JaredCabot/keysight-truevolt-dmm

Keysight Truevolt Series DMMs: 34460A / 34461A / 34465A / 34470A

The complete documented feature set, from the Keysight Truevolt Series Operating and Service Guide (document 34460-90901, English edition; "OSG p.NNN" are its printed page numbers). Everything here is from the guide unless marked [inferred]. For undocumented DIAGnostic/service commands, the AC-mode variant and firmware internals, see the separate 344xxA Firmware Supplement; this skill is the official feature set only.

Syntax conventions: {A|B} is a required choice, [X] an optional node or parameter, <x> a value you supply. SCPI keywords show the short form in capitals; the lower-case tail is optional (VOLTage accepts VOLT or VOLTAGE). MIN, MAX, DEF are accepted wherever a numeric <value> is, and a numeric query takes [{MIN|MAX|DEF}] to ask the limit instead of the current value. Boolean parameters accept {OFF|0|ON|1}; a query returns 0 or 1. Every set command shown has a matching query unless noted "(no query)".

Models, options and what differs

Model	Digits	Notes
34460A	6½	Basic DMM. LAN and the accessory kit are options. No 10 A terminals.
34461A	6½	34401A-replacement. LAN and accessory kit standard. 10 A terminals.
34465A	6½	Adds the 34465A/70A-only features below.
34470A	7½	Highest resolution; same feature set as the 34465A.

A large group of commands and parameters is 34465A/70A only: all APERture and APERture:ENABled nodes; CALCulate:SCALe GAIN/OFFSet/REFerence/UNIT and the PCT and SCALe (Mx-B) scale functions; CALCulate:SMOothing; SAMPle:SOURce / SAMPle:TIMer / SAMPle:COUNt:PRETrigger; TRIGger:LEVel and TRIGger:SOURce INTernal (level triggering, needs DIG); FORMat binary transfer and MMEMory:FORMat:READing; the secondary-measurement "CALCulate:DATA" and "PTPeak" choices; SYSTem:ACALibration and *CAL?; resistance/temperature OCOMpensated and POWer:LIMit; CURRent:SWITch:MODE; the thermocouple transducer; the DC-only 1 µA and 10 µA current ranges and the 1 GΩ resistance range; and the Data Log and Digitize acquisition modes. Sending one to a 34460A/61A returns -203,"Command protected; feature not available on this model". (Histogram, the dB and dBm scale functions, and the other secondary-measurement choices are available on all four models.)

Licensed options, read back with SYSTem:LICense:CATalog?:

• DIG - digitizing and advanced (level) triggering (34465A/70A). Now included with the latest firmware. Without DIG the fastest aperture is 200 µs and fastest NPLC 0.02; with DIG, 20 µs and NPLC down to 0.001.
• MEM - deep reading memory: 2,000,000 readings instead of 50,000 (34465A/70A).
• SEC - NISPOM file security.
• LAN, GPB - the LAN/LXI interface and the user-installable GPIB module.

Reading-memory depth (no MEM): 34460A 1,000; 34461A 10,000; 34465A/70A 50,000 (OSG p.355).

Connecting

Keysight VISA resource strings, one per interface (USB, LAN and the web are enabled by default; GPIB needs the module):

• USB (USB-TMC): USB0::<vid>::<pid>::<serial>::0::INSTR. The exact string is on [Shift] > [Help] > About or from any VISA browser.
• LAN VXI-11: TCPIP0::<ip>::inst0::INSTR
• LAN HiSLIP: TCPIP0::<ip>::hislip0::INSTR
• LAN raw socket: TCP to port 5025 (TCPIP0::<ip>::5025::SOCKET); end each command with \n.
• LAN Telnet: port 5024 (telnet <ip> 5024).
• GPIB: GPIB0::<addr>::INSTR; address set by SYSTem:COMMunicate:GPIB:ADDRess <n> (default 22).

Default LAN is DHCP + Auto-IP on; fallback address 169.254.x.x; host name K-<model>-nnnnn (last 5 serial digits). Interface and LAN-service changes take effect only after a power cycle (OSG p.473).

import pyvisa
rm = pyvisa.ResourceManager()
dmm = rm.open_resource("TCPIP0::192.168.1.50::inst0::INSTR")
dmm.timeout = 10000                      # ms; raise it for long NPLC or big SAMP:COUN
print(dmm.query("*IDN?"))                # Keysight Technologies,34465A,<serial>,<fw>
print(dmm.query("MEAS:VOLT:DC? 10,0.001"))

Raw socket without VISA:

import socket
s = socket.create_connection(("192.168.1.50", 5025), timeout=10)
s.sendall(b"MEAS:VOLT:DC? 10,0.001\n")
print(s.recv(256).decode().strip())

Enable or disable an interface: SYSTem:COMMunicate:ENABle {OFF|ON}, {GPIB|HISLip|USB|LAN|SOCKets|TELNet|VXI11|WEB|USBMtp|USBHost}.

