original packing material for depatch if possible and enclose an expressive
description of the trouble in connection with the corresponding circumstances.
In the following cases a guarantee benefit is excluded:
⚫After forbidden operations and changes in the device by the client
⚫Operating in surrounding conditions that are not valid for this product
⚫Using unsuitable power supply and peripherals
⚫Using the device in a way it is not determined for
⚫Damages through electrostatic discharge or flash of lightning
⚫Not paying attention to the operating instructions
Changes in the product features in favour of technical progress or due to new
components are reserved to the producer.
3.2 Extent of the Delivery
While unwrapping the delivery, pay attention to damages of the device and to
its completeness:
Measuring instrument ALMEMO® 2690-8A with 3 AA NiMH
(nickel-metal hydride) rechargeable batteries
Rubber shock absorber with a stand,
these operating instructions,
ALMEMO® Manual,
CD with Software ALMEMO® Control and useful accessories
In case of a transportation damage, the packing material is to be kept and the
supplier is to be informed immediately.

3. General
9
3.3 Waste disposal
The pictogram showing a waste bin crossed through means
that the product is subject to European Union regulations on
segregated waste disposal. This applies both to the product
itself and to any accessories marked with the same symbol.
Disposal of any such item as unsorted domestic waste is
strictly forbidden.
•Please dispose of all packaging materials according to the applicable national
waste management regulations.
•Please dispose of cardboard boxes, protective plastic packaging materials,
and all preservative substances separately and in the proper manner.
•The disposal of the device itself (also of device parts, accessories, and con-
sumables) is subject to the applicable national and local waste management
regulations and to the environmental protection legislation in force in the coun-
try of use.
•Please dispose of all waste in the proper manner;
this applies in particular to all parts and substances that constitute a hazard
for the environment. This includes inter alia plastics, batteries, and recharge-
able battery packs .
•When disposing of goods, please wherever possible use the original packag-
ing materials.

10
4. SAFETY INSTRUCTIONS
DANGER
Danger to life and limb, risk of damage to equipment
Read the instructions carefully before starting to operate
the device.
Please ensure that you comply with all general safety advice
and the special safety instructions included in other chap-
ters.
Such risks may occur in the following circumstances :
•Failure to heed the operating instructions and all the
safety notes these contain
•Any form of unauthorized tampering or alteration inside
the device
•Use of the device in environments or conditions for
which it is not suited
•Use of the device with an unsuitable power supply and /
or in conjunction with unsuitable peripheral equipment
•Use of the device for any purpose other than that for
which it is intended
•Damage caused by electrostatic discharge or lightning.
DANGER
Risk of fatal injury caused by dangerously high voltage
Such risks may occur in the following circumstances :
•Use of the device with an unsuitable power supply and /
or in conjunction with unsuitable peripheral equipment
•Damage caused by electrostatic discharge or lightning
•Do not run sensor lines in the vicinity of high-voltage
power cables.
•Before you touch any sensor lines, ensure that all static
electricity has been discharged.
DANGER
Warning - explosive atmospheres or substances
In the vicinity of various fuels or chemicals there is a risk of ex-
plosion.
Do not use the device in the close vicinity of blasting work or
filling stations!

4. Safety instructions
11
4.1 Special notes on use
•If the device is brought into the work-room from a cold environment
there is a risk that condensation might form on the electronics. In meas-
uring operations involving thermocouples pronounced changes in tem-
perature may cause substantial measuring errors. You are advised
therefore to wait until the device has adjusted to the ambient tempera-
ture before starting to use it.
•Before using the mains adapter make sure that the mains voltage is
suitable.
•Be sure to observe the maximum load capacity of the sensor power
supply.
•Sensors with their own integrated power supply are not electrically iso-
lated from one another
4.2 Handling batteries / rechargeable batteries
correctly
When inserting batteries / rechargeable batteries ensure that
these are correctly polarized.
If the device will probably not be needed for a relatively long pe-
riod of time or if the batteries are empty, remove the batteries; this
will prevent battery acid leaking onto the device and damaging it.
Rechargeable batteries should be recharged as and when nec-
essary.
You should never attempt to recharge an ordinary (non-recharge-
able) battery; it may explode !
Batteries / rechargeable batteries must never be short-circuited
or thrown onto the fire.
Batteries / rechargeable batteries are special waste and must not
be discarded together with normal domestic waste.

