Kepco BIT 802E Waveform Generator

Desktop GUI for generating, previewing, uploading, and controlling waveforms on a Kepco BIT 802E / BOP power supply. The app uses a hardened SCPI controller with Telnet-first communication, socket fallback, chunked LIST uploads, live status polling, and safety interlocks for disconnect and shutdown.

Key Features

• Generate DC, Sine, Square, Triangle, Sawtooth, and CSV-based waveforms
• Preview waveform shape and timing before anything is sent to hardware
• Upload LIST waveforms in verified chunks that respect device limits
• Connect over Telnet on 5024 with automatic fallback to SCPI socket 5025
• Scan local /24 networks for devices and validate them with *IDN?
• Use manual SCPI controls for diagnostics, measurements, and overrides
• Persist session logs to logs/kepco_dashboard_date_YYYY-MM-DD_HHMMSS.log
• Develop offline with the included simulator in kepco_simulator.py
• Enforce safe disconnect behavior by returning output to 0 V, 0 A, and OFF

Project Files

• kepco_ui.py: main CustomTkinter desktop application
• kepco_simulator.py: simulator that emulates Kepco Telnet and socket behavior
• docs/interface.md: architecture and interface notes
• docs/802e_manual.md: device reference material
• requirements.txt: Python dependencies

Hardware Limits Implemented

• Minimum dwell: 0.0005 s
• Maximum dwell: 10.0 s
• Maximum points per single LIST upload: 1000
• Maximum total staged points in the UI: 4000
• Preferred transport: Telnet on 5024
• Fallback transport: direct SCPI socket on 5025

Getting Started

1. Create and activate a virtual environment.

python -m venv .venv
.\.venv\Scripts\Activate.ps1
pip install -r requirements.txt

2. Optional: run the simulator for offline testing.

python kepco_simulator.py

3. Start the UI.

python kepco_ui.py

4. In the app:

• Select or scan for a device IP
• Connect and confirm identity
• Choose control mode and waveform settings
• Preview the waveform locally
• Upload the waveform
• Toggle output on to run it
• Stop or disconnect when finished

Functional UI Flow

This diagram focuses on the actual user-triggered paths in the UI.

flowchart TD
    A[Launch UI] --> B[Session log opens]
    B --> C[Enter IP or click Scan Network]
    C --> D[Click Connect]
    D --> E{Connection and *IDN? succeed}
    E -- No --> F[Show connection error in log]
    E -- Yes --> G[Connected state enabled and status polling starts]

    G --> H[Select VOLT or CURR mode]
    H --> I[Choose waveform type]
    I --> J[Enter waveform settings or load CSV]
    J --> K[Click Preview Waveform]
    K --> L[Preview plot updates locally]
    L --> M[Click Upload]
    M --> N{Request accepted}
    N -- No --> O[Show validation or upload error]
    N -- Yes --> P[Waveform or DC setpoint becomes ready]

    P --> Q[Click Output toggle]
    Q --> R{Ready waveform is DC, single LIST, or multi-chunk LIST}
    R -- DC --> S[Send OUTP ON]
    R -- Single LIST --> T[Run uploaded LIST]
    R -- Multi-chunk LIST --> U[Start streamed chunk sequence]

    S --> V[Status tab and measurements update]
    T --> V
    U --> V

    G --> W[Manual Override tab]
    W --> X[Send SCPI command or query]
    X --> V

    V --> Y[Click Output toggle OFF or Stop]
    Y --> Z[Return output to safe idle state]
    Z --> G

    G --> AA[Click Disconnect or close app]
    AA --> AB[Run safety shutdown and verify OFF at 0 V and 0 A]
    AB --> AC[Socket closes and UI returns to disconnected state]

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Telnet and SCPI Communication Flow

This diagram focuses on the controller behavior used for connect, command execution, upload, run, and disconnect.

flowchart TD
    A[UI action starts worker thread] --> B[KepcoController]

    B --> C[Try TCP connect on 5024 Telnet]
    C --> D{Telnet connect works}
    D -- Yes --> E[Drain Telnet negotiation bytes]
    D -- No --> F[Try TCP connect on 5025 socket]
    F --> G{Socket connect works}
    G -- No --> H[Return connection failure to UI]
    G -- Yes --> I[Use socket transport]
    E --> J[Send *IDN?]
    I --> J
    J --> K[Read response and strip Telnet prompt or echo noise]
    K --> L[Return connected state to UI]

