Analog measurement specifications

16 single-ended (SE) or 8 differential (DIFF) terminals individually configurable for voltage, thermocouple, current loop, ratiometric, and period average measurements, using a 24-bit ADC. One channel at a time is measured.

Voltage measurements

Terminals:

  • Differential Configuration: DIFF 1H/1L – 8H/8L
  • Single-Ended Configuration: SE1 – SE16

Input Resistance: 20 GΩ typical

Input Voltage Limits: ±5 V

Sustained Input Voltage without Damage: ±20 VDC

DC Common Mode Rejection:

  • >120 dB with input reversal
  • ≥ 86 dB without input reversal

Normal Mode Rejection: > 70 dB @ 60 Hz

Input Current @ 25 °C: ±1 nA typical

Filter First Notch Frequency (fN1) Range: 0.5 Hz to 31.25 kHz (user specified)

Analog Range and Resolution:

 

Differential with input reversal

Single-ended and differential without input reversal
Notch
frequency
(fN1) (Hz)		 Range1
(mV)		 RMS
(µV)		 Bits2 RMS
(µV)		 Bits2
15000 ±5000
±1000
±200		 8.2

1.9

0.75

 20

20

19

11.8

2.6

1.0

19

19

18
50/603 ±5000
±1000
±200

0.6

0.14

0.05

24

23
22

0.88

0.2

0.08

23

23

22
5 ±5000
±1000
±200

0.18

0.04

0.02

25

25

24

0.28

0.07

0.03

25

24

23

1 Range overhead of ~5% on all ranges guarantees that full-scale values will not cause over range

2 Typical effective resolution (ER) in bits; computed from ratio of full-scale range to RMS resolution.

3 50/60 corresponds to rejection of 50 and 60 Hz ac power mains noise.

Accuracy (does not include sensor or measurement noise):

  • 0 to 40 °C: ±(0.04% of measurement + offset)
  • –40 to 70 °C: ±(0.06% of measurement + offset)

Voltage Measurement Accuracy Offsets:

  Typical offset (µV RMS)
Range (mV) Differential
with input reversal		 Single-ended or differential
without input reversal
±5000 ±0.5 ±2
±1000 ±0.25 ±1
±200 ±0.15 ±0.5

Measurement Settling Time: 20 µs to 600 ms; 500 µs default

Multiplexed Measurement Time:

These are not maximum speeds. Multiplexed denotes circuitry inside the data logger that switches signals into the ADC.

Where:

M = 1 (default)
M = 2 if reverse differential or measurement offset is used
Setup Time = 150 µs

  Differential
with input reversal		 Single-ended or differential
without input reversal
Example fN11 (Hz) Time2 (ms) Time2 (ms)
15000 2.04 1.02
60 35.24 17.62
50 41.9 20.95
5 401.9 200.95

1 Notch frequency (1/integration time).

2 Default settling time of 500 µs used.

See also Voltage measurements.