LabSupplyControl

Remote control for Nice-Power / KUAIQU bench DC power supplies — a clean PyQt5 desktop panel with live graphing, presets, battery-charge templates, and timed sequences.

Status: early beta. It works for everyday use, but it's only been tested against one model and there will be rough edges. Bug reports, fixes, and notes on which supplies it works with are very welcome.

These supplies are not Modbus. Despite the "-232" naming and the Modbus manuals floating around, this family speaks a simple ASCII bracket protocol (<CCDDDDDDAAA>). LabSupplyControl implements that protocol directly — see Protocol.

Features

• Auto-detect & connect — finds the supply by its USB-serial bridge (CP2102/CP210x); if exactly one device is present it connects on launch.
• Instrument-style readout — live Volts / Amps / Watts, the applied set-points, and CV/CC mode.
• Set-points with an on-screen keypad — tap a value to type it directly (range-checked); the spin arrows still work for fine steps.
• V/A presets — save, load, and apply named voltage/current presets (persisted under ~/.config/labsupplycontrol/); an optional warning before raising the voltage on a live output. The last set-points are restored on startup.
• Live graph — voltage & current vs. time (dual axis), with a selectable window, per-curve toggles, pause, clear, and CSV export. Logs only while the output is on.
• Over-current trip — optionally power off (like a fuse) when the supply reaches its set current limit.
• Battery-charge templates — lead-acid / Li-ion / LiFePO4 CC-CV charging with automatic taper termination or float. Supervised use only — see Safety.
• Timed sequences — run a CSV of timed steps (set V/A, output on/off) on a timeline, with the active step highlighted.

See the User manual for a full walkthrough.

Supported hardware

Built and tested against the KUAIQU SPS-D305-232 / SPPS-D305-232 (30 V / 5 A, single channel, RS-232 over a USB-serial adapter). It should work with other Nice-Power / KUAIQU supplies that use the same ASCII protocol; pass --max-voltage / --max-current for a different rating.

Installation

Requires Python 3.10+, pyserial, and PyQt5. The live graph additionally needs pyqtgraph and numpy (the rest of the app runs without them).

pip install -r requirements.txt
# On Debian/Ubuntu you can use the system packages instead:
sudo apt install python3-pyqt5 python3-pyqtgraph python3-numpy python3-serial

On Linux your user needs access to the serial port. If you get a permission error on /dev/ttyUSB0, add yourself to the dialout group:

sudo usermod -aG dialout "$USER"   # then log out and back in

Desktop integration (optional)

Add a menu entry and icon for KDE / GNOME (or any freedesktop desktop). This is a user-level install — no root needed:

./install.sh      # adds the launcher + icon; re-run to update
./uninstall.sh    # removes them

LabSupplyControl then appears in your application launcher with its icon, and the correct icon shows in the Wayland/X11 taskbar. (This only sets up the launcher; install the Python dependencies above separately.)

Usage

python3 app.py                               # defaults: 30 V / 5 A limits
python3 app.py --max-voltage 60 --max-current 5

Plug in the supply and pick its port (a USB-serial adapter shows up as /dev/ttyUSB0, /dev/ttyACM0, or COMx on Windows). If only one device is found, LabSupplyControl connects automatically. The controls are split into three tabs — Power supply, Charger, and Sequence — with the connection, live readout, and graph shared across all of them.

diagnose.py is a standalone script that sends the ASCII read commands and prints the raw replies — handy for confirming the link outside the GUI.

Safety

Battery charging drives real current into a cell — treat it with respect:

• This is not a substitute for a proper charger. There is no cell balancing and no temperature sensing.
• Multi-cell lithium packs require a BMS / balance board. Li-ion/LiFePO4 default to 1 cell and warn before you select more.
• Always supervise charging. Use the over-current trip as a backstop.

LabSupplyControl refuses a pack whose target voltage/current exceeds the supply's limits and asks for confirmation before starting a charge.

Protocol

9600 baud, 8 data bits, no parity, 1 stop bit. Each frame is fixed length:

< CC DDDDDD AAA >
  │  │      └── 3-digit device address (send 000; the device echoes its own)
  │  └───────── 6-digit value = volts/amps × 1000, zero-padded
  └──────────── 2-char command code

Action	PC sends	Device replies
Connect / enter remote	<09100000000>	<19OK0000AAA>
Disconnect / local	<09200000000>	—
Set voltage 4.58 V	<01004580000>	<11OK0000AAA>
Set current 6.92 A	<03006920000>	<13OK0000AAA>
Read voltage	<02000000000>	<12VVVVVVAAA> → V = VVVVVV/1000
Read current	<04000000000>	<14AAAAAAAAA> (CV) / <C4AAAAAAAAA> (CC)
Output ON	<07000000000>	—
Output OFF	<08000000000>	—

No checksum. Confirmed against the PowerLinkESP firmware and the vendor's Serial-port-communication-protocol VER 02 document.

Project layout

Path	Purpose
app.py	PyQt5 control panel
kuaiqu/protocol.py	ASCII frame builders and reply parsers
kuaiqu/psu.py	KuaiquPSU driver + serial-port discovery
charging.py	Battery chemistry profiles + CC-CV charge state machine
sequence.py	CSV timed-sequence parser
diagnose.py	Standalone serial-reply diagnostic
test_protocol.py	Unit tests (no hardware needed)
example-sequence.csv	Example timed sequence
install.sh / uninstall.sh	Desktop-integration installer (KDE/GNOME)
assets/	Logo, icon, and screenshot

Development

Everything hardware-independent is unit-tested (framing, parsing, charge state machine, sequence parsing):

python3 test_protocol.py

Contributions welcome — please keep changes focused, match the existing style, and make sure the tests pass.

Acknowledgements

• PowerLinkESP by dobrishinov — a working ESP8266 implementation that confirmed the serial protocol.

License

MIT © Jarl Gjessing

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_{Keywords: KUAIQU / Nice-Power bench power supply PC control software · SPS-D305-232 · SPPS-D305-232 · SPS-W3010 · SPS-3010 · programmable DC power supply · USB / RS-232 serial control · remote control · data logging · battery charger (lead-acid, Li-ion, LiFePO4) · CC-CV · CP2102 · Linux · PyQt5. These supplies use a plain ASCII serial protocol — not Modbus.}