The measurement model

Three layers, from least to most control:

1. MEASure:<fn>? - one-shot: presets the function, autoranges unless you give a range, triggers, returns the reading. Equivalent to CONFigure + READ? with defaults. Easiest, least flexible.
2. CONFigure:<fn> then READ? - configure the function, adjust it with [SENSe:] commands in between, then READ? to trigger and return. CONFigure does not arm the trigger (OSG p.197). CONFigure? returns the present function and its range/resolution as a quoted string.
3. CONFigure / [SENSe:] / TRIGger setup, then INITiate to arm, then FETCh? to retrieve. Use this for triggered bursts, data logging and digitizing.

Retrieval and control verbs:

• INITiate[:IMMediate] - arm: move the instrument from idle to wait-for-trigger. Clears previous readings from memory, then stores new ones as they are taken. Overlapped (returns immediately).
• READ? = INITiate + FETCh?.
• FETCh? - return all readings in memory without re-triggering or erasing them.
• R? [<max>] - return and erase the oldest readings (FIFO); use it to read during a long acquisition without overflowing memory.
• ABORt - stop a measurement in progress and return to trigger idle. Use it to break out of a wait-for-trigger or a long burst.
• Total readings per INITiate = TRIGger:COUNt x SAMPle:COUNt.

# Fast triggered burst of 100 readings, 10 V range, BUS-triggered
dmm.write("CONF:VOLT:DC 10,1e-5")
dmm.write("VOLT:DC:NPLC 1")
dmm.write("TRIG:SOUR BUS; :SAMP:COUN 100")
dmm.write("INIT")
dmm.write("*TRG")
dmm.query("*OPC?")                       # wait for the burst to finish
vals = dmm.query("FETC?").strip().split(",")

Measurement functions

Select with CONFigure:<fn> / MEASure:<fn>?, or [SENSe:]FUNCtion[:ON] "<function>". The 13 valid function strings: "VOLTage[:DC]", "VOLTage[:DC]:RATio", "VOLTage:AC", "CURRent[:DC]", "CURRent:AC", "RESistance" (2-wire), "FRESistance" (4-wire), "CAPacitance", "FREQuency", "PERiod", "TEMPerature", "CONTinuity", "DIODe". The query returns the short form, e.g. "CURR:AC". Each function keeps its own range, resolution and settings; switching back restores them. Changing function turns off all CALCulate math states.

Every measuring function except continuity and diode takes RANGe <v>, RANGe:AUTO {OFF|ON|ONCE}, RESolution <v>, NULL[:STATe], NULL:VALue, NULL:VALue:AUTO, and the integration controls below. Autorange goes up above 120 % of range and down below 10 %. Fixed-range overload shows "Overload" on the panel and returns 9.9E37 over remote.

DC voltage - VOLTage[:DC] and ratio VOLTage[:DC]:RATio

• Ranges 100 mV, 1 V, 10 V, 100 V, 1000 V (:RANGe {<v>|MIN|MAX|DEF}, default autorange; DC default range 1000 V with autorange on).
• VOLTage[:DC]:IMPedance:AUTO {OFF|ON} - OFF fixes 10 MΩ on all ranges; ON gives >10 GΩ ("Hi-Z") on 100 mV/1 V/10 V and 10 MΩ on 100 V/1000 V. CONFigure and MEASure? force it OFF. Default OFF.
• VOLTage[:DC]:ZERO:AUTO {OFF|ON|ONCE} - autozero, default ON.
• :RATio measures the HI-LO input against a DC reference on the Sense terminals; uses the DC settings; NULL is not available for ratio. Read the raw signal and reference with secondary "SENSe:DATA".

AC voltage - VOLTage:AC

• Ranges 100 mV, 1 V, 10 V, 100 V, 1000 V (:RANGe default 10 V; MAX is 1000 V, with a 750 VAC rms safety limit on the top range). True-RMS, AC-coupled.
• VOLTage:AC:BANDwidth {3|20|200} - AC filter in Hz: 3 (Slow), 20 (Medium, default), 200 (Fast). Set it to the lowest frequency present. The Truevolt RMS algorithm is not crest-factor sensitive, so no crest-factor derating is needed (OSG p.163). Per-reading settling: 3 Hz 2.5 s, 20 Hz 0.625 s, 200 Hz 0.025 s.

