Hewlett Packard HP 3457A digital multi meter

Inside the HP 3457A there is not much to see, everything is screened with EMI shielding.

Bild zeigt den 3 Volt DC Bereich. Es ist das Ergebnis der Überprüfung mit einem automatischen Datron Kalibrator (April 2003). Ich habe dazu eine Software geschrieben, mit der sich der gemessene DC Wert sogar korrigieren läßt. Das Gerät ist sehr gut innerhalb der Spezifikation. Ein Kalibration war nicht erforderlich.

Picture shows the 3 V DC range. It is the result of the examination with an automatic Datron Kalibrator (April 2003). I wrote in addition a software, with which measured DC value can be even corrected. The equipment is very good within the specification. Calibration was not necessary.

Rechtes Bild zeigt den 3 Volt AC Bereich. Es ist das Ergebnis der Überprüfung mit einem automatischen Datron Kalibrator. (April 2003). Das Gerät ist sehr gut innerhalb der Spezifikation. Ein Kalibration war nicht erforderlich.

Right picture shows the 3 V AC range. It is the result of the examination with an automatic Datron Kalibrator. (April 2003). The equipment is very good within the specification. Calibration was not necessary.

The HP3457A is a very high precision multimeter which measures:

Voltage DC, AC and DC+AC volts
Currents in AC, DC or DC+AC
Resistance two and four wire connection
Frequency
Period

The instrument can do slower high resolution measurements to 6 1/2 digits and up to 7 1/2 in math mode, or up to 1000 readings/seconds with the lowest digit resolution mode. The instrument has a HP-Interface bus. Mathematical functions. On the backside there can be installed a plug-in-option 44491A Armature Relay Mulitplexer Assembly or 44492A Reed Relay Multiplexer Assembly.

In all cases of my experience, I checked these types of instruments with high quality standards in a certified calibration labority, the instruments were always better than the given specification, even after long periods of recalibration! My compliments to the manufactorer.

SIMPLIFIED SPECIFICATION (not complete, the original specification is much more detailed, taken from a year 1988 service manual)

DC VOLTAGE INPUT CHARACTERISTICS:

6 full scale ranges from 30mV (max.10nV resolution) to 300V (max. 100µV resolution)
Input Resistance for 30mV to 3V range 10 gigaohms

Input Resistance for 30V to 300V range 10 megohms

Maximum Input Voltage: HI or LO to Earth Ground +/-450V peak

Measurement Accuracy: +/-(% of reading + Number of Counts) with Auto Zero ON

DC VOLTAGE ACCURACY 24 HOUR Tcal +/-1°C 2h warm up Accuracy relative to calibrated standard 24 hour specifications apply if the instrument is calibrated between 90% and 100% of full scale. For calibration between 33% and 90% of full-scale, add 0.00015% to %Reading :

24 HOUR		Number of Counts
Range	%Reading	6 1/2 digits 100 PLC	6 1/2 digits 1 PLC	3 1/2 digits 0.0005 PLC
30mV	0.0012	215	350	6
300mV	0.0005	24	35	4
3V	0.00035	5	6	4
30V	0.00065	9	20	4
300V	0.0025	5	6	4

DC VOLTAGE ACCURACY 90 DAYS Tcal +/-5°C After 1h warm up

90 DAYS		Number of Counts
Range	%Reading	6 1/2 digits 100 PLC	6 1/2 digits 1 PLC	3 1/2 digits 0.0005 PLC
30mV	0.0040	365	500	6
300mV	0.0025	39	50	4
3V	0.0017	6	7	4
30V	0.0035	19	30	4
300V	0.0050	6	7	4

DC VOLTAGE ACCURACY 1 YEAR Tcal +/-5°C After 1h warm up

1 YEAR		Number of Counts
Range	%Reading	6 1/2 digits 100 PLC	6 1/2 digits 1 PLC	3 1/2 digits 0.0005 PLC
30mV	0.0045	365	500	6
300mV	0.0035	39	50	4
3V	0.0025	6	7	4
30V	0.0040	19	30	4
300V	0.0055	6	7	4

PLC = Integration in Power Line Cycles. When using integration times of 100 PLC, 10 PLC, or 1 PLC; multiply Number of Counts in the table by 0.1 for 5 1/2 digit readings, 0.01 for 4 1/2 digit readings and 0.001 for 3 1/2 digit readings. Tcal = Temperature ambient during calibration (should 18-28°C).

