Chapter 9 Specifications

DC Measurement and Operating Characteristics

ki u y

DC Measurement Characteristics [1]

DC Voltage

Continuously Integrating,

Measurement Method:

 

Multi-slope III A/D Converter

A/D Linearity:

0.0002% of reading + 0.0001% of range

Input Resistance:

Selectable 10 MΩ or >10 GΩ

100 mV, 1 V, 10 V ranges

100 V, 300 V ranges

10 MΩ ±1%

Input Bias Current:

< 30 pA at 25 °C

Input Protection:

300 V on all ranges

 

 

Resistance

Selectable 4-wire or 2-wire Ohms,

Measurement Method:

 

Current source reference to LO input

Offset Compensation:

Selectable on 100Ω, 1 kΩ, 10 kΩ ranges

Max. Lead Resistance:

10% of range per lead for 100Ω and

 

1 kΩ ranges. 1 kΩ on all other ranges

Input Protection:

300 V on all ranges

 

 

DC Current

5Ω for 10 mA, 100 mA; 0.1Ω for 1A.

Shunt Resistance:

Input Protection:

1.5A 250 V fuse on HP 34901A module

 

 

Thermocouple

ITS-90 software compensation

Conversion:

Reference Junction Type:

Internal, Fixed, or External

Open T/C Check:

Selectable per channel. Open > 5 kΩ

 

 

RTD

α = 0.00385 (DIN) and 0.00392

 

 

Thermistor

44004, 44007, 44006 series

 

Measurement Noise Rejection 60 Hz (50 Hz) [2]

DC CMRR:

140 dB

Integration Time

Normal Mode Rejection [3]

200 PLC / 3.33s (4s)

110 dB [4]

100 PLC / 1.67s (2s)

105 dB [4]

20 PLC / 333 ms (400 ms)

100 dB [4]

10 PLC / 167 ms (200 ms)

95 dB [4]

2 PLC / 33.3 ms (40 ms)

90 dB

1 PLC / 16.7 ms (20 ms)

60 dB

< 1 PLC

0 dB

 

 

DC Operating Characteristics [5]

 

Digits [6]

 

 

Additional

Function

Readings/s

Noise Error

DCV, DCI, and

612

0.6

(0.5)

0% of range

Resistance:

612

6

(5)

0% of range

 

512

60

(50)

0.001% of range

 

512

300

0.001% of range [7]

 

412

600

0.01% of range [7]

Single Channel Measurement Rates [8]

Function

Resolution

Readings/s

DCV, 2-Wire Ohms:

61

2 (10 PLC)

6

(5)

 

51

2

(1 PLC)

57

(47)

 

41

2

(0.02 PLC)

600

Thermocouple:

0.1 °C (1 PLC)

57

(47)

 

(0.02 PLC)

220

RTD, Thermistor:

0.01 °C (10 PLC)

6

(5)

 

0.1 °C (1 PLC)

57

(47)

 

1 °C (0.02 PLC)

220

 

 

 

 

 

 

Autozero OFF Operation

Following instrument warm-up at calibration temperature ±1 °C and < 10 minutes, add 0.0002% range additional error + 5 μV.

Settling Considerations

Reading settling times are affected by source impedance,

low dielectric absorption characteristics, and input signal changes.

[1]300 Vdc isolation voltage (ch-ch, ch-earth)

[2]For 1 kΩ unbalance in LO lead

[3]For power line frequency ±0.1%

[4]For power line frequency ±1%, use 80 dB. For power line frequency ±3%, use 60 dB.

[5]Reading speeds for 60 Hz and (50 Hz) operation; autozero OFF

[6]612 digits=22 bits, 512 digits=18 bits, 412 digits=15 bits

[7]Add 20 μV for DCV, 4 μA for DCI, or 20 mΩ for resistance

[8]For fixed function and range, readings to memory, scaling and alarms off, autozero OFF

IDL 9

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HP 34970A manual Ki u y, DC Measurement and Operating Characteristics