DC / AC current - CURRent[:DC] / CURRent:AC

• 3 A terminal ranges: 100 µA, 1 mA, 10 mA, 100 mA, 1 A, 3 A. The 34465A/70A add DC-only 1 µA and 10 µA ranges. (The 100 µA and 1 mA ranges exist on every model.)
• CURRent:{AC|DC}:TERMinals {3|10} - selects the 3 A or 10 A front terminals (34461A/65A/70A; the 34460A has no 10 A terminal). You cannot pick the 10 A range with :RANGe; use TERMinals 10 or CONF:CURR 10. 10 A is front terminals only.
• CURRent:SWITch:MODE {FAST|CONTinuous} (34465A/70A, 3 A terminals) - internal shunt-switching behaviour. CONTinuous (default) avoids a momentary open circuit but makes range changes up to 3x slower; FAST allows a brief open circuit.
• CURRent:AC:BANDwidth {3|20|200} like AC voltage; ACI settling 3 Hz 1.66 s, 20 Hz 0.25 s, 200 Hz 0.025 s. DC current has ZERO:AUTO.

2-wire / 4-wire resistance - RESistance / FRESistance

• Ranges 100 Ω, 1 kΩ, 10 kΩ, 100 kΩ, 1 MΩ, 10 MΩ, 100 MΩ (default 1 kΩ with autorange on). The 34465A/70A add 1 GΩ.
• OCOMpensated {OFF|ON} (34465A/70A) - offset compensation; two readings at different source currents cancel thermal EMF. Works on 100 Ω to 100 kΩ only; roughly doubles reading time.
• POWer:LIMit[:STATe] {OFF|ON} (34465A/70A) - low-power ohms, sources less current; effective on 100 Ω to 100 kΩ.
• RESistance:ZERO:AUTO {OFF|ON|ONCE} - 2-wire autozero (default ON). 4-wire is always offset-nulled, so FRESistance has no ZERO:AUTO. Use FRESistance to cancel lead resistance; RESistance:NULL nulls it for 2-wire.

Capacitance - CAPacitance

• Ranges 1 nF, 10 nF, 100 nF, 1 µF, 10 µF, 100 µF, default autorange. With autorange off, over-range does not report overload; overload happens when the measurement times out (too large), or if DC or a short is on the input.
• Flagged 34465A/70A-only in the guide's intro, but the capacitance command pages carry no model note; treat availability as model-dependent and check with SYSTem:LICense:CATalog?/-203 if unsure.

Frequency / period - FREQuency / PERiod

• Reciprocal counting on the voltage input, 3 Hz to 300 kHz. FREQ and PER share one set of APERture, RANGe:LOWer and VOLTage:RANGe values; NULL and SECondary are independent.
• {FREQuency|PERiod}:APERture {1e-3|10e-3|100e-3|1} - gate time 1 ms, 10 ms, 100 ms (default), 1 s; 1 ms is 34465A/70A only. Longer gate = finer resolution.
• :RANGe:LOWer {3|20|200} - the AC filter / lowest expected input frequency, default 20 Hz; the gate waits for it.
• :VOLTage:RANGe {<v>|MIN|MAX|DEF} sets the input voltage range (default 10 V), :VOLTage:RANGe:AUTO its autorange, :TIMeout:AUTO {OFF|ON} the gate timeout (OFF waits 1 s with no signal; ON scales with the filter and returns 0.0 on timeout; this is the one non-volatile SENSe setting).

Temperature - TEMPerature

• TRANsducer:TYPE {FRTD|RTD|FTHermistor|THERmistor|TCouple} - 4-wire RTD, 2-wire RTD, 4-wire thermistor, 2-wire thermistor, thermocouple (default FRTD; TCouple is 34465A/70A only).
• CONFigure:TEMPerature [{FRTD|RTD|FTHermistor|THERmistor|TCouple|DEF} [,{<type>|DEF} [,1,{<resolution>|MIN|MAX|DEF}]]]. <type> is the probe value (e.g. CONF:TEMP FRTD,85); the 1 placeholder is reserved.
• RTD: TRANsducer:{FRTD|RTD}:RESistance[:REFerence] <r0> sets R0 (default 100 Ω; range 80-120 Ω on the 34460A/61A, 49-2100 Ω on the 34465A/70A), plus OCOMpensated and POWer:LIMit (34465A/70A).
• Thermistor: the front panel supports 2.2 kΩ (44004), 5 kΩ (44007) and 10 kΩ (44006) probes (Steinhart-Hart), but the remote command TRANsducer:{FTHermistor|THERmistor}:TYPE accepts only 5000. Set other thermistor types from the front panel.
• Thermocouple (34465A/70A): TCouple:TYPE {E|J|K|N|R|T} (default J), TCouple:RJUNction:TYPE {INTernal|FIXed}, TCouple:RJUNction <temp> for a fixed reference (always °C, -20 to +80), TCouple:RJUNction:OFFSet:ADJust <temp> (-20 to +20), and TCouple:CHECk {OFF|ON} to flag a disconnected junction. SYSTem:TEMPerature? reads the internal reference temperature.
• UNIT:TEMPerature {C|F|K} sets the reported unit (default C).

