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.