HP 3478A Multimeter

class pymeasure.instruments.hp.HP3478A(adapter, name='Hewlett-Packard HP3478A', **kwargs)

Bases: HPLegacyInstrument

Represents the Hewlett Packard 3478A 5 1/2 digit multimeter and provides a high-level interface for interacting with the instrument.

class ERRORS(value, names=None, *, module=None, qualname=None, type=None, start=1, boundary=None)

Bases: IntFlag

Enum element for errror bit decoding

property SRQ_mask

Return current SRQ mask, this property can be set,

bit assigment for SRQ:

Bit (dec)

Description

1

SRQ when Data ready

4

SRQ when Syntax error

8

SRQ when internal error

16

front panel SQR button

32

SRQ by invalid calibration
property active_connectors

Return selected connectors (“front”/”back”), based on front-panel selector switch

property auto_range_enabled

Property describing the auto-ranging status

Value

Status

True

auto-range function activated

False

manual range selection / auto-range disabled

The range can be set with the range property

property auto_zero_enabled

Return auto-zero status, this property can be set

Value

Status

True

auto-zero active

False

auto-zero disabled
property calibration_data

Read or write the calibration data as an array of 256 values between 0 and 15.

The calibration data of an HP 3478A is stored in a 256x4 SRAM that is permanently powered by a 3v Lithium battery. When the battery runs out, the calibration data is lost, and recalibration is required.

When read, this property fetches and returns the calibration data so that it can be backed up.

When assigned a value, it similarly expects an array of 256 values between 0 and 15, and writes the values back to the instrument.

When writing, exceptions are raised for the following conditions:

  • The CAL ENABLE switch at the front of the instrument is not set to ON.

  • The array with values does not contain exactly 256 elements.

  • The array with values does not pass a verification check.

IMPORTANT: changing the calibration data results in permanent loss of the previous data. Use with care!

property calibration_enabled

Return calibration enable switch setting, based on front-panel selector switch

Value

Status

True

calbration possible

False

calibration locked
check_errors()

Method to read the error status register

Return error_status

one byte with the error status register content

Rtype error_status

int

display_reset()

Reset the display of the instrument.

property display_text

Displays up to 12 upper-case ASCII characters on the display.

property display_text_no_symbol

Displays up to 12 upper-case ASCII characters on the display and disables all symbols on the display.

property error_status

Checks the error status register

property measure_ACI

Returns the measured value for AC current as a float in A.

property measure_ACV

Returns the measured value for AC Voltage as a float in V.

property measure_DCI

Returns the measured value for DC current as a float in A.

property measure_DCV

Returns the measured value for DC Voltage as a float in V.

property measure_R2W

Returns the measured value for 2-wire resistance as a float in Ohm.

property measure_R4W

Returns the measured value for 4-wire resistance as a float in Ohm.

property measure_Rext

Returns the measured value for extended resistance mode (>30M, 2-wire) resistance as a float in Ohm.

property mode

Return current selected measurement mode, this propery can be set. Allowed values are

Mode

Function

ACI

AC current

ACV

AC voltage

DCI

DC current

DCV

DC voltage

R2W

2-wire resistance

R4W

4-wire resistance

Rext

extended resistance method (requires additional 10 M resistor)
property range

Returns the current measurement range, this property can be set.

Valid values are :

Mode

Range

ACI

0.3, 3, auto

ACV

0.3, 3, 30, 300, auto

DCI

0.3, 3, auto

DCV

0.03, 0.3, 3, 30, 300, auto

R2W

30, 300, 3000, 3E4, 3E5, 3E6, 3E7, auto

R4W

30, 300, 3000, 3E4, 3E5, 3E6, 3E7, auto

Rext

3E7, auto
property resolution

Returns current selected resolution, this property can be set.

Possible values are 3,4 or 5 (for 3 1/2, 4 1/2 or 5 1/2 digits of resolution)

status_desc

alias of Status

property trigger

Return current selected trigger mode, this property can be set

Possibe values are:

Value

Meaning

auto

automatic trigger (internal)

internal

automatic trigger (internal)

external

external trigger (connector on back or GET)

hold

holds the measurement

fast

fast trigger for AC measurements
verify_calibration_data(cal_data)

Verify the checksums of all calibration entries.

Expects an array of 256 values with calibration data.

Return calibration_correct

True when all checksums are correct.

Rtype calibration_correct

boolean

verify_calibration_entry(cal_data, entry_nr)

Verify the checksum of one calibration entry.

Expects an array of 256 values with calibration data, and an entry number from 0 to 18.

Returns True when the checksum of the specified calibration entry is correct.

write_calibration_data(cal_data, verify_calibration_data=True)

Method to write calibration data.

The cal_data parameter format is the same as the calibration_data property.

Verification of the cal_data array can be bypassed by setting verify_calibration_data to False.