Ahlborn ALMEMO 2450-1 User manual

____________________________
Operating instructions
Universal measuring instrument
ALMEMO® 2450-1
V2.3
06.11.2013
www.ahlborn.com

1. Operating controls
1. OPE ATING CONT OLS
(1) Measuring inputs M0
M0 for a wide range of sensors
M10 to M30 3 additional channels
(2) Analog output P0 (option)
P0 Clamp connector (ZA 1000-KS)
(3) Outputs A1, A2
A1 SB interface (ZA 1919-DKU)
RS232 (ZA 1909-DK5)
Optic fiber (ZA 1909-DKL)
Ethernet (ZA 1945-DK)
RS 422 (ZA 5099-NVL/NVB)
Trigger input (ZA 1000-ET/EK)
Relay outputs (ZA 1006-EGK)
A2 Network cable (ZA1999-NK5/NKL)
Trigger input (ZA 1000-ET/EK)
Relay outputs (ZA 1006-EGK)
Analog output (ZA 1601-RK)
(4) Connection DC 12V (not type L)
Mains adapter(ZA1312-NA1 12V 0.2A)
Cable, el. isol. (ZA2690-UK 10-30V)
Interface RS 485 (option)
(5) LCD
Function field
(a) Function
(b) Measuring point, 2nd meas. value
(c) nits for 2nd measured value
Main field
(c) nits for 1st measured value
(e) 1st measured value
(f) Operating states :
LOBAT Battery voltage <3.8 V
REL Relative measuring
CORR Measured value corrected
(6) Operating keys
ON OFF Switch the device on
To switch device OFF, press and hold down
M▲ M▼ Meas. point selection
MAX MIN Max. / min. value
clear: press and hold down
MEM Measured value memory
CLR Relative measuring,
Adjust sensor,
cancel: press and hold down
2 ALMEMO® 2450-1
Rear of device
(7) Battery compartment
3 AA alkaline-manganese batteries

Contents
2. CONTENTS
1. OPE ATING CONT OLS .........................................................................2
3. GENE AL .................................................................................................. 5
3.1 Warranty ..............................................................................................5
3.2 Scope of delivery ................................................................................6
3.3 Waste disposal....................................................................................6
4. SAFETY INST UCTIONS..........................................................................7
4.1 Special notes on use...........................................................................8
4.2 Handling batteries / rechargeable batteries correctly......................8
5. INT ODUCTION ........................................................................................8
5.1 Functions.............................................................................................9
5.1.1 Sensor programming ...................................................................9
5.1.2 Measuring operations ................................................................10
5.1.3 Process control ..........................................................................12
6. INITIAL COMMISSIONING ......................................................................13
7. POWE SUPPLY ....................................................................................14
7.1 Battery operation and supply voltage monitoring .........................14
7.2 Mains operation ................................................................................14
7.3 External DC voltage supply .............................................................14
7.4 Sensor supply ...................................................................................14
7.5 Switching ON / OFF, reinitialization ................................................14
7.6 Data buffering ...................................................................................15
8. CONNECTING THE T ANSDUCE S .....................................................15
8.1 Transducers....................................................................................... 15
8.2 Measuring inputs and additional channels ....................................15
8.3 Potential separation .........................................................................16
9. DISPLAY AND KEYPAD .........................................................................17
9.1 Display ............................................................................................... 17
9.2 Keypad ..............................................................................................18
10. MEASU ING OPE ATIONS ...................................................................19
10.1 Measured value...............................................................................19
10.1.1 Selecting a measuring point ....................................................19
10.1.2 Measuring ranges ....................................................................20
10.1.3 Double display..........................................................................21
10.2 Peak value memory ........................................................................21
10.3 Measured value memory ................................................................22
10.4 elative measuring ........................................................................22
11. OUTPUTS.................................................................................................22
11.1 Interfaces ........................................................................................ 22
ALMEMO® 2450-1 3

