Hewlett-Packard 3458A

Hewlett-Packard

3458A

8.5-digit high-performance digital multimeter

multimeter Proprietary

eBay listing photo

Default Address 22

Termination LF

IEEE 488.2 Yes

IDN Patterns

HEWLETT-PACKARD,3458A,*,*AGILENT TECHNOLOGIES,3458A,*,*

Documentation

• 9018-01360.pdf (original)

The 3458A is widely regarded as the highest-performance bench multimeter ever produced. First introduced in 1989, it remains in production. It does NOT use SCPI — all commands (except IEEE 488.2 common commands) use HP-proprietary short mnemonics. The command parser accepts abbreviated forms (e.g., DCV, OHM, NPLC) rather than SCPI tree-structured syntax. Two ADCs are available: an integrating multi-slope ADC (for high-resolution measurements up to 8.5 digits) and a fast sigma-delta ADC (for digitizing up to 100 kSa/s). Auto-calibration uses built-in 7V and 10k ohm references.

Status Byte

Bit 7	Bit 6	Bit 5	Bit 4	Bit 3	Bit 2	Bit 1	Bit 0
Power On	RQS	ESB	MAV	Auxiliary Error	Error	Unused	Data Ready
Power-on SRQ occurred	Requesting service	Event status byte summary bit	Message available in output buffer	Auxiliary error (calibration, self-test, memory)	Syntax error or hardware error detected	Not used	A reading is available in output buffer

Use *STB? or serial poll to read. The 3458A data-ready bit (0) is critical for high-speed reading workflows. Use *SRE to configure which bits generate SRQ.

Commands

IEEE 488.2 Common Commands

Standard IEEE 488.2 commands — the only SCPI-like syntax this instrument uses

Command	Type	Description
*IDN?	query	Identification query — returns manufacturer, model, serial, firmware
Details Returns (string) — Comma-separated identification Example: HEWLETT-PACKARD,3458A,0,8+9
*RST	command	Reset to power-on state (same as RESET)
*CLS	command	Clear status registers and error queue
*ESE {mask}	command	Set event status enable register
Details Parameters mask (numeric) — Bitmask 0-255
*ESE?	query	Query event status enable register
Details Returns (numeric) Example: 0
*ESR?	query	Read and clear event status register
Details Returns (numeric) Example: 0
*OPC	command	Set operation complete bit in ESR when all pending operations finish
*OPC?	query	Returns 1 when all pending operations complete
Details Returns (numeric) Example: 1
*SRE {mask}	command	Set service request enable register
Details Parameters mask (numeric) — Bitmask 0-255
*SRE?	query	Query service request enable register
Details Returns (numeric) Example: 0
*STB?	query	Read status byte register
Details Returns (numeric) — Status byte value Example: 0
*TST?	query	Self-test; returns 0 for pass, nonzero for failure code
Details Returns (numeric) Example: 0 Note: Takes several seconds to complete. Resets instrument state.
*TRG	command	IEEE 488.2 group execute trigger (same as GET)

Function Selection

Select the measurement function. These are short mnemonics, not SCPI. Each command optionally accepts a range parameter.

