Automatic Peak Positioning (APP)

Whenever powering up the spectrometer, the EM27/SUN does not accurately know the pendulum's position. That is why it is recommended to save the center position of recorded interferograms after every powerup so that no points on one of the sides of the interferogram get lost because it is not stored centered. In OPUS, you can do this in "Measure > Setup Measurement Parameters > Check Signal". Or you can let PYRA do this after every powerup by configuring it in the OPUS Configuration and save a few minutes per system per day.

The Automatic Peak Positioning (APP) feature searches for OPUS files written to the local disk within the last 15 minutes and after the last EM27/SUN powerup. It loads the interferograms from these OPUS files using the tum-esm-utils Python library and calculates the peak position. If the peak position from the last five readable OPUS files is identical and is less than 200 points off the center, this new peak position will be sent to the EM27/SUN.

The logs from the OPUS thread when performing the APP will look something like this:

2025-04-19 04:44:23.020353 UTC+0000 - opus - DEBUG - Starting iteration
2025-04-19 04:44:23.023355 UTC+0000 - opus - DEBUG - Loading configuration file
2025-04-19 04:44:23.042385 UTC+0000 - opus - DEBUG - Checking if OPUS is running
2025-04-19 04:44:23.082358 UTC+0000 - opus - DEBUG - Macro is running as expected
2025-04-19 04:44:23.116354 UTC+0000 - opus - INFO - Trying to set peak position
2025-04-19 04:44:23.140355 UTC+0000 - opus - DEBUG - APP: Time since last powerup is 5280.00 seconds
2025-04-19 04:44:23.148357 UTC+0000 - opus - DEBUG - APP: Found 9 files created since the last powerup and less than 10 minutes old
2025-04-19 04:44:23.152385 UTC+0000 - opus - DEBUG - APP: C:\MESSUNGEN\20250419\ma20250419s0e00a.0009 - Could not determine peak position ([Errno 13] Permission denied: 'C:\MESSUNGEN\20250419\ma20250419s0e00a.0009')
2025-04-19 04:44:23.204388 UTC+0000 - opus - DEBUG - APP: C:\MESSUNGEN\20250419\ma20250419s0e00a.0008 - Found peak position 57123 (ABP = 60237, DC amplitude = 0.03186991322785616)
2025-04-19 04:44:23.258355 UTC+0000 - opus - DEBUG - APP: C:\MESSUNGEN\20250419\ma20250419s0e00a.0007 - Found peak position 57123 (ABP = 60237, DC amplitude = 0.0316972940415144)
2025-04-19 04:44:23.316386 UTC+0000 - opus - DEBUG - APP: C:\MESSUNGEN\20250419\ma20250419s0e00a.0006 - Found peak position 57123 (ABP = 60237, DC amplitude = 0.03151779551059008)
2025-04-19 04:44:23.371357 UTC+0000 - opus - DEBUG - APP: C:\MESSUNGEN\20250419\ma20250419s0e00a.0005 - Found peak position 57123 (ABP = 60237, DC amplitude = 0.031326398849487305)
2025-04-19 04:44:23.427355 UTC+0000 - opus - DEBUG - APP: C:\MESSUNGEN\20250419\ma20250419s0e00a.0004 - Found peak position 57123 (ABP = 60237, DC amplitude = 0.031152355410158636)
2025-04-19 04:44:23.430355 UTC+0000 - opus - DEBUG - APP: Currently configured ABP is 60237
2025-04-19 04:44:23.434366 UTC+0000 - opus - DEBUG - Currently recorded interferograms have peak positions: 57123 (-5 points offset from center)
2025-04-19 04:44:23.437387 UTC+0000 - opus - INFO - Updating peak position from 60237 to 60232
2025-04-19 04:44:23.512354 UTC+0000 - opus - DEBUG - Sleeping 19.51 seconds

Ensure to unload the interferogram files frequently because the files loaded by OPUS cannot be read by any other program. Otherwise, you will see many Permission denied exceptions until Pyra finds the first interferogram file from which to read the peak position.