2. Contents
11.2 Analog outputs................................................................................23
12. DEVICE CONFIGU ATION .....................................................................24
12.1 Device address and networking.....................................................24
12.2 Analog output .................................................................................25
12.3 Switching OFF automatically ........................................................26
12.4 Device locking ................................................................................26
13. T OUBLE-SHOOTING ...........................................................................26
14. DECLA ATION OF CONFO MITY.........................................................28
15. APPENDIX ............................................................................................... 28
15.1 Technical data ................................................................................28
15.2 Product overview ...........................................................................29
15.3 Index.................................................................................................30
15.4 Your contact....................................................................................32
4 ALMEMO® 2450-1

General
3. GENE AL
Congratulations on your purchase of this new and innovative ALMEMO®
measuring instrument. Thanks to the patented ALMEMO® connector the de-
vice configures itself automatically; its operation should be fairly straightfor-
ward. The device can, however, be used with such a wide range of sensors
and peripherals and offers many different special functions. You are advised
therefore to properly familiarize yourself with the way the sensors function
and with the device's numerous possibilities and take the time to carefully
read these operating instructions and the appropriate sections in the
ALMEMO® Manual. This is absolutely necessary to avoid operating and mea-
suring errors and to prevent damage to the device. To help you find the an-
swers to your questions quickly and easily there is a comprehensive index at
the end both of these instructions and of the Manual.
3.1 Warranty
Each and every device, before leaving our factory, undergoes numerous qual-
ity tests. We provide a guarantee, lasting two years from delivery date, that
your device will function trouble-free. Before you send your device to us, please
observe the advisory notes in Chapter 13. Trouble-shooting In the unlikely
event that the device proves defective and you need to return it please wher-
ever possible use the original packaging material for dispatch and enclose a
clear and informative description of the fault and of the conditions in which it
occurs.
This guarantee will not apply in the following cases :
The customer attempts any form of unauthorized tampering or alteration in-
side the device.
The device is used in environments and conditions for which it is not suited.
The device is used with unsuitable power supply equipment and / or periph-
erals.
The device is used for any purpose other than that for which it is intended.
The device is damaged by electrostatic discharge or lightning.
The user fails to observe and comply with the operating instructions.
The manufacturer reserves the right to change the product's characteristics in
the light of technical progress or to benefit from the introduction of new compo-
nents.
ALMEMO® 2450-1 5

3. General
3.2 Scope of delivery
When you unpack the device check carefully for any signs of transport damage
and ensure that delivery is complete.
Measuring instrument ALMEMO® 2450-1 with 3 AA alkaline batteries
These operating instructions
ALMEMO® Manual
CD with the AMR-Control software and various useful accessories
In the event of transport damage please retain the packaging material and in-
form your supplier immediately.
3.3 Waste disposal
The pictogram showing a waste bin crossed through
means that the product is subject to European nion regu-
lations 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 do-
mestic 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
country 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.
6 ALMEMO® 2450-1

Safety instructions
4. SAFETY INST UCTIONS
DANGE Danger to life and limb, risk of damage to equipment
ead the instructions carefully before starting to operate
the device.
Please ensure that you comply with all general safety ad-
vice and the special safety instructions included in other
chapters.
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 in-
side the device
•se of the device in environments or conditions for
which it is not suited
•se of the device with an unsuitable power supply
and / or in conjunction with unsuitable peripheral
equipment
•se of the device for any purpose other than that for
which it is intended
•Damage caused by electrostatic discharge or light-
ning.
DANGE isk of fatal injury caused by dangerously high voltage
Such risks may occur in the following circumstances :
•se of the device with an unsuitable power supply and
/ or in conjunction with unsuitable peripheral equip-
ment
•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.
ALMEMO® 2450-1 7

