The AB 1771-IB is a PLC 5 Digital DC Input Module. It converts DC signals provided by user devices to the logic level needed by the processor. It controls the state of corresponding bits in the PLC data table. It provides modular design with space-saving and pocket-friendly means to add input to a PLC control system. It comes with a 1771-WA wiring arm to replace the module, eliminating the need to disconnect the wiring. It is a series A module and supports ½, 1, and 2-slot I/O addressing. It is compatible with source-switching devices such as dry-contact switches, electro-mechanical transmitters, and panel-switching devices like selector switches and pushbutton.


The 1771-IB module has 8 inputs with a 10 – 60V DC Sink (Source load) voltage category. It has an operating voltage range of 10 – 27V DC. It has a typical signal delay of 12ms (±7) at On-DC state and 20ms (±7) at Off-DC state. It has a maximum Off-state current of 3mA and a backplane current load of 74mA. It has a maximum power dissipation of 5.7W and thermal dissipation of 19.3 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 found between pins 14 and 16 for the upper connector and between pins 4 and 6 for the lower connector.


The 1771-IB module has 8 red status indicators for field side indication at the front panel. It contains opto-electrical isolation to protect the system circuits from electrical transients. It also contains an input filtering feature to reduce electrical noise.