984 SERIES

The Modicon 984 was designed to be rack mounted.   These were top of the range from 1986 through 1994, when the Quantum series became available.
Modicon had been purchased by AEG. The branding then went to AEG Modicon.
Programming was in ladder and we used a P190 programming panel or a PC to enter the program and for diagnostics. The 984 was a really advanced machine for it's time and was a great leap forward from the 584 / 884 families. They were often deployed widely and often served as master PLC's communicating to remote machines and HMI.
These used 800 series I/O, which are still in service in some locations.

Useful Links

984 System Manual
984 Hot Standby Manual
984 and 800 Series I/O