12
5. INTRODUCTION
The data logger ALMEMO® 2690-8 is a new instrument from the unique product
range of measuring devices that are all equipped with the ALMEMO® connector
system, which has been patented by Ahlborn GmbH. The intelligent ALMEMO®
connector provides important advantages with regard to the connection of sen-
sors and peripherals as all parameters are stored in an EEPROM within the
connector. As a result, the programming that usually has to be performed for the
connection is not required. All sensors and output modules can be connected
to all ALMEMO® measuring devices in the same way. The operation and pro-
gramming is identical with all units. Therefore, all of the ALMEMO® measuring
system items listed below are described, in detail, in a separate ALMEMO®
manual that is supplied with every device:
Detailed description of the ALMEMO® system (manual section 1)
Overview of the device functions and measuring ranges (manual section 2)
All sensors with basic principles, operation, technical data (man. section 3)
The options for connecting existing sensors (manual section 4)
All analog and digital output modules (manual section 5.1)
The interface module RS232, fiber optics, Centronics (manual section 5.2)
The entire ALMEMO® networking system (manual section 5.3)
All functions and their control via the interface (manual section 6)
A complete interface command list with all print outputs (manual section 7)
These operating instructions only cover features and controls that are specific
for a certain device. As a result, many sections will often provide a note referring
to the more detailed description within the manual (man. sect. x.x.x).
5.1 Functions
New data logger ALMEMO® 2690-8A now comes fitted with an 1024-KB
EEPROM sufficient for some 200,000 measured values, a low-power A/D con-
verter, and integrated charge circuitry for recharging the batteries. The meas-
uring possibilities are virtually unlimited; there are 5 electrically isolated meas-
uring inputs suitable for all ALMEMO® sensors, or 20 channels in the sensor
connectors and 4 device-internal function channels - with over 70 measuring
ranges. For operation purposes the device incorporates an LCD graphics dis-
play and a softkey keypad with cursor block. The display can be adapted by
means of configurable user menus to suit any application. Two output sockets
allow for connecting any ALMEMO® output modules, for example, the digital
interface, memory card, analogue output, trigger input or alarm contacts. Sev-
eral devices can be networked by simply connecting them with network cables.

5. Introduction
13
5.1.1 Sensor Programming
The measuring channels are automatically programmed by the ALMEMO® con-
nectors. However, the user can easily complete or modify the programming via
keyboard or via interface.
Measuring Ranges
There are corresponding measuring ranges for sensors with a non-linear char-
acteristic such as 10 thermocouple types, Ntc and Pt100 sensors, infrared sen-
sors, and flow sensors (rotating vanes, thermoanemometers, pitot tubes). Hu-
midity sensors are available with function channels that also calculate humidity
data such as dew point, mixture ratio, vapour pressure and enthalpy. Even com-
plex chemical sensors can be used. The acquisition of measured data from
other sensors is easily possible by using the voltage, current and resistance
ranges with individual scaling in the connector. Existing sensors can be used
without problems. Only the corresponding ALMEMO® connector has to be con-
nected using its terminals. Furthermore, there are adapter connectors with an
own microcontroller for digital signals and for measuring frequencies and
pulses. This way, nearly all sensors can be connected to any ALMEMO® meas-
uring instrument and are interchangeable without requiring any settings.
Function Channels
Maximum, minimum, average values and differences of certain measuring junc-
tions can be programmed as function channels, also in device internal channels,
and can be processed like normal measuring junctions. Furthermore, function
channels for special measuring tasks are provided to determine the temperature
coefficient Q/T and wet bulb globe temperature.
Dimension
The 2 digit dimension can be altered for each measuring channel so that the
display and via interface will always indicate the correct dimension, for example
when a transmitter is connected. The conversion from °C to °F is automatically
performed according to the dimension.
Name of Measured Values
For identification of the sensors a 10-digit alphanumeric name is provided. It is
entered via the keypad or the interface and appears on the display, via interface
and in the software.
Correction of Measured Values
For correcting measured values a zero point and slope correction can be applied
to the measured value of each measuring channel. This also allows for sensors
to be interchanged that usually, at first, require an adjustment (expansion, force,
pH). The zero point and the slope correction are virtually performed by the push
of a button.
Scaling