Continuity / diode - CONTinuity / DIODe

• No range or resolution; CONFigure:CONTinuity, CONFigure:DIODe. Selectable through FUNCtion only (no [SENSe:] subtree).

Resolution, NPLC and aperture

You set any one of resolution, NPLC or aperture and the others follow (all on the DC functions, resistance and temperature; AC and frequency use the filter and gate instead).

• [SENSe:]<fn>:NPLC {<PLCs>|MIN|MAX|DEF} - integration in power-line cycles, default 10. Allowed sets:
  • 34460A/61A: 0.02, 0.2, 1, 10, 100
  • 34465A/70A without DIG: 0.02, 0.06, 0.2, 1, 10, 100
  • 34465A/70A with DIG: 0.001, 0.002, 0.006, 0.02, 0.06, 0.2, 1, 10, 100 Only 1, 10 and 100 PLC give power-line (normal-mode) noise rejection.
• [SENSe:]<fn>:APERture <seconds> (34465A/70A) sets integration time directly: 200 µs to 1 s, or 20 µs to 1 s with DIG, 2 µs resolution, default 100 ms. Sending APERture sets APERture:ENABled ON; sending NPLC or RESolution, or any CONFigure/MEASure?, sets it OFF. The last of NPLC/aperture sent wins.
• [SENSe:]<fn>:RESolution <v> is in measurement units (V, A, Ω), not digits; MIN is finest, MAX coarsest; the default maps to 10 PLC.
• The range-and-resolution tables (OSG p.450-453) map each range and NPLC to a resolution figure (e.g. 34461A, 10 V range, 10 NPLC gives 10 µV). Look exact figures up there rather than quoting from memory.

Triggering and reading acquisition

TRIGger:SOURce {IMMediate|EXTernal|BUS|INTernal}
TRIGger:COUNt {<count>|MIN|MAX|DEF|INFinity}      # trigger events to accept
TRIGger:DELay {<seconds>|MIN|MAX|DEF}             # delay trigger -> first sample
TRIGger:DELay:AUTO {OFF|ON}                       # settling-based auto delay
TRIGger:SLOPe {POSitive|NEGative}                 # external-trigger edge
TRIGger:LEVel {<level>|MIN|MAX|DEF}               # 34465A/70A + DIG: level trigger
SAMPle:COUNt {<count>|MIN|MAX|DEF}                # samples per trigger
SAMPle:SOURce {IMMediate|TIMer}                   # 34465A/70A
SAMPle:TIMer {<interval>|MIN|MAX|DEF}             # 34465A/70A: time between samples
SAMPle:COUNt:PRETrigger {<count>|MIN|MAX|DEF}     # 34465A/70A: pre-trigger samples

• IMMediate fires continuously; EXTernal uses the rear Ext Trig BNC (edge set by TRIGger:SLOPe); BUS waits for *TRG (or a GPIB GET); INTernal is level triggering (34465A/70A with the DIG option, with TRIGger:LEVel).
• Sending *TRG when the source is not BUS raises -221,"Settings conflict; *TRG when TRIG:SOUR BUS not selected".
• OUTPut:TRIGger:SLOPe {POSitive|NEGative} sets the VM Complete BNC output edge.
• Automatic trigger delays depend on function, range and filter (OSG p.454).

Acquisition modes

ABORt/INITiate/SAMPle/TRIGger are the Continuous-mode SCPI model. The front panel adds two modes on the 34465A/70A, driven from [Acquire], not from dedicated SCPI (OSG p.47):

• Continuous - default, free-running, the model above.
• Data Log - timed logging to memory or file, front panel only. Up to 1000 readings/s, 100 h, 360,000,000 readings to a file, or the memory depth (50,000, or 2,000,000 with MEM) to memory; trigger is auto or one [Single] only (no external or level). On entry it sets trigger source and delay to auto, pretrigger count 0, sample timer mode on with the chosen interval, and samples per trigger from the chosen duration.
• Digitize - fast fixed-rate sampling (34465A/70A with DIG), front panel only, on DCV or DCI with autorange and autozero off. Sample interval 20 µs (50 kSa/s) to 100 ms; trigger auto, external or level, with a pretrigger count up to total readings minus one. On entry it forces auto/external/level trigger, turns off limits and scaling, and post-processes statistics and histogram.
• Entering either mode also sets trigger count 1, turns off secondary measurements and smoothing, and clears statistics and the histogram. Reproduce the same captures over SCPI with SAMPle:SOURce TIMer + SAMPle:TIMer (timed log) or a short aperture and large SAMPle:COUNt (digitize), plus level triggering.

