SV0459 Hi-Speed 1-Rev Signal (Sep. Detector) fault in Fanuc drive

SV0459 Hi-Speed 1-Rev Signal (Sep. Detector) fault in Fanuc drive

Description

SV0459 is the "External Scale" version of the 1-Rev Signal Error. It appears when using a linear scale or external rotary encoder for positioning. The CNC needs to see the "Reference Mark" (Z-pulse) from the scale to establish the absolute grid. SV0459 triggers if the reading head passes the reference mark location but fails to detect the pulse, or detects it at an improper width/interval.

Cause

• Dirty Scale: The specific location on the glass scale where the reference mark is etched is dirty or scratched.
• Alignment: The read-head is slightly twisted (yaw/pitch angle), making it unable to focus on the fine reference mark grating.
• Speed: Attempting to reference the machine at a speed faster than the scale can process the Z-pulse.

Solution

1. Clean the Mark: Locate the reference mark area on the scale (usually marked with a sticker) and clean it thoroughly.
2. Check Alignment: Use the alignment brackets and shims to ensure the head is perfectly parallel to the scale body.
3. Reduce Homing Speed: Lower the "Grid Search Speed" (Parameter 1425) to give the sensor more time to latch the pulse.