Sln: 3-wire control, FWD: Forward running,
REV: Reverse running
3: 3-wire control 2; This mode defines Sin as
the enabling terminal, and the running
command is generated by FWD or REV, but
the direction is controlled by both FWD and
REV. During running, the Sin terminal needs
to be closed, and terminal FWD or REV
generates a rising edge signal to control the
running and direction of VFD; the VFD needs
to be stopped by disconnecting terminal Sin.