Command	Type	Description
DCV [{range}]	command	Select DC voltage function
Details Parameters range (numeric, optional) — Range in volts: 0.1, 1, 10, 100, 1000 or AUTO Default: AUTO Example DCV 10
ACV [{range}]	command	Select AC voltage function (RMS, AC-coupled)
Details Parameters range (numeric, optional) — Range in volts: 0.01, 0.1, 1, 10, 100, 700 or AUTO Default: AUTO Example ACV 10
ACDCV [{range}]	command	Select AC+DC voltage function (true RMS, DC-coupled)
Details Parameters range (numeric, optional) — Range in volts or AUTO Default: AUTO Example ACDCV 10
OHM [{range}]	command	Select 2-wire resistance function
Details Parameters range (numeric, optional) — Range in ohms: 10, 100, 1E3, 10E3, 100E3, 1E6, 10E6, 100E6, 1E9 or AUTO Default: AUTO Example OHM 1E3
OHMF [{range}]	command	Select 4-wire resistance function
Details Parameters range (numeric, optional) — Range in ohms or AUTO Default: AUTO Example OHMF 1E3
DCI [{range}]	command	Select DC current function
Details Parameters range (numeric, optional) — Range in amps: 100E-9 to 1 or AUTO Default: AUTO Example DCI 0.1
ACI [{range}]	command	Select AC current function (RMS, AC-coupled)
Details Parameters range (numeric, optional) — Range in amps or AUTO Default: AUTO Example ACI 0.1
ACDCI [{range}]	command	Select AC+DC current function (true RMS, DC-coupled)
Details Parameters range (numeric, optional) — Range in amps or AUTO Default: AUTO Example ACDCI 0.1
FREQ [{range}]	command	Select frequency measurement function
Details Parameters range (numeric, optional) — Expected input voltage amplitude for gate sensitivity Default: AUTO Example FREQ
PER [{range}]	command	Select period measurement function
Details Parameters range (numeric, optional) — Expected input voltage amplitude for gate sensitivity Default: AUTO Example PER

Digitizing Functions

Direct-sampling and sub-sampling digitizing modes. These select the function and prepare the 3458A as a high-speed digitizer.

Command	Type	Description
DSDC [{range}]	command	Direct-sampling DC-coupled digitizing — up to 100,000 readings/sec
Details Parameters range (numeric, optional) — Range in volts: 0.1, 1, 10, 100, 1000 or AUTO Default: AUTO Example DSDC 10
DSAC [{range}]	command	Direct-sampling AC-coupled digitizing — up to 100,000 readings/sec
Details Parameters range (numeric, optional) — Range in volts or AUTO Default: AUTO Example DSAC 10
SSDC [{range}]	command	Sub-sampling DC-coupled digitizing — equivalent-time sampling up to 20 MHz bandwidth
Details Parameters range (numeric, optional) — Range in volts or AUTO Default: AUTO Example SSDC 10
SSAC [{range}]	command	Sub-sampling AC-coupled digitizing — equivalent-time sampling up to 20 MHz bandwidth
Details Parameters range (numeric, optional) — Range in volts or AUTO Default: AUTO Example SSAC 10
SWEEP {interval},{count}	command	Configure digitizing sweep — sets sample interval and number of samples
Details Parameters interval (numeric) — Sample interval in seconds (minimum 10E-6 for direct-sampling) count (numeric) — Number of samples to capture Example SWEEP 10E-6,1000 Note: Equivalent to setting TIMER and NRDGS together. Overrides TIMER and NRDGS settings.
ISCALE {state}	command	Enable/disable input scaling for digitizing — applies gain and offset correction
Details Parameters state (enum) Values: ON, OFF

Range and Resolution

Configure measurement range, resolution, integration time, and autozero. These work with the currently selected function.

