The miniSMU MS01 includes built-in I-V sweep functionality starting with firmware version 1.3.4. This feature allows you to configure and execute voltage sweeps directly on the device, significantly reducing the amount of communication needed compared to sending individual voltage points from a host computer.

Overview

The on-board I-V sweep feature provides:

• Reduced I/O overhead: Configure sweep parameters once, then execute and retrieve results
• Consistent timing: More precise dwell times between measurement points, without communication interference between PC and miniSMU
• Flexible output formats: Choose between CSV or JSON data formats
• Real-time monitoring: Query sweep progress during execution
• Automatic output control: Optionally enable/disable channel output during sweeps

Sweep Configuration Commands

Voltage Sweep Parameters

Configure the voltage range and measurement parameters for the sweep:

Channel Output Control

Control whether the channel output is automatically managed during the sweep:

Output Format Selection

Choose the data format for sweep results:

Sweep Execution Commands

Starting and Stopping Sweeps

Status Monitoring

The SOUR1:SWEEP:STATUS? command returns status information in the format: "status,current_point,total_points,elapsed_ms,estimated_remaining_ms"

Example response: "RUNNING,49,100,4495,4641"

• status: Current sweep state (RUNNING, COMPLETED, IDLE, etc.)
• current_point: Current data point being measured
• total_points: Total number of points in the sweep
• elapsed_ms: Time elapsed since sweep started (milliseconds)
• estimated_remaining_ms: Estimated time remaining (milliseconds)

Data Formats

CSV Format

The CSV format provides simple comma-separated values without headers. Each line contains: timestamp,voltage,current

Where:

• timestamp: miniSMU system time in microseconds
• voltage: Voltage measurement in volts
• current: Current measurement in amperes

Example CSV data:

129793905,-9.969e-01,-8.998e-09
129883905,-9.768e-01,9.865e-09
129973905,-9.566e-01,-9.194e-09
130063905,-9.365e-01,1.017e-08

JSON Format

The JSON format includes sweep configuration metadata along with the measurement data:

{
  "sweep_config": {
    "channel": 1,
    "start_voltage": -1,
    "end_voltage": 1,
    "points": 100,
    "dwell_ms": 50,
    "auto_enable": true
  },
  "data": [
    {
      "t": 129793905,
      "v": -0.9969,
      "i": -8.998e-9
    },
    {
      "t": 129883905,
      "v": -0.9768,
      "i": 9.865e-9
    },
    {
      "t": 129973905,
      "v": -0.9566,
      "i": -9.194e-9
    }
  ]
}

Basic I-V Sweep Example

Here's a complete example of configuring and running a basic I-V sweep:

SOUR1:SWEEP:VOLT:START -0.5       # Start at -0.5V
SOUR1:SWEEP:VOLT:END 1.5          # End at +1.5V
SOUR1:SWEEP:POINTS 100            # 100 measurement points
SOUR1:SWEEP:DWELL 50              # 50ms between measurements
SOUR1:SWEEP:AUTO:ENA              # Auto-enable output during sweep
SOUR1:SWEEP:FORMAT JSON           # Use JSON output format
SOUR1:SWEEP:EXECUTE               # Start the sweep
SOUR1:SWEEP:DATA?                 # Retrieve results when complete

Advanced Usage

Monitoring Sweep Progress

To monitor a long-running sweep in real-time:

# Start sweep
SOUR1:SWEEP:EXECUTE

# Check status periodically
SOUR1:SWEEP:STATUS?
# Response: "RUNNING,25,100,2250,6750"

# Continue checking until complete
SOUR1:SWEEP:STATUS?
# Response: "COMPLETED,100,100,9000,0"

# Retrieve data
SOUR1:SWEEP:DATA?

Aborting a Sweep

If you need to stop a sweep before completion:

SOUR1:SWEEP:ABORT
SOUR1:SWEEP:STATUS?
# Response: "ABORTED,45,100,4050,0"

Limitations and Considerations

• Maximum points: 1000 data points per sweep
• Maximum dwell time: 10,000ms (10 seconds) between points
• Channel support: Commands shown for channel 1; replace SOUR1 with SOUR2 for channel 2
• Firmware requirement: On-board I-V sweep requires firmware version 1.3.4 or later