ALMEMO® Measuring Instruments

The ALMEMO® System

 

"It has been one of, if not the most, versatile instrument I have ever purchased
or come across in my long career as a Control and Instrumentation Engineer."

Denis Sturman. Control & Instrumentation Engineer, Saint-Gobain Glass UK

In reference to the Almemo 2690 Data Logger

 

  • One instrument is all you need for all your measurements - Just change the sensor
Almemo 2470 Almemo 2450 Almemo 2690 Almemo 2890 Almemo 5690 Almemo 8590

Once a sensor is connected, the ALMEMO® measuring instrument will automatically indicate the measuring range and the measured value. There's never any need to alter settings when the sensor is changed.

Attach another sensor and it is recognized automatically and the measured value indicated on the display. Change sensors as often as you feel necessary - even during in the course of a measuring operation.

Store your calibration values in the memory chip of the ALMEMO® connector itself. This means all subsequent measuring operations can thus be performed with the highest accuracy. Free software is provided with every measuring instrument making it very easy to program the connectors.

ALMEMO® means you only need one instrument to accomplish virtually measuring task with any measureable variables across a wide variety of sensors and applications. ALMEMO® measuring instruments can be used in all technical fields and are extraordinarily flexible.

Since the first ALMEMO® instrument, there have been continuous improvments to this fascinating system with its infinite possibilities for sensor connection, data processing and device networking. As a result, a wide range of measuring instruments are now available from 1-channel transmitters, to data acquisition systems with more than 1000 measuring points.

The measuring instruments in the ALMEMO® range differ only with regard to their enclosures, i.e. handheld instruments, desktop instruments, 19" systems, switchboard instruments, transmitters as well as the number of measuring inputs (1 to 250), the display, output and operating controls and the power supply.

 

Almemo Connector System

Thanks to the intelligent ALMEMO® connector, when connecting sensors and interface cables the instruments will be completely programmed up to the time-oriented sequential control. This provides a uniform function range and configurable options. Furthermore, all parameters can be accessed via the interface and changes can written be to the ALMEMO® connectors memory which can be repeatedly overwritten if required.

  • As soon as a sensor is connected, the ALMEMO® measuring instrument automatically indicates the measuring range and the measured value.
The ALMEMO® Principle: Only One Instrument for All Sensors.

Using the patented ALMEMO® connector system, a wide range of transducers, sensors and signals can be connected to any measuring input on any the measuring instruments. No programming is required as all sensor data is contained in the connector plug enabling the measuring instrument to be automatically configured as soon as it is connected. 

Using the sensor data memory (EEPROM) all sensors can be calibrated, scaled and identified with a uniquely defined designation. This makes for a very straightforward measurement setup and avoids confusion.

Sensor errors can be corrected within the connector, i.e. simple sensors can become precision transducers. Standard signals can be displayed with their original dimension. Multi sensors, e.g. temperature and humidity, will often only require one shared connector. Programming can also be protected by a graded locking function.

Conclusion: Highest possible precision, no faulty measurements and minimum expenditure.

  • Any sensor subsequently connected is recognized automatically and the measured value is indicated immediately on the display. Sensors can be changed as and when necessary - even in the course of a measuring operation.
Use Your Existing Sensors with the ALMEMO® System.

We can provide you with the matching connector for your own existing sensors, which are very easy to connect. Furthermore, you can program ALMEMO® connectors on your own via keypad, terminal or software. The connectors memory can be repeatedly overwritten if required.

  • ALMEMO® measuring instruments can acquire virtually any measurable variables and master any measuring task. You need only one measuring device to manage a wide variety of sensors and applications. ALMEMO measuring instruments are extraordinarily flexible and can be used in all technical fields.
ALMEMO® Instruments can be Used Universally.

All instruments contain the same test input circuitry. More than 60 standard measuring ranges are available for branch-independent applications, e.g. for measuring the following:- Temperature, humidity, flow, heat flow, pressure, rotational speed, frequency, resistance, current, voltage, force, wire strain gauges, displacement, pH values, redox potential, conductivity, O2, CO2, CO, O3 etc. Maximum and minimum values will be automatically stored. Measured values can be averaged over single measurements, over the output cycle or over the total duration of the measurement; limit values can be monitored by programming max/min values. Measured values can be corrected with regard to the zero point and slope (gain) and can be scaled by factor, exponent and dimension.

