Pfeiffer Vacuum Gauge Controller

Pfeiffer Vacuum Gauge Controller — MCP Server

Let an AI agent read and log chamber and foreline pressures, identify the connected gauges, change the pressure unit and switch ionisation gauges on and off (with a pressure check) on Pfeiffer Vacuum TPG total-pressure gauge controllers.

Try it without hardware

uvx labmcp-pfeiffer-tpg --simulate --check                      # TPG 362: FullRange gauge + Pirani

uvx labmcp-pfeiffer-tpg --simulate --option model=tpg366 --check # 6 channels incl. a cold cathode gauge

The simulated chamber pumps down from 8e-5 mbar towards 2e-7 mbar (10 min time constant) and the foreline sits at about 2.4e-2 mbar.

Connect your controller

1. Protocol (TPG 36x): the *PROTOCOL* parameter must be *AUTO* (factory setting) or *MNE* (mnemonics), not *PV* (Pfeiffer Vacuum telegram protocol).
2. USB (TPG 36x): the USB type B port appears as a virtual COM port. Factory setting 9600 baud, 8N1 (parameter *BAUD USB*; 19200-115200 also possible).
3. Ethernet (TPG 36x, TPG 366): set DHCP or a static IP (front panel or Pfeiffer's Ethernet Configuration Tool); the command port is fixed at 8000.
4. RS-232 (TPG 261/262): 9600 baud 8N1 by default, only TXD/RXD used.
5. Test the connection:

   uvx labmcp-pfeiffer-tpg --address /dev/ttyUSB0 --check

uvx labmcp-pfeiffer-tpg --address COM3 --check uvx labmcp-pfeiffer-tpg --address "serial://COM3?baudrate=115200" --check uvx labmcp-pfeiffer-tpg --address tcp://192.168.1.70:8000 --check

   The model is detected with `AYT` (TPG 36x); a controller that does not know `AYT` is treated as a TPG 26x. Use `--option model=tpg261` (or `tpg262`, `tpg361`, `tpg362`, `tpg366`) to be explicit.

Add to your MCP client

Claude Code

claude mcp add vacuum -- uvx labmcp-pfeiffer-tpg --address tcp://192.168.1.70:8000

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

{

"mcpServers": { "vacuum": { "command": "uvx", "args": ["labmcp-pfeiffer-tpg", "--address", "tcp://192.168.1.70:8000"] } } }

Add --read-only to allow reading and logging but block unit changes and switching gauges on (switch_gauge_off stays available). For other clients, generate the snippet with uvx labmcp config pfeiffer-tpg --address tcp://192.168.1.70:8000 --client vscode (also cursor, codex, claude-code).

Tools

get_connection_info, get_command_log and reconnect are built into every LabMCP server.

Safety limits

Override at launch: --limit max_switch_on_pressure_mbar=1e-3 --limit max_log_duration_s=7200. One log_pressure_series call logs at most 2 h (the tool's timeout); for a longer bake-out, log in consecutive calls to separate files. save_path must end in .csv and must not exist yet (an existing file is never overwritten); it is checked before logging starts.

Example prompts

• "What's the chamber pressure right now, and is the foreline below 5e-2 mbar?"
• "Log all gauges every 10 s for 30 minutes and tell me how many decades per minute the chamber is pumping down."
• "Close the valve, then log channel 1 every 2 s for 5 minutes so I can estimate the leak-up rate."
• "Which gauges are connected, and which ones are ionisation gauges that are switched off?"
• "The chamber is below 1e-5 mbar on the FullRange gauge - switch on the cold cathode gauge on channel 3, using channel 1 as the reference."

Notes

• Switching ionisation gauges on is the hazard. Hot-cathode (Bayard-Alpert) filaments can burn out and cold-cathode (Penning) gauges contaminate when operated at high pressure. set_gauge_power(on=True) requires a reading with status *ok* at or below max_switch_on_pressure_mbar from the gauge itself or from reference_channel on the same vacuum. An *underrange* reading from a Pirani is not accepted as proof (what the controller reports on underrange is not specified), so in a Pirani + Penning setup switch the Penning on at the controller, or use a FullRange gauge as the reference. The 1e-2 mbar default is the upper end of a typical cold cathode measuring range; check your gauge's manual and lower it for hot-filament gauges if recommended.
• Switching a gauge off (switch_gauge_off, or set_gauge_power(on=False)) can change setpoint (switching-function) relays assigned to that channel, which may be wired to valve or pump interlocks.
• Every pressure comes with the controller's status: *ok*, *underrange*, *overrange*, *sensor error*, *sensor off*, *no sensor* or *identification error*. pressure is only filled in when the status is *ok*; raw_value is what the controller sent. Values are converted to mbar (1 Torr = 1.333224 mbar); in *V* mode no conversion is made.
• Every command waits for ACK/NAK; after a NAK the ERROR word (controller error, no hardware, inadmissible parameter, syntax error) is read and reported. get_errors reads and clears it.
• Degas, filter, calibration factors, switching-function setpoints, gauge control (hot start/self control), the data logger and the Pfeiffer Vacuum (PV) telegram protocol are not exposed. RS-485 multi-drop operation has not been tested.

Hardware verification