Fault Phenomenon: SANY SR400 rotary drilling rig when operating in hard rock, the automatic feed function fails, unable to automatically adjust feed pressure based on drill rod resistance.

Troubleshooting Process:
– Checked pressure sensor: feed circuit pressure sensor signal lost.
– Checked control module: feed control ECU software fault.
– Checked proportional valve: feed proportional valve coil burnt.
– Checked settings: incorrect feed mode setting on operation panel.

Root Cause: The feed circuit pressure sensor is internally damaged, preventing the control system from obtaining real-time pressure data, causing the auto-feed logic to interrupt.

Required Parts: Replace feed circuit pressure sensor.