SCXI Quarter-Bridge Strain Gage Input Module

NI SCXI-1521 ................................................................777966-21

NI SCXI-1521B ..........................................................777966-21B

Includes NI-DAQmx software.

For more information on extended warranty and value-added

BUY ONLINE!

Ordering Information

This appendix lists the specifications for the SCXI-1521/B modules. These specifications are typical at

25 °C unless otherwise noted.

Analog Input

Number of channels......................................... 24

Voltage gain ..................................................... 42

Input coupling................................................... DC

Overvoltage protection..................................... ±11 V powered on and off

Inputs protected ............................................... <AI0..23>

Transfer

Nonlinearity...................................................... 0.02% max

Gain error

Input offset error .............................................. 7 mV max

1 mV typ

stored in the onboard EEPROM. These constants are applied automatically when using LabVIEW or NI-DAQmx.

Dynamic

Minimum scan interval (per channel, any gain in multiplexed mode)

±0.012% accuracy ............................................ 3 µs

±0.006% accuracy ............................................ 10 µs

±0.0015% accuracy .......................................... 20 µs

0.1 to 10 Hz ...................................................... 2.5 µVpp

> 10 Hz.............................................................. 1 µV

Filter

Lowpass filter type........................................... 2-pole Butterworth (12 dB/octave rolloff)

3 dB bandwidth ................................................ 10 Hz

Stability

Recommended warm-up time.......................... 30 minutes

Gain drift .......................................................... ±11 ppm /°C max

±4 ppm /°C typ

Offset drift ........................................................ ±3 µV /°C max

±1 µV /°C typ

Offset Null Compensation

Range................................................................ ±0.45% of excitation voltage

Resolutioin........................................................ 4,096 counts of resolution (±9,000 me offset null

compensation range, 4.4 me resolution for GF = 2.0)

Excitation

Type .................................................................. Constant voltage

Settings ............................................................ 0.0 to 5.0 V in 1023 steps

Error .................................................................. ±20 mV ±0.3% max

Maximum output current ................................. 21 mA

Load regulation (open to 240 W) ..................... 0.08%

Temperature drift.............................................. ±10ppm/°C ±30 µV/°C max

Protection ......................................................... Surge arrestors in parallel with excitation terminals,

shunt to ground, short circuit protected

Bridge Completion

SCXI-1521......................................................... 350

Ω, 0.1%, 2 ppm/°C max, 55mW @ °50 C

Long term stability ........................................... 0.02%/yr

SCXI-1521B....................................................... 120

Ω, 0.1%, 2 ppm/°C max, 55mW @ °50 C

Long term stability ........................................... 0.02%/yr

Shunt Calibration

Type .................................................................. Shunt across quarter-bridge completion resistor

Shunt resistor ................................................... Fixed 100 k

Ω, 0.1%, 10 ppm/°C , 150mW

Switch resistance............................................. 15

Ω max

7.5

Ω typ

Power Requirements (from SCXI Backplane)

V+...................................................................... 18.5 to 25 VDC, +170 mA min

V........................................................................ 18.5 to –25 VDC, –170 mA min

+5 V .................................................................. +4.75 to 5.25 VDC, 50 mA min

Physical

Dimensions....................................................... 3.0 by 17.2 by 20.3 cm (1.2 by 6.9 by 8.0 in.)

Maximum Working Voltage

Maximum working voltage refers to the signal voltage plus the common-mode voltage.

Channel-to-earth .............................................. Input should remain within ±11 V of ground.

Installation Category I

Channel-to-channel .......................................... Input should remain within ±11 V of ground.

Installation Category I

Environmental

Operating temperature..................................... 0 to 50 °C

Storage temperature ........................................ 20 to 70 °C

Humidity ........................................................... 10 to 90% RH, noncondensing

Maximum altitude ............................................ 2,000 m

Pollution Degree (indoor use only)................... 2

Safety

The SCXI-1521/B is designed to meet the requirements of the following standards of safety for

electrical equipment for measurement, control, and laboratory use:

• IEC 61010-1, EN 61010-1

• UL 61010-1

• CAN/CSA-C22.2 No 61010-1

search by model number or product line, and click the appropriate link in the Certification column.

Electromagnetic Compatibility

EmissionsEN 55011 Class A at 10 m FCC Part 15A above 1 GHz

Immunity ..EN 61326:1997 + A2:2001, Table 1

EMC/EMICE, C-Tick, and FCC Part 15 (Class A) Compliant

Note: For EMC compliance, operate this device with shielded cabling.

CE Compliance

The SCXI-1521/B meets the essential requirements of applicable European Directives,

as amended for CE marking, as follows:

Low-Voltage Directive (safety)......................... 73/23/EEC

Electromagnetic Compatibility

Directive (EMC) ................................................ 89/336/EEC

Note: Refer to the Declaration of Conformity (DoC) for this product for any additional regulatory

compliance information. To obtain the DoC for this product, visit ni.com/certification, search by

model number or product line, and click the appropriate link in the Certification column.

Specifications