Reading memory and data format

READ?                      # trigger + return readings
FETCh?                     # return memory, no re-trigger
R? [<max>]                 # return + erase oldest (FIFO)
DATA:POINts?               # readings currently in memory
DATA:LAST?                 # most recent reading, with units
DATA:REMove? <n> [,WAIT]   # return + erase n oldest; WAIT blocks until n exist
DATA:POINts:EVENt:THReshold <count>   # memory-threshold event level (Operation bit 9)
FORMat[:DATA] {ASCii|REAL} [,<length>]   # 34465A/70A; REAL,64 is binary doubles
FORMat:BORDer {NORMal|SWAPped}           # byte order for REAL

For large or fast captures use FORMat REAL,64 and query_binary_values. ASCII (the default) is fine for modest counts.

Math (CALCulate)

Math runs on readings as they are taken. Enable a feature's [:STATe] and read its result. Some functions disallow a given math; the instrument replies -221,"Settings conflict; ... not allowed in current measurement function; ... OFF set" and disables it.

• Statistics - CALCulate:AVERage[:STATe] ON, then CALCulate:AVERage:{AVERage|MINimum|MAXimum|PTPeak|SDEViation|COUNt|ALL}?. ALL? returns average, sdev, min, max in one query. :CLEar resets.
• Limit testing - CALCulate:LIMit[:STATe] ON, CALCulate:LIMit:{LOWer|UPPer}[:DATA] <v>. A failed reading sets Questionable bit 11 (lower) or 12 (upper).
• Histogram (all models; the 34465A/70A add on-screen cursors) - CALCulate:TRANsform:HISTogram[:STATe] ON, :POINts <bins> (default 100), :RANGe:AUTO {OFF|ON}, :RANGe:{LOWer|UPPer} <v>; read :DATA?, :ALL?, :COUNt?; :CLEar resets.
• Scaling - CALCulate:SCALe[:STATe] ON, :FUNCtion {DB|DBM|PCT|SCALe}. DB and DBM work on all models (ACV/DCV only); they use :DB:REFerence / :DBM:REFerence (dBm reference resistance default 600 Ω), or :REFerence with :REFerence:AUTO. The PCT (percent) and SCALe (Mx-B) functions are 34465A/70A only: for SCALe, :GAIN <m> and :OFFSet <b> compute m*x+b, and :UNIT <str> / :UNIT:STATe label the result.
• Smoothing (34465A/70A) - CALCulate:SMOothing[:STATe] ON, :RESPonse {SLOW|MEDium|FAST} - a moving-average (boxcar) filter, SLOW over 100 readings, MEDium 50, FAST 10.
• Trend chart - CALCulate:TCHart[:STATe] {OFF|ON} (display feature).
• CALCulate:CLEar[:IMMediate] clears all math.

Secondary measurements

Show a second quantity derived from the primary with [SENSe:]<fn>:SECondary "<choice>" (a quoted string), read with [SENSe:]DATA2?, and clear or restart with [SENSe:]DATA2:CLEar. The feature exists on all models; the "CALCulate:DATA" (pre-math) and "PTPeak" (peak) choices are 34465A/70A only.

Primary function	Allowed secondary strings (default "OFF")
VOLTage[:DC]	"CALCulate:DATA", "VOLTage:AC", "PTPeak"
VOLTage:AC	"CALCulate:DATA", "FREQuency", "VOLTage[:DC]"
VOLTage[:DC]:RATio	"CALCulate:DATA", "SENSe:DATA"
CURRent[:DC]	"CALCulate:DATA", "CURRent:AC", "PTPeak"
CURRent:AC	"CALCulate:DATA", "FREQuency", "CURRent[:DC]"
FREQuency	"CALCulate:DATA", "PERiod", "VOLTage:AC"
PERiod	"CALCulate:DATA", "FREQuency", "VOLTage:AC"
RESistance/FRESistance	"CALCulate:DATA"
CAPacitance	"CALCulate:DATA"
TEMPerature	"CALCulate:DATA", "SENSe:DATA"

• "CALCulate:DATA" mirrors the reading before math (including NULL).
• "PTPeak" returns three values: min peak, max peak, peak-to-peak.
• "SENSe:DATA" returns the raw sensor value (ohms for RTD/thermistor; signal and reference volts for ratio; TC volts and reference temperature).
• The cross-function pairs (DCV<->ACV, DCI<->ACI) work from the front panel only and are ignored over remote; program the two functions separately instead. DATA2? returns 9.91E37 (NaN) when no valid secondary is selected.

