PalmSens Potentiostat

PalmSens Potentiostat — MCP Server

Let an AI agent run cyclic voltammetry, linear sweep voltammetry, differential pulse voltammetry and chronoamperometry on PalmSens potentiostats that speak MethodSCRIPT, and get back downsampled data, peak summaries and optional full-resolution CSV files.

Try it without hardware

uvx labmcp-palmsens --simulate --check

The simulator is an EmStat Pico with a 3 mm disk electrode in 1 mM of a reversible one-electron redox couple (E° = +0.20 V, like ferro/ferricyanide vs Ag/AgCl). It interprets the scripts the server sends and streams correctly encoded data packages, so you get a proper CV "duck", DPV peaks and Cottrell decays. Simulated time runs 10× faster than real time; change that with --option sim_speed=1 (real time) or =100.

Connect your instrument

1. Close PSTrace / MultiTrace. Only one program can hold the serial port.
2. Find the port: uvx labmcp ports. An EmStat Pico development board or Sensit shows up as a USB serial port (FTDI). An EmStat4 or Nexus shows up as a virtual COM port named after the device.
3. Test the connection:
   bash

   uvx labmcp-palmsens --address /dev/ttyUSB0 --check            # EmStat Pico / Sensit (Linux)uvx labmcp-palmsens --address /dev/tty.usbmodemXXXX --check   # EmStat4 (macOS)uvx labmcp-palmsens --address COM7 --check                    # Windows

   Defaults are the EmStat Pico's: 230400 baud, 8N1, XON/XOFF, LF line endings. Over USB the EmStat4 and Nexus ignore the baud rate. For an EmStat4 UART connection use serial://COM7?baudrate=921600&rtscts=true&xonxoff=false.
4. --check sends the firmware-version (t) and serial-number (i) commands and prints the model, firmware and serial.

Add to your MCP client

Claude Code

claude mcp add potentiostat -- uvx labmcp-palmsens --address /dev/ttyUSB0

Claude Desktop / Cursor / Windsurf (claude_desktop_config.json, .cursor/mcp.json, …)

{  "mcpServers": {    "potentiostat": {      "command": "uvx",      "args": ["labmcp-palmsens", "--address", "/dev/ttyUSB0"]    }  }}

Add --read-only to allow device information only: every measurement tool applies potential and is hidden.

Tools

Safety limits

Override at launch, e.g. --limit max_potential_v=1.0 --limit max_duration_s=1800. Whatever the limits say, a single tool call is capped at one hour.

Example prompts

• "Run a CV of my ferrocyanide sample from −0.2 V to +0.6 V and back at 50 mV/s, three cycles, and tell me E½ and the peak separation."
• "Do a scan-rate study: CVs at 25, 50, 100 and 200 mV/s between −0.1 and 0.5 V, save each as CSV, and check whether the peak current scales with √v."
• "Run DPV from 0 to 0.6 V with 50 mV pulses and report the peak potential and height."
• "Hold 0.5 V for 60 s, record the current every 0.2 s, and give me the total charge passed."
• "Which potential window and current ranges does this potentiostat support?"
• "Abort the measurement."

Notes

• What the server sends. Each technique is one MethodSCRIPT modelled on PalmSens' measurement-loop examples: set_pgstat_chan 0, set_pgstat_mode, set_max_bandwidth, set_range_minmax da, set_range ba, set_autoranging ba, set_e, cell_on, optional wait, then meas_loop_cv / lsv / dpv / ca with pck_add of the set potential and current, and on_finished: cell_off. So the cell is switched off after completion and after an abort. A runtime error skips on_finished: (MethodSCRIPT manual §10.1), so after one the server sends a separate cell_off script. The exact script is in get_command_log.
• PGStat mode and bandwidth. Max bandwidth is 6× the data rate (the ratio PalmSens' examples use). On the EmStat Pico and Sensit, the server picks low speed (−1.25 to 2.0 V, 2.2 V window, ≤ 100 Hz), then max range (−1.7 to 2.0 V, 2.6 V window), then high speed (1.214 V window) to fit your potentials. If none fits, it says why before anything is sent. EmStat4 and Nexus use low speed mode; per the manual, the modes do not differ on those instruments.
• Current sign and units. Anodic (oxidation) current is positive; potentials are the set potentials vs RE; time_s comes from the instrument timer for chronoamperometry and from step/scan rate for sweeps.
• Summaries. CV peaks are the raw maximum and minimum current of each scan (no baseline correction). ΔEp and the midpoint are estimates. Staircase sampling makes ΔEp somewhat larger than the ideal 59 mV at large steps.
• Raw scripts. run_methodscript checks literal potentials (and store_var literals) of set_e, set_range_minmax da and the CV/LSV/DPV/SWV/NPV/ACV/CA/PAD/EIS loops and meas_fast_cv/meas_fast_ca against max_potential_v (DPV pulse and 2x SWV amplitude included). Literal current ranges of set_range ba / set_autoranging ba are checked against max_current_range_a. Values computed inside the script are not checked. The script is aborted at timeout_s and a cell_off script is run.
• Abort. abort_measurement sends the communication-protocol Z command. A running technique returns the data measured so far with aborted: true. Afterwards (and when nothing was running) the server runs a one-line cell_off script, so the cell is also switched off after a raw script without on_finished:. If the output of a running script cannot be read (e.g. a USB glitch), the server aborts the script and switches the cell off before reporting the error; a single corrupted data line is skipped with a warning instead.
• Saving data. save_path must end in .csv; missing folders are created and an existing file is never overwritten (choose a new name). The path is checked before the measurement starts. Points with a nan value are left out (with a warning).
• Not covered: galvanostatic techniques, EIS, SWV/NPV/PAD, multiplexers, bipotentiostat mode, multi-channel MultiEmStat4 systems and the CRC16 protocol extension. Use run_methodscript for single-channel scripts beyond the built-in techniques.

Hardware verification