1791-NDC

The Allen-Bradley 1791-NDC module is a 24 Volts DC analog block I/O module. The module supports 4 analog inputs and 2 current outputs. The module is compatible with the Allen-Bradley PLC-2, PLC-3, PLC-5/250, and PLC-5 programmable controllers and with the Allen-Bradley SLC5/02 modular controllers. The 1791-NDC module communicates with the programmable controller via block transfer or discrete transfer. It contains a 24 Volts DC current-limited voltage source for accommodating loop-powered current transducer inputs.  The 1791-NDC module supports 4 selectable inputs per block. The types of inputs are as follows: ±10 Volts (14-bit), ±5 Volts (14-bit), 0 to 10 Volts (14-bit), 0 to 50 Volts (14-bit), 0 to 20 milliamps (14-bit), and ±20 milliamps (14-bit). The update rate per input channel is 108 milliseconds. The input impedance is 10 megaohms for the voltage and 250 Ohms for the current. The absolute accuracy is 0.1% at 25 degrees Celsius. The common-mode rejection is -75 dB. The normal mode rejection is -18 dB at 50 Hertz and -20 dB at 60 Hertz.

There are 2 outputs per block on the Allen-Bradley 1791-NDC analog block I/O module. The output resolution is 13 bits. The output current range is from 0 to 20 milliamps. The output impedance is greater than 1 megaohm. The internal update rate per channel is 10 milliseconds. The module supports indefinite short circuit protection. The absolute accuracy rating is 0.1% at 25 degrees Celsius. The overall accuracy drift is 75 ppm per degree Celsius. The input bandwidth for the 1791-NDC module is 5 Hertz. The input and output overvoltage protection rating is 140 Volts AC. The power requirements for the module are 19.2 to 30 Volts DC at 600 milliamps. The total power and thermal dissipation ratings are 11.52 Watts and 39.28 BTU/hour. The dimensions of the module are 6.95 x 2.7 x 3.85 inches.