Command	Type	Description
RANGE {value}	command	Set measurement range for current function
Details Parameters value (numeric) — Range value in function units, or AUTO for autorange Example RANGE 10
RANGE?	query	Query current range setting
Details Returns (numeric) Example: +1.00000000E+01
ARANGE {state}	command	Enable or disable autoranging
Details Parameters state (enum) Values: ON, OFF Example ARANGE ON
ARANGE?	query	Query autorange state
Details Returns (string) Example: 1
NPLC {value}	command	Set integration time in power line cycles — primary resolution control
Details Parameters value (numeric) — 0 to 1000. Key values: 0 (DSDC/SSDC modes), 1 (5.5 digits), 10 (6.5 digits), 100 (7.5 digits), 1000 (8+ digits) Example NPLC 100 Note: NPLC 100 at 60Hz = 1.67 sec integration. Higher NPLC improves noise rejection but slows measurement. NPLC 0 selects the fast ADC (digitizing modes).
NPLC?	query	Query current NPLC setting
Details Returns (numeric) Example: +1.00000000E+02
APER {seconds}	command	Set integration aperture time directly in seconds
Details Parameters seconds (numeric) — Aperture time in seconds — 500E-9 to 1.0 Example APER 0.1 Note: Overrides NPLC. Provides exact integration time independent of line frequency.
APER?	query	Query current aperture time
Details Returns (numeric) Example: +1.00000000E-01
NDIG {digits}	command	Set display resolution in number of digits — controls NPLC indirectly
Details Parameters digits (numeric) — 3 to 9 (integer) Example NDIG 8 Note: Sets NPLC to achieve the requested number of digits. NDIG 4=NPLC 0.02, NDIG 6=NPLC 10, NDIG 8=NPLC 512 approx.
NDIG?	query	Query current digit resolution setting
Details Returns (numeric) Example: 8
AZERO {state}	command	Enable/disable autozero — reduces thermal drift but halves measurement speed
Details Parameters state (enum) Values: ON, OFF, ONCE Note: ONCE performs a single autozero then disables. OFF doubles reading rate. ON is the default.
AZERO?	query	Query autozero state
Details Returns (string) Example: 1
LFILTER {state}	command	Enable/disable analog low-pass filter (for AC rejection in DC measurements)
Details Parameters state (enum) Values: ON, OFF
LFILTER?	query	Query analog filter state
Details Returns (string) Example: 0
FIXEDZ {state}	command	Enable fixed input impedance (10M ohm on all DCV ranges). When OFF, low ranges use >10G ohm input.
Details Parameters state (enum) Values: ON, OFF Note: ON forces 10M input on all ranges. OFF (default) uses high-impedance input on 100mV and 1V ranges.
FIXEDZ?	query	Query fixed input impedance state
Details Returns (string) Example: 0

Trigger System

Three-level trigger model: trigger arm (TARM) -> trigger (TRIG) -> sample. Each level has its own event source.

Command	Type	Description
TARM {event}	command	Set trigger arm event — the first level of the trigger model
Details Parameters event (enum) — AUTO=continuous, HOLD=wait for TARM SGL, SGL=one arm cycle then hold, SYN=synchronous with controller, EXT=external TTL trigger Values: AUTO, HOLD, SGL, SYN, EXT Example TARM SGL
TARM?	query	Query trigger arm event source
Details Returns (string) Example: 1
TRIG {event}	command	Set trigger event — the second level of the trigger model
Details Parameters event (enum) — AUTO=immediate after arm, SGL=single trigger then hold, HOLD=wait for TRIG SGL, EXT=external input, LEVEL=analog level trigger, LINE=power line sync Values: AUTO, SGL, HOLD, EXT, LEVEL, LINE Example TRIG AUTO
TRIG?	query	Query trigger event source
Details Returns (string) Example: 1
NRDGS {count},{event}	command	Set number of readings per trigger and the sample event
Details Parameters count (numeric) — Number of readings (1 to 16,777,215) event (enum) — Event between samples: AUTO=immediate, EXT=external, TIMER=use TIMER interval, LEVEL=analog level, LINE=line sync Values: AUTO, EXT, TIMER, LEVEL, LINE Example NRDGS 100,TIMER
NRDGS?	query	Query number of readings setting
Details Returns (string) Example: 1,1
TIMER {seconds}	command	Set timer interval between readings when NRDGS uses TIMER event
Details Parameters seconds (numeric) — Interval in seconds (10E-6 to 100000) Example TIMER 0.001
TIMER?	query	Query timer interval
Details Returns (numeric) Example: +1.00000000E-03
DELAY {seconds}	command	Set delay between trigger event and first reading
Details Parameters seconds (numeric) — Delay in seconds (-1 for auto, 0 to 100000) Example DELAY 0.01 Note: DELAY -1 selects automatic delay (recommended for autorange). DELAY 0 for fastest response.
DELAY?	query	Query trigger delay
Details Returns (numeric) Example: +0.00000000E+00
LEVEL {voltage},{slope}	command	Set analog level trigger parameters (used when TRIG LEVEL or NRDGS event LEVEL)
Details Parameters voltage (numeric) — Trigger level in volts slope (enum) — Trigger on positive or negative slope Values: POS, NEG Example LEVEL 0.5,POS