5. Introduction
14
The base value and the factor allow for a further scaling of the corrected meas-
ured value of each measuring channel for zero point and slope. The decimal
point position can be set by the exponent. By setting to zero and entering the
nominal value the scaling values can be automatically calculated.
Limit Values and Alarm
Two limit values (1 max and 1 min) can be set for each meas. channel. If a limit
value is exceeded alarm contacts, that can be individually allocated to limit val-
ues, are provided by means of relay output modules. As a standard, the hyste-
resis is set to 10 digits; however, it can also be adjusted between 0 and 99 digits.
Furthermore, limit value exceeding can also be used to start or stop a data log-
ging.
Sensor Locking
All sensor data stored in the EEPROM of the connector can be protected against
undesired access by means of a graded locking function.
5.1.2 Measurement
A total of up to 20 meas. channels are available for 5 transducers, i.e. it is also
possible to evaluate double sensors, individually scaled sensors, or sensors
with function channels. The meas. channels can be successively selected for-
wards or backwards via keypad. By default all measuring points are scanned
continuously at a measuring rate of 10 mops and the data thus obtained is listed
on the display. However, if you want to have the measured values for the se-
lected channel sent to an analog output, it may be an advantage to use semi-
continuous mode instead; the output value will then always be refreshed at half
the measuring rate set - irrespective of the number of measuring points involved.
Measured Values
The measured values of 1 to 20 measuring points can be indicated on the dis-
play in different menus (that can also be configured) in three font sizes, as bar
graph or as line chart. They are automatically acquired with auto zero and self
calibration and can also be arbitrarily corrected and scaled as required. A sensor
breakage condition is, with most sensors, automatically detected.
Analog Output and Scaling
By means of analog start and analog end any measuring point can be scaled so
that the resulting measuring range covers the full range of the bar graph or line
chart or of an analog output (2V, 10V or 20mA). The measured value of any
measuring point as well as a programmed value can be output to the analog
output
Measuring Functions
Special measuring functions are required for some sensors to achieve an opti-
mal data acquisition. The cold junction compensation is available for thermo-
couples, a temperature compensation for dynamic pressure and pH and con-
ductivity probes, and an atmospheric air pressure compensation for humidity

5. Introduction
15
sensors, dynamic pressure sensors and O2 sensors. With infrared sensors the
parameters zero point and slope correction are used for background tempera-
ture and emissivity factor.
Max and Min Value
Each measurement involves an acquisition and storage of the Max value and
the Min value including the time and date. The values can be displayed, output
or cleared.
Average Value
Measured values can be expressed as a sliding average obtained by continuous
automatic smoothing or averaged over a particular period or cycle or over a
series of individual measuring operations.
5.1.3 Process flow control
A continuous measuring point scan with a time-based process flow control for
the output of measuring valures is required to register the measuring data of all
connected sensors. For this purpose, an output cycle is available and, if fast
processing is required, the conversation rate is available. The measurement can
be started and stopped by using the keyboard, the interface, an external trigger
signal, the real time clock or an exceeding of limit values.
Time and Date
The real time clock with data function or the pure measuring time are used for
an accurate recording of any measurement. Start and end time/date can be pro-
grammed in order to start or stop a measurement.
Cycle
The Cycle is programmable between 1 s and 59 h, 59 min and 59 s and provides
a cyclic output of measured values to the interfaces or memories and also pro-
vides a cyclic averaging.
Print Cycle Factor
If necessary, the print cycle factor allows for limiting the data output of particular
channels so that an excessice data flow can be limited, especially during data
storage.
Average Value over Measuring Point Scans
The measured values resulting from scanning measuring junctions can be av-
eraged as desired either over the total measuring time or over the cycle time.
Function channels are available for a cyclic output and storage of these average
values.
Conversion Rate
With the ALMEMO® 2690-8A all measuring points can be continuously scanned
with the conversion rate (2.5;10 50 or 100 M/s). To realize a high recording
speed it is possible to store all measured values in the memory and/or to perform
an output via the interface.

