684 SERIES

The Modicon 684 was short lived. I don't believe any came to Australia. These had local I/O and could support one remote drop. This allowed a maximum of 256 Inputs and 256 Outputs. They had from 2k to 8k of memory. These were produced around 1981/2
These used 600 series I/O and allowed hot swap without the need to shutdown the processor.
Programming was compatible with the 484 series.
Programming was in ladder and generally used a P180 programming panel to enter the program and for diagnostics.