Troubleshooting Analog AC Servo - Full Speed at "Analog Scale Max = 0"

Bench testing my configuration 7i96s + 7i77 with 1 Yasakawa AC Servo drive (SGDA-04AS) w/servo. Goal here is to get a baseline for PID settings.

Drive enable is an "active low" type and upon initial wiring I experienced a "chatter" with the relay. I fixed this by integrating a filter onto power leads for my bench setup. I'm still not 100% convinced I've eliminated all noise from the system, however, the issue below does not seem noise is root cause.

Issue: When setting parameter "hm2_7i96s.0.7i77.0.1.analogena" to enable, the servo immediately vibrates and the axis will rapidly move back and forth (the encoder does record this movement) in small increments. In the "calibration" settings, I've tried messing with the PID values to attempt to dampen this out and have observed no change. However, when I set the "ANALOG_SCALE_MAX" from it's default value to 0 and enable the drive, the servo will immediately spin at what it seems to be full speed until I disable the drive. I've changed servo drives and replicated this behavior so it seems it's something to do with my configuration.

Any idea what is going on here? 

Thanks