2  System Setup

2.1  Package contents

2.2  Unpacking and packing

The instrument is delivered in a plywood box which is padded with a foam rubber layer. The NAIS should always be transported in the original box. It can protect the instrument well when left in the hands of a delivery company.

The NAIS weights about 60 kg. It should be lifted by at least two persons. The instrument can be lifted from the metal handles. When taken out of the transport box, the NAIS should be placed on a flat level surface in the upright position.

The inlet and exhaust tubes of the instrument are covered during transport. Keep the covers on whenever the instrument is transported but also when the instrument is idle for longer periods of time.

Note when packing the instrument back in the box: make sure that the surrounding foam rubber stays flat and does not fold.

2.3  Instrument placement

The instrument should be placed on a firm, non-vibrating, level surface. The instrument can tolerate some amount of vibration when measuring (e.g. on board an aircraft or automobile), however any vibration will increase the noise level of the measurements.

2.4  Inlet considerations

The inlet tube can significantly affect the quality of the measurement results of the NAIS by increasing losses for the smallest particles or allowing insects or water to enter the instrument.

Diffusion losses are highly critical for particles with diameters below 2 nm. Therefore the inlet must be short and must not have any turbulences.

The mobility analyzer is sensitive to insects and fibers that may deposit on the electrodes and cause electric noise and parasitic currents.

Make sure that rain does not get into the instrument. Choose the angle of the inlet accordingly. Add a bent tube pointing downwards at the end of a horizontal inlet.

2.5  Temperature and water condensation

When the temperature of the instrument is lower than the sample air then there is danger of water condensation inside the instrument. The risk is highest in a hot and humid climate when the NAIS is placed in an air conditioned room and sample air is pulled from the outside. Such situation must be avoided. Water condensation inside the NAIS can and will severely damage the instrument.

If it is not possible to prevent the negative temperature difference between the instrument room and outside then it is recommended to place thermal isolation around the NAIS and avoid direct airflow from the air-conditioner onto the instrument.

The measurement software will show a warning when a negative temperature difference between the body of the instrument and sample air is detected. However the lack of this warning does not guarantee that everything is ok. The device user should independently assess the situation.

2.6  Power connection and grounding

The instrument has a standard power C14 plug and accepts 110V to 240 V AC 50Hz line voltage. The average power requirement of the device is well below 100 W. The power may shortly increase to 150 W for maximum duration of a few seconds when the instrument blowers are starting up.

The NAIS should be properly electrically earthed. A missing or bad grounding connection in the power plug may leave the body of the instrument at an electric potential. There will be danger or electric shock to the instrument user and significantly increased particle losses and increased noise in the measurement results.

2.7  Data connection

The NAIS uses Ethernet for data communications. The following connection options are available:

In all cases the measurement software will attempt to automatically discover the instrument network address and typically it is not necessary to manually enter the IP into the measurement software.

2.8  Software installation

There are two programs in the measurement software package provided with the NAIS.

Spectops for running the measurements and viewing live data.
Retrospect for viewing and reprocessing the results later.

In addition, each instrument have individual instrument configuration files which are necessary for running measurements. These contain calibration info and other instrument specific data.

To install the program on a computer, please follow the steps:

  1. Create a folder on your computer where you want the software to reside.

    Usually the measurement results will be stored into a sub-folder of that folder. So make sure that there is sufficient free disk space.

  2. Download the instrument configuration package and the compatible measurement software package for your instrument.

    Please send and email to Airel Support support@airel.ee if you don’t have access to the measurement software pages.

  3. Extract both files into the same folder.

  4. Run the Spectops program that was just extracted.

  5. Open the measurement setup file in Spectops (Menu: File → Open…).

    1. Choose “Auto discover” for finding the instrument on the local network

    2. Specify the IP address of the instrument if auto discover does not work

  6. Specify the measurement cycle or use the default.

    For example: “particles 60, ions 60, offset 30”

  7. Run the measurements.

  8. Optional: Use “Create shortcut…” from File menu to create a shortcut that will automatically start measurements with the current measurement setup file.

    Place the shortcut into the Windows Startup folder to start the measurement automatically when the computer starts.

Note: For browsing the measurement results using Retrospect the instrument configuration files are not needed.

2.9  First run

The instrument needs a minimum of 5 minutes and at least three measurement cycles to “warm-up”. Before that, the software may show diagnostic warnings and the data will not be correct.

The blowers will start and stabilize immediately at startup, so first check that the blowers are working and airflows are not obstructed.

When measuring in particle mode for the first time after the software has been installed, the postfilter voltages will not be ideal. It may take at least 30 minutes and possibly up to a few hours until the posftilter adjustment algorithm has settled on good value (see Postfilter).

If you are unsure whether the instrument is operating correctly, collect at least 1 hour of data and send it to Airel Support (support@airel.ee). Make sure that you send all the data files (records, log and spectra). Please send only block average files initially.

Further checks and diagnostics can be carried out via remote access to the measurement computer (for example, using Teamviewer or AnyDesk).

For experienced users: See Diagnostic Checks for a list of conditions that can be checked to make sure that the instrument runs correctly.