Display, files and state

• DISPlay[:STATe] {OFF|ON} - turning the display off speeds up remote readings. DISPlay:VIEW {NUMeric|HISTogram|TCHart|METer}; DISPlay:TEXT[:DATA] "<s>" / DISPlay:TEXT:CLEar to post a message.
• HCOPy:SDUMp:DATA? grabs a screen image; HCOPy:SDUMp:DATA:FORMat {PNG|BMP}.
• State slots: *SAV {0|1|2|3|4} / *RCL {0|1|2|3|4} for the five slots. MMEMory:STORe:STATe <file> / MMEMory:LOAD:STATe <file> store named state files; MMEMory:STORe:PREFerences / LOAD:PREFerences the I/O and display preferences. Power-on recall: MMEMory:STATe:RECall:AUTO ON with MMEMory:STATe:RECall:SELect <file>; check a slot with MMEMory:STATe:VALid? <file>.
• Files: MMEMory:CATalog[:ALL]?, CDIRectory, MDIRectory, RDIRectory, COPY <a>,<b>, MOVE <a>,<b>, DELete. Transfer: MMEMory:UPLoad? <file> (read out) and MMEMory:DOWNload:FNAMe <file> + MMEMory:DOWNload:DATA <block> (write in). Store readings with MMEMory:STORe:DATA RDG_STORE, <file>; CSV layout with MMEMory:FORMat:READing:{CSEParator|INFormation|RLIMit} (34465A/70A).

System

• SYSTem:BEEPer[:IMMediate] (beep now) / :BEEPer:STATe, SYSTem:CLICk:STATe, SYSTem:DATE <y>,<m>,<d> / :TIME <h>,<m>,<s>, SYSTem:LABel "<s>" (banner), SYSTem:WMESsage "<s>" (power-on message), SYSTem:LFRequency?, SYSTem:TEMPerature?, SYSTem:UPTime?, SYSTem:VERSion?, SYSTem:HELP?, SYSTem:PRESet (front-panel Preset), SYSTem:LOCal (return to local), SYSTem:USB:HOST:ENABle {OFF|ON}.
• *TST? / TEST:ALL? run the full self-test (0 = pass; failures queue a +6xx error). *OPT? returns the installed options as a comma-separated string; SYSTem:LICense:CATalog? lists them by name. ROUTe:TERMinals? returns the Front/Rear input switch position (FRON or REAR; the 34460A always returns FRON), the only way to read it over remote.
• SYSTem:IDENtify {DEFault|AT34460A|AT34461A|AT34410A|AT34411A|HP34401A} makes *IDN? emulate another model's identity; the valid set depends on the model (34460A: AT34460A/HP34401A; 34461A: AT34461A/HP34401A; 34465A/70A: AT34410A/AT34411A).
• Interface lock for exclusive control: SYSTem:LOCK:REQuest? (returns 1 if granted), SYSTem:LOCK:RELease, SYSTem:LOCK:OWNer?, SYSTem:LOCK:NAME?. Holding a lock sets Operation bit 10.
• Licensing: SYSTem:LICense:CATalog? (installed options), :INSTall [{<folder>|<file>}], :INSTall? "<opt>", :DELete "<opt>", :DELete:ALL, :DESCription? "<opt>", :ERRor?, :ERRor:COUNt?.
• File security (SEC): SYSTem:SECurity:IMMediate sanitizes all user memory (NISPOM); SYSTem:SECurity:COUNt? returns the sanitize count.
• LAN config: SYSTem:COMMunicate:LAN: DHCP, IPADdress, SMASk, GATeway, DNS[1|2], HOSTname, DOMain?, MAC?, WINS[1|2], CONTrol?, TELNet:PROMpt, TELNet:WMESsage; queries take [{CURRent|STATic}]. Apply changes with SYSTem:COMMunicate:LAN:UPDate, then cycle power.
• LXI: LXI:IDENtify[:STATe] {OFF|ON} (flash the identify indicator), LXI:MDNS:ENABle, LXI:MDNS:HNAMe[:RESolved]?, LXI:MDNS:SNAMe:DESired "<n>" / SNAMe[:RESolved]?, LXI:RESet, LXI:RESTart.

Status system

Standard IEEE-488.2 model: a Questionable Data group, a Standard Operation group, the Standard Event register and the Status Byte. Each group has a condition register (:CONDition?, live, not latched), an event register ([:EVENt]?, latched, cleared on read) and an enable register (:ENABle <mask>). *CLS clears every event register and the error queue. The enable masks survive *RST, SYSTem:PRESet and *CLS; only STATus:PRESet clears the Operation and Questionable enable registers.

