DM_Control

Python interface for the Boston Micromachines (BMC) deformable mirror (DM). This submodule is part of the ArbPotential_Optical_Control project.

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Environment overview

This submodule requires two separate Python environments that must never be mixed:

Environment	Python	Purpose
venv_bmc_py36	3.6.8 only	Scripts that directly control the DM hardware
venv_main	3.11+	Analysis, plotting, profile generation

The split is forced by the BMC SDK: its compiled extension (_bmc.pyd) is ABI-locked to Python 3.6. No other Python version will load it (to my knowledge was the "newest version" where I hadn't any issues).

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Prerequisites

Install these before setting up any environment:

1. Python 3.6.8 (64-bit) — download from python.org
2. BMC DM SDK 4.2.1 — download and install from bostonmicromachines.com/dmsdk After installation the SDK lives at:

   C:\Program Files\Boston Micromachines\Bin64\
   C:\Program Files\Boston Micromachines\Bin64\Python3\site-packages\bmc\
   

3. Microsoft Visual C++ Redistributable (x64) — required for the native DLLs
4. Ensure the BMC Bin64 folder is on your system PATH:

   C:\Program Files\Boston Micromachines\Bin64
   

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1. Hardware control environment (venv_bmc_py36)

This environment lives outside the project in a central location so it can be reused across future DM-related projects. (can also live inside if you have good reason)

Create the environment

# Verify Python 3.6 is available
py -3.6 --version   # expected: Python 3.6.8

# Create the environment (adjust path to your preference)
py -3.6 -m venv C:\Users\<username>\Documents\my_venvs\venv_bmc_py36

# Activate
C:\Users\<username>\Documents\my_venvs\venv_bmc_py36\Scripts\activate

Install packages

pip install -r requirements_bmc.txt

requirements_bmc.txt is at the root of ArbPotential_Optical_Control.

Integrate the BMC SDK

The bmc package is not on PyPI. Expose it to the environment via a .pth file:

# From inside the activated environment
cd C:\Users\<username>\Documents\my_venvs\venv_bmc_py36\Lib\site-packages

# Create the .pth file (PowerShell)
"C:\Program Files\Boston Micromachines\Bin64\Python3\site-packages" | Out-File bmc_sdk.pth -Encoding ascii

Deactivate and reactivate the environment, then verify:

python -c "import bmc; print(bmc.BmcDm_version_string())"
# Expected output: 4.2.1

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2. Analysis environment (venv_main)

This environment is already created at the project root (ArbPotential_Optical_Control/venv_main/). To recreate it from scratch:

py -3.11 -m venv venv_main
venv_main\Scripts\activate
pip install -r requirements_main.txt

This environment never imports bmc and never controls hardware.

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PyCharm setup

1. Set venv_main as the project default interpreter (Settings → Project → Python Interpreter → venv_main\Scripts\python.exe)
2. For scripts that control the DM hardware, create a dedicated Run Configuration:
   • Run → Edit Configurations → + → Python
   • Set interpreter to venv_bmc_py36\Scripts\python.exe
   • Save the configuration — you will reuse it for all hardware scripts

This means you never manually switch environments: analysis scripts run with the project default, hardware scripts run via their saved configuration.

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Project structure

DM_Control/
├── DM_Control_Class/
│   ├── dm_wrapper.py        # DMClass — hardware wrapper (venv_bmc only)
│   ├── patterns.py          # Zernike and flat pattern generators
│   └── project_DM_shape.py  # Projects a target shape onto the DM
├── DM_generate_profiles/
│   └── DM_generate_Profile.py  # Generates DM command profiles (venv_main)
└── RIN_analysis/
    └── Spectrum_RIN_class.py   # RIN spectrum analysis (venv_main)

Which environment to use per script

File	Environment
DM_Control_Class/dm_wrapper.py	venv_bmc_py36
DM_Control_Class/patterns.py	venv_bmc_py36
DM_Control_Class/project_DM_shape.py	venv_bmc_py36
DM_generate_profiles/	venv_main
RIN_analysis/	venv_main

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Safety guards

The following guards are at the top of hardware control scripts to prevent accidental execution with the wrong interpreter:

import sys
if sys.version_info[:2] != (3, 6):
    raise RuntimeError(
        "BMC DM control requires Python 3.6 — activate venv_bmc_py36"
    )

Analysis scripts that must not run in the BMC environment:

import sys
if sys.version_info < (3, 10):
    raise RuntimeError("This script requires Python >= 3.10 — activate venv_main")