5. Introduction
16
Data Memory
During the cycle, all measured values can be manually or automatically stored in
an EEPROM. The memory capacity is, as standard, 1024 Kilobyte, which allows
up to 200.000 measured values. The memory organisation can be configured as
linear or ring memory.The output can be carried out via the display or the interface.
It is possible to specify a selection according to a time interval or number.
Numbering of Measurements
By entering a number, single scans or entire series of measurements can be
identified and selectively read out from the memory.
Control Outputs
Via keyboard and interface allows to individually trigger up to 4 output relays
and one analog output.
Operation
All measuring and function values can be displayed in different menus on the
dot matrix LCD display. 3 user menus can be individually configured from nearly
50 functions for your specific applications. Using texts, lines and blank lines al-
lows to format the display in an application-specific style. Nine keys (four of them
are soft keys) can be used to operate the device. This also allows you to fully
program the sensors, the device and the process control.
Output
All data logs, menu functions and stored measured values and programmed
parameters can be provided as output to any peripheral equipment. Various in-
terface cables can be used to provide a RS232, RS422, Centronics or Ethernet
interface. The output of measuring data can be selected in list format, columns
or spreadsheet format. Files in spreadsheet format can be processed by each
spreadsheet software. The print header can be programmed specifically to the
company or application.
Networking
All ALMEMO® devices can be addressed and can be easily networked by
simply linking them using network cables, or RS422 network distributors for
longer distances.
Software
The ALMEMO® Control software, which allows for the entire programming of the
sensors, the configuration of the measuring instrument, of the user menus and
the read-out of the data memory is supplied with each ALMEMO®manual. The
integrated terminal also allows for online measurements. The WINDOWS® soft-
ware WINControl is available for data acquisition of networked devices, graph-
ical presentation and complex data processing.

17
6. INITIAL OPERATION
Sensor connection Connect transducers to the sockets M0 to M4 (1), s. 8.
Power supply with batteries/accumulators or mains adapter on DC (3) s. 7.1, 7.3
Switch-on Press key ON / PROG (6), s. 7.6
Automatical display of the last measuring menu, s. 10. keys:
Menu selection MEAS.-Menus: call up with key: < ESC > or F4
e.g. select menu StandardDisplay , s. 9.1  /  ... ( F )
Call up the menu with key: 
Select meas. point (s. 10.1.1) with keys:  /  ... ( M)
Select function Max/MinVal (s. 9.4) with: PROG ,  ...
Clear max/min values, s. 10.1.2 < CLR > or F1
Output of measuring data or memory via interface:
- Connect peripheral device, via data cable, to socket A1 (2), s. man. 5.2
- Set 9600bd, 8 data bits, 1 stop bit, no parity at peripheral device
Single output/storage, s. 10.3.1 < MANU > or F2
Cyclic measurement: Select Cycle-Timer : PROG ,  ...
Enter cycle (hh:mm:ss) s. 9.5 Cycle-Timer: 00:05:00Sn
Output format list ´ ´, columns ´n´, table ´t´ < FORM> or F3 ...
Stop programming < ESC> or F4
Start/stop the cyclic measurement, s. 10.3.2 <START> , <STOP> or F1
Output of memory data to computer:
Select the function Memory Free with: PROG ,  ...
Memory data output, s. 11.2.6 < PRINT> or F3
Clear memory, s. 11.2.6 < CMEM >
F1 F2 | F3 F4



 ON PROG 


* ALMEMO 2690-8 *
±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±±
MEASURING-Menus:
Standard display ©
U1 Meas. value correction
U2 Averaging
U3 Volume flow
Data logger
Multi channel display
*List of measuring points
Bar charts
Line diagram
_____________________
Menu1 PROGRAMMING-Menus
Menu2 ASSISTANT-Menus
POFF *ON F MENU1 MENU2
C © REC COM l© ©l R01 * ´´´´´´µµµµ¶
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
01: Velocity m/s
æ» H º
28.67
Maximum value: 31.34 mls
Minimum value: 25.37 mls
Cycle-timer: 00:02:30 Un
Memory free: 512.0 kB
START MANU M PRINT ESC
F1 F2 | F3 F4



