Fanuc Parameter 1829 -

Never treat 1829 as a substitute for proper mechanical maintenance. If an axis is binding due to worn thrust bearings, low lubrication, or way damage, raising 1829 will just mask the problem—until something breaks catastrophically.

  • Never change parameters while a program is running or when the machine is in motion unless the manual explicitly permits it.

    • | Parameter | Function | |-----------|----------| | 1320 | Negative software limit (first stage) | | 1321 | Positive software limit (first stage) | | 1828 | Positive software limit 1 (auxiliary) | | 1829 | Positive software limit 2 (auxiliary) |

    | Symptom | Likely Cause | Relation to 1829 | |--------|--------------|------------------| | PS081 (Subprogram not found) | Program number exists but search range exceeded | Direct – Increase 1829 | | PS082 (External subprogram not found) | M198 fails due to buffer limits | Indirect – Also check I/O channel settings | | Long delay before subprogram executes | 1829 set to 9999 in a memory with 5000 programs | Performance – Unnecessary scanning | | Intermittent DNC failures | DNC buffer resets between blocks; search fails unpredictably | Systemic – Needs larger 1829 + stable handshaking | fanuc parameter 1829

    | Parameter | Function | Relationship to 1829 | | :--- | :--- | :--- | | 1825 | Servo Loop Gain | Determines natural following error. 1829 must exceed 1825's error. | | 1826 | In-Position Width | Defines "enough" error before servo settles. Must be smaller than 1829. (Rule: 1829 >= 10 * 1826) | | 1827 | Stop Mismatch Limit | Alarm if error remains after stopping. Usually set smaller than 1829. | | 1828 | Move Mismatch Limit (High gain) | Used with high-gain mode. Overlaps 1829 function in some controls. |

    Subject: Servo Alarm Detection Threshold (Excessive Error) System: FANUC Series 16i / 18i / 21i / 30i / 31i / 32i (and equivalent 0i models) Category: Servo Parameter (Axis-Specific) Never treat 1829 as a substitute for proper

  • If parameter appears not to exist or behaves differently, consult model-specific Fanuc manuals or contact Fanuc support with control model and software versions.

    • Imagine commanding the X-axis to move 100 mm at 10,000 mm/min. The servo drive sends power to the motor. The motor’s encoder reports back every few milliseconds. Ideally, the difference between "where it should be" and "where it is" (called the following error) remains small—typically a few microns.

    However, consider these scenarios:

    In these cases, the actual position lags far behind the command. Once the error exceeds Parameter 1829’s threshold, the CNC fires a SV0410 alarm and disables the servo drives. This is a safety feature, not a bug.