4. Safety instructions
DANGE 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 fill-
ing stations!
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
measuring operations involving thermocouples pronounced changes in
temperature may cause substantial measuring errors. You are ad-
vised therefore to wait until the device has adjusted to the ambient
temperature 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 damag-
ing it.
Rechargeable batteries should be recharged as and when nec-
essary.
You should never attempt to recharge an ordinary (non-
rechargeable) 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.
8 ALMEMO® 2450-1

Introduction
5. INT ODUCTION
The ALMEMO® 2450-1 is a new member in our family of unique measuring de-
vices - all equipped with Ahlborn's patented ALMEMO® connector system. The
intelligent ALMEMO® connector offers decisive advantages when connecting
sensors and peripherals because all parameters are stored in an EEPROM lo-
cated on the connector itself; repeat programming is thus no longer necessary.
All sensors and output modules can be connected to all ALMEMO® measuring
instruments in the same way. Programming and functioning are identical for all
units. The following points apply to all devices in the ALMEMO® measuring
system; these are described in detail in the ALMEMO® Manual which is in-
cluded in delivery with each device.
Detailed explanation of the ALMEMO® system (Manual Ch 1)
Overview of the device functions and measuring ranges (Manual Ch 2)
Basic principles, operation, and technical data for all sensors (Manual Ch 3)
Options for connecting your own existing sensors (Manual Ch 4)
All analog and digital output modules (Manual Section 5.1)
Interface modules SB, RS232, optic fiber (Manual Section 5.2)
The whole ALMEMO® networking system (Manual Section 5.3)
All functions and their operation via the interface (Manual Ch 6)
Complete list of interface commands with all the printouts (Manual Ch 7)
The operating instructions you are now reading cover only those features and
controls that are specific to this device. Many sections therefore also refer to
the more detailed description in the Manual; (see Manual, Section xxx).
5.1 Functions
The ALMEMO® 2450-1 measuring instrument has just one measuring input
suitable for most ALMEMO® sensors - with the single exception of resistance
sensors and some special sensors. The measuring possibilities are numerous;
there are 4 channels in the sensor connectors with over 40 measuring ranges.
For operation purposes the device incorporates a large LCD display and a key-
pad. An option is available with an internal electrically isolated analog output
(socket P0) including a DC socket for a mains adapter. The standard interface
version has three output sockets for ALMEMO® output modules, namely A1
and A2 for digital interfaces and trigger and relay cables, A2 for an analog out-
put, and a DC socket for a mains adapter. Several devices can be networked
by simply linking them together via cable.
5.1.1 Sensor programming
The measuring channels are programmed, completely and automatically, by
the ALMEMO® connectors. The user can supplement or modify this program-
ming; this applies to the interface version only. However, devices without the
interface also behave according to all the programmed parameters.
ALMEMO® 2450-1 9

5. Introduction
Measuring ranges
Appropriate measuring ranges are available for all sensors with a non-linear
characteristic, e.g. 7 thermocouple types, NTC probes, and flow transducers
(rotating vanes, thermoanemometers). For humidity sensors additional function
channels are available for calculating humidity variables such as dew point,
mixture ratio, vapor pressure, and enthalpy. Measured values from other sen-
sors can also be acquired using the voltage and current ranges with individual
scaling in the connector. Existing sensors can also be used - so long as the ap-
propriate ALMEMO® connector is connected via its screw terminals. For digital
input signals, frequencies, and pulses, adapter connectors are available with
an integrated microcontroller. It is thus possible to connect numerous sensor
types to any ALMEMO® measuring instrument and to change sensors without
the need for any extra settings.
Function channels
Maximum, minimum, and average values of certain measuring points can be
programmed as function channels and can be processed and printed like nor-
mal measuring points.
Units
The 2-character units display can be adapted for each measuring channel so
that both the display and the printout always indicate the correct units, e.g.
when a transmitter is connected. Conversion between °C (Centigrade) and °F
(Fahrenheit) is performed automatically.
Measured value designation
Each sensor is identified by means of a 10-character alphanumeric name. This
name is entered via the interface and will appear in the printout or on the com-
puter display.
Correction of measured values
The measured value on each measuring channel can be corrected both in
terms of zero-point and gain; this means that even sensors usually requiring
initial adjustment (e.g. expansion, force) can be freely interchanged. Sensors
with multi-point calibration can also be connected; (see Manual Section
6.3.13).
Scaling
The corrected measured value on each measuring channel can also be further
scaled in terms of zero-point and gain - using the base value and factor. The
decimal point position can be set by means of the exponent function.
Limit values and alarm
Per measuring channel two limit values can be set (1 maximum and 1 mini-
mum). In the event of one of these limit values being exceeded relay output
modules actuate the associated alarm contacts; these can be allocated individ-
ually to specific limit values. Hysteresis is set by default to 10 digits but this can
be adjusted to any number between 0 and 99. The exceeding of a limit value
can also be used to start or stop measured value recording automatically.
10 ALMEMO® 2450-1