  • It is also possible to store calibration values in the memory chip in the ALMEMO® connector. Subsequent measuring operations can thus be performed with the highest accuracy. Programming the connectors is very easy. Software for this purpose is supplied free-of-charge with every ALMEMO measuring instrument.
ALMEMO® Instruments are Nevertheless Individual.

ALMEMO® instruments automatically identify the characteristic data of the connected sensor. Specific functions will only be activated if the corresponding connector, interface cable or module are present. With humidity sensors the dew point, mixture ratio, vapour pressure and enthalpy will be automatically calculated. For measurements with psychrometers, Pitot tubes and probes for solute oxygen, the latest atmospheric pressure data can be entered or automatically compensated using pressure sensors. The influence of temperature can be compensated when measuring dynamic pressure, pH value, solute oxygen and conductivity. For volume flow measurements the cross section can be entered for flow sensors. Connectors with an integrated interface circuitry are available for special sensors.

ALMEMO® Instruments Meet The Most Demanding Requirements!

16 bit or 24-bit A/D converter, digital linearization (for Pt100 sensors according to the new ITS 90 temperature scale), digital calibration . Optimal cold junction compensation is ensured by using precision thermistors in the socket spring. Measuring inputs, power supply and interfaces are electrically isolated from each other.

ALMEMO® Data Acquisition Adapts To Your Requirements!

Data loggers have a 512-KB memory (sufficient for 100,000 measured values), expandable up to 32 MB, and configurable as linear memory or ring memory. Data logger memories can be selectively read out according to time or number. The switchover between measuring points is electrically isolated using semiconductor relays that are totally wear-resistant. This permits continuous measuring point scanning at 10 or 50 measuring operations per second; this can even be performed on a permanent basis. Measuring point scans can be individually programmed. Measuring cycles and output cycles can be selected independently; and measured values, average values, and maximum / minimum values can be either output or saved to memory. The start and stop of each measuring point scan can be controlled, as required, via keypad or interface, by date and time-of-day, by limit value, or by means of an external signal. All measuring instruments can be addressed via the interface and can, therefore, be networked. Up to 100 instruments can be easily linked by using network cables. The output of measured values of all instruments in the whole network can be performed from any instrument. RS422 drivers and distributors are available for longer distances. This system minimises the equipment required, cabling costs and EMC problems, and can be extended as required.

ALMEMO® Instruments Accept Any Peripheral Equipment At Optimal Data Transmission!

Analog or digital interfaces are not installed in the instruments but in the connectors and connecting cables. Depending on the requirements it is possible to connect the most varied peripheral devices, e.g.: Analog outputs, various interfaces (RS232, RS422, optic fiber, current loop, Ethernet, Bluetooth), alarm signal transmitters or trigger inputs. For remote enquiries with a maximum baud rate of 9600Bd data can be also transmitted via a standard communication line (analog or ISDN) or mobile radiocommunication modems.

ALMEMO® Instruments Allow For A Convenient Evaluation Of Measuring Data!

Matching output formats are provided for printer or spreadsheet software. Various AMR software packages are available for the graphical presentation and evaluation of measuring data.

ALMEMO® Instruments Can Be Easily Programmed!

The software protocol and the instruction list are identical for all instruments. Only one terminal is required to program all parameters and scan the measuring data. Free WINDOWS configuration software AMR-Control with terminal is available for this purpose.

Measurement Functions

We have only listed some of the more fundamental ALMEMO® measuring functions here. Listing all the measuring functions and application options is well beyond the scope of this web page.

If you require more information than is displayed here, please ask for a copy of the detailed ALMEMO® Manual.

 

Humidity Measurement:

The humidity sensors provide 4 channels, which can be optionally programmed for the variables temperature, relative humidity, dew point, mixture ratio, partial vapour pressure or enthalpy. The first 4 variables are available as standard. All measuring and programming functions (max, min, limit values) can be applied to all channels. In addition, the function atmospheric pressure will be activated for psychrometers and allows for entering and compensating a strongly deviating atmospheric pressure (e.g. for high elevations above MSL). A special moisture probe is set with the base value to the most varied materials within the material groups: construction materials, wood and paper.

