FROST (Fridge Remote Operations, Status, and Thermometry)

Primary cryostat control software for MEC' (MKID Exoplanet Camera) Prime

Overview

FROST provides a single interface for controlling and monitoring all cryostat hardware via serial communication. It exposes both a command-line interface for scripting and direct device control, and a desktop GUI for interactive operation.

Device	Role
Lakeshore 625	Superconducting Magnet Power Supply — ramps/de-ramps ADR magnet
Lakeshore 370	AC Resistance Bridge — monitors device stage temperature, controls PID loop with LS625
Lakeshore 350	Temperature Controller — all stage and GL7 thermometers, GL7 heater and switch outputs
Heatswitch	Zaber T-NM17A04 stepper motor — opens/closes heat switch during ADR ramp
Compressor	Cryomech compressor — turns PT cooling on/off during cooldown

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Requirements

• Rust 1.70+
• GUI environment (X11 or Wayland) for the GUI mode
• cryomech_api crate at ../cryomech_api/ (path dependency — see Dependencies)

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Installation

After building, the binary lives at target/release/frost. The recommended installation is a symlink — it survives rebuilds without any extra steps:

sudo ln -sf $(pwd)/target/release/frost /usr/local/bin/frost

Only needs to be run once. Every subsequent cargo build --release automatically updates the installed binary. This enables the user to use FROST functionality from any directory without being inside the project directory.

Verify the installation:

frost --help

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Building

# Build optimized release binary
cargo build --release

# Run tests (no hardware required — all tests use nonexistent port paths)
cargo test

# Run hardware-dependent tests (requires physical devices connected)
cargo test -- --include-ignored

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Serial Port Configuration

All device ports have hardcoded defaults that match the lab setup. They can be overridden per-command with --port and --baud flags.

Device	Default Port	Default Baud
Lakeshore 625	/dev/ttyUSB0	9600
Lakeshore 370	/dev/ttyUSB1	9600
Lakeshore 350	/dev/ttyUSB2	57600
Compressor	/dev/ttyUSB3	115200
Heatswitch	/dev/ttyUSB4	9600

To use a different port for a single command:

frost lakeshore625 --port /dev/ttyUSB5 current
frost lakeshore370 --port /dev/ttyUSB2 --baud 1200 kelvin 1
frost heatswitch --port /dev/ttyUSB1 --device-id 2 open
frost compressor --port /dev/ttyUSB0 --addr 17 status

There are no config files — if you need permanent port reassignment, update the DEFAULT_PORT constants in the relevant src/<device>.rs file.

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GUI

Launch the interactive GUI:

frost gui
# or, to build and run in one step:
cargo run --release -- gui

The GUI runs a background worker thread that polls all devices every 30 seconds (staggered to avoid serial bus contention) while keeping the interface responsive. All serial I/O happens off the render thread.

GUI Sections

Compressor

• Start/Stop buttons with live status display
• Shows running state and last update time
• Compressor intent is persisted to disk (state/.compressor_intent) — if FROST CLI or GUI is restarted, the GUI restores the last known compressor state

Magnet (Lakeshore 625)

• Live readouts: current (A), voltage (V), field
• Editable fields: current setpoint, current/voltage/rate limits, ramp rate, compliance voltage
• "Set" buttons apply each parameter to the instrument
• Values are auto-populated from hardware polls when new data arrives

GL7 Outputs (Lakeshore 350)

• Displays output percentage for each of the 4 GL7 heater/switch outputs
• Editable percentage fields with "Set" buttons to apply

Thermometry

• Live temperature readings from all LS350 inputs (A, B, C, D2, D3, D4, D5) and LS370 input 1
• Inputs using custom calibration (3-head, 4-head, pump diodes) show calibrated temperatures in Kelvin
• Direct Lakeshore-calibrated inputs (B, D3) show kelvin directly

Temperature Recording

• Start/Stop buttons for continuous CSV logging
• Logs all thermometry inputs at 30-second intervals to temps/YYYY-MM-DD_temperature_log.csv
• Recording state persists across restarts (temps/.recording_active lock file) — the GUI detects an interrupted recording on startup and resumes it

ADR Ramp

• Input fields for ramp rate (A/s), target current (A), and soak time (minutes)
• Start button executes the full automated ramp sequence
• Live log output displayed in the GUI during ramp
• Ramp state persisted to state/.adr_ramp_running — detects interrupted ramps on restart

Theme

17 color themes selectable from the top of the GUI window (Default, Dark, Light Blue, Purple, and more).