Functions
Sensor locking
All sensor data stored in the connector EEPROM can be protected by means
of a graduated locking function against undesired access.
5.1.2 Measuring operations
A total of up to 4 measuring channels are available for 1 transducer; i.e. it is
also possible to evaluate double sensors, individually scaled sensors, and sen-
sors with function channels. You can move forwards or backwards from one
measuring channel to the next using the keypad. The selected measuring point
is by default assigned preferred status and is scanned at half the measuring
rate; all other active channels are also scanned but in the background (semi-
continuous mode). The data is output on the display and, if available, to an
analog output. To shorten the response time when there are several measur-
ing points the measuring rate can be set to continuous and increased accord-
ingly.
Measured values
The measured value for the selected measuring point is shown continuously
with autozero and, as and when necessary, with measured value correction.
With most sensors, sensor breakage is detected automatically (except for con-
nectors with shunt, dividers, or additional electronics).
Analog output and scaling
Each measuring point can be scaled by means of analog start and analog end
(also via the keypad) in such a way that the measuring range thus defined cov-
ers the full range of the analog output (2 V, 10 V, or 20 mA). At the analog out-
put the device can output the measured value from any measuring point or a
programmed value.
Measuring functions
With some sensors, to achieve optimal measured value acquisition, certain
special measuring functions are required. These include e.g. cold junction
compensation for thermocouples and temperature and atmospheric pressure
compensation for certain humidity variables.
Measured value smoothing
Measured values of an unstable or strongly fluctuating nature can be smoothed
by means of a sliding average over a number of values programmable from 2
to 99.
Maximum and minimum values
For each measuring operation the maximum value and minimum value are ac-
quired and saved to memory. These values can then be displayed, output, or
deleted from memory.
Measured value memory
A measured value in the display can be saved by simply pressing a key.
ALMEMO® 2450-1 11

5. Introduction
5.1.3 Process control
To record the measured values from all connected sensors in digital form mea-
suring point scanning is performed continuously with measured value output
according to a time-based process control. This may be per cycle or, if really
rapid results are required, at the measuring rate itself. The measuring opera-
tion can be started and stopped via the interface by means of an external trig-
ger signal or by a specified limit value being exceeded.
Date and time-of-day
Date and time-of-day can be freely set and then used in the logging of measur-
ing operations. When the batteries are replaced these date and time-of-day
settings are lost and have to be reset.
Cycle
The cycle can be programmed to any value between 00:00:01 (1 second) and
59:59:59 hh:mm:ss. This function permits cyclic output of measured values to
the interfaces and cyclic calculation of average values.
Print cycle factor
The print cycle factor can be used to limit data output from particular channels;
this may be necessary in order to reduce excessive data flow especially while
data is being saved.
Averaging over measuring point scans
The measured values from measuring point scans can be averaged either over
the whole measuring duration or over the specified cycle. These average val-
ues can then be output and saved on a cyclic basis to function channels pro-
vided for this purpose.
Measuring rate
All measuring points are scanned at the measuring rate (2.5 or 10 mops). To
accelerate recording it is also possible to output all measured values at this
measuring rate via the interface.
Control outputs
Output relays and analog outputs can be individually addressed via the inter-
face.
Output
All data logs, measured values, and programming parameters can be output to
any peripheral equipment. RS232, RS422, SB, and Ethernet interfaces are
available using the appropriate interface cables. Measured data can be output
in list, column, or table format. Files in table format can be processed directly
using any standard spreadsheet software. The print header can be pro-
grammed to refer specifically to your company or to your application.
Networking
All ALMEMO® devices can be addressed and can be easily networked by sim-
ply linking them together via network cable or over longer distances via an in-
ternal RS485 interface (option) or RS422 network distributors.
12 ALMEMO® 2450-1
(interface functions, see Manual Ch 6, not type L)

