> For the complete documentation index, see [llms.txt](https://docs.aethlabs.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.aethlabs.com/microaethalometer-tm-ma450/quick-start-guide/07-performing-measurements.md).

# Performing Measurements

The inlet and outlet ports are 10-32 UNF imperial (inch) threaded ports.

**The inlet port, outlet port, and all connections to the inlet port must be properly protected from the environment.** There must be limited restriction to flow while protection from water, insects, bugs, and other objects that can block or infiltrate the instrument air pathway through both the inlet and outlet ports of the instrument. Extra precaution must be taken as the internal pump of the instrument is pulling air into the instrument through the inlet port.

![Inlet and outlet port locations shown across the MA200, MA300, and MA350 enclosures](https://272274374-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1fOQ2MnLWcq0ntHW3LLY%2Fuploads%2Fgit-blob-82055168100c4f6cdc3dbc6f9e1332d3beeffaa0%2Fma-inlet-outlet-ports.png?alt=media)

## To Start Sampling and Measurements

1. Ensure there is a filter cartridge installed and clamped.
2. Confirm that all settings are correct for the sampling campaign.
3. To start measurement, scroll through menu options to 'Start Measurement' and press the center button.
4. 'SAMPLER PREPARING' will be displayed on screen. The microAeth will automatically advance the filter tape cartridge to a new sampling location and run its start up routine.

![LCD 'Start Measurement' → 'Press Center to Stop / -Advancing Tape / SAMPLER PREPARING'](https://272274374-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1fOQ2MnLWcq0ntHW3LLY%2Fuploads%2Fgit-blob-1113f39dd44de57eea22f6ad91ba2fd439e4b009%2Fma-lcd-sampler-preparing.png?alt=media)

5. When sampling and measurement begins, the screen will display a "play" ▶ symbol in the top left cornter, 'Press Center to Stop' on line 2, the DualSpot (DS) or SingleSpot (SS) target total flow rate on line 3, and 'SAMPLING' on line 4.

![LCD during sampling — 'Press Center to Stop / DS Target 100.00 / SAMPLING'](https://272274374-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1fOQ2MnLWcq0ntHW3LLY%2Fuploads%2Fgit-blob-32b1148ad6e59e326a1a170232b3ac73caaad763%2Fma-lcd-sampling-active.png?alt=media)

## To Stop Sampling and Measurements

1. While the microAeth is sampling, the screen will display a "play" ▶ symbol in the top left cornter, 'Press Center to Stop' on line 2, the DualSpot (DS) or SingleSpot (SS) target total flow rate on line 3, and 'SAMPLING' on line 4.
2. Press and hold the center button for 2 seconds to stop sampling and measurement. The screen will display a "stop" ▮ symbol in the top left corner and 'STOPPED' will be displayed on the screen and sampling and measurement will finish.