Key Specifications
Parameter Specification
Model RD77MS8
Control Axes 8 axes per module (expandable via multiple modules)
Communication SSCNET III/H (fiber-optic, 150Mbps)
Maximum Command Speed 4 Mpulses/s (per axis)
Control Cycle 888 µs (for 8 axes)
Interpolation Linear, circular, helical
Compatible Servo Drives MR-J5 Series (22-bit encoder), MR-J4 Series
Positioning Range -2,147,483,648 to +2,147,483,647 pulses
I/O Points Dedicated high-speed I/O for motion control
Power Supply 5V DC (from base unit, 0.7W max)
Dimensions (W×H×D) 27.4 × 98 × 90 mm
3. Key Features
Nanosecond Synchronization: Precise multi-axis coordination for high-speed applications.

Advanced Vibration Suppression: Reduces mechanical resonance during acceleration/deceleration.

Flexible Programming: Supports Motion SFC, ladder logic, and structured text in GX Works3.

Real-Time Monitoring: Built-in trace function for troubleshooting.

Backlash Compensation: Improves positioning accuracy.

4. Communication & Integration
SSCNET III/H: Dedicated fiber-optic network for real-time servo control (up to 50m per link).

Ethernet (via CPU): For programming (GX Works3) and data exchange.

MELSEC iQ-R Compatibility: Seamless integration with R Series CPUs (e.g., R32CPU).