Allen-Bradley 1791-NDC DC analog block I/O module

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.

Technical specifications for 1791-NDC

Part Number1791-NDC

Product TypeAnalog Block I/O Module

Inputs4

Input TypeAnalog

Outputs2

Output TypeCurrent

Power Suppply Voltage24V DC

Update Rate per Channel108 ms

Power Dissipation11.52 W max.

Thermal Dissipation39.28 BTU/hr. max.

Current600 mA

Input Bandwidth5 Hz

Product Lifecycle Status*Discontinued/Obsolete