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Automatic Weighing System AWS-1RE

Climate-controlled automatic weighing system with RFID technology for the gravimetric assessment of sampling filters

The automatic weighing system AWS-1RE provides a precise filter conditioning and weighs up to 750 filters in an automated process. Integrated RFID technology identifies and tracks the filters during the entire process. If a PC is connected, the weighing results are recorded in a database along with relevant ancillary data, such as temperature and relative humidity. Automation contributes to the very high reliability and precision of both weighing and documentation. A weighing chamber with a fan filter unit (FFU) and climate control unit maintains controlled, dustproof conditions throughout the weighing operation. Its modular design allows the system to be adapted to customers’ specific requirements.


Key Features

  • Precise and reliable climatization
  • Ideal and time-saving filter conditioning by open filter storage
  • Dustprotected weighing chamber with FFU
  • Filter encoding and identification by RFID
  • Automatic data capture and documentation
  • Filter magazine for storing filters
  • Ionization fan


System configuration

The automatic weighing system AWS-1RE consists of the following principal components:

  • Dustproof weighing chamber with:
    • Filter disc magazines for holding filters before and after weighing
    • Patented RFID filter trays with data storage for contactless encoding and identification of the filters
    • Microbalance with draft shield
    • Ultra-microbalance (optional, most existing balances can be integrated after modification)
    • Fan filter unit (FFU) to protect the weighing chamber against contamination
    • Climate control unit
    • Ionization system for neutralizing the filters (“eliminating” static electricity)
  • PC with system software AWS Control (featuring custom encoding function)
  • Power supply cabinet underneath the weighing chamber

Operating principle and weighing process

Before the first weighing operation is performed, the unsampled filters are manually placed into filter trays and inserted into the filter magazines of the AWS-1RE. The system automatically recognizes each individual filter by contactless RFID technology. During the weighing process, the system stores environmental and ancillary data on the filter tray’s chip and also in the database of a connected PC.

First, the filters are preconditioned for the desired time, according to chosen parameters. The next step is the first weighing series, which consists of weighing the unsampled filters, usually in two weighing passes. The ionization system located near the balance “eliminates” the static electricity of the filters, and thus enhances weighing accuracy. Once the unsampled filters have been weighed, they are taken out of the weighing chamber and made ready for sampling.

After sampling, the filters are returned to the filter trays, introduced into the weighing chamber and conditioned again. The second weighing series (weighing the sampled filters) follows, once again with two or possibly three weighing passes. Previously coded filters can be identified by the RFID station, which allows the sampled reading to be compared directly with the preceding unsampled reading. Both before and during the weighing series, verification weighing operations can be performed with reference filters in order to monitor the climatic conditions inside the weighing chamber. During the weighing operation, all the data (weighed values, mean values, weight difference between unsampled and sampled filters, and ancillary data, such as temperature and relative humidity) are saved in the database on the system PC.

The saved data can subsequently be exported for analysis and processing. The concentration of particulate matter is calculated from the weight difference between the sampled and unsampled filters, giving consideration to the air flow rate.


Compared with manual lab weighing, the AWS-1RE offers the benefits of an automatic filter handling in a contamination-free weighing chamber, designed specifically for weighing filters. The connected system PC facilitates reliable recording of the weighing results, comparisons between individual weighing passes, and continuous monitoring of the climatic conditions. The system rules out inaccurate records and delivers reliable, precise results by manual weighing. An integrated filter magazine can accommodate a large number of filters in a protected environment. The climate control unit maintains the necessary climatic conditions throughout the entire process.

Detailed information is contained in the data sheet “Automatic Weighing System AWS-1RE”.


The information on this website represents the state of knowledge at the time of writing. Technical specifications are subject to modifications. Comde-Derenda GmbH accepts no liability whatsoever for the content provided or for damages resulting from the use of its products.

Technical Data

Filters and filter trays
Filter material Glass fiber, quartz fiber, cellulose nitrate, Teflon
Filter diameter 47 mm
Filter encoding Via RFID system and RFID transponders in the filter trays
Filter identification Non-contact identification using RFID technology
Filter magazine Number of magazine discs 14 – 25
Number of filters per magazine disc 15
Total filter capacity max. 750
Potential equilization Through consistent conductive design
Mikrobalance (optional) Integrable models Sartorius WZA-26-HC (others upon request)
Readability (resolution) 0.001 mg
Balance placement On platform with a large mass (approx. 155 kg), decoupled from system structure
Calibration weights Integrated in the balance
Additional specifications Cleanroom class (within the weighing chamber) 6
Electronics Interface LAN (RJ-45)
Data export TCP/IP (example) Weight of unloaded filter (average value)
Weight of loaded filter (average value)
Difference of weight between unloaded and loaded filter (average value)
Temperature, rel. humidity, barometric pressure
Filter number, sampler number, number of weighing per filter
Power supply
Power source 230 V ± 10 %, 50 Hz
Power requirement (without chiller unit) approx. 1800 VA
Power requirement chiller approx. 1300 VA
Dimensions Width 1190 mm
Height with protective hood 1995 mm
Height of work surface 875 mm
Depth 930 mm
Weight (incl. balance platform) < 700 kg
Weight external chiller < 75 kg
Climate control
Temperature regulation Climate control unit (heating, cooling, humidification, dehumidifica­tion), with external water connection and external compressor
Humidifier unit Evaporator as air cooler unit
Accuracy of temperature regulation ± 0.5 K (with set value 20 … 22 °C)
Accuracy of humidity regulation ± 2.5 % RH (with set value 45 … 50 % RH)
Accuracy of dew point regulation ± 1 K (with set value 7.7 … 11.1 °C)
Operating conditions 16 … 28 °C, 30 … 60 % rel. humidity

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