Math Operations

Built-in math processing on readings. Multiple math operations can be chained.

Command	Type	Description
MATH {operation}	command	Enable a math operation on readings
Details Parameters operation (enum) — NULL=offset subtraction, SCALE=gain+offset, PERC=percentage deviation, FILTER=digital averaging, STAT=statistics accumulation, OFF=disable all math Values: NULL, SCALE, PERC, FILTER, STAT, OFF Example MATH STAT
MATH?	query	Query active math operations
Details Returns (string) Example: 0
MMATH {operation}	command	Enable multiple math operations simultaneously (additive to current state)
Details Parameters operation (enum) — Operation to add to active math chain Values: NULL, SCALE, PERC, FILTER, STAT, OFF Example MMATH FILTER
NULL [{value}]	command	Store null (offset) value — if no parameter, uses the last reading
Details Parameters value (numeric, optional) — Offset value in current function units Example NULL Note: Automatically enables MATH NULL. Send with no parameter to null the current reading.
NULL?	query	Query stored null value
Details Returns (numeric) Example: +0.00000000E+00
SCALE {gain},{offset}	command	Set scale factors — result = (reading * gain) + offset
Details Parameters gain (numeric) — Multiplicative gain factor offset (numeric) — Additive offset Example SCALE 1000,0
SCALE?	query	Query scale factors
Details Returns (string) Example: +1.00000000E+03,+0.00000000E+00
PERC {reference}	command	Set percentage reference value — result = ((reading - ref) / ref) * 100
Details Parameters reference (numeric) — Reference value for percentage calculation Example PERC 10.0
PERC?	query	Query percentage reference value
Details Returns (numeric) Example: +1.00000000E+01
SMATH?	query	Query statistics — returns count, mean, variance, and standard deviation
Details Returns (string) — Count, mean, variance, standard deviation Example: 100,+1.23456789E+00,+1.23456789E-12,+1.11111111E-06 Note: Only valid when MATH STAT or MMATH STAT is active.
RMATH	command	Reset statistics accumulators to zero

Memory and Output

Reading memory buffer and output format control. The 3458A can store up to ~16,000 readings in internal memory.

Command	Type	Description
MEM {mode}	command	Set memory mode for reading storage
Details Parameters mode (enum) — LIFO=last-in-first-out, FIFO=first-in-first-out, OFF=direct output (no buffering) Values: LIFO, FIFO, OFF Example MEM FIFO Note: MEM FIFO is required for digitizing workflows. Readings are stored in memory and retrieved with RMEM.
MEM?	query	Query memory mode
Details Returns (string) Example: 2
RMEM {start},{count}	command	Recall readings from memory buffer
Details Parameters start (numeric) — Starting reading number (1-based) count (numeric) — Number of readings to retrieve Example RMEM 1,1000 Note: Readings are returned in the current OFORMAT. Use after capture with MEM FIFO.
MCOUNT?	query	Query number of readings stored in memory
Details Returns (numeric) Example: 1000
MSIZE?	query	Query memory size (maximum number of readings that can be stored)
Details Returns (numeric) Example: 16384
OFORMAT {format}	command	Set output format for readings
Details Parameters format (enum) — ASCII=human-readable text, SINT=16-bit integer, DINT=32-bit integer, SREAL=IEEE 754 single, DREAL=IEEE 754 double Values: ASCII, SINT, DINT, SREAL, DREAL Example OFORMAT ASCII Note: Binary formats (SINT, DINT, SREAL, DREAL) are much faster for bulk transfer but require binary parsing on the controller.
OFORMAT?	query	Query output format
Details Returns (string) Example: 1
END {mode}	command	Control when EOI is asserted on output
Details Parameters mode (enum) — ON=EOI with last byte of response, OFF=never assert EOI, ALWAYS=EOI on every response byte Values: ON, OFF, ALWAYS Example END ON
END?	query	Query EOI mode
Details Returns (string) Example: 1

