The 1746-NIO4V by Allen-Bradley and Rockwell Automation is an SLC 500 4-Channel Analog I/O Module. General specifications for this module include input and output channels, with the 1746-NIO4V having 2 input channels per module; these inputs are differential, voltage or current selectable per channel, and not individually isolated. The 1746-NIO4V has 2 voltage output channels per module, which are also not individually isolated. It has a 5 Volt backplane current draw of 55 milliamperes and a 24 Volt backplane current draw of 115 milliamperes. The 1746-NIO4V has a converter resolution of 16 bits and a repeatability of ±1 LSB. Non-linearity is 0.01% and it has a channel bandwidth of 10 Hertz. Step response for this module is 60 milliseconds at 95% and it has a delta-sigma modulation conversion method. Impedance channel-to-channel is 1M Ohms. Common mode rejection at 0 to 10 Hertz is 50 decibels, while common mode rejection at 60 Hertz is 105 decibels.


Environmental specifications for the 1746-NIO4V include an operating temperature of 0 to 60 degrees Celsius and a storage temperature of -40 to 85 degrees Celsius; relative humidity is 5% to 95% (non-condensing). Current-loop input specifications for this hardware include a normal operation input range of -20 to +20 milliamperes and an absolute maximum input current of -30 to +30 milliamperes. Input impedance is 250 Ohms and full scale is 20 milliamperes. Voltage input specifications for the 1746-NIO4V include an input range between -10 and +10 Volts DC – 1 LSB, while full scale is 10 Volts DC. Overvoltage protection is either 220 Volts AC RMS continuously or 220 Volts DC continuously.

The Allen-Bradley 1746-NIO4V is an analog input/output module that is used for analog signal processing. The analog signal can be voltage or current. This module has 2 input channels and each of them can be connected to voltage or current and it has 2 output channels with voltage outputs. After the installation and before the operation, the module must be configured according to the application requirements. The usual method at the input is current loop of 0 – 20 milliamperes connected in series with 250 ohm resistance which is then connected to 1746-NIO4V input channel, otherwise the module can do that from -20 to +20 milliamperes input current. The input signal enters into module A/D processor in which the output is a digital number, in which 16 bits represent the value of that input current (or voltage). The resolution of this unit is 1.22070 microamperes per LSB where LSB is the low significant bit of that 16-bit number. The error is only ± 7 LSB at 77 degrees Fahrenheit and the overall accuracy is maximum ±0.365% of full scale. The inputs are not isolated and configured using the DIP switches. If the input is voltage signal, its signal range is -10 to +10 volts DC (direct current). In reverse manner, the 1746-NIO4V can transform digital number from PLC controller using R-2R ladder conversion method into analog voltage on output channel so the full output scale is 10V DC with resolution of 1,22070 millivolts/LSB. The offset error at 77 degrees Fahrenheit is maximum ±9 LSB. The normal operating temperature should remain between 32 and 140 degrees Fahrenheit.