TEMPERATURE COEFFICIENT: +/-(% of Reading + Number of Counts)/°C 6 1/2 digits displayed, Auto zero OFF are given for a stable environment (+/-1°C) and over a ten minute period. Multiply number of counts by 0.1 for 5 1/2 digits, 0.01 for 4 1/2 digits and 0.001 for 3 1/2 digits.

Range	Auto Zero ON	Auto Zero OFF
30mV	0.0005 + 30	0.0005 + 40
300mV	0.0005 + 3	0.0005 + 13
3V	0.0005 + 0.3	0.0005 + 10.3
30V	0.0005 + 1	0.0005 + 11.0
300V	0.0005 + 0.3	0.0005 + 10.3

MAXIMUM READING RATES: (Readings/Second)

Integration Time	Digits Displayed	Reading Rate
Integration Time	Digits Displayed	60 Hz	50 Hz
0.0005 PLC	3 1/2	1350	1350
0.005 PLC	4 1/2	1250	1250
0.1 PLC	5 1/2	360	312
1 PLC	6 1/2	53	45
10 PLC	6 1/2	4.8	4.0
100 PLC	6 1/2	0.48	0.40

DC CURRENT INPUT CHARACTERISTICS:

6 full scale ranges from 300µA (max. 100pA) to 1A (max.1µA)

Shunt resistance from 1000 Ohm to 0.1 Ohm

DC CURRENT ACCURACY 24 HOUR Tcal +/-1°C 2h warm up Accuracy relative to calibrated standard

24 HOUR		Number of Counts
Range	%Reading	6 1/2 digits 100 PLC	6 1/2 digits 1 PLC	3 1/2 digits 0.0005 PLC
300µA	0.0020	54	65	4
3mA	0.002	54	65	4
30mA	0.0020	54	65	4
300mA	0.03	154	165	4
1A	0.03	504	515	5

DC CURRENT ACCURACY 1 YEAR Tcal +/-5°C 1h warm up Accuracy relative to calibrated standard

1 YEAR		Number of Counts
Range	%Reading	6 1/2 digits 100 PLC	6 1/2 digits 1 PLC	3 1/2 digits 0.0005 PLC
300µA	0.04	104	115	4
3mA	0.04	104	115	4
30mA	0.04	104	115	4
300mA	0.08	204	215	4
1A	0.08	604	615	5

RESISTANCE (4-WIRE OHMS, 2-WIRE OHMS, OFFSET COMPENSATED OHMS)

Input Characteristics:

Input Protection: HI sense to LO sense +/-350V peak

HI or LO to Earth ground +/-450V peak

Max. open circiut voltage 30 Ohm to 3M ranges: 12V. 30M to 3G ranges: 8.5V

Range (Ohms)	Maximum Reading 6 1/2	Resolution	Current through Unknown
30	30.3	10µ	1mA
300	303	1m	1mA
3k	3.03k	10m	1mA
30k	30.3k	100m	100µA
300k	303k	1	10µA
3M	3.03M	10	1µA
30M	30.3M	100	100nA
300M	303M	1k	100nA
3G	3.03G	10k	100nA

RESISTANCE 4-WIRE ACCURACY 24 HOUR Tcal +/-1°C 2h warm up Accuracy relative to calibrated standard

24 HOUR		Number of Counts
Range	%Reading	6 1/2 digits 100 PLC	6 1/2 digits 1 PLC	3 1/2 digits 0.0005 PLC
30	0.003	215	350	6
300	0.0015	24	35	4
3k	0.001	5	6	4
30k	0.001	5	6	4
300k	0.001	6	8	4
3M	0.003	12	16	5
30M	0.02	80	93	4

RESISTANCE 4-WIRE ACCURACY 1 YEAR Tcal +/-5°C 1h warm up Accuracy relative to calibrated standard

