MEMS Studio AFS error with ST1VAFE3BX: magnetometer unit mismatch when using vAFE [LSB]
- May 5, 2026
- 1 reply
- 146 views
I am using MEMS Studio (v2.3.1) with ST1VAFE3BX to train an MLC model using AFS (Automatic Filter & Feature Selection).
My input data contains:
- 3-axis accelerometer: A_X [mg], A_Y [mg], A_Z [mg]
- vAFE channel: vAFE [LSB]
The CSV header follows the format described in AN6208:
A_X [mg], A_Y [mg], A_Z [mg], vAFE [LSB]
However, when running AFS, I get the following error:
"External sensor unit mismatch between provided external sensor name magnetometer and units LSB.
Correct units are gauss or mgauss."
This is confusing because:
- No magnetometer data is used
- Input type is set to accelerometer + vAFE
- vAFE [LSB] is consistent with ST documentation
I have already tested the following:
1. Verified CSV format (no missing values, consistent headers across all files)
2. Tested minimal dataset (only 2 CSV files)
3. Tried different headers:
- vAFE [LSB]
- vAFE_X [LSB]
- tab-separated format
4. Tested accelerometer-only input (works)
5. Tested vAFE-only input (fails)
6. Cleared workspace and settings
7. Did not reuse previous JSON configuration
The issue consistently occurs only when vAFE is included.
My questions are:
1. Does AFS in MEMS Studio 2.3.1 fully support vAFE [LSB] input for ST1VAFE3BX?
2. Is this a known issue or limitation of AFS?
3. Is there a recommended CSV format or naming convention for vAFE input?
4. Should vAFE be processed only through manual MLC configuration instead of AFS?
5. Is there a recommended MEMS Studio version that properly supports this use case?