Functions
Software
Each ALMEMO® Manual is accompanied by the AMR-Control software pack-
age, which can be used to configure the measuring instrument and to program
the sensors . sing the integrated terminal, measuring operations can also be
performed online. The WINDOWS® software package WIN-Control is provided
for the purposes of measured value acquisition via networked devices, for
graphical presentation, and for more complex data processing.
6. INITIAL COMMISSIONING
1. Connect sensor to socket M0 (1); see 8.
2. Ensure that the power supply is provided by 3 AA batteries or mains adapter;
3. To switch ON press key ON (6); see 7.5
4. Select measuring channels by pressing key M▲ (6), read out measured
values (5e); see 10.1.1
5. Save the measured value by pressing key MEM (6); see 10.3
6. elative measuring to a reference value by pressing key CLR (6)
Revert to normal measured value by pressing and holding down key CLR
7. Evaluating a measuring operation
Call up maximum / minimum values by pressing keys MAX / MIN (6)
To delete max. / min. value(s) press and hold down key MAX or MIN see
10.2
8. Programming or data output via interface (option)
Connect computer via interface cable to socket A1: see Manual 5.2.
Activate supplied software AMR-Control.
Via ‘Setup interface’ set the COM port and transmission rate to 9600 bauds.
Program the sensors via ‘Program measuring point list’.
Measured value display and sensor adjustment via ´Measuring points -
Measured values´
Data logging on the computer :
Program the cycle via ´Devices - Programming´
Open the terminal window via ´File - Terminal´
´File - Terminal - Open log ´, enter file name, ´Save´
Start the measuring operation by click ´Start´
Stop the measuring operation by click ´Stop´
´File - Terminal - Close log´
Activate file e.g. from MS-Excel and import using ´;´ as separator;
see Manual 6.1.4.
ALMEMO® 2450-1 13

7. Power supply
7. POWE SUPPLY
Power can be supplied to the measuring instrument in any of the following
ways : 3 AA alkaline batteries (included in delivery)
Mains adapter 12V, 0.2A with ALMEMO® connector ZA1312-NA1
Electrically isolated power supply cable (10 to 30 VDC, 0.25 A) ZA2690- K
12V DC clamp connector to socket DC (options and I) ZA1000-FSV
Our product spectrum includes all the appropriate accessories.
7.1 Battery operation and supply voltage monitoring
Power is supplied to the measuring instrument as delivered by 3 AA batteries.
At a current consumption of approx. 10 mA the operating time will be approx.
250 hours. The current operating voltage is displayed each time the the device
is switched on; this gives you a basis for estimating the remaining operating
time. When the remaining battery capacity drops to approx. 10 percent, the LO-
BAT arrow will appear in the display. If the batteries are completely discharged
the device will switch off. To replace old batteries first unscrew the battery
compartment cover (7) on the rear of the device.
7.2 Mains operation
The ALMEMO® 2450-1 can be supplied with power from an external source
preferably using mains adapter ZA 1312-NA1 (12 V / 0.2 A) via the DC socket
(4). Please ensure that the mains voltage is correct.
7.3 External DC voltage supply
The DC socket (4) can also be used to connect another DC voltage, 10 to 30 V
(minimum 200 mA). This is via an ALMEMO® connector (ZA1000-KS). If, how-
ever, the power supply has to be electrically isolated from the transducers, then
option (OA 2450- ) is needed or electrically isolated supply cable ZA 2690- K
must be used It will then be possible to use the measuring instrument in a 12-volt
or 24-volt on-board supply system.
7.4 Sensor supply
At the terminals + (plus) and – (minus) in the ALMEMO® connector there is a 9-
volt sensor supply voltage available (maximum 150 mA) (self-healing fuse, 500
mA). Other voltages (12, 15, or 24 V or references for a potentiometer and
strain gauge) can be obtained using special connectors; (see Manual 4.2.5 and
4.2.6).
7.5 Switching ON / OFF, reinitialization
To switch the device ON briefly press and release the key ON OFFr (6) in the
middle of the keypad; to switch the device, OFF press and hold down the key
ON OFFr. After the device is switched off all saved values and settings are re-
tained intact; (see 7.6).
If interference (e.g. electrostatic) or a malfunction (e.g. battery failure) causes
14 ALMEMO® 2450-1