Questionable Data register bits (STATus:QUEStionable):

Bit	Dec	Meaning
0	1	Voltage overload (event only)
1	2	Current overload (event only)
2	4	Sample timing violation (SAMPle:TIMer; 34465A/70A)
4	16	Temperature overload (event only)
5	32	Frequency overload/underflow (event only)
8	256	Calibration data corrupt
9	512	Resistance overload (event only)
10	1024	Capacitance overload (event only)
11	2048	Lower limit failed
12	4096	Upper limit failed
14	16384	Reading memory overflow (oldest readings lost)

Overload bits latch once per INITiate; clearing one does not re-set it until the next INITiate.

Standard Operation register bits (STATus:OPERation):

Bit	Dec	Meaning
0	1	Calibrating
4	16	Measuring (initiated, taking or about to take a reading)
5	32	Waiting for trigger
8	256	Configuration changed since last INIT/READ?/MEASure?
9	512	Memory threshold reached (DATA:POINts:EVENt:THReshold)
10	1024	Instrument locked by a remote interface
13	8192	Global error (some interface has an error queued)

Standard Event register (*ESE / *ESR?): bit 0 Operation Complete, 2 Query error, 3 Device-specific error (any -300 or positive error), 4 Execution error (-200s), 5 Command error (-100s), 7 Power-on.

Status Byte (*STB? / *SRE): bit 2 Error queue, 3 Questionable summary, 4 Message available, 5 Standard Event summary, 6 Master summary (RQS), 7 Standard Operation summary.

*OPC / *OPC? / *WAI synchronize: *OPC? returns 1 when a pending overlapped operation (an INIT) finishes. *PSC {0|1} controls power-on status clearing.

dmm.write("INIT")
dmm.query("*OPC?")            # blocks until the acquisition completes
n = int(dmm.query("DATA:POIN?"))

Errors

SYSTem:ERRor[:NEXT]? pops the oldest error as <code>,"<text>"; +0,"No error" when empty. Up to 20 errors, FIFO, per I/O session plus a global hardware queue; *CLS and power cycle clear them, *RST and SYSTem:PRESet do not. The queue overflows to -350,"Queue overflow".

By range (OSG p.458-471): command errors -100s, execution -200s, device-specific -300s, query -400s, network +100s, instrument +200s, licensing +600s, self-test +611 to +666, calibration +701 onward. The ones worth recognising:

• -113,"Undefined header" - misspelled command.
• -221,"Settings conflict; ..." - the text after the semicolon says exactly what the instrument changed to resolve the conflict (e.g. ...TRIG:SOUR IMM set, ...SAMP:TIM changed, ...CALC:LIM:STAT OFF set). Read it.
• -222,"Data out of range" - optionally ; value clipped to lower/upper limit or ; value requires license DIG/MEM.
• -203,"Command protected; ..." - the feature needs an unsecured instrument (instrument must be unsecured), a license (requires license DIG/SEC/LAN, large memory requires license MEM), or a higher model (feature not available on this model).
• +6xx self-test failures name the failing subsystem (ADC, FPGA, references, autocal points); +7xx are calibration errors (secure code provided was invalid, calibration memory is secured).

def check_errors(dmm):
    errs = []
    while True:
        code, msg = dmm.query("SYST:ERR?").strip().split(",", 1)
        if int(code) == 0:
            return errs
        errs.append((int(code), msg.strip('"')))

Calibration (documented)

The guide documents the secured/unsecured workflow; the full adjustment procedure, with its reference standards, is OSG p.521-567.

*CAL?                                 # autocalibration (34465A/70A); 0 = pass
CALibration[:ALL]?                    # full calibration; 0 = pass
CALibration:ADC?                      # ADC cal; 0 = pass
CALibration:COUNt?                    # times calibrated (increments on STORe)
CALibration:DATE? / :TIME? / :TEMPerature?
CALibration:SECure:STATe {OFF|ON} [,<code>]   # unsecure with the code
CALibration:SECure:CODE <new_code>            # change the code (while unsecured)
CALibration:VALue <value>             # the known value of the applied standard
CALibration:STRing "<string>"         # free-text cal message
CALibration:STORe                     # commit cal constants to nonvolatile memory
SYSTem:ACALibration:DATE? / :TIME? / :TEMPerature?   # 34465A/70A autocal info

An adjustment is: unsecure (CALibration:SECure:STATe OFF,<code>), apply a standard, tell the instrument its value (CALibration:VALue), run the relevant CALibration...? step, repeat per point, then CALibration:STORe. Compare CALibration:COUNt? before and after to confirm the store. A lost security code is recovered with the guide's Security Code Override hardware-jumper procedure (OSG p.497), which this skill does not reproduce.