    L --> M{Operation}
    M -- Preview --> N[No SCPI traffic]
    M -- Manual command --> O[Send SCPI command]
    M -- Manual query --> P[Send SCPI query and read one response]
    M -- Upload LIST --> Q[Prepare LIST upload]
    M -- Output ON --> R[Run DC output or LIST mode]
    M -- Output OFF or Disconnect --> S[Stop output and verify safe state]

    O --> T[Pause about 35 ms between non-query commands]
    T --> U[If using Telnet drain echoed bytes]

    P --> V[Read one response line]
    V --> W[Remove IAC bytes prompt text and echoed command]

    Q --> X[Optional disarm of active LIST mode]
    X --> Y[Send FUNC:MODE mode and mode:RANG 1]
    Y --> Z[Send LIST:CLE and wait]
    Z --> AA[Send LIST values in small batches]
    AA --> AB[Pause between commands and drain Telnet echo]
    AB --> AC[Send LIST:DWEL and wait]
    AC --> AD[Query LIST points accepted]
    AD --> AE[Query SYST:ERR?]
    AE --> AF[Return upload success or failure to UI]

    R --> AG[DC: OUTP ON]
    R --> AH[LIST: LIST:COUN then mode:MODE LIST]
    AG --> AI[Status polling continues]
    AH --> AI

    S --> AJ[For LIST stop return mode to FIX and turn output OFF]
    AJ --> AK[Send VOLT 0 and CURR 0 for disconnect]
    AK --> AL[Verify OUTP? VOLT? and CURR?]
    AL --> AM{Verification passed}
    AM -- No --> AN[Block disconnect and report interlock error]
    AM -- Yes --> AO[Close socket and reset UI state]

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Runtime Behavior Summary

• Preview is local-only and does not send SCPI commands.
• Upload sends SCPI only after input validation, dwell calculation, and software interlock checks.
• Single-chunk waveforms are uploaded once and can then be armed or run.
• Multi-chunk waveforms are streamed chunk-by-chunk because the device accepts at most 1000 LIST points per upload.
• The controller spaces non-query commands by about 35 ms to respect device throughput limits.
• On Telnet, the controller drains echoed command bytes so the device echo buffer does not block later commands.
• Status polling runs only while connected and updates output state, measurements, and the status tab.

CSV Behavior

• CSV input accepts numeric values and flattens rows into one point list.
• The UI uses the loaded CSV values as the waveform data and computes dwell from the requested frequency.
• CSV data is truncated to the app's maximum supported total point count when necessary.
• CSV waveforms require at least 2 valid points.

Safety and Interlocks

• The app prevents disconnect while an upload or multi-chunk stream is active.
• Before disconnect, the controller attempts the following sequence:
• Stop LIST mode
• Set VOLT 0
• Set CURR 0
• Send OUTP OFF
• Verify OUTP?, VOLT?, and CURR?
• If verification fails, disconnect is blocked and the user is shown an interlock error.

Troubleshooting

• If connection fails, confirm the device is reachable on port 5024 or 5025.
• If the app connects but commands appear to stall, inspect Telnet echo handling and device firmware behavior.
• If uploads fail, check waveform size, dwell constraints, and software limits in the selected control mode.
• Use kepco_simulator.py to reproduce connection and upload behavior without hardware.
• Review the log panel or the saved session log file for command-level details.

Development Notes

• The SCPI controller is implemented in KepcoController inside kepco_ui.py.
• Device discovery is handled by Discovery.scan_subnet.
• Waveform timing and point generation live in WaveformGen.
• The GUI orchestration is handled by DashboardApp.

Known Limitations

• The repository does not currently include automated tests.
• CSV mode is labeled untested in the UI and should be validated on target hardware.
• During AC waveform uploads using the LIST command, Live Measurement readback values are inaccurate due to limitations of the 802E BIT LAN card.
• Higher frequency waveforms are limited by the number of points that can be sent due to a dwell time minimum of 0.0005 seconds. This produces a larger step difference between each point.