"""Keysight 34461A Truevolt DMM driver (SCPI over LAN, USB, or GPIB)."""
from __future__ import annotations
from instro.dmm import DMMDriverBase
from instro.dmm.types import MeasurementFunction
from instro.lib.transports.visa import VisaConfig, VisaDriver
_FUNCTION_COMMANDS = {
MeasurementFunction.DC_VOLTAGE: "VOLT",
MeasurementFunction.AC_VOLTAGE: "VOLT:AC",
MeasurementFunction.DC_CURRENT: "CURR",
MeasurementFunction.AC_CURRENT: "CURR:AC",
MeasurementFunction.TWO_WIRE_RESISTANCE: "RES",
MeasurementFunction.FOUR_WIRE_RESISTANCE: "FRES",
}
[docs]
class Keysight34461A(DMMDriverBase):
"""Keysight 34461A Truevolt DMM."""
def __init__(self, visa_resource: str | VisaConfig) -> None:
self._visa = VisaDriver(visa_resource)
[docs]
def open(self) -> None:
"""Open transport and clear status/error queue. Truevolt has no ``SYST:REM``; remote is automatic."""
self._visa.open()
with self._visa.lock():
self._visa.write("*CLS")
self._check_errors()
[docs]
def close(self) -> None:
self._visa.close()
[docs]
def set_measurement_function(self, function: MeasurementFunction) -> None:
"""Select the function with ``FUNC``; per-function range/NPLC settings are retained across switches."""
self._write_checked(f'FUNC "{_FUNCTION_COMMANDS[function]}"')
[docs]
def set_digits(self, n: int) -> None:
"""Unsupported — Truevolt SCPI has no digits command; use ``set_aperture_nplc`` for resolution."""
raise NotImplementedError(
"Keysight 34461A does not support set_digits; use set_aperture_nplc(...) for resolution."
)
def _set_range(self, scpi_root: str, value: float | None) -> None:
with self._visa.lock():
if value is None:
self._visa.write(f"{scpi_root}:RANG:AUTO ON")
else:
self._visa.write(f"{scpi_root}:RANG {value:.6e}")
self._check_errors()
[docs]
def set_dc_voltage_range(self, value: float | None) -> None:
self._set_range("VOLT:DC", value)
[docs]
def set_ac_voltage_range(self, value: float | None) -> None:
self._set_range("VOLT:AC", value)
[docs]
def set_dc_current_range(self, value: float | None) -> None:
self._set_range("CURR:DC", value)
[docs]
def set_ac_current_range(self, value: float | None) -> None:
self._set_range("CURR:AC", value)
[docs]
def set_two_wire_resistance_range(self, value: float | None) -> None:
self._set_range("RES", value)
[docs]
def set_four_wire_resistance_range(self, value: float | None) -> None:
self._set_range("FRES", value)
def _set_nplc(self, scpi_root: str, nplc: float) -> None:
self._write_checked(f"{scpi_root}:NPLC {nplc:.4f}")
[docs]
def set_dc_voltage_nplc(self, nplc: float) -> None:
self._set_nplc("VOLT:DC", nplc)
[docs]
def set_dc_current_nplc(self, nplc: float) -> None:
self._set_nplc("CURR:DC", nplc)
[docs]
def set_two_wire_resistance_nplc(self, nplc: float) -> None:
self._set_nplc("RES", nplc)
[docs]
def set_four_wire_resistance_nplc(self, nplc: float) -> None:
self._set_nplc("FRES", nplc)
[docs]
def set_ac_voltage_nplc(self, nplc: float) -> None:
"""Unsupported — AC functions integrate via filter bandwidth (``VOLT:AC:BAND``), not NPLC."""
raise NotImplementedError("Keysight 34461A AC voltage has no NPLC; integration is set by filter bandwidth.")
[docs]
def set_ac_current_nplc(self, nplc: float) -> None:
"""Unsupported — AC functions integrate via filter bandwidth (``CURR:AC:BAND``), not NPLC."""
raise NotImplementedError("Keysight 34461A AC current has no NPLC; integration is set by filter bandwidth.")
def _measure(self, function: MeasurementFunction) -> float:
# FUNC + READ? instead of MEAS:...? — MEAS (like CONF) resets range/NPLC
# to defaults, discarding anything the set_* methods programmed.
with self._visa.lock():
self._visa.write(f'FUNC "{_FUNCTION_COMMANDS[function]}"')
value = self._visa.query("READ?")
self._check_errors()
return float(value)
[docs]
def measure_dc_voltage(self) -> float:
return self._measure(MeasurementFunction.DC_VOLTAGE)
[docs]
def measure_ac_voltage(self) -> float:
return self._measure(MeasurementFunction.AC_VOLTAGE)
[docs]
def measure_dc_current(self) -> float:
return self._measure(MeasurementFunction.DC_CURRENT)
[docs]
def measure_ac_current(self) -> float:
return self._measure(MeasurementFunction.AC_CURRENT)
[docs]
def measure_resistance(self) -> float:
return self._measure(MeasurementFunction.TWO_WIRE_RESISTANCE)
[docs]
def measure_four_wire_resistance(self) -> float:
return self._measure(MeasurementFunction.FOUR_WIRE_RESISTANCE)
def _write_checked(self, command: str) -> None:
with self._visa.lock():
self._visa.write(command)
self._check_errors()
def _check_errors(self) -> None:
err = self._visa.query("SYST:ERR?")
parts = err.strip().split(",", 1)
code_str = parts[0] if parts else ""
# No-error response is +0,"No error" (Truevolt Operating and Service Guide, SYSTem:ERRor?).
code_val = int(code_str) if code_str.lstrip("-+").isdigit() else -1
if code_val != 0:
raise RuntimeError(f"Keysight 34461A reported error: {err.strip()}")
instro