Switching ON / OFF, reinitialization
the device to behave abnormally, the device can be reinitialized. To activate
ESET press and hold down the key CLR r when switching on. This will restore
all settings - except the device designation - to the factory default status. Only
the programming of the sensors in the ALMEMO® connectors remains unaf-
fected.
7.6 Data buffering
The sensor's programming is stored in the EEPROM on the sensor connector
and the device's calibration and programmed parameters are stored in the
EEPROM on the instrument itself, both on a fail-safe basis. Date and time-of-
day are retained intact if the device is just switched off but are lost when the
batteries are replaced.
8. CONNECTING THE T ANSDUCE S
Only certain ALMEMO® sensors can be connected to ALMEMO® input socket
M0 (1), namely those programmed with measuring ranges as per Ch 10.1.2.
Attempting to connect any other sensor here will trigger an error message. To
connect your own existing sensors you simply need the appropriate
ALMEMO® connector.
8.1 Transducers
The ALMEMO® Manual includes detailed descriptions of the ALMEMO® range
of sensors (see Manual Ch 3) and instructions for connecting your own existing
sensors to ALMEMO® instruments (see Manual Ch 4). All suitable sensors with
an ALMEMO® connector (see above) have the measuring range and units al-
ready programmed and can thus be connected to the input socket without fur-
ther adjustment. A mechanical coding system ensures that sensors and output
modules can only be connected to the correct sockets. All ALMEMO® connec-
tors incorporate two snap-lock levers; these snap into position as soon as the
connector is inserted into the socket, thus preventing unintended disconnection
if the cable is accidentally pulled. To withdraw the connector, both these levers
must be pressed in at the sides.
For the ALMEMO® 2450-1 version with the optional seal new specially de-
signed sensors are available with spray-coated ALMEMO® connectors incorpo-
rating a double sealing lip to protect the socket unit against the effects of
splashing water. For any unused sockets protective stoppers are available.
8.2 Measuring inputs and additional channels
The ALMEMO 2450-1 measuring instrument has one input socket (1) to which
initially measuring channel M0 is assigned. ALMEMO® sensors can, however,
if necessary, provide up to four channels. The additional channels can be used
in particular for humidity sensors with four measuring variables (temperature /
humidity / dew point / mixture ratio) or for function channels. Each sensor can if
ALMEMO® 2450-1 15

