The Allen-Bradley 1771-IFF is a PLC 5 Analog Input Module. It interfaces analog inputs with PLC processors by using block transfer programming. The 1771-IFF uses up to 16-bit resolution and performs analog-to-digital conversions and the reverse conversions for interfacing analog signals with the PLC data table values. If input communication is disrupted, it can respond automatically to the fault with default user configuration. Thus, it provides a predictable and safe response to a fault and limits the extent of faults.  The 1771-IFF is useful for applications such as temperature sensing, pressure sensing, level sensing, and flow metering.

The 1771-IFF Series A module has 16 single-ended or 8 differential selectable inputs. It has Natural Binary or BCD scaling to ±9999 data format. It has voltage ranges of 0 – 5V DC, 1 – 5V DC, -5 – 5V DC, and -10 – 10V DC. It has a current range of 4 – 20mA, 0 – 20mA, -20 – 20Ma, and -40 – 40mA. Its backplane current load is 750mA. The 1771-IFF has a channel update time of 5ms for 8 channels, 10ms for 16 channels, and 12 bits plus sign resolution. It has a maximum power dissipation of 2.5W and thermal dissipation of 8.52 BTU/hr. It has a 1771-WG wiring arm to replace the module eliminating the need to disconnect wiring. The 1771-IFF requires one slot for installation in an I/O chassis and keying bands for correct installation is between pins 10 and 12 for the lower connector and pins 24 and 26 for the upper connector.

The 1771-IFF module contains a green RUN and a red FAULT indicator light on the front panel. It has optoelectrical isolation to protect the system circuits from electrical transients. The 1771-IFF also has input filtering feature for reducing electrical noise.