> 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-ma600/quick-start-guide/05-operation.md).

# Operation

You can use the microAethalometer on-board user interface to operate and configure the instrument for basic operations.

## Turn On

1. Press and hold only one of the three buttons for 2 seconds. The screen and instrument will turn on and the AethLabs logo will be displayed.

## Turn Off

1. Scroll through menu options to 'Turn Off'. Press the center button to select the 'Turn Off' option.

## On-board Status Indications

The on-board screen displays status information on the top line that rotates through three status layouts:

![LCD status layout 1 — Serial Number, Measurement Status, and Active Menu Option indicators](https://272274374-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1fOQ2MnLWcq0ntHW3LLY%2Fuploads%2Fgit-blob-f4214fd78167e3d96fb9de26b0c193069d403105%2Fma-lcd-status-layout-1.png?alt=media)

![LCD status layout 2 — Current Attenuation (ATN) value / Tape Advance ATN Threshold and Tape Position indicators](https://272274374-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1fOQ2MnLWcq0ntHW3LLY%2Fuploads%2Fgit-blob-9f95303fa0499fbfb4b560de68e4acce31c7514f%2Fma-lcd-status-layout-2.png?alt=media)

![LCD status layout 3 — Instrument UTC Date / Time](https://272274374-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1fOQ2MnLWcq0ntHW3LLY%2Fuploads%2Fgit-blob-7f4f65d7dd37107afed7d585d5a191d173ce446f%2Fma-lcd-status-layout-3.png?alt=media)

* **Measurement Status:** A "play" ▶ symbol will be shown if the instrument is sampling and making measurements. A "stop" ▮ symbol will be shown if the instrument is idle.
* **Serial Number:** Displays the instrument serial number.
* **Current Attenuation (ATN) value / Tape Advance ATN Threshold:** Displays the current attenuation (ATN) symbol and the current attenuation value out of the tape advance ATN threshold trigger value for the lowest enabled wavelength that will trigger an automatic tape advance.
* **Tape position:** Displays the tape position symbol next to the current tape position value in the top middle of the screen.
* **Instrument UTC Date / Time:** Displays the instrument UTC date and time.

## Menu Options

1. The currently active menu option is displayed on the second line below status indicators.
2. Scroll menu options to select an operation or a desired setting to configure. With the desired menu option displayed on the interface, press the center button to manage each setting.

![LCD menu navigation — left button scrolls menu options to the left, right button scrolls to the right, and the center button selects an operation or setting to configure](https://272274374-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1fOQ2MnLWcq0ntHW3LLY%2Fuploads%2Fgit-blob-b85587e8b521a0eef93a9b7116fb476e8c0d6b32%2Fnav-buttons-labeled.png?alt=media)

## During Startup

The Firmware Version, Serial Port Baud Rate, and AutoSample setting value are displayed on boot.

![Startup screens — AethLabs logo followed by Version, Serial Baud, and AutoSample values](https://272274374-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1fOQ2MnLWcq0ntHW3LLY%2Fuploads%2Fgit-blob-ca1e23eb092a9d3492eb470c26f6354633d939af%2Fma-lcd-startup-screens.png?alt=media)

## During Sampling

When the instrument is sampling and making measurements the standard status indications are displayed on line one. Line two displays 'Press Center to Stop' informing the user to press the center button to stop sampling and measurements. Line three displays `<XX> Target <FFF.FF>` where `<XX>` equals DS when sampling in DualSpot mode or SS when sampling in SingleSpot mode and where `<FFF.FF>` equals the current user selected target flow rate. Line four displays 'SAMPLING'.

![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-e988867f585a56e852b4218fba2c92a8f31124be%2Fma-lcd-sampling.png?alt=media)

## Operating Parameters

To change the Timebase, Flow Rate, or Tape Advance (Adv.) ATN (more options available on screen and all settings available in microAeth® Manager):

1. Scroll through the menu options to the Change `<setting>`
2. Press the center button to select the setting to adjust and enter the sub menu.
3. Use the left or right buttons to scroll through value options (value options vary depending on which setting being adjusted).
4. Press the center button, 'OK' to select the current value option. Once selected, the value is saved and the user interface returns to the top menu level.

![LCD 'Change Timebase' sub menu — left button decreases value, right button increases value, center 'OK' selects the current value and returns to the top menu level](https://272274374-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1fOQ2MnLWcq0ntHW3LLY%2Fuploads%2Fgit-blob-a5b30f811dc243f6d9b38e17a7f6b0bed57e5f96%2Fchange-timebase-menu.png?alt=media)

**IMPORTANT:** When adjusting Adv. ATN, the lowest wavelength light source enabled will typically trigger the attenuation (ATN) tape advance.