8. Connecting the transducers
necessary be programmed with several measuring ranges or scaling settings;
and two or three sensors, if pin assignment so permits, can be combined in a
single connector (e.g. rH / NTC, mV / V, mA / V, etc.). The additional measur-
ing channel numbers per connector go up in steps of 10 (e.g. the first sensor
has channels M0, M10, M20, M30).
Double connectors with 2x differential voltage / differential current
cannot be used with this device.
On the measuring instrument this gives the following channel assignment :
8.3 Potential separation
When organizing a properly functioning measuring setup it is very important to
ensure that no equalizing current can flow between sensors, power supply, and
peripherals. All points must therefore lie at the same potential and / or any un-
equal potentials must be electrically isolated.
Sensors combined within one connector and sensors with their own power
supply are electrically interconnected and must therefore be operated in isola-
tion. The voltage at the measuring inputs themselves must not exceed 5 volts
(between B, C, D, A and - ).
The power supply is isolated by the transformer in the mains adapter or by a
DC/DC converter (OA2450- or ZA2690- K). Data and trigger cables are
equipped with optocouplers. Where analog output cables are not electrically
isolated the recording device or the sensors must be zero-potential.
16 ALMEMO® 2450-1
M0
00
10
20
30
1. chan.
2. chan.
3. chan.
4. chan.
A2 A1 DC
sensor channels
P0
M0
data cable
AC
DC
DC
DC
ADC uC
U-
U+
Sensor
Power supply
10..30V=
230V≈


Display and keypad
9. DISPLAY AND KEYPAD
9.1 Display
The display (5) on the ALMEMO® 2450-1 measuring instrument is a 2-row LCD
arrangement; the main field comprises 5x 7-segment digits (e) plus 2x 16-seg-
ment digits (d) for depicting the measured value;,the function field comprises
41/2x 7-segment digits (b) for depicting various measuring functions (a); there
are also 2 arrows (f) for depicting the operating status.
Function field
Main field
Display of measuring functions in the function field
Measuring point
Maximum value
Minimum value
Saved value
Temperature value from double sensors
Configuration of device address
Configuration of analog reference channel
Configuration of locking
Configuration of automatic OFF
ALMEMO® 2450-1 17
MAX 36.5
MIN 17.3
M 36.2
M O
26.5 °C
Adr
ACh1
Loc
AOFF

9. Display and keypad
Special operating states and faults
Display segment test : runs automatically after switch ON
Supply voltage Display after segment test
nder 3.8 V : LOBAT arrow lights up
Relative measuring with respect to a reference value : REL arrow lights up
Measured value corrected : CORR arrow lights up
Checksum error in
device calibration :
Non-connected sensors,
deactivated measuring points :
Measuring range / function not permitted :
Multiplexer M5 (D-B) is not permitted :
Sensor breakage : flashes
Outside of measuring range, undershoots
cold junction compensation flashes
or cold junction compensation breakage :
Overshoots values range (>65000) : flashes
Overshoots measuring range : Maximum value flashes
ndershoots measuring range : Minimum value flashes
9.2 Keypad
To operate the device a keypad with 7 keys is provided :
Function : Key
To switch ON the device : (see Section 7.5) ON OFF
To switch OFF the device : ON OFF
must be pressed and held down
18 ALMEMO® 2450-1
CALEr
-----
Err
NiCr
CJ
65OOO
ErrI

Keypad
Function : Key
Selection of measuring points (see Section 10.1.1) M ▲ or M ▼
Displaying the maximum value : (see Section 10.2) MAX
To delete press and hold down
Displaying the minimum value : (see Section 10.2) MIN
To delete press and hold down
Zero-setting the measured value : (see Section 10.4) CLR
To delete press and hold down
Saving the measured value : (see Section 10.3) MEM
Displaying the battery voltage : ON OFF
10. MEASU ING OPE ATIONS
On the ALMEMO® 2450-1 all measuring channels, whenever available, are
scanned semi-continuously at 2.5 mops; (see Manual 6.5).
p to 4 measuring points can be displayed; (see Section 8.2)
A measured value can be sent to an analog output; (see 12.2, Manual Section
5.1.1).
10.1 Measured value
After switching ON first of all a segment test
is performed; then the battery voltage ap-
pears and if the batteries are almost empty
(<3.8 V) the LOBAT arrow also appears.
The measured value is then displayed with
the appropriate units in the main field and the
measuring point is displayed in the function
field. All special operating states possible for
the measured value are explained in Section.
10.1.1 Selecting a measuring point
By pressing key M ▲ you can select one after
the other all active measuring points and have the current measured value dis-
played for each. By pressing key M ▼ you can return to the previous channel.
To increment the measuring channel press key : M ▲
To decrement the measuring channel press : M ▼
When switching between channels the abbreviation for the measuring range is
briefly displayed; (see 10.1.2).
ALMEMO® 2450-1 19