Reset / power-on defaults (the ones that bite)

After *RST or SYSTem:PRESet (OSG p.472): function DC volts, autorange, 10 NPLC (resolution to match, aperture off/100 ms), autozero on, AC filter 20 Hz (Medium), frequency gate 100 ms, temperature transducer FRTD (R0 100 Ω, TC type J, internal reference 0 °C), current terminals 3 A, current switch mode Continuous, all nulls off (reference 0, auto-reference on), secondary measurements off, math off (histogram 100 bins auto, statistics cleared), screen-shot format PNG, reading memory cleared. Nonvolatile (survive reset, bulleted in the guide): dBm reference resistance (600 Ω), beeper, thousands separator, stored states, calibration state (secured), and all I/O configuration. The error queue is cleared only at power-on, not by *RST.

Common recipes

# 1. Single reading
dmm.query("MEAS:VOLT:DC? 10,1e-5")

# 2. 4-wire resistance, offset compensated (34465A/70A), 10 NPLC
dmm.write("CONF:FRES 1e3")
dmm.write("FRES:OCOM ON; :FRES:NPLC 10")
print(dmm.query("READ?"))

# 3. Thermocouple type K, internal reference junction (34465A/70A)
dmm.write("CONF:TEMP TCouple,K")
dmm.write("TEMP:TRAN:TC:RJUN:TYPE INT; :UNIT:TEMP C")
print(dmm.query("READ?"))

# 4. 1000-point timed log at 10 ms spacing (34465A/70A), binary transfer
dmm.write("CONF:VOLT:DC 10")
dmm.write("VOLT:DC:NPLC 0.02")
dmm.write("SAMP:SOUR TIM; :SAMP:TIM 0.01; :SAMP:COUN 1000; :TRIG:SOUR IMM")
dmm.write("FORM:DATA REAL,64")
dmm.write("INIT"); dmm.query("*OPC?")
data = dmm.query_binary_values("FETC?", datatype='d')

# 5. Statistics over 100 readings
dmm.write("CONF:VOLT:DC 10")
dmm.write("CALC:AVER:STAT ON; :SAMP:COUN 100; :TRIG:SOUR IMM")
dmm.write("INIT"); dmm.query("*OPC?")
avg, sdev, mn, mx = dmm.query("CALC:AVER:ALL?").strip().split(",")

# 6. Limit test with status
dmm.write("CONF:VOLT:DC 10")
dmm.write("CALC:LIM:LOWer 4.9; :CALC:LIM:UPPer 5.1; :CALC:LIM:STAT ON")

# 7. DCV secondary = AC (program both functions; cross-function secondary is
#    front-panel only over remote). Here: read DCV, then ACV separately.
dmm.write("CONF:VOLT:DC 10"); dc = dmm.query("READ?")
dmm.write("CONF:VOLT:AC 10"); ac = dmm.query("READ?")

Front panel, Probe Hold and web interface

Most front-panel settings have a direct SCPI command; the Front Panel Menu Reference (OSG p.50) maps them. [Shift] is the gold/second key, and a label printed above a key is its shifted function ([Shift]+[DCV] = DCI, [Shift]+[Freq] = Capacitance, [Shift]+[Null] = Math, [Shift]+[Display] = Utility, [Shift]+[Run/Stop] = Reset). [Shift] > [Help] > About shows model, serial, firmware and options; the Help key shows the remote error queue; [Acquire] selects Continuous/Data Log/Digitize on the 34465A/70A. SYSTem:LOCal or the Local key returns to front-panel control.

• Probe Hold ([Shift]+[Single], OSG p.100) captures up to 8 stable readings automatically (a beep on each), useful when probing where you cannot watch the screen. Front panel only; the held list cannot be read over remote.
• Web interface: browse to the instrument's IP. It offers an HTML5 soft front panel and an Instrument IO page that sends SCPI, plus LAN configuration. The default password for control is Keysight; a LAN Reset ([Utility] > I/O Config > LAN Reset, or LXI:RESet) clears a changed password and re-enables mDNS. Monitoring from the web does not put the instrument in remote, so it is the safe way to watch a data-log or digitize run.
• Reading memory is cleared by: a function change, entering or leaving Probe Hold, a temperature-unit change, any dB/dBm parameter change, a histogram binning change, a probe or R0 change, a state recall, calibration, switching 3 A/10 A terminals, the Front/Rear switch, a remote-to-local transition, and turning null on or off. It is not cleared by a range, aperture, limit or display-mode change (OSG p.99).

Notes and limits

• This is the documented feature set of firmware A.03.03. Undocumented DIAGnostic/service commands, the AC-mode variant and firmware internals are in the 344xxA Firmware Supplement, kept separate on purpose.
• Exact resolution-vs-NPLC figures, accuracy and temperature coefficients are in the guide's tables (OSG p.450-453) and the datasheet; look them up rather than quoting from memory.
• Where the guide itself is inconsistent (capacitance model availability, the 5 kΩ-only thermistor type versus the prose, the capacitance NULL default), this skill flags it rather than inventing a resolution. Confirm on the instrument when it matters.