 ON PROG 



18
7. POWER SUPPLY
Power can be supplied to the instrument in any of the following ways :
3 AA NiMH batteries with integrated charge circuitry (supplied as standard).
3 AA alkaline batteries
Mains adapter 12 V, 1,5 A, with ALMEMO® connector ZA 1312-NAx
Electrically isolated power supply cable (10 to 30 VDC, 1 A) ZA 2690-UK2
USB data supply cable (5 V, 0.4 A) ZA 1919-DKU5
Our product line includes corresponding accessories.
7.1 Rechargeable battery operation voltage mon-
itoring
Power is supplied to the measuring instrument as standard by 3 NiMH batteries.
At a current consumption of approx. 17 mA the operating time will be approx.
110 hours. If the display illumination is left switched on, this operating time will
be reduced to approx. 20 to 50 hours (depending on brightness). To prolong the
operating time for the purposes of long-term recording the device can be left in
SLEEP mode. (see 11.2.5) The operating voltage can be checked in the power
supply menu; this gives you a basis for estimating the remaining operating time.
(see 11.7)
As soon as the remaining battery capacity drops to approx. 10%, the battery
symbol ´´µµµµµµµµµ¶ in the status bar of the display will start to flash. As and when this
happens you should connect mains adapter ZB 1112-NA7 (12 V / 1 A) and re-
charge the batteries; this will take around 3 hours; further delay may result in
critically low discharge and this may damage the batteries. (see 7.3)
The NiMH rechargeable batteries can in fact be recharged at any time and in
any charge status using the intelligent charge circuitry. The charging current
and charge status can be checked and monitored at any time in the power sup-
ply menu. If the batteries are completely discharged, the device will switch off
but measured data and the time-of-day will be saved. (see 7.7)
Rechargeable batteries have specially coded bare contacts (serial numbers up
to 1110...) so that the device will charge these only - and not normal batteries.
7.2 Battery operating mode
Instead of the rechargeable batteries you can use 3 AA alkaline batteries. Those
have higher capacity permitting operation over 160 hours. In order to replace the
batteries, the sensors must be disconnected and removed, the rubber protection (7)
must be pulled off, and the battery cover (8) on the rear of the device must be un-
screwed and lifted off in the direction indicated by the arrow.

7. Power supply
19
7.3 Mains operation
To power the device from an external source preferably use the mains adapter
ZA 1312-NAx (12 V / 1,5 A); connect this to the DC socket (3). The sensor volt-
age is set automatically to 12 volts. If rechargeable batteries are being used,
these will then be charged. (see 11.7)
7.4 External DC voltage supply
It is also possible, at DC socket (3), to connect a USB data supply cable (5 V,
0.4 A) ZA1919-DKU5 or, via ALMEMO® connector (ZA1000-FSV), to connect
any other DC voltage (6 to 12 V, minimum 200 mA). If, however, the power
supply has to be electrically isolated from the transducers or if a larger input
voltage range (10 to 30 V) is required, then electrically isolated supply cable
ZA2690-UK (250 mA) or -UK2 (1 A) must be used. It will then be possible to
use the measuring instrument in a 12-volt or 24-volt on-board supply system.
7.5 Sensor Supply
At the terminals + (plus) and - (minus) in the ALMEMO® connector there is a
configurable sensor supply voltage available (self-healing fuse, 500 mA). The
sensor voltage supplied by the device is set automatically, depending on the
minimum supply voltage requirements of the sensors, to 6 V (200 mA), 9 V (150
mA), or 12 V (100 mA). (s. 11.4.2) (see also the power supply menu 11.7)
Other voltages (12, 15, or 24 volts or references for a potentiometer and strain
gauge) can also be obtained using special connectors. (see Manual. Sections
4.2.5 and 4.2.6) .
7.6 Switch On/Off, Reinitialisation
To switch on the device press the key ON PROGr (6) in the middle of the cursor
block. There always appears the last called up meas. menu first in the display.
To switch off the device leave a working menu with <ESC>r and press the softkey
<P-OFF>r in the menu selection. After switch-off the real time clock continues its
operation and all stored data remains available (s. 7.7).
If the device shows an irregular behaviour due to interference influences (e.g.
electrostatic charging or battery failure), the device can be reinitialised. The re-
set can be achieved if the key F1 r is pressed during switch-on. If the complete
device programming with times, terms of device, user menus etc. is to be set to
the delivery defaults, the key F4 r must be pressed during switch-on. Only the
sensor programming within the ALMEMO® connectors will not be attached by
this reset.
The reset function on power are not possible when the AC adapter is
plugged in and the batteries are charged!


7. Power supply
20
7.7 Data buffering
The sensor programming is stored in the EEPROM of the sensor connector, the
calibration and the programmed parameter of the device is fail-safe stored in
the EEPROM of the device. Time and date are buffered by a lithium battery so
that storage of the data is also guaranteed without batteries and when the de-
vice is switched off.