1 YEAR		Number of Counts
Range	%Reading	6 1/2 digits 100 PLC	6 1/2 digits 1 PLC	3 1/2 digits 0.0005 PLC
30	0.0075	315	450	6
300	0.0055	34	45	4
3k	0.005	6	7	4
30k	0.005	6	7	4
300k	0.005	7	9	4
3M	0.0065	12	16	5
30M	0.04	80	93	5

RESISTANCE 2-WIRE ACCURACY 24 HOUR Tcal +/-1°C 2h warm up Accuracy relative to calibrated standard

24 HOUR		Number of Counts
Range	%Reading	6 1/2 digits 100 PLC
30	0.003	20215
300	0.0015	2024
3k	0.001	205
30k	0.001	25
300k	0.001	8
3M	0.003	12
30M	0.02	80
300M	0.6	1000
3G	6.0	1000

RESISTANCE 2-WIRE ACCURACY 1 YEAR Tcal +/-5°C 1h warm up Accuracy relative to calibrated standard

1 YEAR		Number of Counts
Range	%Reading	6 1/2 digits 100 PLC
30	0.0075	20315
300	0.0055	2034
3k	0.005	206
30k	0.005	26
300k	0.005	9
3M	0.0065	12
30M	0.04	80
300M	1.6	1000
3G	16	1000

TRUE RMS AC coupled VOLTAGE ACCURACY INPUT CHARACTERISTICS

Input Impedance: 1Megohm +/-1% shunted by <90pF (<115pF rear input)

Maximum Input Voltage: +/-450Vpeak

HI or LO to Earth Ground: +/-450Vpeak

CREST FACTOR: 3.5 to 1 at full scale

Range	Maximum Reading	6 1/2 digits Resolution
30mV	32.50000mV	10nV
300mV	325.0000mV	100nV
3V	3.250000V	1µV
30V	32.50000V	10µV
300V	325.0000V	100µV

TRUE RMS AC coupled VOLTAGE ACCURACY 24 HOUR Tcal +/-1°C 2h warm up Accuracy relative to calibrated standard

24 HOUR 30mV to 30V ranges		Number of Counts
Frequency	%Reading	6 1/2 digits >=1 PLC
20Hz-45Hz	0.5	720
45Hz-100Hz	0.15	720
100Hz-20kHz	0.07	720
400Hz-20kHz	0.08	720
20kHz-100kHz	0.6	1700
100kHz-300kHz	3.1	9300
300kHz-1MHz	10.1	66000

TRUE RMS AC coupled VOLTAGE ACCURACY 90 DAYS Tcal +/-5°C 1h warm up Accuracy relative to calibrated standard

90 DAYS 30mV to 30V ranges		Number of Counts
Frequency	%Reading	6 1/2 digits >=1 PLC
20Hz-45Hz	0.56	1120
45Hz-100Hz	0.21	1120
100Hz-20kHz	0.13	1120
400Hz-20kHz	0.14	1120
20kHz-100kHz	0.66	2100
100kHz-300kHz	3.16	9700
300kHz-1MHz	10.16	66400

300V range is similar to the 30mV to 30V ranges, a little more bad.

TRUE RMS AC coupled CURRENT ACCURACY 24 HOUR Tcal +/-1°C 2h warm up Accuracy relative to calibrated standard

24 HOUR 30mA and 300mA ranges		Number of Counts
Frequency	%Reading	6 1/2 digits >=1 PLC
20Hz-45Hz	0.8	2800
46Hz-100Hz	0.25	2800
101Hz-20kHz	0.2	2800
400Hz-20kHz	0.2	2800
21kHz-100kHz	0.9	4000

TRUE RMS AC coupled CURRENT ACCURACY 24 HOUR Tcal +/-1°C 2h warm up Accuracy relative to calibrated standard

24 HOUR 1A range		Number of Counts
Frequency	%Reading	6 1/2 digits >=1 PLC
20Hz-45Hz	0.9	2800
46Hz-100Hz	0.35	2800
101Hz-20kHz	0.30	2800
400Hz-20kHz	0.30	2800

FREQUENCY and PERIOD ACCURACY

Frequency	Period	%Reading
10Hz-400Hz	100ms - 2.5ms	0.05
400Hz-1.5MHz	2.5ms to 667ns	0.01