This is the deceleration feedrate used after the machine hits the homing limit switch until it finds the grid Z-pulse. If set too slow, homing takes forever. If set too fast, the machine may overshoot the grid mark, causing a "90 Reference Position Return" alarm.
| Symptom | Likely Cause | Better Fix | |---------|--------------|-------------| | Home position drifts 0.1mm+ daily | Loose encoder coupling | Tighten mechanically, then reset grid shift | | Over-travel alarm on zero return | Decel switch stuck or P0082 too high | Clean switch, reduce P0082 | | Home position changes after power cycle | Battery low on absolute encoder | Replace battery, re-reference | | Axis slams into hard stop | Wrong decel direction (P0124) | Reverse bit for that axis | | Position after home is wrong coordinate | P0048 set incorrectly | Set to desired machine coord |
OEMs set rapid traverse rates conservatively to protect the machine during shipping and initial setup. If your mechanical ways and ball screws are well-lubricated, you can optimize these limits.
The parameters that dictate this position, direction, and speed are typically located in the (specifically parameter
The value entered here tells the control to inject extra pulses into the servo motor whenever the axis reverses direction. fanuc ot reference parameter better
Understanding this sequence is the first step. Now, let's examine the parameters that control it.
Before making any changes to your reference parameters, you must follow a strict protocol to avoid locking up the control or losing your existing memory.
. The control will likely show an alarm (e.g., Alarm 100), which is normal. Step 3: Configure Parameter 1815 Go to the screen and search for 1815 . Locate Parameter 1815 for the desired axis (e.g., for Axis 1). Set bit 5 (APC) to (using absolute encoder). Set bit 4 (APZ) to Carefully toggle bit 4 (APZ) back to
The FANUC 0-T uses binary bits (0 or 1) for many functions. A "better" reference sheet must annotate what each bit does. This is the deceleration feedrate used after the
: Setting this bit to 1 establishes the current position as the machine's zero/home position.
I can provide the precise parameter numbers and calculations for your exact scenario. Share public link
Many operators fear these parameters because changing one can cause a crash. However, with a clear strategy, adjusting them is not only safe but necessary for machine reliability, accurate tool changes, and eliminating annoying alarms.
If you find that the X-axis is inverted (common in older Fanuc machines), parameter 0003#0 to #3 allows you to change the positive/negative reference direction. | Symptom | Likely Cause | Better Fix
Eliminates the need to "Home" each axis daily.
If you'd like, I can help you create a for your specific machine's 1815 settings. Fanuc Zero Return Procedure Sharing - Manufacturing Forums
These store specific numerical values, such as feed rate limits, backlash compensation values, or timers measured in milliseconds.