The 1746-NIO4V SLC 500 Analog Combination I/O Module by Allen-Bradley is an I/O module installed on the 1746 Chassis that has 2 user-selectable (per channel) current or voltage inputs and 2 voltage outputs. It has 2 current-loop inputs with a normal rating of -20 to 20mA at a 250 Ohm impedance and an input accuracy of +/- 0.642% at a drift rate of 79 ppm/5 degrees Celsius. Its two input points also have voltage ratings of -10 to 10 Volts DC with an impedance of 1M Ohm and a 10 Volt DC full-scale resolution of 305.176 ? V per LSB.

The voltage inputs have an accuracy of +/-0.504%, an overall drift accuracy of +/- 63 ppm/degree Celsius, and a maximum gain error of +/- 0.461%. The inputs have an offset error of +/- 14 LSB at 0 to 60 degrees Celsius, and the 1746-NIO4V maximum overvoltage protection across the input terminals comes in at either 220 Volts AC or 220 Volts DC. It uses the R-2R Ladder Digital-to-Analog Converter (DAC) with a converter resolution of 14 bits at its voltage output and a response time of 2 milliseconds. The output has a load range greater than 1KOhms with a load reactance of 1? F and an overall output range of -10 to 10 Volts. The voltage has an overall accuracy of +/- 0.384% of a 10 Volt DC full-scale voltage and a maximum drift accuracy of +/- 54 ppm per degree Celsius. The 1746-NIO4V also has a maximum gain error of +/- 0.374% with a drift error of ±47 ppm/ degree Celsius and an output offset error of +/-11 LSB. The 1746-NIO4V offers Field Wiring-to-Backplane Isolation at 500 Volts DC and uses the Shielded Belden #8761 recommended cable with a rated 14 AWG size.

The Allen-Bradley 1746-NIO4V is an analog I/O combination module. This module features Two (2) input channels and Two (2) output channels. The input channels features compatibility with differential voltage and current inputs that are individually configurable. For current input configuration, accepted signal range is -20 to +20 mA with a resolution of 16-bit with repeatability of ±1 LSB and non-linearity of 0.01%. It uses Delta-Signa modulation conversion method. When configured for voltage input, the accepted voltage signal range is -10 to +10V dc - 1 LSB with resolution of 305.176 µV per LSB.

The output channels of the 1746-NIO4V does not come with isolation. It can provide an output current range of 0-20 mA with resolution of 14-bit, using R-2R Ladder conversion method. It has a step response of 2.5 ms (at 95%).

This combination I/O module has a backplane current draw of 55 mA at 5.1 VDC and 145 mA at 24VDC. It occupies single slot of the chassis and comes with a removable terminal block for terminating signal wires to and from the module.

Additionally, the 1746-NIO4V may become part of the CompactLogix and ControlLogix Programmable Automation Controllers (PAC), acting as a distributed I/O module.