10. Measuring operations
10.1.2 Measuring ranges
With each channel switchover or sensor breakage the abbreviation for the
measuring range appears in the display. For identification purposes the follow-
ing table lists all possible measuring ranges supported by this device.
Transducer Sensor / con-
nector
Measuring range Units Abbre-
viation
NiCr-Ni (K) FT Axxx -200.0...+1370.0 °C NiCr
NiCroSil-NiSil (N) ZA 9020-FSN -200.0...+1300.0 °C NiSi
Fe-CuNi (L) ZA 9000-FSL -200.0... +900.0 °C FECO
Fe-CuNi (J) ZA 9000-FSJ -200.0... +950.0 °C IrCo
Cu-CuNi ( ) ZA 9000-FS -200.0... +600.0 °C CUCO
Cu-CuNi (T) ZA 9000-FST -200.0... +400.0 °C CoCo
PtRh10-Pt (S) FS Axxx 0.0...+1760.0 °C Pt10
Ntc Typ N FN Axxx -20.00...+100.00 °C Ntc
Millivolt ZA 9000-FS0 -10.000...+55.000 mV U 55
Millivolt 1 ZA 9000-FS1 -26.000...+26.000 mV U 26
Millivolt 2 ZA 9000-FS2 -260.00...+260.00 mV U260
Volt ZA 9000-FS3 -0.2600...+2.6000 V U2.60
Difference millivolt ZA 9000-FS0D -10.000...+55.000 mV d 55
Difference millivolt 1 ZA 9000-FS1D -26.000...+26.000 mV d 26
Difference millivolt 2 ZA 9000-FS2D -260.00...+260.00 mV d260
Difference volt* ZA 9000-FS3D -0.2600...+2.6000 V d2.60
Sensor voltage any 0.00...20.00 V UbAt
Milliampere ZA 9601-FS1 0.000...+26.000 mA I032
Percent (4 to 20mA) ZA 9601-FS2 0.00... 100.00 % P420
Frequency ZA 9909-AK1 0... 32000 Hz FrE
Pulses ZA 9909-AK2 0... 65000 PULS
Digital input ZA 9000-EK2 0.0... 100.0 % Inp
Digital inerface ZA 9919-AKxx -65000... +65000 diGi
Snap-on head normal 20 FV A915-S120 0.30... 20.00 m/s S120
Snap-on head normal 40 FV A915-S140 0.40... 40.00 m/s S140
Snap-on head micro 20 FV A915-S220 0.50... 20.00 m/s S220
Snap-on head micro 40 FV A915-S240 0.60... 40.00 m/s S240
Macro FV A915-MA1 0.10... 20.00 m/s L420
Water-Micro FV A915-WM1 0.00... 5.00 m/s L605
Relative air humidity, capacitive FH A646 0.0... 100.0 %H °orH
Rel. air humidity, capacitive TC FH A646-C 0.0... 100.0 %H HcrH
Rel. air humidity, capacitive TC FH A646-R 0.0... 100.0 %H H rH
Mixture ratio, capacitive, with PC FH A646 0.0 ... 500.0 g/k H AH
Dew-point temperature, cap. FH A646 -25.0... 100.0 °C H dt
Partial vapor pressure, cap. FH A646 0.0 ...1050.0 mb H UP
Enthalpy, capacitive FH A646 0.0 ... 400.0 kJ H En
* Double connectors with differential voltage / differential current (D-B) cannot be used
20 ALMEMO® 2450-1