User`s guide

26
Measurement characteristics with
optional internal DMM
DC voltage
Measurement method Continuously integrating multi-slope
III A-D converter
A-Dlinearity 0.0002%ofreading+0.0001%of
range on 10 V range
Input resistance
100mV,1V,10Vranges Selectable10MΩor>10,000MΩ
100V,300Vranges 10MΩ±1%
Input bias current < 50 pA at 25°C
Input protection 300 V all ranges
True RMS AC voltage
Measurementmethod ACcoupledTrueRMS—measures
the AC component of the input with
up to 300 VDC of bias on any range
Crest factor Maximum of 5:1 at full scale
Additional crest factor
errors(non-sinewave) Crestfactor1-20.05%ofreading
 Crestfactor2-30.15%ofreading
 Crestfactor3-40.30%ofreading
 Crestfactor4-50.40%ofreading
ACFilterBandwidth:
Slow 3 Hz - 300 kHz
Medium 20 Hz - 300 kHz
Fast 200 Hz - 300 kHz
Inputimpedance 1MΩ±2%inparallelwith150pF
Input protection 300 Vrms all ranges
Resistance
Measurement method Selectable 4-wire or 2-wire ohms
Currentsource referencedtoLOinput
Offsetcompensation Selectableon100Ω,1kΩ,
 10kΩranges
Maximumleadresistance 10%ofrangeperleadfor100Ω
 and1kΩranges.1kΩonall
other ranges
Input protection 300 V on all ranges
Frequency and period
Measurementmethod Reciprocalcountingtechnique
Voltage ranges Same as AC voltage function
Gate time 1 s, 100 ms, or 10 ms
Measurementtimeout Selectable3Hz,20Hz,200HzLFlimit
Measurement Consideration (Frequency and Period)
All frequency counters are susceptible to error when measuring low-voltage,
low-frequency signals. Shielding inputs from external noise pickup is criti-
cal for minimizing measurement errors.
DC current
Shuntresistance 5Ωfor10mA,100mA;
 0.1Ωfor1A
Input protection 1A 250 V fuse on 34921A module
True RMS AC current
Measurement method Direct coupled to the fuse and shunt.
 ACcoupledTrueRMSmeasurement
(measures the ac component only)
Shuntresistance 5Ωfor10mA;0.1Ωfor100mA,1A
Input protection 1A 250 V fuse on 34921A module
Thermocouple
Conversion ITS-90 software compensation
Referencejunctiontype Internal,fixed,orexternal
Openthermocouplecheck Selectableperchannel.Open>5kΩ
Thermistor  44004,44007,44006series
RTD  a=0.00385(DIN)anda=0.00392
Measurement noise rejection 60 (50) Hz
[1]
DCCMRR 140dB
ACCMRR 70dB
Integration time Normal mode rejection
[2]
200plc/3.33s(4s) 105dB
[3]
100plc/1.67s(2s) 100dB
[3]
20plc/333ms(400ms) 95dB
[3]
10plc/167ms(200ms) 90dB
[3]
2plc/33.3ms(40ms) 85dB
1plc/16.7ms(20ms) 60dB
<1plc 0dB
[1] For1KΩunbalanceinLOlead
[2] Forpowerlinefrequency±0.08%
[3] Forpowerlinefrequency±1%use75dBor±2.5%use60dB
continued