The Allen-Bradley 1771-IAD is a discrete input module. This module is part of the 1771 family of Programmable Logic Controller (PLC). This module is designed to accept AC and DC signal voltages such as 120VAC with frequency of 50/60 Hz and 125VDC. It has Sixteen (16) input channels and compatible for installation in a variety of 1771 chassis such as 1771-A1B through A4B or later universal I/O chassis. It may also be installed in the 1771-AM1 and AM2 chassis.

The 1771-IAD is primarily used to interface discrete devices such as pushbuttons, switches of different varieties, auxiliary contacts from relays, contactors and other devices.

The 1771-IAD has an input signal delay such as 120V ac/60Hz: 5ms (+3ms) or 20ms(+5ms) selectable 120V dc: 3ms (+0.1ms) or 10ms (+1ms) selectable for Off to On transition and 25ms (+5ms) for 120V ac or dc for ON to OFF transition. It has an On state voltage range of 79 VAC to 138VAC or VDC. It has a maximum power dissipation of 8.8 Watts and minimum of 1.0 Watts with Thermal dissipation 30.1 BTU/hr, maximum and 3.42 BTU/hr, minimum. It has a backplane Current draw of 195 mA at 5V.

The 1771-IAD has uses a field wiring arm of 1771-WH. This field wiring arm is comparable to removable terminal blocks, which is used for modular wiring and simplified installation and maintenance of the input module. When installing the 1771-IAD to any of the compatible chassis, it requires keying position between 10 and 12 or between 14 and 16.

The Allen-Bradley 1771-IAD is a PLC 5 Digital AC/DC Input Module. It contains information of various input devices such as pushbuttons, limit switches, pilot lights, motor starters, and annunciators to interface with on/off sensors and actuators. It provides a modular design with space-saving and pocket-friendly means to add input to a PLC control system. It comes with a 1771-WH wiring arm to replace the module, eliminating the need to disconnect the wiring. It is a series D module and supports ½, 1, and 2-slot I/O addressing.

The 1771-IAD module has 16 inputs with a 120V AC/DC voltage category. It has an operating voltage range of 79 - 138V AC or 79 - 138V DC. It has a typical signal delay of 5ms (+/-3) at on AC state, 3ms (+/-0.1) or 10ms (+/-1) at on DC state, and 25ms (+/-5) at off AC/DC state. It has a maximum Off-state current of 3mA for AC and 0.8mA for DC and a backplane current load of 195mA. It has a maximum power dissipation of 8.8W and a thermal dissipation of 30.1 BTU/hr. It is installed in a 1771 I/O chassis containing a PLC processor. Keying bands for putting it in the right slot are between pins 14 and 16 for the upper connector and between pins 10 and 12 for the lower connector.

The 1771-IAD module has 1 green module active indicator and 16 red status indicators for system logic side indication at the front panel. It contains optoelectrical isolation to protect the system circuits from electrical transients. It also contains input filtering feature to reduce electrical noise.