The Mitsubishi RD77MS16 is an iQ-R Series Motion Controller built for multi-axis servo systems. It communicates over SSCNET?/H, the high-speed motion network, which means it talks to servo drives on a dedicated fiber-optic loop — no shared-bus collisions, deterministic timing down to the sub-millisecond range. That SSCNET?/H compatibility is the first thing to check against your existing drive lineup; if your amps are SSCNET?/H-native, this controller drops right in. It handles 16 controlled axes independently or in coordinated moves, with 600 positioning data points stored per axis. That data set covers point-to-point moves, speed changes, and dwells — enough for a multi-station assembly cell or a gantry with several tool heads. The interpolation function supports 2-axis circular arcs and linear moves across 2, 3, or 4 axes, so contouring a path (say, a pick-and-place head tracing a rounded corner) is handled onboard without the PLC breaking it into segments. The single control unit accepts positioning in pulses, millimeters, inches, or degrees — you pick the unit that matches your machine's native coordinate system and the parameter set adapts. No scaling math in the PLC scan.
The RD77MS16 mounts in the iQ-R backplane alongside the power supply, CPU, and I/O modules. It occupies one slot in the base rack or extension rack — no separate power feed needed beyond the backplane bus. The SSCNET?/H fiber cables run from the module's optical connectors to each servo drive; keep the fiber bends above the minimum radius specified in the manual to avoid signal loss.