National Instruments 777966-21B Strain/Bridge Input Module for SCXI

The part number 777966-21B from National Instruments is the identifying part number for the SCXI-1521B Strain/Bridge Input Module for SCXI. This module features 24 analog input channels with an input coupling of DC and is equipped with voltage gain settings of 40 Volts. This module is also incorporated with overvoltage protection which includes ±11 V when powered on and off as well as the analog inputs from 0 to 24 are also protected which ensures safe and reliable operation.

One of the most important features of the 777966-21B is a constant excitation voltage that can be set between 0.0 to 5.0 V in 1,023 steps with an error of ±20 mV ±0.3% max and protective features including the surge arrestors in parallel with excitation terminals, shunt to ground and short circuit protected as well. It has excellent calibration capabilities with switching resistance of 15 Ω max 7.5 Ω typ, and a fixed shunt resistor of 100 kΩ, 0.1%, 10 ppm/°C, 150 mW.

This module has a compact design with physical dimensions of 3.0 cm × 17.2 cm × 18.8 cm (1.2 × 6.8 × 7.4 in.) and weighs 748 gm (26.4 oz). Its operating temperature is 0 degrees Celsius to 55 degrees Celsius and a storage temperature of -20 degrees Celsius to 70 degrees Celsius with a relative humidity of 10% to 90% RH, noncondensing. The 777966-21B is required to be mounted at a maximum altitude of 2000 meters and has a pollution degree of 2. It is compliant with IEC 61010-1, EN 61010-1, UL 61010-1, CSA 61010-1 standards making it suitable for measurement, control, and laboratory use.

The 777966-21B Strain/Bridge Input Module for SCXI is made to operate at required power consumption from the SCXI backplane of 18.5 to 25 VDC, +170 mA minimum while +4.75 to 5.25 VDC, 50 mA minimum at +5 V. Its maximum working voltage from channel to earth the input should remain within +11 Volts relative to ground while from channel to channel the input should also remain within +11 Volts relative to ground, thus with these distinctive features enables this module to operate in low voltage environment and protects the module from potential overvoltage damage.