1.77 ms calculation cycle, 600 data points per axis
The QD75MH1 is a single-axis positioning module for the Mitsubishi Q-series PLC platform, communicating with the servo amplifier via high-speed SSCNET III serial link. The calculation cycle runs at 1.77 ms, which sets the update rate for the position command to the servo loop — fast enough for cam profiles and electronic gearing on a single axis, but the cycle time stacks when coordinating multiple modules across the backplane. It stores 600 positioning data points per axis, covering the typical point-to-point move table for a pick-and-place or indexing station without needing a separate data table in the PLC. The external signal interface handles five points per shaft — upper/lower limit, near-point dog, stop, and speed/position switching — all at 24 VDC level, which matches standard industrial sensor and limit-switch wiring without level translation.
Emergency stop input and servo interface
A dedicated 24 VDC emergency stop input is built into the module, one point per unit, so the safety circuit can kill the axis drive directly at the positioning controller without routing through the PLC scan. It connects to Mitsubishi general-purpose servo amplifiers in the MR-J3-B series via SSCNET III, a high-speed serial network that carries position command, feedback, and status on a single fiber or cable pair.