The GE Series Six 6 PLC was introduced in the early 1980’s and was the first modular PLC. It is estimated that over 500,000 of these units have been installed worldwide. It came in a Model 60, Model 600 and Model 6000 configuration. Three CPU versions allowed for more memory and larger I/O capacity. The instruction set was identical as well as the I/O type. The GE Fanuc DPU - Data Processing Unit and the GE Fanuc RPU -Redundant Processing Unit were used to off load additional functions. A PDT programming terminal was used as the programming device and included many of the same boards as the DPU.
