How to design the EMC of the motion controller MC pulse output

The EMC performance of a motion controller's MC pulse output design must balance drive capability and noise suppression. For PWM or step pulse outputs, a small resistor or ferrite bead should be connected in series at the output of the driver chip to control rise time and reduce high-frequency harmonics. A common-mode choke, such as the CML series, should be configured for the output line to suppress common-mode radiation. A TVS diode array, such as the ESDLC series, should be connected in parallel at the output port for ESD and transient protection. Shielded twisted-pair cables must be used for the output cables, with the shield grounded 360 degrees at the controller end.

On the PCB layout, the pulse output drive loop area should be minimized, and high-current paths should be short and wide. The power supply of the driver chip must be isolated and adequately decoupled through a ferrite bead. For long-distance transmission, impedance matching is required; a resistor can be connected in series at the output to match the cable's characteristic impedance. The EMC design should be verified by measuring the waveform and spectrum of the output pulse, as well as the system's radiated emissions.