pfeiffer-turbo

Python interface for RS485 connections to Pfeiffer HiPace turbo drive units. Supports the TM700 and TC110 electronic drive units, and can also communicate through a TCP/IP socket, for example when using a serial-to-TCP/IP converter for the turbo controller.

Supported drive units

• TM700
• TC110

Examples

RS485 connection example

from pfeiffer_turbo import TC110, SerialTransport

pump = TC110(address=1, transport=SerialTransport(port="COM9"))
# or: pump = TC110.from_serial("COM9", address=1)

# get the rotation speed in Hz
pump.actual_spd

# start the pump
pump.start()

# stop the pump
pump.stop()

TCP/IP connection example

from pfeiffer_turbo import TM700, TcpTransport

pump = TM700(address=1, transport=TcpTransport(host="10.10.222.8", port=12345))
# or: pump = TM700.from_tcp("10.10.222.8", 12345, address=1)

# get the rotation speed in Hz
pump.actual_spd

# start the pump
pump.start()

# stop the pump
pump.stop()

query() accepts only the reply from the queried address for the queried parameter. A late reply to an earlier query (for example one still buffered in a serial-to-TCP gateway after a timeout), an echo of the request, or a garbled frame is discarded, and reading continues until the matching reply arrives or the transport timeout runs out. The timeout bounds the whole exchange, not each byte. A reply in which the drive unit rejects the request (NO_DEF, _RANGE, _LOGIC) raises PfeifferProtocolError.

Writable parameters and validation

Parameters marked read-write or write-only by the parameter metadata can be assigned. When assigning values, the library validates:

• type (bool/int/float/str as defined per parameter)
• allowed options (options map when present)
• value limits (min/max when present)

Write-only parameters raise AttributeError when read.

Example:

# writable
pump.set_rot_spd = 600
pump.error_ackn = True

# raises ValueError (invalid option)
# pump.gas_mode = 999

# raises AttributeError (write-only parameter)
# pump.error_ackn

Implementation

A baseclass DriveUnit:

class DriveUnit:
    def __init__(
        self,
        transport: BaseTransport,
        address: int,
        supported_parameters: Sequence[int],
    ):

takes a set of integers that correspond to Pfeiffer vacuum parameters supported by a particular drive unit. Implemented vacuum parameters are defined in parameters.py. Getters and setters are then generated dynamically from supported_parameters and the metadata in parameters.py.

The enum Parameters contains all implemented Pfeiffer vacuum parameters, and the dictionary parameters maps Parameters values to ParameterInfo objects, where ParameterInfo is a dataclass containing the implementation details for a particular parameter:

@dataclass
class ParameterInfo:
    designation: str
    data_type: DataType
    access: Access | str
    min: Optional[Union[int, float]] = None
    max: Optional[Union[int, float]] = None
    unit: Optional[str] = None
    default: Optional[Union[int, float, str]] = None
    options: Optional[dict[int, str]] = None

New drive units can be implemented by inheriting from DriveUnit and specifying which Pfeiffer parameters are supported by the model. New parameters can be implemented by extending the Parameters enum and the parameters dictionary. Generated class attributes are named similarly to the Pfeiffer parameter names, with underscores inserted between uppercase-to-lowercase transitions and all letters lowercased, for example GasMode becomes gas_mode.