Flow Measurement:

When using flow sensors, rotating vanes or dynamic pressure sensors the universal instrument ALMEMO® 2590-2 allows for activating averaging functions, volume flow, as well as cross sectional area or diameter of a channel. The volume flow is calculated over the cross sectional area by net measurements with averaged single values or continuous averaging. An automatic temperature compensation is available as the calculation of the flow velocity in Pitot tubes strongly depends on the air temperature. Furthermore, an attenuation filter with selectable time constant can be set so that undisturbed measured values can be used for critical measuring points within a channel.

Infrared Measurement with Emission Factor and Background Temperature:

For infrared temperature measurements it is essential to consider the emission factor and background temperature. These two functions will be also activated and parameters will be stored in the connector when connecting IR probes.

Wet Bulb Globe Temperature Measurement:

The Wet Bulb Globe Temperature (WBGT) is used for evaluating the heat stress at a working place. It is calculated from the dry temperature TT, the natural humid temperature HT and the globe temperature GT, by means of a psychrometer with disengageable ventilator and a globe thermometer:

WBGT = 0.1µTT + 0.7µHT + 0.2µGT

A function channel, WBGT, is available for evaluating this formula.

Measurement of Heat Flow, Temperature Coefficient and U Value:

For each heat flow plate the calibration value is stored in the connector as factor allowing for heat flow measurements without requiring a setting of the calibration value. Furthermore, it is possible to use function channels to determine the average heat flow value, a temperature difference with an average value, and a temperature coefficient from the quotient of both average values. Depending on the arrangement of the temperature sensors the heat transfer coefficient α, the heat conductivity coefficient Λ or the heat transition coefficient U (U value) can be determined.

Force Measurement including Adjustment of Zero Point and Final Value:

Force transducers allow you to adjust the constant load (tare) and to enter the final value as nominal value. The correction value will be automatically calculated from this. A connector that switches on this resistor for the adjustment is available for force transducers with integrated reference resistor.

Adjustment and Temperature Compensation of pH Probes:

pH probes are subject to ageing and, therefore, must be periodically re-calibrated. The calibration of zero point and slope (gain) can be performed by the push of a button using the standard reference buffer solutions. A big advantage is the fact that the calibration setting will be stored in the connector so the probe can also be operated with other instruments. It is even possible to use several probes with individual calibrations.

The temperature compensation function can be automatically performed by using a combined temperature/pH value probe, or manually, by entering the temperature of the medium.

Conductivity Measurement with Temperature Compensation:

By using the conductivity probe the temperature of the medium is measured and the conductance referred to 25°C will be calculated.

Listed below are the General Technical Specifications. If you wish to see full details of the measuring ranges of all the ALMEMO® sensors and their relevant connectors:

