feat(driver): Keysight AC6800B Series Programmable AC Power Source

[abduznik]

Instrument

Keysight AC6800B Series Programmable AC Power Source (single-phase AC/DC output, up to 4 kVA).

Why

• New category: every PowerSupply driver in the codebase (TDK-Lambda Z+, BK Precision 9130B) is DC-only — setpoints are a single voltage/current pair with no concept of frequency, phase, or waveform. An AC source needs frequency programming, AC/DC/AC+DC output modes, crest-factor/inrush handling, and often arbitrary-waveform output — none of which fits the existing PowerSupply ABC cleanly.
• Zero AC-source coverage today despite AC sources being a standard fixture in EMC/product-safety and international line-voltage-compliance test labs (testing products against 100V/50Hz, 240V/60Hz, etc., and simulating brownouts/surges).
• LXI/LAN + USB, SCPI — fits the existing PyVISA driver shape directly.

Protocol

SCPI (IEEE 488.2) over LAN (LXI) or USB. Standard *IDN?/*RST/*OPC?; voltage/frequency/output-mode setpoints and measurement queries (MEAS:VOLT:AC?, MEAS:CURR:AC?, MEAS:POW:AC?). Synchronous scalar queries for basic operation; waveform/transient programming is more involved but optional.

Programming Manual

Keysight AC6800B Series Programming Guide (PDF) — verified reachable.

Scope

• New ACPowerSource base class (or extend PowerSupply with an AC-mode mixin if that proves cleaner during implementation): set/get AC voltage, set/get frequency, output mode (AC/DC/AC+DC), output on/off, measure voltage/current/power (AC true-RMS), OVP/OCP.
• KeysightAC6800B(RealDriver, ACPowerSource).
• Transient/waveform-step programming and simulated/ReplayDriver coverage as stretch scope.

Complexity

Medium — basic AC output control (voltage/frequency/on-off/measurement) is straightforward SCPI; transient and arbitrary-waveform programming (if implemented) adds real complexity and can be deferred to a follow-up.