"""Fluke 8845A DMM driver: the Agilent 34401A driver, run against the 8845A's 34401A-compatible command set."""
from __future__ import annotations
from instro.dmm.drivers import Agilent34401A
from instro.lib.transports.visa import VisaConfig
[docs]
class Fluke8845A(Agilent34401A):
"""Fluke 8845A 6.5-digit DMM, driven through its Agilent 34401A-compatible ``8845`` command set.
The meter's default remote command set (``8845``) is compatible with the Agilent 34401A, so
every command comes from `Agilent34401A` and this class adds none. Two front-panel settings
must be made before use; neither can be changed over the remote interface, and both are
non-volatile:
* **Command set** ``8845`` (INSTR SETUP → COMMANDS → 8845). The Fluke 45 emulation command set
is not supported.
* **RS-232 mode** ``COMPUTER`` (INSTR SETUP → PORT IF → RS232 → COMP/TERM ECHO → COMPUTER).
``TERMINAL`` mode echoes each command and prints a ``NNN>`` prompt, which the driver reads
back as the reply; ``open`` then fails with an error such as
``Fluke 8845A reported error: *CLS``.
Over RS-232, also match the meter's line settings to the ``VisaConfig`` defaults: 9600 baud,
8 data bits, no parity, 1 stop bit, no flow control, and EOL ``CR LF``.
"""
def __init__(self, visa_resource: str | VisaConfig) -> None:
"""Create the driver; the connection opens on ``open``.
Args:
visa_resource (str | VisaConfig): VISA resource string, e.g. ``"ASRL6::INSTR"`` for
RS-232 on COM6, or a `VisaConfig` to customize the serial line or backend.
Example::
from instro.dmm import InstroDMM, MeasurementFunction
from instro.unstable.dmm.drivers import Fluke8845A
dmm = InstroDMM(name="fluke", driver=Fluke8845A("ASRL6::INSTR"))
dmm.open()
dmm.set_measurement_function(MeasurementFunction.DC_VOLTAGE)
volts = dmm.read().latest
dmm.close()
"""
super().__init__(visa_resource)
def _check_errors(self) -> None:
err = self._visa.query("SYST:ERR?")
parts = err.strip().split(",", 1)
code_str = parts[0] if parts else ""
code_val = int(code_str) if code_str.lstrip("-+").isdigit() else -1
if code_val != 0:
raise RuntimeError(f"Fluke 8845A reported error: {err.strip()}")
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