General Technical Specifications
Channel switching
between input sockets
4-contact with photo-MOS relay
Potential separation : Maximum 50 V (for measuring modules with higher potential separation. Click here for more on Input Connectors.)
Offset voltage : <5 µV
Cold junction compensation Effective in range -30 to +100 °C Accuracy ±0.2 K ±0.01 K / °C
Nominal temperature 22 °C ±2 K
Sensor power supply 6 to 12 V depending on power supply
Self-calibration Automatic zero-point correction, measuring current calibration
Check functions Automatic sensor and sensor breakage detection
A/D Converter:
Delta Sigma, 15-bit resolution
Measuring rate 2.5 mops
Common-mode input range -0.26 to +2.6 V Overload -4 to +5 V
Input current <2 nA
System accuracy ±0.1 % of measured value ±3 digits
Temperature drift 0.01 %/K
16-bit resolution
  Multi-slope, integrating Delta-sigma
  (ALMEMO® 6290) (ALMEMO® 2490, 2590, 8390)
Measuring rate 2.5 or 10 Measuring operations per second
Common-mode input range -4...+4 V overload ± 5V -2.0...+5 V overload -2 ...+5V
Input current < 50 nA < 20 nA
Measuring current Pt 100: appr. 1 mA Pt 1000: appr. 0,1 mA Pt100, Pt1000 0.3 mA
System accuracy ±0.03% of measured value ±2 digits (at 2.5 measuring operations per second)
Temperature drift 0.005 % / K
16-bit resolution
  Multi-slope, integrating Delta-sigma
  (ALMEMO® 6290) (ALMEMO® 2490, 2590, 8390)
Measuring rate 2.5 or 10 Measuring operations per second
Common-mode input range -4...+4 V overload ± 5V -2.0...+5 V overload -2 ...+5V
Input current < 50 nA < 20 nA
Measuring current Pt 100: appr. 1 mA Pt 1000: appr. 0,1 mA Pt100, Pt1000 0.3 mA
System accuracy ±0.03% of measured value ±2 digits (at 2.5 measuring operations per second)
Temperature drift 0.005 % / K
Delta-sigma 24-bit resolution
Measuring rate 2.5 / 10 / 50 / 100 mops with option SA0000Q4 400 mops (see below)
Common-mode input range -3 to +3 V in DC range (2.6 V), -2.0 to +1.7 V in all other measuring ranges
Overload maximum ±12 V
Input current 500 nA in DC range (2.6 V), 500 pA in all other measuring ranges
Measuring current Pt100 approx. 1 mA; Pt1000 approx. 0.1 mA
System accuracy 0.02% ±1 digit at 2.5 und 10 measuring operations per second
0.05% ±3 digit at 50 measuring operations per second
Temperature drift 0.003 % / K
Functional restrictions Impaired sensor breakage detection and higher interference - at 50 mops and above caused by : mains hum (suppression no longer possible, can be remedied by using twisted wiring)
24-bit resolution Delta-sigma, low power (ALMEMO® 2690-8A new variant)
Technical data as above, but  
Common-mode input range 2.5 / 10/ 50 / 100 mops with option SA0000Q5 500 mops (see below)
Overload maximum ±12 V
Input current 500 nA in DC range (2.6 V), 500 pA in all other measuring ranges
Measuring current Pt100 approx. 1 mA; Pt1000 approx. 0.1 mA
System accuracy 0.02% ±1 digit at 2.5 und 10 measuring operations per second
0.05% ±3 digit at 50 measuring operations per second
Temperature drift 0.003 % / K
Functional restrictions Impaired sensor breakage detection and higher interference - at 50 mops and above caused by : mains hum (suppression no longer possible, can be remedied by using twisted wiring)

 

Listed above are the General Technical Specifications. If you wish to see full details of the measuring ranges of all the ALMEMO® sensors and their relevant connectors:

 

NEW 400 mops Measuring Rate Option SA0000Q4 or 500 mops Measuring Rate Option SA0000Q5 Only with 24-bit delta-sigma converter, low power.

It is also possible, in addition to the standard conversion rates, to set 400 mops (measuring operations per second). It is thus possible to save 1 selected measuring channel at the rate of 400 mops. This can only be used with sensors with voltage or current ranges or NTC sensors. Change channels during such a measuring operation is not permitted. The resolution, the accuracy, and the sensitivity to disturbance caused by mains hum or electromagnetic interference are comparable with measuring operations performed at 50 mops. Care must be taken to ensure that the working environment is free from interference and that the sensor lines are short. Data can only be output to an MMC card. Accessories ZA1904MMC Memory connector with MMC (as of connector version 1.17, 2.04). The data is saved in table format (separated by semi-colons) and with a time-stamp whose resolution is 0.0001 seconds. This format can be processed using the WinControl software (as of version 6.1.1.6).

Measurement Functions

Depending on the sensor and measuring instrument the ALMEMO® measuring system allows for acquiring a varying number of measuring channels at any measuring input. The reason for this advantage is the patented ALMEMO® connector system:

The Patented ALMEMO Connector

Inside the patented ALMEMO® connector 6 screw terminals are located: 2 for sensor power supply and 4 for the measuring signal of the sensor. If Pt100 sensors with 4-conductor circuit are used, all of the 4 free connectors will be required for the measuring signal. Therefore, only one sensor of this type can be connected for each measuring input. Electrical signals only require 2 terminals for the measuring signal. As a result, one connector allows you to acquire two different measuring signals with one single measuring channel. For example, humidity sensors also often combine a temperature sensor. The corresponding operands (e.g. dew point, mixture ratio, partial vapour pressure, enthalpy) are programmed within the connector as additional measuring channels. However, one measuring input allows for an output of four measuring channels at maximum.

Document, Acquire, Evaluate!

ALMEMO® instruments allow you to perform a wide range of measuring tasks. The option to document series of measurements and to perform a decentralised (local) data acquisition and computer-aided evaluation of the measuring results is often a must for metrology users in the most varied industrial fields.