Status and Error

Status register, error reporting, and service request configuration. The 3458A uses a proprietary status model alongside IEEE 488.2 registers.

Command	Type	Description
STB?	query	Read status byte (same as serial poll but does not clear RQS)
Details Returns (numeric) — Status byte value 0-255 Example: 0
ERR?	query	Read and clear the error register
Details Returns (numeric) — Error code — 0 means no error Example: 0 Note: Nonzero indicates an error condition. See manual for error code definitions.
AUXERR?	query	Read auxiliary error register (provides detail on calibration and hardware errors)
Details Returns (numeric) Example: 0
ERRSTR?	query	Read error string for the most recent error
Details Returns (string) Example: 0,NO ERROR

System and Display

System control, display, identification, and housekeeping commands

Command	Type	Description
PRESET	command	Set instrument to a known, fast-measurement state (different from *RST — PRESET selects DCV AUTO, NPLC 10, TARM AUTO, TRIG AUTO)
Details Note: PRESET is the preferred way to initialize the 3458A for measurement. Unlike *RST, PRESET selects reasonable defaults for remote operation.
RESET	command	Full reset to power-on defaults (equivalent to *RST)
INBUF {state}	command	Enable/disable input buffer — when ON, commands are queued and executed sequentially
Details Parameters state (enum) Values: ON, OFF Note: INBUF ON is recommended for GPIB operation. It allows the controller to send commands without waiting for each to complete.
INBUF?	query	Query input buffer state
Details Returns (string) Example: 1
ID?	query	Query instrument identification string (HP-proprietary, shorter than *IDN?)
Details Returns (string) Example: HP3458A
REV?	query	Query firmware revision numbers
Details Returns (string) — Main CPU and I/O processor revision Example: 8,9
OPT?	query	Query installed hardware options
Details Returns (string) Example: 0
LINE?	query	Query detected power line frequency
Details Returns (numeric) — Line frequency in Hz Example: +6.00000000E+01 Note: Returns 50 or 60. Affects NPLC timing. Measured at power-on.
TEMP?	query	Query internal temperature of the instrument
Details Returns (numeric) — Temperature in degrees Celsius Example: +3.50000000E+01
DISP {state}	command	Control front panel display
Details Parameters state (enum) — ON=enable display, OFF=disable (improves speed), CLR=clear custom message Values: ON, OFF, CLR Note: Disabling the display improves measurement throughput.
DISP {state},"{message}"	command	Display a custom message on the front panel
Details Parameters state (enum) Values: MSG message (string) — Message text (up to 16 characters) Example DISP MSG,"CALIBRATING"
BEEP	command	Sound the front panel beeper
LOCK {state}	command	Lock/unlock front panel controls
Details Parameters state (enum) Values: ON, OFF Note: LOCK ON prevents local operation from the front panel.
EMASK {mask}	command	Set error mask — controls which errors set the error bit in the status byte
Details Parameters mask (numeric) — Bitmask for error types
EMASK?	query	Query error mask
Details Returns (numeric) Example: 0

Calibration

Self-calibration commands. ACAL runs internal auto-calibration routines using built-in references. Full calibration (CAL) requires external standards.