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CLI Reference

frost <device> [OPTIONS] <command> [ARGS]

frost adr — ADR Operations

# Run a full automated ADR ramp sequence
frost adr ramp <rate_A_per_s> <target_current_A> [--soak-mins N]

# Example: ramp at 0.005 A/s to 9.44 A, soak 60 minutes
frost adr ramp 0.050 9.44 --soak-mins 60

# Start LS625 ramp data logging only (writes to ramps/ CSV)
frost adr logging

The ramp command runs the full automated sequence:

1. Start background ramp logger (LS625 data to CSV, 1 row/min)
2. Set ramp rate and target current — instrument begins ramping
3. Wait for current to reach within 0.04 A of target
4. Soak at constant current for --soak-mins (default 45)
5. Open heat switch + wait 3 minutes
6. Ramp current to 0 A, wait until ≤ 0.004 A
7. Stop logger

frost compressor — Compressor Control

frost compressor [--port PORT] [--baud BAUD] [--addr ADDR] <command>

frost compressor status          # Running state, runtime, error flags
frost compressor start           # Start the compressor
frost compressor stop            # Stop the compressor
frost compressor temperature     # Water/helium/oil/CPU temps + min/max
frost compressor pressure        # High/low side pressures + motor current
frost compressor system          # Firmware info, memory status, CPU temp
frost compressor all             # All of the above in one call
frost compressor clear-min-max   # Reset min/max records

frost heatswitch — Heat Switch (Zaber Motor)

frost heatswitch [--port PORT] [--baud BAUD] [--device-id ID] <command>

frost heatswitch open            # Move +115200 microsteps (open position)
frost heatswitch close           # Move CCW until motor stalls against mechanical stop (blocking)
frost heatswitch home            # Home the motor
frost heatswitch reset           # Re-home
frost heatswitch stop            # Stop motion
frost heatswitch estop           # Emergency stop (3x STOP)
frost heatswitch move-abs <pos>  # Move to absolute position (microsteps)
frost heatswitch move-rel <steps> # Move relative (microsteps)
frost heatswitch cw <steps>      # Rotate clockwise
frost heatswitch ccw <steps>     # Rotate counter-clockwise
frost heatswitch safe-cw <steps> # Clamped CW move (1–1000 steps)
frost heatswitch safe-ccw <steps> # Clamped CCW move (1–1000 steps)
frost heatswitch move-vel <vel>  # Move at velocity

Note: open returns immediately — the motor executes asynchronously. Poll status separately to check completion. close is blocking: it moves CCW with 4× the standard travel (460800 steps) so the motor always reaches the mechanical stop regardless of starting position, then polls until the position stops changing (stall detected) or a 30-second timeout elapses, then sends STOP.

frost lakeshore625 — Magnet Power Supply

frost lakeshore625 [--port PORT] <command>

frost lakeshore625 identify
frost lakeshore625 current            # Live current readout
frost lakeshore625 voltage            # Live voltage readout
frost lakeshore625 field              # Live field readout
frost lakeshore625 all                # Current + voltage + field
frost lakeshore625 get-current        # Programmed current setpoint (SETI?)
frost lakeshore625 set-current <A>    # Set target current
frost lakeshore625 get-rate           # Ramp rate (A/s)
frost lakeshore625 set-rate <A/s>     # Set ramp rate
frost lakeshore625 start-ramp         # Begin ramping to setpoint
frost lakeshore625 stop-ramp          # Halt ramp
frost lakeshore625 get-compliance     # Compliance voltage (V)
frost lakeshore625 set-compliance <V> # Set compliance voltage (0.1–5.0 V)
frost lakeshore625 get-limits         # Current/voltage/rate limits
frost lakeshore625 set-limits <A> <V> <A/s>  # Set all limits
frost lakeshore625 quench-status
frost lakeshore625 enable-quench
frost lakeshore625 disable-quench
frost lakeshore625 set-quench <step_limit>
frost lakeshore625 error-status       # Hardware/operation/PSH error register
frost lakeshore625 logging            # Start ramp data logging to CSV
frost lakeshore625 raw "<SCPI cmd>"   # Send arbitrary SCPI command

frost lakeshore370 — Device Stage Thermometry / PID

frost lakeshore370 [--port PORT] [--baud BAUD] <command>

frost lakeshore370 identify
frost lakeshore370 kelvin <input>          # Temperature in K (input 1–16)
frost lakeshore370 resistance <input>      # Resistance in Ω
frost lakeshore370 power <input>           # Excitation power
frost lakeshore370 input-status <input>    # Input status flags
frost lakeshore370 all <input>             # Kelvin + resistance + power
frost lakeshore370 get-range <input>       # Resistance range config
frost lakeshore370 set-range <input> <mode> <excitation> <range> <autorange> <cs_off>
frost lakeshore370 get-heater             # Heater output (%)
frost lakeshore370 set-heater <pct>       # Set heater output 0–100%
frost lakeshore370 get-heater-range       # Heater range (0=Off, 1–8)
frost lakeshore370 set-heater-range <N>   # Set heater range
frost lakeshore370 heater-status          # Heater error status
frost lakeshore370 get-analog <ch>        # Analog output config (ch 1–2)
frost lakeshore370 analog-output <ch>     # Analog output value
frost lakeshore370 set-analog-off <ch>
frost lakeshore370 set-analog-channel <...>
frost lakeshore370 set-analog-manual <...>
frost lakeshore370 set-analog-still <...>
frost lakeshore370 raw "<SCPI cmd>"

