National Instruments 777459-11

The National Instruments 777459-11 Digital Input Module, also known as the SCC-DI01, is a high-performance, single-channel module designed for SCC systems. This module features optically isolated inputs capable of measuring both AC and DC digital signals, with voltage levels ranging up to 30 VDC or 30 VAC. The module defines digital logic levels with a low voltage threshold of ±1 V and a high voltage threshold of ±2 V to ±30 V for DC signals and 4 Vrms to 30 VAC at 1 kHz for AC signals. The input current is 1.5 mA for 5 V signals and 7.0 mA for 24 V signals, providing efficiency in power consumption with a maximum digital power rating of 61 mW.

The propagation delays are specified as 10 µs for low to high transitions and 250 µs from high to low, with both rise time and fall time capped at 10 ns. The physical dimensions of the module are 3.50 inches in length, 1.15 inches in width, and 0.73 inches in height, with a weight of 1.0 oz. Connectivity is facilitated via a 20-pin right-angle male connector and a 2-pin screw terminal, supporting field wiring sizes between 28 to 16 AWG. With a maximum working voltage of 42 V—accounting for the signal voltage and common-mode voltage—the module meets Installation Category II standards.

For optimal performance, the module should operate within a temperature range of 0 °C to 50 °C and a relative humidity of 10% to 90%. It can be stored in temperatures ranging from -20 °C to 70 °C. The unit is intended for indoor use, requiring a sealed enclosure for outdoor applications, and must be used at altitudes not exceeding 2000 m. The 777459-11 complies with several safety standards, including IEC 61010-1, EN 61010-1, UL 3101-1, UL 61010B-1, and CAN/CSA C22.2 No. 1010.1, ensuring its reliability for measurement, control, and laboratory environments.