Command	Type	Description
ACAL {type}	command	Run auto-calibration — uses internal DC and resistance references
Details Parameters type (enum) — DCV=DC voltage only, ALL=full auto-cal, AC=AC flatness, OHMS=resistance Values: DCV, ALL, AC, OHMS Example ACAL ALL Note: ACAL ALL takes several minutes. Allow 2-hour warm-up before running for best results. Disconnect all inputs first.
ACAL?	query	Query auto-calibration status
Details Returns (string) — Calibration state information
CAL {value}	command	Enter a calibration reference value during a full calibration sequence
Details Parameters value (numeric) — Known reference value for calibration step Note: Full calibration requires external standards and should only be performed by qualified metrology personnel.
CALNUM?	query	Query total number of calibrations performed on this unit
Details Returns (numeric) Example: 42

Subprogram and Macro

The 3458A supports stored subprograms (macros) in non-volatile memory that can execute command sequences.

Command	Type	Description
SUB {number}	command	Begin recording a subprogram
Details Parameters number (numeric) — Subprogram slot number (1 to 4) Example SUB 1
SUBEND	command	End recording a subprogram
CALL {number}	command	Execute a stored subprogram
Details Parameters number (numeric) — Subprogram slot number (1 to 4) Example CALL 1
DELSUB {number}	command	Delete a stored subprogram
Details Parameters number (numeric) — Subprogram slot number (1 to 4)

Common Workflows

High-Resolution DC Measurement

Take a single DC voltage measurement at maximum resolution (8.5 digits) with full noise rejection

1

Initialize to known state

PRESET

2

Select DC voltage function with 10V range

DCV 10

3

Set integration to 100 NPLC for ~7.5 digit resolution

NPLC 100

4

Enable autozero for best accuracy

AZERO ON

5

Set trigger to single measurement

TARM HOLD

6

Arm a single trigger cycle

TARM SGL

7

Read the measurement result

Manual step

Expected: +X.XXXXXXXXE+XX

Fast Digitizing

Capture 1000 DC-coupled samples at 100 kSa/s using the direct-sampling ADC

1

Initialize to known state

PRESET

2

Select direct-sampling DC mode, 10V range

DSDC 10

3

Configure sweep: 10us interval, 1000 samples

SWEEP 10E-6,1000

4

Enable FIFO memory for burst capture

MEM FIFO

5

Arm a single sweep

TARM SGL

6

Wait for sweep to complete (100ms for 1000 samples at 10us)

Manual step

Poll status byte bit 0 or use SRQ

7

Read all captured samples from memory

RMEM 1,1000

Continuous Readings with Statistics

Take continuous DC voltage readings and accumulate statistics (min, max, mean, std dev)

1

Initialize to known state

PRESET

2

Select DC voltage, autorange

DCV AUTO

3

Set moderate integration

NPLC 10

4

Enable statistics math

MATH STAT

5

Clear previous statistics

RMATH

6

Set continuous triggering

TARM AUTO

7

Let readings accumulate, then query statistics

SMATH?

Expected: count,mean,variance,std_dev

4-Wire Resistance with Null

Measure 4-wire resistance with lead compensation using null offset

1

Initialize to known state

PRESET

2

Select 4-wire resistance, autorange

OHMF AUTO

3

Set high resolution

NPLC 100

4

Enable autozero

AZERO ON

5

Short the test leads and take a reading

TARM SGL

Record this value as the lead resistance

6

Null the lead resistance (uses last reading)

NULL

7

Connect DUT and measure

TARM SGL

Expected: Compensated resistance value

AC Voltage Measurement

Measure AC voltage with appropriate settling time for accurate RMS

1

Initialize to known state

PRESET

2

Select AC voltage, 10V range

ACV 10

3

Set trigger delay for RMS settling

DELAY 1

4

Single trigger and read

TARM SGL

Expected: +X.XXXXXXXXE+XX

5

For signals below 100 Hz, increase delay

Manual step

Low-frequency AC requires longer settling. Use DELAY 3 for signals near 10 Hz.