# Example: read device stage temperature
frost lakeshore370 kelvin 1

frost lakeshore350 — Stage Thermometry / GL7 Control

frost lakeshore350 [--port PORT] [--baud BAUD] <command>

frost lakeshore350 identify
frost lakeshore350 read <input>           # Single input reading (A, B, C, D1–D5)
frost lakeshore350 all                    # All inputs with calibrated temps
frost lakeshore350 display-show <input>   # Show display name for input
frost lakeshore350 display-show-all       # All display names
frost lakeshore350 display-set-name <input> <name>
frost lakeshore350 set-output <N> <pct>   # Set output N (1–4) to percentage
frost lakeshore350 query-output <N>       # Query output N parameters
frost lakeshore350 query-all-outputs      # Query all 4 outputs
frost lakeshore350 outputs-set-params <N> <params...>  # Set HTRSET or ANALOG params
frost lakeshore350 outputs-set-range <N> <range>       # Set output range
frost lakeshore350 raw "<SCPI cmd>"

# Examples
frost lakeshore350 all                   # All stage temperatures
frost lakeshore350 set-output 1 50.0     # Set 4-pump heater to 50%
frost lakeshore350 query-all-outputs     # GL7 output status

Input reference:

Input	Sensor	Calibration
A	3-head thermometer	CSV (Ω → K)
B	RuOx	LS350 internal curve (K direct)
C	4-head thermometer	CSV (Ω + 34.56Ω offset → K)
D2	Switch diode	CSV (V → K)
D3	4K stage diode	LS350 curve 21 (K direct)
D4	3-pump diode	CSV (V → K)
D5	4-pump diode	CSV (V → K)

frost record-temps — Continuous Temperature Logging

frost record-temps [--port-350 PORT] [--port-370 PORT] <command>

# Take a single snapshot and print to stdout
frost record-temps snapshot

# Log continuously at 30-second intervals (Ctrl+C to stop)
# Note that loop will continuously print out in the terminal and Ctrl+C will end the recording and truncate the .csv. It is recommended to run this command in a tmux pane
frost record-temps loop

# Log at a custom interval (seconds)
frost record-temps loop --interval 60

Logs are written to temps/YYYY-MM-DD_temperature_log.csv. If a file already exists for the current date, subsequent runs write to _2.csv, _3.csv, etc. The CSV format is 19 fixed-width space-padded columns covering all LS350 inputs and LS370 input 1.

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Data Logging

Ramp Logs

Written during frost adr ramp or frost adr logging. Location: ramps/

ramps/YYYY-MM-DD_ramp_log.csv
ramps/YYYY-MM-DD_ramp_log_2.csv   # if first file exists, auto-increments

Columns: Timestamp, Rate, Current, Voltage, Field, Error Status Interval: 1 row per minute

Temperature Logs

Written during frost record-temps loop or via the GUI recording controls. Location: temps/

temps/YYYY-MM-DD_temperature_log.csv
temps/YYYY-MM-DD_temperature_log_2.csv

Columns (19 total, fixed-width space-padded): Timestamp, Date, Time, 4K_Stage_Temp, ADR_Res, ADR_Temp, Switch_Volt, Switch_Temp, 3Head_Res, 3Head_Temp, 4Head_Res_Raw, 4Head_Res_Adj, 4Head_Temp, 3Pump_Volt, 3Pump_Temp, 4Pump_Volt, 4Pump_Temp, LS370_In1_Res, LS370_In1_Temp

Interval: 30 seconds (default), configurable with --interval

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Dependencies

cryomech_api

compressor.rs uses the cryomech_api crate (SMDP V2 protocol) as a path dependency. It must be present at ../cryomech_api/ relative to the FROST directory. The cryomech_api crate itself requires smdp at ../smdp/.

# Clone both into the parent directory (sibling folders next to FROST/)
git clone <cryomech_api-repo-url> ../cryomech_api
git clone <smdp-repo-url> ../smdp

Expected directory layout:

parent/
├── FROST/
├── cryomech_api/
└── smdp/

If you do not have the compressor hardware and want to build without it, remove the cryomech_api dependency from Cargo.toml and the mod compressor; declaration from src/lib.rs and src/cli.rs.

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Architecture Notes

Serial communication: All devices communicate over serial. Each command opens the port, executes, and closes immediately — there is no persistent connection. SCPI devices (LS625, LS370, LS350) use 7-bit odd parity framing; Zaber uses 6-byte binary frames; the compressor uses SMDP V2 binary protocol via cryomech_api.

Worker thread: The GUI spawns a background thread for all serial I/O so the render loop is never blocked. Device state is shared via Arc<Mutex<DeviceSnapshot>> and polled every 30 seconds.

Persistent state: The state/ directory holds lock files that survive process restarts. The GUI reads these on startup to restore compressor intent and detect interrupted ADR ramps.

Calibration files: The LS350 loads calibration CSVs (Ω→K or V→K interpolation tables) lazily on first use for the 3-head, 4-head, and pump diode sensors.

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License

Apache 2.0