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It is always a good idea to close all your active programs and disable your anti-virus program before installing any new program. If you have and earlier version of the program, it is suggested that you uninstall it first. The uninstall for the program can be found in the START menu under the the program name. You do not have to restart after uninstalling the program.

A Note on USB to Serial Converters

If a USB-to-serial converter is needed to interface to an Optec instrument, it is necessary to confirm that the converter is compatible with the Optec control software. Many low cost converters using the Prolific chip set will not work with the Optec control software. We suggest that the converter use the FTDI chip set for best compatibility. The #17690 single port and the #17691 4-port USB-to-serial converter sold by Optec uses the FTDI chip set.

Vista and Windows 7 Tips

As usual with Microsoft VISTA, there is a problem with running some of the older Optec control programs. It is necessary that the program be given administrator rights otherwise the program will crash with a message indicating that a file cannot be opened. The next release of Liberty Basic is suppose to fix this incompatibility. To make it work now for VISTA, find the program executable in Program Files. An easy way would be to look at the target for the shortcut in your start menu. For example, the NGN-2a control program is named NGN-2aControl.EXE and has the NGN-2a icon associated with it. Right click on the program and select properties and then the compatibility tab. Under the privilege level make sure there is a check mark for "Run this program as an administrator". If you want to be walked through, give us a call at Optec.

When you click the download button, save the setup program file to your desktop or other folder of your choice. RUN the program from your computer and follow the instructions.

The installed program files are placed in a folder called OPTEC found in the Program Files. The runtime program shortcuts are placed in the START menu along with a README file, HELP file, UNINSTALL program and link to www.optecinc.com. After the program is installed, you can delete the setup program.


NGN-2AControl.NET control program for the NGN-2A ambient air Nephelometer. Current version 1.08 now supports Mode 5 option that allows 5 second integration times.  Microsoft .NET framework required. Click to Start Download
NGN-3AControl.EXE control program for the NGN-3A PM2.5 size cut Nephelometer. Current version 1.02 now allows the selected COM port number to be stored in a configuration file. Click to Start Download
LPV-3Control.EXE control program for the LPV-3 long path Transmissometer. Click to Start Download
LPV-3 Calibration Calculator program to calculate Lamp Calibration(CAL) numbers using the Differential Path Method or ND Filter Method.
Click to Start Download